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The CD14+ CD16+ blood monocytes: Their role in infection and inflammation
Abstract
Blood monocyte subpopulations have been defined in man initially, and the two major types of monocytes are the CD14++ CD16- and the CD14+ CD16+ monocytes. These cells have been shown to exhibit distinct phenotype and function, and the CD14+ CD16+ were labeled proinflammatory based on higher expression of proinflammatory cytokines and higher potency in antigen presentation. The current review describes these properties, including the relationship to dendritic cells, and summarizes the host of publications about CD14+ CD16+ monocytes in inflammation and infectious disease in man, all of which suggest a crucial role of these cells in the disease processes. The review also covers the more recent description of homologues of these cells in other model species, which is expected to better define the role of monocyte subsets in disease.
... A total of 91 individuals, including 49 COVID-19 patients and 42 healthy controls, were included in this study. The median ages of COVID-19 patients and healthy controls were 41 (IQR, [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] and 50 (IQR, 37-64) years, respectively. Twenty-nine (59 %) patients were male, and 20 (41 %) were female. ...
... In the event of infection, monocytes are responsible for pathogen recognition, the initiation and resolution of inflammation, and the repair of tissue damage [35]. Three main monocyte types have been identified in peripheral blood based on their CD14 and CD16 (FcR III) expression [36,37]. These monocyte types are known to exhibit different phenotypes and functions. ...
... These monocyte types are known to exhibit different phenotypes and functions. CD16 + monocytes have been shown to express more proinflammatory cytokines with a higher potential for antigen presentation but a reduced ability to perform Fc receptor-mediated phagocytosis [36,37]. Previous studies have reported an increase in the amount of CD14 + / CD16 + (intermediate and non-classical) monocytes in sepsis, tuberculosis, and HIV infection [38,39]. ...
Objectives
We aimed to investigate the lymphocyte subsets and monocytes by flow cytometry and the correlations between their HLA-DR expressions and inflammatory markers in patients with COVID-19.
Methods
The study included 49 patients with COVID-19 and 42 healthy controls. Blood samples were taken into EDTA tubes. WBC counts were analyzed by the Sysmex/XN-1000i device, and lymphocyte subsets and monocytes were analyzed by flow cytometry. The percentage of HLA-DR expression on cells and median fluorescence intensity (MFI) values were recorded to detect activation. Lymphocyte counts were calculated using the dual-platform method. Correlations between antigen expression and ferritin, CRP, and D-dimer levels were analyzed.
Results
The patient group had lower WBC and lymphocyte counts but significantly higher monocyte counts and neutrophil/lymphocyte ratios compared to controls (p=0.009, p=0.045, respectively). The patient group had significantly lower T lymphocyte counts (p=0.008). B lymphocyte counts and percentages were lower (p<0.001, p=0.004) in the patient group. There was no significant difference between the two groups in terms of NK cells. T helper and T cytotoxic lymphocyte counts were significantly lower, but there was no change in CD4/CD8 ratios. The percentage of HLA-DR expression on T lymphocytes, HLA-DR MFI values of T cytotoxic cells, and HLA-DR MFI values of CD16⁺ monocytes were significantly increased in the patient group (p=0.001, p=0.004, p<0.001, respectively). CRP was positively correlated with HLA-DR expression on T lymphocytes (r=0.501, p<0.001).
Conclusions
HLA-DR MFI values may be an important marker for demonstrating the function of both T cytotoxic cells and CD16⁺ monocytes in COVID-19.
... Our study found that the risk of AS increased with an elevation in the proportion of CD11c + monocyte. CD11c + monocyte mostly consists of intermediate monocytes and nonclassical monocytes [63], comprising only 10% of total blood monocytes, yet secreting high levels of proinflammatory cytokines [64][65][66]. They have also been found to be related with high body mass index (BMI), hyperlipidemia and cardiovascular diseases [65,[67][68][69][70], including atherosclerosis and coronary artery diseases. ...
... CD11c + monocyte mostly consists of intermediate monocytes and nonclassical monocytes [63], comprising only 10% of total blood monocytes, yet secreting high levels of proinflammatory cytokines [64][65][66]. They have also been found to be related with high body mass index (BMI), hyperlipidemia and cardiovascular diseases [65,[67][68][69][70], including atherosclerosis and coronary artery diseases. Our study adds new evidence of the possibly crucial role of these monocytes in the development of AS. ...
Background: Aortic stenosis is the most prevalent valvular heart disease in high-income population, and there are currently no medical therapies to slow the disease progression. Given that gut microbiota influences the immune system, lipid metabolism, and inflammation, there may be a potential link between gut microbiota and AS.
Aims: We aimed to examine the causal effects of gut microbiota on AS and to investigate the mediating roles of inflammatory proteins, blood metabolites, and immune cells.
Methods: Bidirectional Mendelian randomization analysis was performed to assess the causal relationships between gut microbiota, inflammatory proteins, blood metabolites, immune cells, and AS. Two-step Mendelian randomization was utilized to explore direct and indirect effects. The data were derived from genome-wide association study summary statistics available in public databases.
Results: The study identified nine gut microbial features (six microbial taxa and three pathways), four inflammatory proteins, 91 blood metabolites, and four immune cell traits associated with AS. However, no significant mediating roles were found for inflammatory proteins, blood metabolites, and immune cells in the causal pathway between gut microbiota and AS.
Conclusion: This study revealed novel causal associations between gut microbial features, inflammatory proteins, blood metabolites, and immune cell traits with AS. These findings offer new insights into the pathophysiology of AS and provide potential targets for therapeutic approaches.
... These immune cells also retained their functionality despite their contact with antibiotic-loaded BSA/prGOx/GNP/ab coatings (BSA/prGOx/GNP/G, BSA/prGOx/GNP/Cx) as indicated by continued expression of co-stimulatory molecules CD14, human leukocyte antigen DR (HLA-DR), and CD83 (Figure 4a-c). CD14 pertains to the classical CD14 ++ CD16 − monocyte subpopulation, whereas CD14 -CD16 + monocytes are precursors for pro-fibrotic M2 macrophages, which are crucial players in infection, inflammation, and disease pathogenesis [37][38][39]. Similarly, while indicative of immune deficiency in critically ill patients, HLA-DR also correlates with reduced antigen presentation and pro-inflammatory cytokine release, providing a prediction of mortality or risk of secondary infection [39,40]. ...
... These immune cells also retained their functionality despite their contact with antibiotic-loaded BSA/prGOx/GNP/ab coatings (BSA/prGOx/GNP/G, BSA/prGOx/GNP/Cx) as indicated by continued expression of co-stimulatory molecules CD14, human leukocyte antigen DR (HLA-DR), and CD83 (Figure 4a-c). CD14 pertains to the classical CD14 ++ CD16 − monocyte subpopulation, whereas CD14 − CD16 + monocytes are precursors for pro-fibrotic M2 macrophages, which are crucial players in infection, inflammation, and disease pathogenesis [37][38][39]. Similarly, while indicative of immune deficiency in critically ill patients, HLA-DR also correlates with reduced antigen presentation and pro-inflammatory cytokine release, providing a prediction of mortality or risk of secondary infection [39,40]. ...
Biofouling and foreign body responses have deleterious effects on the functionality and longevity of implantable biosensors, seriously impeding their implementation for long-term monitoring. Here, we describe a nanocomposite coating composed of a cross-linked lattice of bovine serum albumin and pentaamine-functionalized reduced graphene that is covalently coupled to antibody ligands for analyte detection as well as antibiotic drugs (gentamicin or ceftriaxone), which actively combats biofouling while retaining high electroconductivity and excellent electrochemical immunosensor behavior. Sensors overlaid with this coating inhibit the proliferation of Pseudomonas aeruginosa bacteria and adhesion of primary human fibroblasts while not having any significant effects on fibroblast viability or on the immune function of primary human monocytes. Under these conditions, the sensor maintains its electrochemical stability for at least 3 weeks after exposure to soluble proteins that interfere with the activity of uncoated sensors. Proof-of-concept for the coating’s applicability is demonstrated by integrating the antimicrobial coating within an immunosensor and demonstrating the detection of cytokines in both culture medium and complex human plasma. This new coating technology holds the potential to substantially increase the lifespan of implanted biosensors and widen their application areas, potentially enabling continuous monitoring of analytes in complex biofluids for weeks in vivo.
... These subgroups have different functions, where CD14++CD16-mainly exhibits a phagocytic phenotype, CD14++CD16+ shows an inflammatory/antigen-presenting phenotype, and CD14+CD16++ patrols blood vessels and also has the capacity to present antigens [43,44]. The CD14++CD16+ and CD14+CD16++ subgroups only account for 5-15% of total human monocytes, but their frequency can significantly increase under certain inflammatory conditions [43,[45][46][47]. A study on Polish asthma patients showed a significant increase in CD14++CD16+ monocyte frequency in severe asthma patients compared to healthy controls or those with mild and moderate asthma [48]. ...
... For eosinophilic asthma, CD40 on CD14+ CD16+ monocyte may be a protective factor. Researchers like Reem Al-Rashoudi [49] mentioned that in moderate and severe asthma patients, the mean fluorescence intensity (MFI) of CD16 expression is significantly reduced in intermediate (CD14++CD16+) and non-classical (CD14+CD16++) monocyte subgroups compared to healthy controls, and CD16+ monocytes typically increase in inflammatory conditions like sepsis and arteriosclerosis [43,46,49]. Studies suggest that in inflammatory responses, monocytes are released from the bone marrow as classical monocytes and differentiate into intermediate and non-classical types in circulation [50], indicating that a reduction in CD16 in intermediate and non-classical monocytes is associated with increased severity of asthma. ...
Objective: Using two-sample Mendelian Randomization (MR) and Bayesian Weighted Mendelian Randomization (BWMR), this study explores the causal links between 731 immune cell phenotypes and asthma, providing useful biomarkers for potential therapeutic targets for asthma.
Methods: The study employed two-sample MR and BWMR to evaluate the causal relationships between 731 immune cell phenotypes and asthma, using large-scale Genome-Wide Association Study (GWAS) datasets to exclude confounding factors and conduct various sensitivity analyses.
Results: The study conducted an in-depth analysis of the causal relationship between 731 immune cell phenotypes and asthma across three databases (ebi, finn, and ukb). Integrating the results from IVW and BWMR across these databases, we identified CD16+ monocyte %monocyte as a protective factor against asthma, whereas CD62L- myeloid Dendritic Cell Absolute Count, CD62L- myeloid Dendritic Cell %Dendritic Cell, CD62L- CD86+ myeloid Dendritic Cell Absolute Count, and CD62L- CD86+ myeloid Dendritic Cell %Dendritic Cell were identified as risk factors.
Conclusion: Our research confirms that CD16+ monocyte %monocyte serves as a protective factor against asthma, while CD62L- myeloid Dendritic Cell Absolute Count, CD62L- myeloid Dendritic Cell %Dendritic Cell, CD62L- CD86+ myeloid Dendritic Cell Absolute Count, and CD62L- CD86+ myeloid Dendritic Cell %Dendritic Cell pose risks for asthma.
... Hyperinflammation in the lung during SARS-CoV-2 infection has been linked to dysfunctional and exhausted SARS-CoV-2-specific CD4+ and CD8 + T cells, which play an important role in viral clearance and control of SARS-CoV-2 [36][37][38] . CD4 + T cells can be found in the lung infiltrates of COVID-19 patients and have been reported to express a variety of cytokines including IFN-γ 39,40 , IL-17 41 , Granulocytemacrophage colony-stimulating factor (GM-CSF) 42 and IL-4 43 in response to antigenic stimulation, suggesting that different CD4 + T cell subsets might participate in the inflammation and pathogenesis of COVID-19 44 . ...
... In this regard, this study provides a functional link between innate activation of Mo in response to SARS-CoV-2 proteins and their ability to activate T cell responses involved in the pathogenesis of severe COVID-19. Mo can act as antigen presenting cells (APC) and T-Mo express high levels of Human Leukocyte Antigen-class II (HLA-DR), which allows them to mediate efficient activation and polarization of CD4 + T cells in vitro 16,17 and during viral infections 37 . We have shown that S1-primed Mo promote high levels of IFN-γ expression on CD4 + T cells. ...
Increased recruitment of transitional and non-classical monocytes in the lung during SARS-CoV-2 infection is associated with COVID-19 severity. However, whether specific innate sensors mediate the activation or differentiation of monocytes in response to different SARS-CoV-2 proteins remain poorly characterized. Here, we show that SARS-CoV-2 Spike 1 but not nucleoprotein induce differentiation of monocytes into transitional or non-classical subsets from both peripheral blood and COVID-19 bronchoalveolar lavage samples in a NFκB-dependent manner, but this process does not require inflammasome activation. However, NLRP3 and NLRC4 differentially regulated CD86 expression in monocytes in response to Spike 1 and Nucleoprotein, respectively. Moreover, monocytes exposed to Spike 1 induce significantly higher proportions of Th1 and Th17 CD4 + T cells. In contrast, monocytes exposed to Nucleoprotein reduce the degranulation of CD8 + T cells from severe COVID-19 patients. Our study provides insights in the differential impact of innate sensors in regulating monocytes in response to different SARS-CoV-2 proteins, which might be useful to better understand COVID-19 immunopathology and identify therapeutic targets.
... Intermediate Mø are important mediators during acute inflammation [39], so we evaluated multiple antibodies (CD11b, CD11c, CD80, and CD86) in a panel to quantify their degrees of activation (Figures 2C-F and S6C-F). Figure S6. ...
... Intermediate Mø are important mediators during acute inflammation [39], so we evaluated multiple antibodies (CD11b, CD11c, CD80, and CD86) in a panel to quantify their degrees of activation (Figures 2C-F and S6C-F). ...
Zika fever is a reemerging arthropod-borne viral disease; however, Zika virus (ZIKV) can be transmitted by other, non-vector means. Severe Zika fever is characterized by neurological disorders, autoimmunity, or congenital Zika syndrome. Monocytes are primary ZIKV targets in humans and, in response to infection, release extracellular vesicles like exosomes. Exosomes mediate intercellular communication and are involved in the virus’s ability to circumvent the immune response, promoting pathological processes. This study aimed to evaluate the role of monocyte exosomes in cell-to-cell viral transmission. We isolated exosomes from ZIKV-infected monocytes (Mø exo ZIKV) by differential ultracentrifugation and identified them by nanoparticle tracking analysis; transmission electron microscopy; and CD63, CD81, TSG101, and Alix detection by cytofluorometry. Purified exosome isolates were obtained by uncoupling from paramagnetic beads or by treatment with UV radiation and RNase A. We found that Mø exo ZIKV carry viral RNA and E/NS1 proteins and that their interaction with naïve cells favors viral transmission, infection, and cell differentiation/activation. These data suggest that Mø exo ZIKV are an efficient alternative pathway for ZIKV infection. Knowledge of these mechanisms contributes to understanding the pathogenesis of severe disease and to the development of new vaccines and therapies.
... Non-classical monocytes(CD14-CD16+) [48] were also detected (M2, Fig. 6H). CD16+ monocytes promote T cell proliferation more strongly than CD16-monocytes [49]. Comparing the frequencies of monocyte subsets ...
Background
Patients with stage II colorectal cancer (CRC) show considerable variability in prognosis. Circulating immune cells play a vital role in systemic tumor surveillance. This study aimed to determine the clinical significance of the frequency and phenotype of circulating immune cell subsets in patients with stage II CRC.
Methods
We applied a 37-marker-cell-lineage-agnostic panel to perform single-cell mass cytometry on peripheral blood mononuclear cells (PBMCs) from 73 patients with stage II CRC and 21 patients with stage III CRC. To categorize the stage II patients into consensus molecular subtypes (CMS), we performed RNA sequencing on tumor and adjacent normal tissues from 51 of the 73 patients. We then compared the immune cell phenotypes and frequencies based on tumor location and CMS classification in patients with stage II CRC. Wilcoxon test was employed to compare the mean frequencies of cell clusters between different tumor locations. Krustal–Wallis analysis with post-hoc Dunn test was used to assess differences across multiple CMS groups.
Results
Stage II CRC patients with left- and right-sided tumors, as well as in different CMS groups, exhibit significantly different tumor characteristics. Single-cell mass cytometry revealed profound interpatient variability in immune cell subpopulation distribution and phenotypes in PBMCs in stage II CRC. We identified unique T:monocyte complexes in the peripheral blood of patients with stage II CRC, with significantly higher frequencies in these patients compared to those with stage III CRC. Left- and right-sided stage II CRCs differed in peripheral immunity. Patients with right-sided CRC had significantly higher frequencies of circulating CD8+CD27-CD28- immunosenescent T cell subsets compared to patients with left-sided CRC. Significant variations were observed in the subpopulations of the T:monocyte complex, T cells, and monocytes across different CMS groups Patients with CMS1 tumors (immune-active) exhibited significantly higher frequencies of CD4+ central memory and CD8+ terminal effector T cell: classical monocyte complexes, as well as CD8+ terminal effector T cells in the circulation.
Conclusions
The frequency and phenotype of circulating immune cells are influenced by tumor side and CMS subtypes in stage II CRC. These observations provide a basis for further investigation into the mechanisms linking tumors and systemic immunity.
... Following acute in ammation, MCs predominantly comprised the CD14++/CD16+ subset. Many clinical studies have shown the pro-in ammatory role of CD16+ mononuclear cells, as their counts increase in numerous acute and chronic in ammatory conditions [24]. Intriguingly, in blood samples collected at longer durations after acute in ammation, the CD14++/CD16+ subset gradually shifted toward the CD14++/CD16++ subset. ...
The plasticity of blood mononuclear cells (MCs) and their role in vascular remodeling have been the focus of many studies; however, their in vitro differentiation efficiency remains poorly understood. Herein, we demonstrate that the inflammatory response accelerates the efficiency of MCs differentiation into endothelial-like cells through chemical cues in vitro . RT-PCR and RNA sequencing revealed that the differentiated cells exhibited upregulated pathways associated with vascular remodeling and regeneration. In contrast, MCs collected from normal blood showed a differentiation bias towards macrophages. Notably, under inflammatory conditions, most MCs transitioned into the CD14++/CD16+/CD163 + subset, which primarily contributed to vascular regeneration. This transition was triggered by inflammation, as confirmed by in vitro cytokine differentiation. These results imply that acute inflammation accelerates MCs-induced vascular remodeling.
... 6,7,13 A small portion of CMs differentiate into IMs, which increase during several inflammatory conditions including dengue virus infection, sepsis and influenza. 7,[13][14][15][16][17] NCMs seem to be the most differentiated monocyte subset, with patrolling functions in the vasculature. 13,14,18,19 DCs are subdivided into conventional DCs (cDCs) and plasmacytoid DCs (pDCs). ...
Objectives
Monocytes and dendritic cells (DCs) are essential players in the immune response to infections, involved in shaping innate and adaptive immunity. However, a complete understanding of their specific roles in respiratory infections, including SARS‐CoV‐2, remains elusive.
Methods
To investigate the dynamics of monocytes and DCs in blood as well as the upper and lower airways, we sampled 147 patients with varying degree of COVID‐19 severity longitudinally during the spring of 2020.
Results
Using flow cytometry, proteomics and in vitro TLR stimulation, we found differences in the distribution and function of monocytes and DCs in patients compared with controls, and importantly, reduced levels of DCs in both blood and airways. In fact, lower frequencies of cDC2s (Lin⁻ HLA‐DR⁺ CD1c⁺) early after symptom onset predicted subsequent severe disease, and depletion of DC subsets lasted longer in patients with more severe disease. In contrast, severe COVID‐19 was associated with increased frequencies of activated monocytes in the lower, but not the upper, airways. Proteomic analysis showed that monocyte and DC‐related cytokines in plasma and airways associated with disease severity. During convalescence, cell frequencies and responses to TLR ligands normalised in blood, except for persistently low plasmacytoid DCs.
Conclusion
Our study reveals a distinct pattern of recruitment of monocytes but not DCs to the airways during severe COVID‐19. Instead, decreased levels of DCs in both blood and airways were found, possibly contributing to more severe COVID‐19. The connection between low blood DCs early in disease course and more severe outcomes provides insight into COVID‐19 immunopathology, with possible therapeutic implications.
... CD14 + CD16 + monocytes represent a mature subset that comprises 5-10% of circulating monocytes. These monocytes have been characterized as more inflammatory than the other two subsets, and increase rapidly in number in response to injury, infection, or inflammation (8)(9)(10)(11). CD14 + CD16 + monocytes specifically have been implicated in HIV-NCI (12- 14), where they can increase and comprise up to 50% of total monocytes in the blood of people with HIV (PWH) (9,12,15). They also preferentially transmigrate across the BBB compared to other monocyte subsets (16)(17)(18)(19). ...
Monocytes in the central nervous system (CNS) play a pivotal role in surveillance and homeostasis, and can exacerbate pathogenic processes during injury, infection, or inflammation. CD14⁺CD16⁺ monocytes exhibit diverse functions and contribute to neuroinflammatory diseases, including HIV-associated neurocognitive impairment (HIV-NCI). Analysis of human CD14⁺CD16⁺ monocytes matured in vitro by single-cell RNA sequencing identified a heterogenous population of nine clusters. Ingenuity pathway analysis of differentially expressed genes in each cluster identified increased migratory and inflammatory pathways for a group of clusters, which we termed Group 1 monocytes. Group 1 monocytes, distinguished by increased ALCAM, CD52, CD63, and SDC2, exhibited gene expression signatures implicated in CNS inflammatory diseases, produced higher levels of CXCL12, IL-1Ra, IL-6, IL-10, TNFα, and ROS, and preferentially transmigrated across a human in vitro blood-brain barrier model. Thus, Group 1 cells within the CD14⁺CD16⁺ monocyte subset are likely to be major contributors to neuroinflammatory diseases.
... 2,7,41 Intermediate and non-classical monocytes are known for their pro-inflammatory phenotype, characterized by their ability to secrete higher inflammatory cytokines than classical monocytes. [41][42][43][44][45] In this study, RvD2 induces a shift in monocyte subsets from intermediate to classical when LPS-stimulated monocytes. The shift in monocyte subsets from intermediate to classical indicates a change in the population of monocytes toward a more dominant population, the classical subset. ...
Circulating monocytes contribute to the defense against pathogens and play a crucial role in maintaining immune homeostasis. While there is substantial evidence regarding the triggers of monocyte activation, our understanding of how monocyte function is restored toward homeostasis after activation remains limited. Here, we assessed the changes in monocyte anisocytosis upon activation in blood, measured by monocyte distribution width (MDW), a biomarker for sepsis. We determined that the increase in MDW post‐lipopolysaccharide (LPS) stimulation in the blood can be reversed promptly by adding resolvin D2 (RvD2), and we measured a decrease in interleukin‐1 beta (IL‐1β) in blood, and a decrease in the size of the population of intermediate monocyte subsets. Moreover, the ex vivo addition of RvD2 to blood samples from burn patients with high MDW restored normal MDW values. Further studies are needed to probe the potential therapeutic role of RvD2 in the context of burn injuries.
... In humans, monocytes are primarily categorized into two subsets: the CD14highCD16− monocytes, the dominant population, and the CD16+ monocytes, which include CD14highCD16+ and CD14lowCD16+ subsets. CD16+ monocytes are known for their pro-inflammatory properties, secreting high levels of cytokines like IL-1β and TNF-α in response to tolllike receptor ligands and immune complexes (Belge et al. 2002;Ziegler-Heitbrock 2007;Wong et al. 2011). The CD14highCD16+ monocytes, characterized by high expression of MHC class II, enhance antigen presentation, while CD14lowCD16+ monocytes, with elevated MHC class I expression, exhibit increased migratory activity but reduced phagocytic capacity. ...
Background
The involvement of immune cells in the pathophysiology of intracerebral hemorrhage (ICH) is becoming increasingly recognized, yet their specific causal contributions remain uncertain. The objective of this research is to uncover the potential causal interactions between diverse immune cells and ICH using Mendelian randomization (MR) analysis.
Methods
Genetic variants associated with 731 immune cell traits were sourced from a comprehensive genome‐wide association study (GWAS) involving 3757 participants. Summary statistics data for ICH were acquired from FinnGen, comprising 4056 ICH cases and 371,717 controls. The principal analytical tool utilized in our study was the inverse‐variance weighted (IVW) method, incorporated as a key component of a two‐sample MR approach. To mitigate potential biases and verify the stability of the conclusions drawn from the primary analytical methods, a series of sensitivity analyses were performed.
Results
MR analysis elucidated 33 immune cell traits with causal associations, comprising B cells (eight traits), conventional dendritic cells (cDC, two traits), maturation stages of T cells (two traits), monocytes (two traits), myeloid cells (five traits), TBNK cells (six traits), and regulatory T cells (Treg, eight traits). DP (CD4+CD8+) %T cell (OR = 0.83, CI = 0.72–0.96, p = 0.013) exhibited the strongest protective effect. In contrast, transitional AC (OR = 1.09, CI = 1.02–1.16, p = 0.006) and IgD− CD27− %lymphocyte (OR = 1.08, CI = 1.00–1.17, p = 0.045) showed a higher tendency to increase the ICH risk. The sensitivity analyses validated the robustness and consistency of these results.
Conclusion
Our research provides robust evidence substantiating the causal relationship between specific immunophenotypes and ICH risk. The identification of these findings significantly enhances our understanding of the pathogenic mechanisms underlying ICH, particularly pertaining to the immune system. This breakthrough paves the way for innovative clinical and pharmaceutical research opportunities, potentially promoting the development of targeted therapies and enhanced strategies for managing and preventing ICH.
... Repple et al. (15) performed flow cytometry on the cerebrospinal fluid of methadone-intoxicated patients and found cell composition alterations that were characterized by the transformation of monocytes from the classical (CD14 + CD16 − ) to the nonclassical (CD14 + CD16 + ) and a switch from CD56 bright nonkilling cells to CD56 dim nonkilling cells. Notably, CD14 + CD16 + monocytes and CD56 dim nonkilling cells are pro-inflammatory cells that may be involved in delayed encephalopathy (16). These findings from Repple et al. may explain the lymphocyte aggregation observed in the current case, which provides the first reported cerebrospinal fluid findings of chlorfenapyr intoxication. ...
Background
Emamectin·chlorfenapyr is a compound comprising chlorfenapyr and emamectin benzoate that is widely used in agriculture. Chlorfenapyr toxicity has been verified in animals; however, its true mechanism and progression in humans remain to be elucidated. Cases of emamectin·chlorfenapyr poisoning are seldom.
Case presentation
We present a case of a 65-year-old female who attempted suicide by consuming 30 g of 9.5% chlorfenapyr and 0.5% emamectin benzoate 14 days before admission to our hospital. Laboratory tests revealed extremely high creatinine kinase levels upon admission. Magnetic resonance imaging revealed diffuse and symmetric T2 hyperintensities in the entire white matter tract of the brain and spinal cord, and cytological smears of the cerebrospinal fluid showed abnormal lymphocyte aggregation. The patient died 19.5 h after admission owing to cardiopulmonary arrest and hyperthermia.
Conclusion
Further research is needed on how to perform flow cytometry in patients with emamectin·chlorfenapyr intoxication, and to elucidate the immunological mechanism underlying the inflammatory response caused by emamectin·chlorfenapyr and provide new insights into antidote development.
... CCR2 is a chemokine receptor involved in monocyte recruitment to sites of inflammation 28 . The specific subset of CD14 + CD16 + monocytes is known for its pro-inflammatory properties 29 . The higher expression of CCR2 might reflect a more controlled recruitment and activity of these cells, preventing an overwhelming inflammatory response. ...
Research exploring the link between immune cell profiles and the development of endometritis remains scant. This gap necessitates further study to decode the complex interrelations influencing this condition. In this analysis, we leveraged two-sample Mendelian randomization to examine the causal ties between the phenotypes of immune cells and the incidence of endometritis. Our evaluation hinged on data from 3757 participants hailing from Sardinia, focusing on a diverse array of 731 immune phenotypes, and cross-referenced with endometritis data sourced from the UK Biobank. To ensure rigor, we performed sensitivity analyses, utilized MR-Egger and MR-Presso to check for pleiotropy, and applied Cochran’s Q test for assessing the heterogeneity of our findings. Our investigation identified numerous immune characteristics associated with endometritis. For certain immune traits, a lower risk of endometritis was observed, including: Absolute Counts of CD39 + CD4 + T cells, CD25 + CD39 + CD4 regulatory T cells, and CD25 + + CD8 + T cells; Absolute Counts of Switched Memory B cells; CD19 expression on IgD + CD38dim and Switched Memory B cells; CD20 expression on IgD + CD38− Unswitched Memory B cells; percentage of Switched Memory B cells among lymphocytes; CD16-CD56 expression on HLA DR + Natural Killer cells; percentage of CD11c + CD62L− monocytes; CD86 expression on monocytes; CCR2 expression on CD14 + CD16 + monocytes; and CD14 expression on Monocytic Myeloid-Derived Suppressor Cells, with Odds Ratios (ORs) between 0.413 and 0.703. On the contrary, increased risks of endometritis were linked with: the percentage of Effector Memory CD4 + T cells within the CD4 + T cell population; percentages of HLA DR + T cells and HLA DR + CD8 + T cells among T cells; CD4 expression on CD28 + CD4 + T cells; CD20 expression on CD20- CD38- B cells; percentage of IgD + CD24 + B cells within the B cell population; CD62L expression on CD62L + myeloid Dendritic Cells; and Absolute Counts of Plasmacytoid Dendritic Cells, with ORs from 1.473 to 2.677, indicating these traits potentially elevate the risk of developing endometritis. Our research delineates distinct causal links between specific immune cell phenotypes and endometritis, offering new perspectives that could contribute to the pinpointing of new therapeutic avenues for this condition.
... Our study revealed that two monocyte populations, CX3CR1 on CD14 + CD16monocytes and CX3CR1 on CD14 + CD16 + monocytes, were associated with a reduced risk of PD. CD14 + CD16-and CD14 + CD16 + are recognized as the two main subpopulations of blood monocytes, with CD14 + CD16 + monocytes being activated cells marked by pro-inflammatory cytokines, demonstrating an ability to enhance inflammatory activity and interact with endothelial cells (Ziegler-Heitbrock, 2007;Merino et al., 2011). An increased proportion of CD14 + CD16 + monocytes has been observed in both peripheral blood and gingival tissue of patients with chronic PD (Jagannathan et al., 2014). ...
Introduction
Immune cells are dynamic in the inflammatory environment and play a key role in eradicating periodontal pathogens, modulating immune responses, and instigating tissue destruction. Identifying specific immune cell phenotypes associated with periodontitis risk is essential for targeted immunotherapeutic interventions. However, the role of certain specific immune cell phenotypes in the development of periodontitis is unknown. Mendelian randomization offers a novel approach to reveal causality and address potential confounding factors through genetic instruments.
Methods
This two-sample Mendelian randomization study assessed the causal relationship between 731 immune cell phenotypes and periodontitis using the inverse variance weighting method with the GWAS catalog genetic database. Methodological robustness was ensured through Cochran’s Q test, MR-Egger regression, MR-PRESSO, and Leave-One-Out analysis.
Results
14 immune cell phenotypes showed potential positive causal associations with periodontitis risk (p < 0.05), suggesting an increased risk, while 11 immune cell phenotypes exhibited potential negative causal associations (p < 0.05), indicating a reduced risk. No significant heterogeneity or pleiotropy was observed.
Conclusion
This study underscores certain immune cell types as potential periodontitis risk biomarkers, laying a theoretical foundation for future individualized treatment and precision medicine development.
... It is noteworthy, however, that patients with KAD presented an increased proportion of intermediate monocytes showing ASCspeck compared with PWH, likely due to an enrichment of those cells in their monocyte compartment. Intermediate monocytes are known to secrete proinflammatory cytokines, 53 to present antigens, 36 and to migrate into inflamed tissues, 54 FLICA + specks/mL Patrolling Figure 5. In vitro stimulation of monocytes with supernatants from KSHV-infected cells. ...
Kaposi sarcoma herpesvirus (KSHV)-associated disorders include Kaposi sarcoma (KS), primary effusion lymphoma (PEL), KSHV-associated multicentric Castleman disease (MCD) and KSHV-inflammatory cytokine syndrome (KICS). PEL, MCD, and KICS are associated with elevated circulating inflammatory cytokines. However, activation of the inflammasome, which generates IL-1 and IL-18 via active caspase-1/4/5, has not been evaluated in patients with KAD. Here we report that patients with HIV and one or more KAD present with higher plasma levels of IL-18 and increased caspase-1/4/5 activity in circulating monocytes as compared to HIV-negative healthy volunteers (HV) or people with HIV without KAD (PWH). Within KAD subtypes, KICS and MCD shared enhanced caspase-1/4/5 activity and IL-18 production when compared to HV and PWH, while patients with PEL showed remarkably high levels of inflammasome complex formation (known as apoptosis-associated speck-like protein containing a caspase recruitment domain (CARD) (ASC)-speck). Moreover, caspase-1/4/5 activity and IL-18 plasma levels correlated with KSHV viral load, indicating KSHV-driven inflammasome activation in KAD. Accordingly, factors released by KSHV-latently infected cells triggered inflammasome activation and cytokine production in bystander monocytes, in vitro. Finally, both supervised and unsupervised analyses with inflammasome measurements and other inflammatory biomarkers demonstrate a unique inflammatory profile in patients with PEL, MCD, and KICS as compared to KS. Our data indicate that detrimental inflammation in patients with KAD is at least partially driven by KSHV-induced inflammasome activation in monocytes, thus offering novel approaches to diagnose and treat these complex disorders.
... These include classical (CD14 + CD16 -) accounting for 90% of monocytes circulation in the blood, while nonclassical (CD14 + CD16 + ) constitutes 10%. (9) Although the composition of non-classical monocytes subset is 10%, the increase is relatively related to the occurrence of infection and inflammation. (10) According to a study, monocyte differentiation is not transcriptionally imprinted, but can be influenced by external cues such as cytokines, retinoic acid, and pathogenderived products. ...
BACKGROUND: Type 2 Diabetes (T2D) impairs the innate immune system including monocytes. Monocytes are divided into two subgroups depending on the expression of cluster of differentiation (CD)14 and CD16 receptors, namely CD14+CD16- and CD14+CD16+. CD14+CD16+ are proinflammatory monocytes and develop into M1 type macrophages, which contribute to foam cell production, a risk factor for cardiovascular disease (CVD). Therefore, it is important to determine the influence of T2D conditions on changes in monocyte subsets and whether these changes correlate with CVD risk markers.
METHODS: Peripheral blood mononuclear cell (PBMC) was obtained from 10 T2D subjects and 10 healthy donors. Subsequently, PBMC was incubated for 24 hours with and without 10 mL lipopolysaccharide. Flow cytometry was used to evaluate CD14 and CD16 expression, while multiplex immunoassays were applied to measure interleukin (IL)-1b and IL-10 concentrations in supernatants.
RESULTS: In T2D, the percentage of CD14+CD16+ monocytes increased (p=0.07), and an increase in CD14+CD16+ monocytes more than 6.8% was linked with CVD risk markers (r=10.146, p=0.002). Meanwhile, inflammatory mediators released by monocytes shown an increase in IL-1b (p=0.041) but not in IL-10 (p=0.082) in T2D subjects. Fasting blood glucose levels were also found to be substantially linked with an increase in CD14+CD16+ monocytes (r=0.530, p=0.016).
CONCLUSION: T2D patients had a higher percentage of CD14+CD16+ monocytes and IL-1b levels than healthy donors. An increase in CD14+CD16+ monocytes above 6.8% associated with CVD risk markers in T2D patients.
KEYWORDS: type 2 diabetes, monocytes, CD14, CD16, cardiovaskular disease risk marker
... In this neuroinflammatory response, the upregulation of the cell adhesion molecule (CAM) and CAM ligand expression on blood-brain-barrier endothelial cells mediate peripheral immune cells, prompting them to cross the blood-brain barrier and interact with immune cells residing in the CNS (Engelhardt and Ransohoff, 2005). The subpopulations of peripheral blood immune cell types are sophisticated and diverse, and each subpopulation and its cytokines exert various or opposing influences on AD development (Skias et al., 1985;Ziegler-Heitbrock, 2007;Lueg et al., 2015;Xu and Jia, 2021;Aries and Hensley-Mcbain, 2023). The intricate relationship between the peripheral immune system and AD can be adequately understood only by systematic and exhaustive studies of different subgroups. ...
Introduction
Alzheimer’s disease (AD) is the most widespread neurodegenerative disease in the world. Previous studies have shown that peripheral immune dysregulation plays a paramount role in AD, but whether there is a protective causal relationship between peripheral immunophenotypes and AD risk remains ambiguous.
Methods
Two-sample Mendelian randomization (MR) was performed using large genome-wide association study (GWAS) genetic data to assess causal effects between peripheral immunophenotypes and AD risk. Utilizing the genetic associations of 731 immune cell traits as exposures. We adopted the inverse variance weighted method as the primary approach. The Weighted median and MR-Egger regression methods were employed as supplements. Various sensitivity analyses were performed to assess the robustness of the outcomes.
Results
Based on the IVW method, we identified 14 immune cell traits that significantly reduced the risk of AD, of which six demonstrated statistical significance in both IVW and Weighted median methods. Among the seven immune traits, four were related to regulatory T (Treg) cells : (1) CD25++ CD45RA- CD4 not regulatory T cell % T cell (odds ratio (OR) [95% confidence interval (CI)] = 0.96 [0.95, 0.98], adjusted P = 1.17E−02), (2) CD25++ CD45RA- CD4 not regulatory T cell % CD4+ T cell (OR [95% CI] = 0.97 [0.96, 0.99], adjusted P = 3.77E−02), (3) Secreting CD4 regulatory T cell % CD4 regulatory T cell (OR [95% CI] = 0.98 [0.97, 0.99], adjusted P = 7.10E−03), (4) Activated & secreting CD4 regulatory T cell % CD4 regulatory T cell(OR [95% CI] = 0.98 [0.97, 0.99], adjusted P = 7.10E−03). In addition, HLA DR++ monocyte % monocyte (OR [95% CI] = 0.93 [0.89, 0.98], adjusted P = 4.87E−02) was associated with monocytes, and HLA DR on myeloid Dendritic Cell (OR [95% CI] = 0.93 [0.89, 0.97], adjusted P = 1.17E−02) was related to dendritic cells (DCs).
Conclusion
These findings enhance the comprehension of the protective role of peripheral immunity in AD and provide further support for Treg and monocyte as potential targets for immunotherapy in AD.
... The intestinal CD14 monocytes included CD14 + CD16 + intermediate monocytes and CD14 + CD16-classical monocytes. CD14 + CD16 + monocytes exhibit increased antigen-presenting ability and increased expression of in ammatory factors such as TNF and IL-12 due to the expression of HLA-DR, endothelial growth factor module-containing mucin-like receptor 2 (EMR2), Ig-like transcript 4 (ILT-4), CD43, and CD45RA on their surface [43] . Due to the proin ammatory nature of monocytes, eliminating monocytes was once considered a therapy for UC. ...
Background
Immune cells change in Ulcerative colitis (UC). However, the causal relationship between the immunophenotypes and UC is not clear.
Methods
731 immunophenotype databases and the UC database with 463,010 participants were utilized. Five Mendelian randomization (MR) analysis methods were used, with inverse variance weighted (IVW) as the main method and single nucleotide polymorphisms (SNPs) as the instrumental variable (IV), to explore the causal relationship. False discovery rate (FDR) correction and sensitivity analysis were used to examine the MR hypothesis. Next, the MR results were cross-verified in FinnGen Consortium R9 with 369,652 participants to confirm the reliability. Finally, reverse MR is performed.
Results
At the significance level of p < 0.05, 71 immunophenotypes associated with UC were screened. After FDR correction, 7 immunophenotypes were still associated. Cross-analysis of the MR analysis results from the UC database with the MR results from the external IBD (FinnGen) database confirmed that CX3CR1 on CD14 + CD16- monocyte (OR = 1.001, pFDR = 0.075) and CX3CR1 on CD14 + CD16 + monocyte (OR = 1.001, pFDR = 0.002) immunophenotypes were significantly associated with an increased risk of UC. Reverse MR revealed no significant correlations.
Conclusion
This study verified the causal link between immunophenotypes and UC, which may provide a theoretical basis for developing new targeted drugs.
... Discover Oncology (2024) 15:155 | https://doi.Research crucial biological process in liposarcoma progression [23]. Furthermore, it has been reported that NINJ1 has two distinct functions in p53-dependent tumorigenesis [27,28]. NINJ1 represses the translation of both wild-type and mutated p53 and acts as an oncogene and a tumor-suppressor gene, respectively, in cells with wild-type and mutant p53. ...
Background
Retroperitoneal liposarcoma (RPLS) is known for its propensity for local recurrence and short survival time. We aimed to identify a credible and specific prognostic biomarker for RPLS.
Methods
Cases from The Cancer Genome Atlas (TCGA) sarcoma dataset were included as the training group. Co-expression modules were constructed using weighted gene co-expression network analysis (WGCNA) to explore associations between modules and survival. Survival analysis of hub genes was performed using the Kaplan–Meier method. In addition, independent external validation was performed on a cohort of 135 Chinese RPLS patients from the REtroperitoneal SArcoma Registry (RESAR) study (NCT03838718).
Results
A total of 19 co-expression modules were constructed based on the expression levels of 26,497 RNAs in the TCGA cohort. Among these modules, the green module exhibited a positive correlation with overall survival (OS, p = 0.10) and disease-free survival (DFS, p = 0.06). Gene set enrichment analysis showed that the green module was associated with endocytosis and soft-tissue sarcomas. Survival analysis demonstrated that NINJ1 , a hub gene within the green module, was positively associated with OS ( p = 0.019) in the TCGA cohort. Moreover, in the validation cohort, patients with higher NINJ1 expression levels displayed a higher probability of survival for both OS ( p = 0.023) and DFS ( p = 0.012). Multivariable Cox analysis further confirmed the independent prognostic significance of NINJ1.
Conclusions
We here provide a foundation for the establishment of a consensus prognostic biomarker for RPLS, which should not only facilitate medical treatment but also guide the development of novel targeted drugs.
... CCR2 is a chemokine receptor involved in monocyte recruitment to sites of in ammation [26] . The speci c subset of CD14 + CD16 + monocytes is known for its pro-in ammatory properties [27] . The higher expression of CCR2 might re ect a more controlled recruitment and activity of these cells, preventing an overwhelming in ammatory response. ...
Background: Research exploring the link between immune cell profiles and the development of endometritis remains scant. This gap necessitates further study to decode the complex interrelations influencing this condition.
Methods: In this analysis, we leveraged two-sample Mendelian randomization to examine the causal ties between the phenotypes of immune cells and the incidence of endometritis. Our evaluation hinged on data from 3,757 participants hailing from Sardinia, focusing on a diverse array of 731 immune phenotypes, and cross-referenced with endometritis data sourced from the UK Biobank. To ensure rigor, we performed sensitivity analyses, utilized MR-Egger and MR-Presso to check for pleiotropy, and applied Cochran's Q test for assessing the heterogeneity of our findings.
Results: Our investigation identified numerous immune characteristics associated with endometritis. For certain immune traits, a lower risk of endometritis was observed, including: Absolute Counts of CD39+ CD4+ T cells, CD25+ CD39+ CD4 regulatory T cells, and CD25++ CD8+ T cells; Absolute Counts of Switched Memory B cells; CD19 expression on IgD+ CD38dim and Switched Memory B cells; CD20 expression on IgD+ CD38- Unswitched Memory B cells; percentage of Switched Memory B cells among lymphocytes; CD16-CD56 expression on HLA DR+ Natural Killer cells; percentage of CD11c+ CD62L- monocytes; CD86 expression on monocytes; CCR2 expression on CD14+ CD16+ monocytes; and CD14 expression on Monocytic Myeloid-Derived Suppressor Cells, with Odds Ratios (ORs) between 0.413 and 0.703. On the contrary, increased risks of endometritis were linked with: the percentage of Effector Memory CD4+ T cells within the CD4+ T cell population; percentages of HLA DR+ T cells and HLA DR+ CD8+ T cells among T cells; CD4 expression on CD28+ CD4+ T cells; CD20 expression on CD20- CD38- B cells; percentage of IgD+ CD24+ B cells within the B cell population; CD62L expression on CD62L+ myeloid Dendritic Cells; and Absolute Counts of Plasmacytoid Dendritic Cells, with ORs from 1.473 to 2.677, indicating these traits potentially elevate the risk of developing endometritis.
Conclusion: Our research delineates distinct causal links between specific immune cell phenotypes and endometritis, offering groundbreaking perspectives that could contribute to the pinpointing of new therapeutic avenues for this condition.
... Moreover, CD16-expressing cells are considered by macrophage-similar characteristics, strong endocytosis effects, and high antigen presentation function associated with the excess making of pro-inflammatory cytokines 13 . Previous studies explained amplified fractions of these cells by induction of phagocytic/activated monocytes that might help in phagocytosis of neighbouring dead cells after cyclophosphamide treatment associated with a lack of these cells' responsiveness to cyclophosphamide cytotoxicity 14 . ...
Background
Cyclophosphamide (CP) is one of the most effective immunosuppressive agents. To understand the mechanisms used by the CP and MSCs in the kidney, we investigated their effects on some pathways.
Experimental animals and methods
4 groups of female rats were used. GI: was the normal control group treated with saline solution. Groups G II, G III, and G IV were treated with CP. G I and G II groups were sacrificed on the fourth day after treatment., G III (Auto healing group) was left without treatment after the CP injection for six days. The G IV group was treated with MSCs on the fourth day after the CP injection. G III and G IV groups were sacrificed six days after treatment, and the kidney was removed and processed.
Results
CP induced up-regulation in CD14 and CD21 positive cells and caspase. Significant down-regulation of previous markers in groups III and IV. CP exerted a downregulation effect on AKT/ PI3K, that were ameliorated in groups III and IV. A significant increase in P53, BCL2, as well as VEGF in Group IV (P < 0 05).
Conclusion
MSCs play a vital function in the immune inhibition in CP-treated rats through PI3K/AKT pathway.
... It has been shown that the same cells, or certain subsets of classical monocytes and neutrophils, can actually oppose the initial activation and subsequent increase in pathogenic T cells [63]. CD16 + monocytes are described as being superior at activating T cells, suggesting that they are more active inducers of inflammation than the CD14 + monocytes [64] and that they can migrate through the blood-brain barrier more effectively than lymphocytes and CD14 + [65]. The findings of Waschbisch et al. [35] support the idea of the important role of CD16 + monocytes in shifting to sites of inflammation in the steady-state immune surveillance of the CNS, and they suggest that CD16 + monocytes cause the breakdown of the blood-brain barrier in CNS autoimmune diseases. ...
The objective of this study was to investigate regulatory T cells (Tregs) and monocytes; specifically, the expression of CTLA-4 (CD152) and FOXP3+ in CD4+CD25+ Tregs and the expression of CD40+ and CD192+ monocyte subpopulations in subjects with primary progressive multiple sclerosis (PPMS). Immunological analysis was conducted on peripheral blood samples collected from the 28 PPMS subjects (15 treated with ocrelizumab and 13 untreated PPMS subjects) and 10 healthy control subjects (HCs). The blood samples were incubated with antihuman CD14, CD16, CD40, and CD192 antibodies for monocytes and antihuman CD4, CD25, FOXP3, and CTLA-4 antibodies for lymphocytes. The study results showed that in comparison to HCs both ocrelizumab treated (N = 15) and untreated (N = 13) PPMS subjects had significantly increased percentages of CTLA-4+ and FOXP3+ in CD4+CD25+ Tregs. Further, ocrelizumab treated PPMS subjects, compared to the untreated ones, had significantly decreased percentages of CD192+ and CD40+ nonclassical monocytes. Increased percentages of CTLA-4+ and FOXP3+ in CD4+CD25+ Tregs in both ocrelizumab treated and untreated PPMS subjects indicates the suppressive (inhibitory) role of Tregs in abnormal immune responses in PPMS subjects. Decreased percentages of CD40+, CD192+, and CD14+CD16++ monocytes for treated compared to untreated PPMS subjects suggests a possible role for ocrelizumab in dampening CNS inflammation.
... Monocytes also appear to be impaired in chemotaxis. In addition, although reduced in their total count, there is an increased percentage of non-classical or CD14dimCD16+ sub-populations, which has been associated to chronic inflammation, sepsis and malignancies [47,48]. Furthermore, TLR2, a pathogen receptor implicated in Gram-positive infections and chronic inflammation, seems to be increasingly expressed on neutrophils and monocytes in DS patients. ...
Down Syndrome (DS) is the most common chromosomal abnormality compatible with life. The life of patients suffering from DS can be strongly impacted by Recurrent Respiratory tract Infections (RRIs), leading to an increased rate of hospitalisation, a higher need for intensive care and fatality. With a literature review, we summarise here the main etiological factors for RRI in this category of patients, particularly focusing on airway malformations such as tracheomalacia, tracheal bronchus and bronchomalacia, comorbidities associated with the syndrome, like congenital heart diseases, dysphagia, gastroesophageal reflux, musculoskeletal involvement and obesity, and immunologic impairments, involving both innate and adaptive immunity. For these patients, a multidisciplinary approach is imperative as well as some preventive strategies, in particular vaccinations in accordance with their national schedule for immunization.
... The number of CD14+CD91low cells increased 15-fold in BSI, and up to 20-fold after cardiac surgery, compared to healthy controls. In contrast, CD14+CD16+ intermediate monocytes were only 5-fold higher than controls, although they have been considered in previous studies as the prominent inflammatory subset [31,32]. Thus, the CD91low monocytes seems to be the most specific monocyte fraction expanded in acute inflammation from infectious or non-infectious origin. ...
Objectives
This study was undertaken to assess CD91 expression on monocytes and changes in monocyte subset distribution during acute tissue damage and bloodstream infection (BSI).
Methods
We investigated blood specimens from healthy individuals, trauma and cardiac surgery patients as a model of tissue damage, and patients with BSI, by flow cytometry using a panel of antibodies comprising CD45, HLA-DR, CD14, CD16 and CD91 for the identification of monocyte subsets.
Results
While infrequent in healthy subjects, CD91low/neg monocyte levels were markedly high in BSI, trauma and after cardiac surgery. This monocyte subset expanded up to 15-fold in both patient cohorts, whereas CD14+CD16+ inflammatory monocytes were multiplied by a factor of 5 only. CD14+CD91low monocytes displayed a significantly lower density of HLA-DR and markedly reduced expression of CD300e, compared to the other subsets. They also expressed high levels of myeloperoxidase and showed robust phagocytic and oxidative burst activity.
Conclusions
Expansion of CD91low monocytes is a sensitive marker of acute inflammatory states of infectious and non-infectious etiology.
... Repple et al. [16] arranged ow cytometry for the CSF from the methadone intoxicated patient and found cell compositon alternations characterized by a transformation of monocytes from classical (CD14 + CD16-) to non-classical (CD14 + CD16+) and a switch from CD56bright non-killing (NK) cells to CD56dim NK cells. It should be noted that CD14 + CD16 + monocytes and CD56dim NK cells are known as proin ammatory cells, both may be involved in the process of delayed encephalopathy [17]. These proofs might explain the lymphocytes aggregation, which is the rst report of CSF ndings in chlorfenapyr intoxication. ...
Background
Emamectin·chlorfenapyr is compounded with chlorfenapyr and emamectin benzoate. It has been wildly used in agriculture. Although chlorfenapyr toxicity has been verified in animals, the true mechanism and progression in human beings still needs to be unveiled. Furthermore, cases of the compound emamectin·chlorfenapyr poisoning are very scarce.
Case presentation
We present the case of a 65-year-old female who had attempted suicide by taking 30g of 9.5% chlorfenapyr and 0.5% emamectin benzoate orally 14 days before being admitted to our hospital. Laboratory tests showed extremely high creatinine kinase levels on admission. Magnetic resonance imaging showed diffuse and symmetric T2 hyperintensity in entire white matter tract of brain and spinal cord. Cerebrospinal fluid cytology pathological smear showed abnormal lymphocyte aggregation. 19.5 hours after admission, the patient died because of cardiopulmonary arrest and hyperthermia.
Conclusions
Further research is needed on performing flow cytometry in emamectin·chlorfenapyr intoxication patients and elucidating immunological mechanism beneath the inflammatory process caused by emamectin·chlorfenapyr, and providing new thoughts in antidotal drug development.
... They are highly phagocytic cells that produce high levels of inflammatory mediators, such as TNF-alpha, and low levels of IL-10, and remove apoptotic cells, showing a higher degree of maturation than classical monocytes and being related to the differentiation into macrophages and dendritic cells. As intermediate monocytes were considered part of the subpopulation of non-classical monocytes, they were neglected in several previous studies; however, their clinical relevance was shown in patients with high cardiovascular risk, where the intermediate monocyte count was shown to be high in these individuals [31]. ...
The current study aims to evaluate the effect of non-surgical periodontal treatment on the modulation of monocyte phenotype, in the presence or absence of diabetes.
The identification, quantification, and phenotypic characterization of monocyte subtypes (classical, intermediate, and non-classical) were performed by flow cytometry, at baseline and 1 month after the end of non-surgical periodontal treatment, in patients with periodontitis, associated or not with diabetes.
There was an increase in non-classical monocytes after treatment and a reduction in intermediate monocytes, without differences for the classical subtype, regardless of the diabetes status. Furthermore, there was a reduction in intermediate monocytes and an increase in non-classical and classical monocytes after treatment in the diabetes group, while no significant differences were observed for classical, intermediate, and non-classical monocytes in the group without diabetes. Comparisons between the two groups showed significant differences for classical, intermediate, and non-classical monocytes at baseline; these differences were not found one month after treatment.
Non-surgical periodontal treatment leads to modulation of monocytes to a less inflammatory phenotype, especially in individuals with diabetes.
Clinical relevance.
A better understanding of the role of these biomarkers in the periodontitis contex may constitute a new strategic target for a better treatment of patiens with diabetes associated to periodontitis.
Clinical Trial Registration.
Brazilian Registry of Clinical Trials—RBR-35szwc.
Jhefferson Miranda Alves and Danielle Borges Germano contributed equality to this study and should be considered first authors.
... Monocytes are congenital inflammatory cells that can trigger inflammatory reactions and liver injury in patients with PBC. [29] In the livers of PBC patients, monocytes comprised approximately 30% of the cells that infiltrated the portal vein area, and mostly concentrated around damaged bile ducts. [30] Additionally, the number of CD14 low CD16 + monocytes were positively associated with disease progression, particularly in PBC patients with liver cirrhosis. ...
This study aimed to evaluate the clinical value of the monocyte to high-density lipoprotein cholesterol ratio (MHR) and alkaline phosphatase-to-platelet ratio (APPR) in the diagnosis and prognosis of primary biliary cholangitis (PBC). Clinical and laboratory data were retrospectively collected and analyzed from 92 PBC patients, 92 patients with autoimmune hepatitis (AIH), 120 patients with chronic hepatitis B (CHB) and 124 healthy controls (HCs). We compared the levels of MHR and APPR among the groups with PBC, AIH, CHB and HCs, and analyzed the correlations between MHR and APPR with laboratory indices including aspartate aminotransferase platelet ratio index, fibrosis index based on 4 factors, and Mayo score in PBC. Receiver operating characteristic curves were used to analyze the diagnostic performance of MHR and APPR for PBC, AIH, and CHB, respectively. MHR and APPR were significantly increased in PBC group than that in AIH, CHB and HCs groups (each P < .05). MHR and APPR were significantly higher in Child class B|C than that in class A in PBC patients. ( P < .01, P < .05, respectively). MHR and APPR were positively related to the Mayo score [ R = 0.508 ( P < .001), R = 0.295 ( P = .008), respectively]. The area under the receiver operating characteristic curves of MHR and APPR in diagnosing PBC were 0.764 (95% confidence interval [CI]: 0.699–0.821, P < .001) and 0.952 (95% CI: 0.915–0.977, P < .001), respectively, and the area under the curve of the combination of both was 0.974 (95% CI: 0.941–0.991, P < .001). MHR and APPR may prove to be useful prognostic biomarkers for PBC, and the combination of MHR and APPR have some clinical diagnostic value of PBC.
Background
Sepsis, a systemic inflammatory response syndrome triggered by infection, is associated with high mortality rates and an increasing global incidence. While N ⁶-methyladenosine (m⁶A) RNA methylation and ferroptosis are implicated in inflammatory diseases, their specific genes and mechanisms in sepsis remain unclear.
Methods
Transcriptomic datasets of sepsis, along with m⁶A-related genes (m⁶A-RGs) and ferroptosis-related genes (FRGs), were sourced from public databases. Differentially expressed genes (DEGs) were identified between the sepsis and control groups, and m⁶A-RGs were analyzed through weighted gene co-expression network analysis (WGCNA) to uncover m⁶A module genes. These were then intersected with DEGs and FRGs to identify candidate genes. Biomarkers were identified using two machine learning methods, receiver operating characteristic (ROC) curves, and expression validation, followed by the development of a nomogram. Further in-depth analyses of the biomarkers were performed, including functional enrichment, immune infiltration, drug prediction, and molecular docking. Single-cell analysis was conducted to identify distinct cell clusters and evaluate biomarker expression at the single-cell level. Finally, reverse transcription–quantitative PCR (RT-qPCR) was employed to validate biomarker expression in clinical samples.
Results
DPP4 and TXN were identified as key biomarkers, showing higher expression in control and sepsis samples, respectively. The nomogram incorporating these biomarkers demonstrated strong diagnostic potential. Enrichment analysis highlighted their involvement in spliceosome function and antigen processing and presentation. Differential analysis of immune cell types revealed significant correlations between biomarkers and immune cells, such as macrophages and activated dendritic cells. Drug predictions identified gambogenic acid and valacyclovir as potential treatments, which were successfully docked with the biomarkers. Single-cell analysis revealed that the biomarkers were predominantly expressed in CD4⁺ memory cells, and CD16⁺ and CD14⁺ monocytes. The expression of DPP4 was further validated in clinical samples.
Conclusions
DPP4 and TXN were validated as biomarkers for sepsis, with insights into immune infiltration and therapeutic potential at the single-cell level, offering novel perspectives for sepsis treatment.
Monocytes are circulating blood cells derived from bone marrow. They are the body’s first line of defense against pathogens and are involved in immune responses against viruses, bacteria, fungi and parasites invasion. For a long time, monocytes were considered a homogeneous group of cells, but then by means of flow cytometry development it was shown that they can be divided into three subpopulations according to surface molecules CD14 and CD16 expression: classical (CD14++CD16–), proinflammatory (CD14+CD16++) and intermediate (CD14++CD16+). This review focuses on various mechanisms of an implementation of the functional activity of various monocytes subpopulations and their impairment in various viral diseases, bacterial infections and sepsis.
Background/Objectives: Obesity is closely linked to chronic low-grade inflammation and the development of cardio-metabolic comorbidities. Monocyte subsets, which are crucial in immune responses, have been reported to be altered in individuals with obesity, potentially exacerbating inflammation. Although very-low-calorie ketogenic diets (VLCKDs) are recognized for their efficacy in promoting weight loss and improving metabolic health, their impact on circulating monocyte subsets remains poorly understood. The objective of our study is to investigate the impact of VLCKDs on monocyte subset distribution in people with obesity. Methods: Thirty-six participants were divided into four groups—healthy controls, individuals with obesity and no dietary intervention, and individuals with obesity following either a low-calorie diet (LCD) or VLCKD for 28 days. Blood samples were analyzed to assess the distribution of classical monocytes (CMs), intermediate monocytes (IMs), and non-classical monocytes (NCMs) using flow cytometry. Results: Individuals with obesity exhibited significant increases in IMs and NCMs, alongside a decrease in CMs compared to healthy controls. The VLCKD led to a notable shift in monocyte distribution, with increased CMs and reduced IMs and NCMs, restoring levels closer to those observed in healthy individuals. In contrast, the LCD group showed no significant changes in monocyte subsets. Conclusions: VLCKDs may exert anti-inflammatory effects by modulating monocyte subset distribution, offering potential therapeutic benefits in mitigating obesity-related inflammation. These preliminary findings suggest that VLCKDs could be an effective strategy for improving immune function in individuals with obesity.
Immunotherapy utilizes immune cells to target cancer and improves treatment outcomes with few side effects. Despite the effectiveness of immunotherapy, the limited availability of monocytes, which are essential for the differentiation of antigen-presenting cells, remains a major challenge. In this study, we developed a technique for inducing monocytes from hematopoietic stem and progenitor cells by using a serum-free (SF) medium supplemented with optimal concentrations of serum substitutes and cytokines. Three key serum substitutes, namely lipids, ascorbic acid, and β-glycerophosphate, were identified through factorial design screening, with their concentrations optimized through steepest ascent path analysis. Iscove's modified Dulbecco's medium was identified as the optimal basal medium. Long-term culturing confirmed the successful induction of CD14+CD16+ and CD14+CD16- monocytes. Functional assays validated the efficacy of this technique with comparable gene expression, cytokine secretion, phagocytosis ability, and T-cell stimulating ability between SF and serum-containing cultures. Under SF conditions, high expression levels of CD16 were detected, indicating the broad range of potential applications of CD16+ monocytes. Overall, this technique represents a feasible SF alternative for monocyte generation, with potential benefits for immunotherapy.
Monocyte/macrophages are cells of myeloid origin which play critical roles in innate and adaptive immune responses as well as surveillance and tissue repair. Only recently, the role of monocytes/macrophages in acute and chronic HIV Infection has become accepted. Here, we will focus on monocyte/macrophages on transmigration events and their role as viral reservoirs.
Activation of the Toll-like receptor 4 (TLR4) by bacterial endotoxins in macrophages plays a crucial role in the pathogenesis of sepsis. However, the mechanism underlying TLR4 activation in macrophages is still not fully understood. Here, we reveal that upon lipopolysaccharide (LPS) stimulation, lysine acetyltransferase CBP is recruited to the TLR4 signalosome complex leading to increased acetylation of the TIR domains of the TLR4 signalosome. Acetylation of the TLR4 signalosome TIR domains significantly enhances signaling activation via NF-κB rather than IRF3 pathways. Induction of NF-κB signaling is responsible for gene expression changes leading to M1 macrophage polarization. In sepsis patients, significantly elevated TLR4-TIR acetylation is observed in CD16+ monocytes combined with elevated expression of M1 macrophage markers. Pharmacological inhibition of HDAC1, which deacetylates the TIR domains, or CBP play opposite roles in sepsis. Our findings highlight the important role of TLR4-TIR domain acetylation in the regulation of the immune responses in sepsis, and we propose this reversible acetylation of TLR4 signalosomes as a potential therapeutic target for M1 macrophages during the progression of sepsis.
Transmission of HIV-1 to newborns and infants remains high, with 130,000 new infections in 2022 in resource-limited settings. Half of HIV-infected newborns, if untreated, progress to disease and death within 2 years. While immunologic immaturity likely promotes pathogenesis and poor viral control, little is known about immune damage in newborns and infants. Here we examined pathologic, virologic, and immunologic outcomes in rhesus macaques exposed to pathogenic simian-human immunodeficiency virus (SHIV) at 1-2 weeks, defined as newborns, or at 4 months of age, considered infants. Kinetics of plasma viremia and lymph node seeding DNA were indistinguishable in newborns and infants, but levels of viral DNA in gut and lymphoid tissues 6-10 weeks after infection were significantly higher in newborns versus either infant or adult macaques. Two of 6 newborns with the highest viral seeding required euthanasia at 25 days. We observed age-dependent alterations in leukocyte subsets and gene expression. Compared with infants, newborns had stronger skewing of monocytes and CD8+ T cells toward differentiated subsets and little evidence of type I interferon responses by transcriptomic analyses. Thus, SHIV infection reveals distinct immunological alterations in newborn and infant macaques. These studies lay the groundwork for understanding how immune maturation affects pathogenesis in pediatric HIV-1 infection.
Background
Aging skin, exacerbated by external factors like UV radiation and pollutants, is a major cosmetic concern. Taurine, renowned for its antioxidant and anti‐inflammatory properties, may combat skin aging. We performed mendelian randomization (MR) analysis to investigate the causal link between taurine and immune cells linked to skin aging.
Objectives
To investigate the association between taurine and immune cells using mendelian randomization, to thereby explore the mechanism through which taurine exerts anti‐aging effects on the skin via immune modulation.
Methods
A MR approach was employed using taurine‐level data from the Ieu Open GWAS Project and immunocyte traits from a large European cohort. MR‐Egger regression, weighted median estimation, and inverse variance weighting all provided statistical insights into causality. Sensitivity analyses assessed the heterogeneity and pleiotropy among the genetic instruments used.
Results
MR analysis identified a causal relationship between taurine levels and 10 immunocyte phenotypes, with taurine found to be negatively and positively associated with three and seven phenotypes, respectively. Sensitivity analysis revealed no significant heterogeneity or pleiotropy, suggesting reliable MR findings.
Conclusion
This study provides insights into the immunological pathways by which taurine contributes to skin anti‐aging effects, suggesting that increasing taurine levels could offer a novel strategy for anti‐aging skincare.
Background
Sepsis is a life-threatening organ dysfunction resulting from a dysregulated host response to infection, yet the potential causal relationship between the immunophenotype and sepsis remains unclear.
Methods
Genetic variants associated with the immunophenotype served as instrumental variables (IVs) in Mendelian randomization (MR) to elucidate the causal impact of the immunophenotype on three sepsis outcomes. Additionally, a two-step MR analysis was conducted to identify significant potential mediators between the immunophenotype and three sepsis outcomes.
Results
Our MR analysis demonstrated a significant association between the immunophenotype and sepsis outcome, with 36, 36, and 45 the immunophenotype associated with the susceptibility, severity, and mortality of sepsis, respectively. Specifically, our analysis highlighted the CD14+ CD16+ monocyte phenotype as a significant factor across all three sepsis outcomes, with odds ratios (ORs) and corresponding confidence intervals (CIs) indicating its impact on sepsis (OR = 1.047, CI: 1.001-1.096), sepsis in Critical Care Units (OR = 1.139, CI: 1.014-1.279), and sepsis-related 28-day mortality (OR = 1.218, CI: 1.104-1.334). Mediation analyses identified seven cytokines as significant mediators among 91 potential cytokines, including interleukin-5 (IL-5), S100A12, TNF-related apoptosis-inducing ligand (TRAIL), T-cell surface glycoprotein CD6 isoform, cystatin D, interleukin-18 (IL-18), and urokinase-type plasminogen activator (uPA). Furthermore, reverse MR analysis revealed no causal effect of sepsis outcomes on the immunophenotype.
Conclusion
Our MR study suggests that the immunophenotype is significantly associated with the susceptibility, severity, and mortality of patient with sepsis, providing, for the first time, robust evidence of significant associations between immune traits and their potential risks. This information is invaluable for clinicians and patients in making informed decisions and merits further attention.
Interleukin-22 (IL-22) is a vital cytokine that is dysregulated in various autoimmune conditions including rheumatoid arthritis (RA), multiple sclerosis (MS), and Alzheimer's disease (AD). As the starting point for the activation of numerous signaling pathways, IL-22 plays an important role in the initiation and development of autoimmune diseases. Specifically, imbalances in IL-22 signaling can interfere with other signaling pathways, causing cross regulation of target genes which ultimately leads to the development of immune disorders. This review delineates the various connections between the IL-22 signaling pathway and autoimmune disease, focusing on the latest understanding of the cellular sources of IL-22 and its effects on various cell types. We further explore progress with pharmacological interventions related to targeting IL-22, describing how such therapeutic strategies promise to usher in a new era in the treatment of autoimmune disease.
Since 1/3 of patients deteriorate after their admission to the emergency department (ED), assessing the prognosis of COVID-19 patients is of great importance. But to date, only lymphopenia and PaO2/FiO2 (P/F) ratio have been reported as partly predictive of COVID-19 further deterioration and their association has not been evaluated. We asked whether other key biomarkers of SARS-CoV2 immunologic defects - increase in circulating immature granulocytes (IGs), loss of monocyte HLA-DR (mHLA-DR) expression and monocyte differentiation blockade - could also predict further COVID-19 deterioration.
A series of 284 consecutive COVID-19 patients with, as sole inclusion criterion of being an adult, were prospectively enrolled at ED admission (D0) of two different hospitals: one for the exploratory (180 patients) and one for the confirmatory cohort (104 patients). Deterioration was assessed over the next seven days.
Neither increased IG levels nor monocyte differentiation blockade predicted patient worsening. Among more than 30 clinical, biological and radiological parameters, the value of decreased PaO2/FiO2 (P/F) ratio and lymphopenia for prediction of further COVID-19 deterioration was strongly confirmed and the loss of mHLA-DR was the only additional independent marker. Combined together in a simple OxyLymphoMono score, the three variables perfectly predicted patients who did not worsen and correctly predicted worsening in 59% of cases.By highlighting lymphocyte and monocyte defects as preceding COVID-19 deterioration, these results point on early immunosuppression in COVID-19 deterioration. Combining P/F ratio, lymphopenia and loss of mHLA-DR together in a simple and robust score could offer a pragmatic method for COVID-19 patient stratification.
Introduction
The clinical manifestations of acute severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) suggest a dysregulation of the host immune response that leads to inflammation, thrombosis, and organ dysfunction. It is less clear whether these dysregulated processes persist during the convalescent phase of disease or during long COVID. We sought to examine the effects of SARS-CoV-2 infection on the proportions of classical, intermediate, and nonclassical monocytes, their activation status, and their functional properties in convalescent COVID-19 patients.
Methods
Peripheral blood mononuclear cells (PBMCs) from convalescent COVID-19 patients and uninfected controls were analyzed by multiparameter flow cytometry to determine relative percentages of total monocytes and monocyte subsets. The expression of activation markers and proinflammatory cytokines in response to LPS treatment were measured by flow cytometry and ELISA, respectively.
Results
We found that the percentage of total monocytes was decreased in convalescent COVID-19 patients compared to uninfected controls. This was due to decreased intermediate and non-classical monocytes. Classical monocytes from convalescent COVID-19 patients demonstrated a decrease in activation markers, such as CD56, in response to stimulation with bacterial lipopolysaccharide (LPS). In addition, classical monocytes from convalescent COVID-19 patients showed decreased expression of CD142 (tissue factor), which can initiate the extrinsic coagulation cascade, in response to LPS stimulation. Finally, we found that monocytes from convalescent COVID-19 patients produced less TNF-α and IL-6 in response to LPS stimulation, than those from uninfected controls.
Conclusion
SARS-CoV-2 infection exhibits a clear effect on the relative proportions of monocyte subsets, the activation status of classical monocytes, and proinflammatory cytokine production that persists during the convalescent phase of disease.
Myocarditis is an inflammatory heart disease that mostly affects young people. Myocarditis involves a complex immune network; however, its detailed pathogenesis is currently unclear. The diversity and plasticity of immune cells, either in the peripheral blood or in the heart, have been partially revealed in a number of previous studies involving patients and several kinds of animal models with myocarditis. It is the complexity of immune cells rather than one cell type that is the culprit. Thus, recognizing the individual intricacies within immune cells in the context of myocarditis pathogenesis and finding the key intersection of the immune network may help in the diagnosis and treatment of this condition. With the vast amount of cell data gained on myocarditis and the recent application of single-cell sequencing, we summarize the multiple functions of currently recognized key immune cells in the pathogenesis of myocarditis to provide an immune background for subsequent investigations.
Despite effective antiretroviral therapy, HIV co-morbidities remain where central nervous system (CNS) neurocognitive disorders and cardiovascular disease (CVD)-pathology that are linked with myeloid activation are most prevalent. Comorbidities such as neurocogntive dysfunction and cardiovascular disease (CVD) remain prevalent among people living with HIV. We sought to investigate if cardiac pathology (inflammation, fibrosis, cardiomyocyte damage) and CNS pathology (encephalitis) develop together during simian immunodeficiency virus (SIV) infection and if their co-development is linked with monocyte/macrophage activation. We used a cohort of SIV-infected rhesus macaques with rapid AIDS and demonstrated that SIV encephalitis (SIVE) and CVD pathology occur together more frequently than SIVE or CVD pathology alone. Their co-development correlated more strongly with activated myeloid cells, increased numbers of CD14+CD16+ monocytes, plasma CD163 and interleukin-18 (IL-18) than did SIVE or CVD pathology alone, or no pathology. Animals with both SIVE and CVD pathology had greater numbers of cardiac macrophages and increased collagen and monocyte/macrophage accumulation, which were better correlates of CVD-pathology than SIV-RNA. Animals with SIVE alone had higher levels of activated macrophage biomarkers and cardiac macrophage accumulation than SIVnoE animals. These observations were confirmed in HIV infected individuals with HIV encephalitis (HIVE) that had greater numbers of cardiac macrophages and fibrosis than HIV-infected controls without HIVE. These results underscore the notion that CNS and CVD pathologies frequently occur together in HIV and SIV infection, and demonstrate an unmet need for adjunctive therapies targeting macrophages.
Background
We explored the efficacy and main biological mechanism of geniposide intervention in sepsis.
Methods
A sepsis model was established in male BALB/c mice through cecal ligation and puncture (CLP). Different doses of geniposide (20 or 40 mg/kg) were administered intravenously at 0 and/or 24 h after CLP surgery. The survival rate of different groups was observed. Additionally, the expression levels of CD16 and MHC-II in monocytes were assessed using flow cytometry. The concentration of TNF-α, IL-1β, IL-6, and IL-10 in the serum were measured by ELISA. We also observed the biological effects of geniposide on CD16 and MHC-II expression levels in RAW264.7 cells, as well as the secretion of TNF-α, IL-1β, IL-6, and IL-10, in the LPS-induced RAW264.7 cell model. The PPARγ levels were determined using western blot analysis.
Results
Intravenous administration of 40 mg/kg of geniposide at 0 h after CLP significantly improved the survival outcomes in the septic mouse model, with no significant benefits from low dosing (20 mg/kg) or delayed administration (24 h). The effective dose of geniposide significantly decreased the serum cytokine TNF-α, IL-1β, IL-6, and IL-10 concentrations in septic mice ( P < 0.05). Notably, in vitro assays showed that geniposide specifically increased the IL-10 level. Geniposide significantly reduced the CD16 expression ( P < 0.05) and increased MHC-II expression in monocytes ( P < 0.05). Additionally, geniposide elevated the PPARγ level in monocytes ( P < 0.05).
Conclusions
High-dose early-stage geniposide administration significantly improved the survival rate in a CLP mouse sepsis model by modulating the monocyte phenotype and regulating the cytokine network (IL-6/IL-10 levels). The pharmacological mechanism of geniposide action might be exerted primarily through PPARγ upregulation.
The subpopulation of strongly CD14-positive (CD14++) monocytes and monocytes coexpressing the CD16 antigen and low levels of CD14 (CD14+/CD16+ cells) were isolated by fluorescence-activated cell sorting (FACS) followed by stimulation with lipopolysaccharide (LPS) at 1 micrograms/mL. Polymerase chain reaction (PCR) after reverse transcription of isolated mRNA (RT-PCR) revealed similar levels of tumor necrosis factor (TNF) transcripts in both subpopulations. By contrast, transcripts for interleukin-10 (IL-10) were only detectable in CD14++ monocytes, whereas CD14+/CD16+ cells produced no detectable IL-10 transcripts after 4 hours. Only after 16 hours of LPS stimulation was a low level of IL-10 transcripts discernible in CD14+/CD16+ monocytes. The same pattern was seen at the protein level in that TNF in LPS-stimulated supernatants was comparable for both subpopulations, whereas IL-10 was detected in CD14++ monocytes but not in CD14+/CD16+ cells. To avoid interference of cell activation by CD14 and CD16 antibodies, cells were also isolated based on the high and low level of CD33 antigen expression. Again, weakly CD33-positive cells, which comprise the CD14+/CD16+ cells, showed no or only minimal IL-10 mRNA. When comparing blood monocyte subpopulations with alveolar macrophages (AM), AM showed high levels of LPS-stimulated TNF, whereas IL-10 transcripts were undetectable. Our data show that CD14+/CD16+ blood monocytes produce high levels of proinflammatory cytokines like TNF, whereas the anti-inflammatory IL-10 is low or absent, a pattern similar to what is seen in AM.
Experimental protocols for cancer immunotherapy include the utilization of autologous monocytederived dendritic cells (moDC) pulsed with tumor antigens. However, disease can alter the characteristics of monocyte precursors and some patients have increased numbers (up to 40%) of the minor CD16 monocyte subpopulation, which in healthy individuals represent 10% of blood monocytes. At the present, the capacity of CD16 monocytes to differentiate into DC has not been evaluated. Here, we investigated the ability of CD16 monocytes cultured with granulocyte– macrophage colony-stimulating factor, IL-4 and tumor necrosis factor-α to generate DC in vitro, and we compared them to DC derived from regular CD16 – monocytes. Both monocyte subsets gave rise to cells with DC characteristics. They internalized soluble and particulate antigens similarly, and both were able to stimulate T cell proliferation in autologous and allogeneic cultures. Nevertheless, CD16 moDC expressed higher levels of CD86, CD11a and CD11c, and showed lower expression of CD1a and CD32 compared to CD16 – moDC. Lipopolysaccharide-stimulated CD16 – moDC expressed increased levels of IL-12 p40 mRNA and secreted greater amounts of IL-12 p70 than CD16 moDC, whereas levels of transforming growth factor-β1 mRNA were higher on CD16 moDC. Moreover, CD4 T cells stimulated with CD16 moDC secreted increased amounts of IL-4 compared to those stimulated by CD16 – moDC. These data demonstrate that both moDC are not equivalent, suggesting either that they reach different stages of maturation during the culture or that the starting monocytes belong to cell lineages with distinct differentiation capabilities.
Healthy donors infused with high doses of glucocorticoids [GCs; methyl-prednisolone (MP); 500 mg/day for 3 days] suffer a selective depletion of the CD14 CD16 monocytes such that these cells are reduced by 95% on day 5. In vitro studies revealed that at 11 h of culture in the presence of 10 5 M MP, no depletion was observed as yet, but a reduction by 80% was seen after 24 h. In dose-response analysis, MP still led to a 50% reduction of CD14 CD16 monocytes at 10 7 M. Depletion could not be overcome by addition of the cytokines interleukin-1 or macro-phage-colony stimulating factor, and it was independent of CD95. Depletion was, however, inhibited by the caspase 3,8 blocker z-Val-Ala-Asp, suggesting that cell death occurs in a caspase-dependent manner. Furthermore, blockade of depletion by RU-486 indicates that the intracellular GC receptor (GCR) is involved. Measurement of GCR by flow cytometry revealed a 50% higher level of expression in the CD14 CD16 monocytes. Our studies show a selective depletion of CD14 CD16 monocytes by GC treatment in vivo and in vitro, an effect to which the modestly increased level of GCR may contribute.
Objective. To investigate whether in rheumatoid arthritis (RA) patients the immunological changes induced by adrenaline are different from healthy controls (HC). Methods. Fifteen female RA patients and 14 HC were infused with 1 mgukg adrenaline over 20 min. Blood was drawn before, immediately after, and 1 h after the end of infusion. Lymphocyte subpopulations, cytokine production and natural killer cell cytotoxicity were determined. Results. Subjects exhibited mild cardiovascular changes with no differences between patients and controls. CD16 + CD56 + CD3 – NK cells increased by a factor of 5.7, CD3 + T cells by 1.5, monocytes by 1.6 and PMN by 1.2 in both groups. The numbers of IL-8- and IL-10-producing monocytes were higher in patients and presented a larger increase after infusion. NK cytotoxic activity was higher in RA patients and increased after infusion in both groups. Activated monocytes and T cells were preferentially recruited in patients and controls. Values returned to baseline 1 h later. Conclusion. We describe an altered response to adrenaline in patients with RA with both pro- and anti-inflammatory effects. Additionally, activated T cells and monocytes recruited to the peripheral blood may influence disease activity.
The macrophage is well established as a target of HIV and simian immunodeficiency virus (SIV) infection and a major contributor
to the neuropathogenesis of AIDS. However, the identification of distinct subpopulations of monocyte/macrophages that carry
virus to the brain and that sustain infection within the central nervous system (CNS) has not been examined. We demonstrate
that the perivascular macrophage and not the parenchymal microglia is the primary cell productively infected by SIV. We further
demonstrate that although productive viral infection of the CNS occurs early, thereafter it is not easily detectable until
terminal AIDS. The biology of perivascular macrophages, including their rate of turnover and replacement by peripheral blood
monocytes, may explain the timing of neuroinvasion, disappearance, and reappearance of virus in the CNS, and questions the
ability of the brain to function as a reservoir for productive infection by HIV/SIV.
Monocytes in the circulation of normal individuals express two receptors for the constant region of immunoglobulin, Fc gamma RI and Fc gamma RII. In contrast, we have observed that AIDS monocytes express significant levels of a third Fc gamma R, Fc gamma RIII (CD16), which is normally associated with activation or maturation of the monocyte population. By dual-fluorescence analysis using a monoclonal antibody specific for Fc gamma RIII (MAb 3G8), 38.5 +/- 3.2% of the LeuM3 (CD14)-positive monocytes in AIDS patients were CD16 positive as compared to 10.4 +/- 1.0% for healthy individuals (n = 29; P less than 0.005). Furthermore, AIDS monocytes expressed Fc gamma RIII-specific mRNA which is expressed minimally or not at all in control monocytes. As a recently identified inducer of Fc gamma RIII expression on blood monocytes, transforming growth factor-beta (TGF-beta) was found to be elevated in the serum and/or plasma of AIDS patients. Moreover, incubation of normal monocytes with AIDS serum or plasma induced CD16 expression which correlated with serum TGF-beta levels (r = 0.74, P less than 0.001) and was inhibited with a neutralizing antibody to TGF-beta. Thus, the increased CD16 expression on peripheral blood monocytes in AIDS patients may be the consequence of elevated circulating levels of the polypeptide hormone TGF-beta.
With the aid of two-color immunofluorescence and flow cytometry, a new subset of cells coexpressing CD14 and CD16 antigens can be identified in human peripheral blood. Using the monoclonal antibody My4, these CD14+/CD16+ cells account for 2.2% of the mononuclear cells and form about 13% of all cells identified by the monocyte-specific CD14 monoclonal antibody. The CD14+/CD16+ cells can be assigned to the monocyte lineage based on typical morphology, on expression of additional monocyte-associated molecules, on the ability to form reactive oxygen intermediates and on the expression of monocyte-specific NaF-sensitive esterase. Light scatter analysis revealed lower forward angle and right angle light scatter for the CD14+/CD16+ cells compared with the regular monocytes, and the average cell size was determined to be 13.8 and 18.4 microns, respectively. Expression of class II antigens on these "small monocytes" was twofold higher compared with the regular monocytes. By contrast, the capacity to perform adherence to plastic surfaces, as well as the ability to phagocytize antibody-coated erythrocytes was clearly reduced in the CD14+/CD16+ monocyte subset as compared with the regular monocytes. Hence the CD14+/CD16+ cells appear to represent a new monocyte subset with a distinct functional repertoire. A survey of various tissues revealed that a large proportion of the alveolar macrophages, but not of the peritoneal macrophages, express the CD14+/CD16+ phenotype.
We have demonstrated that one Fc receptor for IgG (FcR) (CD16) on cultured human monocytes appears to be a developmentally regulated membrane protein. This receptor appears to contain less carbohydrate (if any) than does its counterpart on human neutrophils. Expression of CD16 on cultured monocytes increases with respect to both percentage of positive cells and numbers of sites per cell with length of time in culture. This was in contrast to expression of other types of FcRs that either decreased (CDw32) or did not change (FcRp72). Unlike an FcR that binds monomeric IgG (FcRp72), expression of CD16 on monocytes from most normal individuals was not influenced by IFN-gamma. After 14 d in culture, CD16 appeared to be the predominant FcR on cultured monocytes, and was capable of mediating both ligand attachment and phagocytosis. These findings support the hypothesis that CD16 plays an important role in mediating immunophagocytosis.
Several monoclonal antibodies directed against the human CD14 antigen have been established. We now report that the antibody My4, but not LeuM3, reacts with porcine monocytes. Among porcine peripheral blood mononuclear cells (PBMC), 14.6% of the cells stain with the CD14 antibody My4, which is similar to the percentage obtained with the antiporcine monocyte antibody 74-22-15. Two-colour immunofluorescence reveals that My4 and 74-22-15 antigens are coexpressed on the same cells, and cell sorter-purified My4+ cells exhibit the morphology of monocytes. Whole blood analysis (which also shows staining of granulocytes) reveals that the average percentage of My4+ monocytes amongst all leucocytes is 5.8% with 580 cells/microliters. Furthermore, porcine peritoneal macrophages (PM) and alveolar macrophages (AM), both stain for My4, with a four-fold lower level on AM. Treatment of cells with phosphatidylinositol-specific phospholipase C decreases My4 staining, but does not affect staining with antibody 74-22-15. Immunoprecipitation with the My4 antibody from surface labelled pig mononuclear cells demonstrates a 54 kDa band similar to human CD14, and Western blotting with pig serum demonstrates two bands similar to the alpha and beta forms of human soluble CD14. Finally, the My4 antibody is capable of blocking lipopolysaccharide- (LPS)-induced interleukin-6 production in isolated PBMC. These data show that the My4 antibody recognizes genuine CD14 on porcine monocytes and macrophages.
Staining with CD14 and CD16 monoclonal antibodies will identify two monocyte subpopulations in human blood: a major population of regular monocytes, which strongly expresses the CD14 antigen (CD14++), and a minor population with weak expression of CD14 and expression of the CD16 antigen (CD14+/CD16+ cells). As shown herein, the latter cells account for 45 +/- 22 cells/microL and 9% +/- 5% of the monocytes in healthy control donors (n = 35). In septicemia patients, the CD14+/CD16+ cells can become a major population, with more than 50% of all monocytes in 3 of 18 patients and with more than 500 cells in 4 of 18 cases. There was no correlation of CD14+/CD16+ cells to any clinical parameter except for CD14+/CD16+ percentage and body temperature (P = .013). The CD14++ regular monocytes showed a substantial decrease in CD14 antigen density in 9 of 11 patients. Three-color immunofluorescence shows that the CD14+/CD16+ monocytes in septicemia patients when compared with the CD14++ monocytes exhibit a higher level of class II antigen and a lower level of CD11b and CD33 antigens, consistent with a more mature nature of the CD14+/CD16+ cells. Levels of interleukin-6 (IL-6) were increased in septicemia patients; 3 of 5 patients with high numbers of CD14+/CD16+ cells (> 200/microL) had high levels of IL-6 (> 250/U/mL). These data suggest that septicemia may lead to substantial changes in blood monocyte composition and this may be related to elevated levels of cytokines such as IL-6.
The subpopulation of strongly CD14-positive (CD14++) monocytes and monocytes coexpressing the CD16 antigen and low levels of CD14 (CD14+/CD16+ cells) were isolated by fluorescence-activated cell sorting (FACS) followed by stimulation with lipopolysaccharide (LPS) at 1 micrograms/mL. Polymerase chain reaction (PCR) after reverse transcription of isolated mRNA (RT-PCR) revealed similar levels of tumor necrosis factor (TNF) transcripts in both subpopulations. By contrast, transcripts for interleukin-10 (IL-10) were only detectable in CD14++ monocytes, whereas CD14+/CD16+ cells produced no detectable IL-10 transcripts after 4 hours. Only after 16 hours of LPS stimulation was a low level of IL-10 transcripts discernible in CD14+/CD16+ monocytes. The same pattern was seen at the protein level in that TNF in LPS-stimulated supernatants was comparable for both subpopulations, whereas IL-10 was detected in CD14++ monocytes but not in CD14+/CD16+ cells. To avoid interference of cell activation by CD14 and CD16 antibodies, cells were also isolated based on the high and low level of CD33 antigen expression. Again, weakly CD33-positive cells, which comprise the CD14+/CD16+ cells, showed no or only minimal IL-10 mRNA. When comparing blood monocyte subpopulations with alveolar macrophages (AM), AM showed high levels of LPS-stimulated TNF, whereas IL-10 transcripts were undetectable. Our data show that CD14+/CD16+ blood monocytes produce high levels of proinflammatory cytokines like TNF, whereas the anti-inflammatory IL-10 is low or absent, a pattern similar to what is seen in AM.
Infection with the human immunodeficiency virus HIV-1 is associated with the expansion of a CD14lowCD16high monocyte subset in peripheral blood. This subset, which represents a minor subpopulation of monocytes in healthy individuals, increases during HIV infection and, in patients with AIDS, may represent up to 40% of the total circulating monocyte cell population. The CD14lowCD16high circulating monocytes co-express MAX.1, p150,95 and HLA-DR which are typical of tissue macrophage markers. These cells also express higher levels of intracellular interleukin (IL)-1 alpha and tumor necrosis factor (TNF)-alpha than the CD14highCD16low monocyte population from the same patients. The CD14lowCD16high cells also express low levels of CD35, CD11a and CD4 in common with normal monocytes. When cultured in vitro, monocytes from HIV-seropositive individuals differentiated within a few hours into an elongated fibroblastoid shape characteristic of migratory cells. Our results suggest that the expansion of the CD14lowCD16high monocyte subset, which produce high amount sof TNF-alpha and IL-1 alpha, may participate in the immune dysfunction observed during HIV infection.
The Fc gammaR receptors for IgG, Fc gammaRI, Fc gammaRII and Fc gammaRIII were measured on neutrophils and monocytes from 36 patients suspected of systemic infection. These results were compared with 30 blood donor controls to assess the level of expression as an early indicator of bacterial infection. Fc gammaRI expression on neutrophils was found to be significantly increased from patients with systemic or localised infections, when compared to non-infected patient group, i.e., patients with no cultural evidence of bacterial infections, (p=0.02, p=0.04) or normal controls (p<0.0001, p=0.0005). Fc gammaRI expression on monocytes was also significantly increased in both of the infected groups compared to normal controls (p<0.0001, p=0.001); however, no significant difference could be seen when compared with the non-infected patients. Fc gammaRIII was found to be significantly increased on a subset of monocytes in patients with systemic or localised infections compared to the non-infected group (p=0.009, p=0.006) and compared to the normal controls (p=0.009, p=0.003). Infections caused by gram-negative bacilli induced a higher Fc gammaR response than infection with either streptococci or staphylococci. These data suggest that the measurement of Fc gammaRI on neutrophils and Fc gammaRIII on monocytes may be a useful rapid indicator of bacterial infection.
The CD16 receptor (Fc gamma R-III) is found on many tissue macrophages (M phi s), but its expression on circulating monocytes is restricted to a small, phenotypically distinct subset. The number of these CD16+ monocytes may be markedly increased in response to sepsis, human immunodeficiency virus infection, or metastatic malignancy. We have recently shown that the CD16+ monocyte population is selectively expanded by administration of recombinant human macrophage colony-stimulating factor (rhM-CSF). In the current study, we used the highly rhM-CSF-responsive cynomolgus primate model to further characterize this novel monocyte population. Animals treated with rhM-CSF underwent a progressive and essentially complete conversion to the CD16+ monocyte phenotype, with up to a 50-fold increase in the number of CD16+ cells. This increase was paralleled by the emergence of a population of circulating cells that morphologically resembled large granular lymphocytes (LGLs). However, quantitatively, this population corresponded closely to the number of CD16+ monocytes, and fluorescence-activated cell sorting (FACS) confirmed that they were the same. In addition to their LGL-like morphology, many rhM-CSF-induced CD16+ monocytes showed a pattern of size, granularity, and quantitative cell surface marker expression that closely resembled the pretreatment LGL/natural killer (NK) cell population but that did not resemble the pretreatment monocyte population. However, rhM-CSF-induced CD16+ monocytes could be distinguished from LGL/ NK cells by fact that they all expressed cell surface receptors for rhM-CSF, and many of them showed reduced but detectable phagocytic and respiratory burst activity. Studies of human subjects treated with rhM-CSF also showed an analogous population of "LGL-appearing" CD16+ mononuclear cells. Thus, our studies reveal a previously unsuspected ability of cells in the monocyte lineage to adopt a phenotype similar to that of LGL/NK cells. The extent of this phenotypic convergence suggests that the two lineages retain access to elements of a similar developmental pathway.
Cells of the monocyte/macrophage lineage are heterogenous in that some types express the CD16 molecule (Fc receptor for IgG, type III), while others are negative. We now show that culture of human blood monocytes with interleukin-10 (IL-10) will induce high levels of cell surface CD16 within 18 hr, and this goes along with increased transcript levels. After prolonged culture for 36 hr, control cultures also become CD16 positive and this induction can be prevented by anti-IL-10, but not by anti-tumor necrosis factor (TNF) antibody or isotype control. In vitro culture of blood monocytes results in a spontaneous decrease of the myelomonocytic stem cell antigen CD33, suggesting that the cells undergo maturation. IL-10 treatment will accelerate this process and result in a further reduction of cell surface CD33. These data indicate that IL-10 promotes monocyte maturation and directs these cells to develop into CD16 positive macrophages.
Infections are frequent complications in end-stage renal failure patients undergoing hemodialysis (HD), and peripheral blood monocytes are important cells in host defense against infections. The majority of circulating monocytes express high levels of lipopolysaccharide receptor antigen CD14 and are negative for the immunoglobulin Fcgamma receptor type III (CD16). We studied the occurrence of a minor subpopulation coexpressing low levels of CD14 together with CD16 in HD patients. In healthy controls CD14+ CD16+ monocytes account for 8% +/- 4% of CD14+ monocytes, with an absolute number of 29 +/- 14 cells/microl. In stable HD patients the CD14+ CD16+ subpopulation was significantly elevated (14% +/- 3%, or 66 +/- 28 cells/microl), while the number of CD14(++) monocytes (monocytes strongly positive for CD14) remained constant. In HD patients suffering from chronic infections a further rise in CD14+ CD16+ monocytes was observed (128 +/- 71 cells/microl; P < 0.01) such that this subpopulation constituted 24% of all blood monocytes. In contrast, numbers of CD14++ cells did not change compared to those for stable HD patients, indicating that the CD14+ CD16+ monocyte subpopulation was selectively expanded. During acute infections the CD14+ CD16+ cell subpopulation always expanded. A whole-blood assay revealed that CD14+ CD16+ monocytes exhibited a higher phagocytosis rate for Escherichia coli bacteria than CD14++ monocytes, underlining their role during host defense. In addition, CD14+ CD16+ monocytes expressed higher levels of major histocompatibility complex (MHC) class II antigens (HLA-DR, -DP, and -DQ) and equal amounts of MHC class I antigens (HLA-ABC). Thus, CD14+ CD16+ cells constitute a potent phagocytosing and antigen-presenting monocyte subpopulation, which is expanded during acute and chronic infections commonly observed in chronic HD patients.
The nonclassical MHC class I molecule human histocompatibility leukocyte antigen (HLA)-G is selectively expressed on fetal trophoblast tissue at the maternal-fetal interface in pregnancy. It has long been suggested that HLA-G may inhibit maternal natural killer (NK) cells through interaction with particular NK cell receptors (KIRs). To investigate interactions of HLA-G, we constructed phycoerythrin-labeled tetrameric complexes of HLA-G refolded with a self-peptide. These HLA-G tetramers failed to bind to NK cells and cells transfected with CD94/NKG2 and killer immunoglobulin-like NK receptors. In contrast, HLA-G tetramers did bind to peripheral blood monocytes, staining a CD16(+)CD14(mid) subset with greater intensity. On transfectants, HLA-G tetramers bound to inhibitory immunoglobulin-like transcript (ILT)2 and ILT4 receptors. However, staining in the presence of antibodies reactive with ILT receptors revealed that the interaction of HLA-G tetramers with blood monocytes was largely due to binding to ILT4. These results suggest that the primary role of HLA-G may be the modulation of myelomonocytic cell behavior in pregnancy.
CD163, also referred to as M130, a member of the scavenger receptor cysteine-rich family (SRCR) is exclusively expressed on cells of the monocyte lineage. In freshly isolated monocytes the CD14bright CD16+ monocyte subset revealed the highest expression of CD163 among all monocyte subsets. CD163 mRNA and protein expression is up-regulated during macrophage colony-stimulating factor (M-CSF)-dependent phagocytic differentiation of human blood monocytes. In contrast, monocytic cells treated with GM-CSF and interleukin-4 (IL-4) for dendritic differentiation down-regulate this antigen. CD163 expression is also suppressed by proinflammatory mediators like lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), and tumor necrosis factor alpha, whereas IL-6 and the antiinflammatory cytokine interleukin-10 (IL-10) strongly up-regulate CD163 mRNA in monocytes and macrophages. The effects of the immunosuppressants dexamethasone, cyclosporin A (CA), and cortisol differ in their capacity to influence CD163 mRNA levels. Our results demonstrate that CD163 expression in monocytes/macrophages is regulated by proinflammatory and antiinflammatory mediators. This expression pattern implies a functional role of CD 163 in the antiinflammatory response of monocytes.
Hemophagocytic lymphohistiocytosis (HLH) is an extremely rare and highly lethal chronic inflammatory disease, which is mediated by proinflammatory cytokines. In the peripheral blood of a boy suffering from HLH, a chronic expansion of CD14dim/CD16bright inflammatory monocytes was detected. Compared with CD14bright monocytes, their immunophenotype correlated withmore mature monocytic cells differentiating to macrophages: they showed lower expression of CD11b, CD64 and CD35. Such CD14dim/CD16bright monocytes produce the inflammatory cytokines IL‐1β, IL‐6 and TNF‐α. They fit in well with the pathophysiological concept of HLH as an inflammatory state of lymphocytes and of the monocyte/macrophage system. In the presented patientthe percentage of these circulating inflammatory monocytes decreased over time during clinical response to immunosuppressive therapy. This finding may indicate that CD14dim/CD16bright monocytes represented the degree of inflammation in this extremely rare and highly lethal disease.
With the aid of two-color immunofluorescence and flow cytometry, a new subset of cells coexpressing CD14 and CD16 antigens can be identified in human peripheral blood. Using the monoclonal antibody My4, these CD14+/CD16+ cells account for 2.2% of the mononuclear cells and form about 13% of all cells identified by the monocyte-specific CD14 monoclonal antibody. The CD14+/CD16+ cells can be assigned to the monocyte lineage based on typical morphology, on expression of additional monocyte-associated molecules, on the ability to form reactive oxygen intermediates and on the expression of monocyte- specific NaF-sensitive esterase. Light scatter analysis revealed lower forward angle and right angle light scatter for the CD14+/CD16+ cells compared with the regular monocytes, and the average cell size was determined to be 13.8 and 18.4 microns, respectively. Expression of class II antigens on these “small monocytes” was twofold higher compared with the regular monocytes. By contrast, the capacity to perform adherence to plastic surfaces, as well as the ability to phagocytize antibody-coated erythrocytes was clearly reduced in the CD14+/CD16+ monocyte subset as compared with the regular monocytes. Hence the CD14+/CD16+ cells appear to represent a new monocyte subset with a distinct functional repertoire. A survey of various tissues revealed that a large proportion of the alveolar macrophages, but not of the peritoneal macrophages, express the CD14+/CD16+ phenotype.
Staining with CD14 and CD16 monoclonal antibodies will identify two monocyte subpopulations in human blood: a major population of regular monocytes, which strongly expresses the CD14 antigen (CD14++), and a minor population with weak expression of CD14 and expression of the CD16 antigen (CD14+/CD16+ cells). As shown herein, the latter cells account for 45 +/- 22 cells/microL and 9% +/- 5% of the monocytes in healthy control donors (n = 35). In septicemia patients, the CD14+/CD16+ cells can become a major population, with more than 50% of all monocytes in 3 of 18 patients and with more than 500 cells in 4 of 18 cases. There was no correlation of CD14+/CD16+ cells to any clinical parameter except for CD14+/CD16+ percentage and body temperature (P = .013). The CD14++ regular monocytes showed a substantial decrease in CD14 antigen density in 9 of 11 patients. Three-color immunofluorescence shows that the CD14+/CD16+ monocytes in septicemia patients when compared with the CD14++ monocytes exhibit a higher level of class II antigen and a lower level of CD11b and CD33 antigens, consistent with a more mature nature of the CD14+/CD16+ cells. Levels of interleukin-6 (IL-6) were increased in septicemia patients; 3 of 5 patients with high numbers of CD14+/CD16+ cells (> 200/microL) had high levels of IL-6 (> 250/U/mL). These data suggest that septicemia may lead to substantial changes in blood monocyte composition and this may be related to elevated levels of cytokines such as IL-6.
Recently, a population of M-DCS-positive leukocytes has been described as a new subpopulation of human dendritic cells (DC). In view of the expression of the CD16 antigen on these cells, as well as the finding that DC can arise from blood monocytes, we hypothesized that the expression of M-DCS is mainly associated with the CD14+CD16+phenotype of blood monocytes. Immunofluorescence analysis of whole blood showed that the percentage of M-DCS+ cells is about three times lower than the percentage of CD14+CD16+monocytes among all leukocytes (0.32% versus 1.10%). Further, in addition to the expression of CD16, these M-DCS+ cells were also positive for CD14 at low density. Multi color flow cytometric analysis of whole blood revealed that more than one third of the CD14+CD16+monocyte population expressed the M-DCS antigen (42.3%), and almost all M-DC8+cells were CD14-CD16-double-positive (87.5%). Finally, the M-DCS antigen was also expressed on alveolar macrophages from healthy individuals, i.e., cells that are phenotypically and functionally related to the CD14+CD16+monocytes. Taken together, the data presented here dearly demonstrate that the M-DC8+leukocytes are a subpopulation of the CD14+CD16+monocytes and may represent DC
The quantitative and phenotypic changes of peripheral blood monocytes during the acute stage of simian immunodeficiency virus infection were investigated. We inoculated intravenously three cynomolgus monkeys (Macaca fascicularis) with 100 TCID50 of SIVmac239 and collected whole blood twice a week until 35 days postinoculation, We found that the relative number of monocytes in peripheral blood leukocytes significantly increased at 7-17 days postinoculation. This increase was concomitant with the peak of primary SIV antigenemia, To determine if the monocytes observed during the acute stage were phenotypically altered, they were periodically examined for the expression of surface markers (i.e., CD11b, CD14, CD16, CD29, D32, CD56, CD62L, CD64, CD80, and MHC-II-DR) by flow cytometry, The results showed that the expression levels of CD14 and CD56 on most of the monocytes were remarkably reduced at 7-17 days postinoculation, and a new subpopulation, CD14(low)CD16(+)CD80(+) monocytes, was clearly detected at 10 days postinoculation, These results indicate that the phenotypic alteration of peripheral blood monocytes occurs during the primary SIV infection.
Monocytes play a central role in the inflammatory disease atherosclerosis. CD14+CD16+ monocytes are considered proinflammatory monocytes, as they have an increased capacity to produce proinflammatory cytokines, such as TNF-alpha, and are elevated in various inflammatory diseases. We hypothesized that :patients with coronary artery disease (CAD) have increased levels of CD14+CD16+ monocytes, and that CD14+CD16+ monocytes are associated with inflammation markiers.We investigated CD14+CD16+ monocytes in 247 Patients with CAD and 61 control subjects using flow cytometry. In addition serum concentrations of TNF-alpha IL-6, and Hs-CRP w ere assessed. Patients with CAD had higher levels of CD 14+CD 16+ monocytes than controls (13.6% versus 11.4%; p<0.001). Logistic regression analysis including quartiles of CD 14+CD 16+ monocytes showed that CD 14+CD 16+ monocytes were associated with prevalence of CAD (OR 4.9,95% Cl 2.5-19.1, for subjects in the fourth quartile in comparison to subjects in the first quartile). The association between CD14+CD16+ monocytes and CAD remained independently significant after adjustment for most potential confounders (OR 5.0, 95% Cl 1.2-20.0). Serum concentrations of TNF-alpha were elevated in subjects within the highest cluartiles of CD 14+CD 16+ monocytes (p=0.018). Our study showed that increased numbers of CD 14+CD 16+ monocytes are associated with coronary atherosclerosis and TNF-alpha. In accordance, recent animal studies suggest a possibly important role of these monocytes in the development of atherosclerosis.
Fc-receptors for IgG (FcγR) are important triggers of effector function in macrophages. We have investigated the distribution of cells bearing FcγR 1, FcγR II, and FcγR III in 14 synovia and 3 nodules from rheumatoid arthritis (RA) patients, using monoclonal antibodies on serial cryostat sections. 8 osteoarthritis (OA), 2 ankylosing spondylitis (AS) patients and one sarcoid patient were also studied. Significant numbers of macrophages bearing FcγR were present in inflamed synovial tissue with no significant difference in relative frequency between RA and OA. There was no correlation with the degree of lymphocytic infiltration. Distinctive staining patterns for the three Fc-receptors suggest differential regulation of these molecules on macrophages in synovium.
Objective
To investigate the expression of human cartilage (HC) gp-39, a possible autoantigen in rheumatoid arthritis (RA), in peripheral blood and synovium, to characterize its cellular source, and to analyze correlations with clinical features.Methods
The expression of HC gp-39 in synovium and peripheral blood mononuclear cells (PBMC) was assessed by immunohistochemistry and flow cytometry. Synthesis and secretion were investigated by both reverse transcription–polymerase chain reaction and enzyme-linked immunosorbent assay.ResultsPBMC expressing HC gp-39 were increased in RA patients compared with spondylarthropathy patients (P = 0.0029) and with healthy control subjects (P = 0.0013). HC gp-39+ cells were also slightly overrepresented in RA synovium (P = 0.01). In both blood and synovium, HC gp-39+ cells were identified as CD14dim,CD16+ monocytes, a phenotype which can differentiate from classic CD14++ monocytes by maturation in vitro. HC gp-39 messenger RNA was detected in RA synovium and PBMC, and PBMC secreted HC gp-39 in vitro. The number of HC gp-39+ PBMC correlated with serum levels of C-reactive protein (r = 0.39, P = 0.003) and HC gp-39 (r = 0.52, P = 0.014). HC gp-39 expression in RA synovial lining correlated with joint destruction (r = 0.77, P < 0.001).ConclusionCD16+ monocytes, a cellular source of HC gp-39 in vivo, are overrepresented in both RA peripheral blood and synovial tissue. The presence of HC gp-39+ cells in RA synovium is correlated with the degree of joint destruction. These data support a role of these cells in the local autoimmune response that leads to chronic inflammation and joint destruction.
Several monoclonal antibodies directed against the human CD14 antigen have been established. We now report that the antibody My4, but not LeuM3, reacts with porcine monocytes. Among porcine peripheral blood mononuclear cells (PBMC), 14.6% of the cells stain with the CD14 antibody My4, which is similar to the percentage obtained with the antiporcine monocyte antibody 74-22-15. Two-colour immunofluorescence reveals that My4 and 74-22-15 antigens are coexpressed on the same cells, and cell sorter-purified My4+ cells exhibit the morphology of monocytes. Whole blood analysis (which also shows staining of granulocytes) reveals that the average percentage of My4+ monocytes amongst all leucocytes is 5.8% with 580 cells/μl. Furthermore, porcine peritoneal macrophages (PM) and alveolar macrophages (AM), both stain for My4, with a four-fold lower level on AM. Treatment of cells with phosphatidylinositol-specific phospholipase C decreases My4 staining, but does not affect staining with antibody 74-22-15. Immunoprecipitation with the My4 antibody from surface labelled pig mono-nuclear cells demonstrates a 54 kDa band similar to human CD14, and Western blotting with pig serum demonstrates two bands similar to the alpha and beta forms of human soluble CD14. Finally, the My4 antibody is capable of blocking lipopolysaccharide- (LPS)-induced interleukin-6 production in isolated PBMC. These data show that the My4 antibody recognizes genuine CD14 on porcine monocytes and macrophages.
Fcγ receptor I-positive (CD64+) and Fcγ receptor I-negative (CD64−) monocytes were prepared from highly purified (elutriation-derived) human monocytes by cytofluorograph cell sorting, and a phenotypical and functional dissociation of the isolated CD64+ and CD64− monocyte subsets is demonstrated. Surface analyses revealed that the surface antigen pattern of CD64+ monocytes corresponds to the phenotype of typical unseparated monocytes. In contrast, CD64− monocytes are characterized by high expression of major histocompatibility complex (MHC) class I antigens (HLA-A, -B, -C) and MHC class II antigens (HLA-DR, -DP, -DQ), and low expression of the monocyte-specific marker CD14 which is found on nearly all CD64+ monocytes. However, 75% of the CD64− cells were found to be esterase-positive, and 85% were positive for the monocyte/macrophage-specific intracellular antigen CD68. Furthermore, CD64+ monocytes show significantly higher expression of CD45RA and Fcγ receptor III (CD16) than CD64+ monocytes, but lack the natural killer cell markers CD56 and CD57. Functional studies showed that cells of the minor CD64− monocyte subset have a higher accessory cell capacity in antigen-driven T cell activation than CD64+ monocytes. CD64− monocytes pretreated with PPD (purified protein derivative of tuberculin) induced up to tentimes more interferon-γ and also higher proliferation in responding autologous T cells than PPD-pretreated CD64+ monocytes. Similar results were obtained for T cells in mixed leukocyte reaction. Interferon-γ release and proliferation of allogeneic lymphocytes were consistently higher in the presence of irradiated CD64− monocytes than of irradiated CD64+ monocytes. Furthermore, when CD64− and CD64+ monocytes were stimulated with Newcastle disease virus, we measured an up to 67-fold higher interferon-a release from CD64− than from CD64+ monocytes, indicating a higher anti-viral capacity of this subset. CD64− monocytes showed lower activity in the phagocytosis of unopsonized particles and also lower zymosan- or latex-induced chemiluminescence than CD64+ monocytes. These findings indicate that CD64− monocytes, although comprising only less than 10% of all peripheral blood monocytes, represent a monocyte subpopulation efficiently interacting in vitro with T cells and, additionally, are the major source of interferon-α.
Human peripheral blood (PB) CD14lo/HLA-DR+ cells were initially described as a subset of mature monocytes. Recently, it has been suggested that these represent a part of a new subset of dendritic cells (DC), characterized by the coexpression of MDC-8/HLA-DR/CD16. The aim of the present paper was to analyze the morphological, cytochemical, phenotypical, and functional characteristics of PB CD16+/HLA-DR+ cells compared to both PB CD14+ monocytes and CD16− DC. In contrast to CD14+ monocytes, purified CD16+/HLA-DR+ cells displayed cytoplasmic veils and lacked cytoplasmic myeloperoxidase and α-naphthyl acetate esterase. Normal human PB CD16+/HLA-DR+ cells also displayed phenotypic characteristics different from those of CD14+ monocytes: they lacked the CD64 Fcγ receptor, showed lower levels of CD32, and expressed higher amounts of CD16 compared to CD14+ monocytes. They also displayed a different pattern of expression of other antigens, including CD14, HLA-DR, CD45RA, CD45RO, complement receptors and complement regulatory surface proteins, adhesion and costimulatory molecules, and cytokine receptors, among others. When compared to CD16− DC, CD16+/HLA-DR+ cells showed reactivity for CD16, dim positivity for CD14, higher expression of both Ig- and complement-receptors and lower reactivity for HLA-DR, adhesion, and costimulatory molecules (with the exception of CD86). The CD16+/HLA-DR+ cell subset displayed a higher Ig/complement-mediated phagocytic/oxidative activity than CD16− DC, although this activity was significantly lower than that of mature monocytes. Regarding cytokine production at the single cell level, LPS plus IFN-γ-stimulated PB CD16+/HLA-DR+ cells produced significant amounts of IL1β, IL6, IL12, TNFα, and IL8; however, the percentage of cytokine-producing cells and the amount of cytokine/cell were lower in CD16+/HLA-DR+ cells than in CD14+ monocytes. In addition, upon comparing CD16+/HLA-DR+ cells with CD33+++/CD16− DC, we found that the percentage of cytokine-producing cells and the amount of cytokine/cell were significantly different in both cell subsets. In summary, our results show that CD16+/HLA-DR+ cells clearly display different morphologic, cytochemical, immunophenotypical, and functional characteristics compared to both mature monocytes and CD16− DC. Interestingly, these cells are more frequent than other DC in normal human adult PB and cord blood samples, while they are less represented in normal bone marrow.
Mononuclear phagocytes in the synovium of patients with arthritis, in contrast to blood monocytes, were found to express a third receptor for the constant region of Ig (Fc gamma RIII), in addition to Fc gamma RI and Fc gamma RII. Previously identified on mature mononuclear phagocytes or phagocytes exposed to transforming growth factor-beta (TGF-beta) in vitro, this study documents the presence of Fc gamma RIII (CD16) expressing cells at an inflammatory site. Furthermore, the presence of CD16 on the majority of the LeuM3 (CD14) positive synovial monocytic cells could be mimicked by exposing blood monocytes to synovial fluids from patients with rheumatoid arthritis (17 of 19) and synovial fluids from patients with osteoarthritis (4 of 4). In additional studies, the soluble factor in inflammatory synovial fluids responsible for regulating CD16 expression was found to be consistent with the presence of TGF-beta. Inhibition of the activity in synovial fluids with a neutralizing antibody to TGF-beta confirmed a role for this peptide in synovial phagocytic cell CD16 expression. Moreover, signal transduction through CD16 on synovial phagocytes resulted in augmented extracellular release of superoxide anion that may contribute to tissue damage and other inflammatory sequelae. Identification of TGF-beta and its association with upregulation of CD16 at sites of chronic inflammation may provide insight into the destructive lesions associated with inflammatory arthropathies.
The monoclonal antibody (MAB) My4 was produced against human myelo-monocytic leukemia cells and stains regular monocytes with high intensity. Employing logarithmic amplification in immunofluorescence flow cytometry an additional low intensity - My4+ - and a very low intensity population - My4(+) - can be identified. Light scatter analysis reveals monocyte features for the My4++ and for the My4+ cells, while the My4(+) cells exhibit characteristics of lymphocytes. The two low intensity (My4+ and My4(+)) populations are clearly discernable only after two color immunofluorescence analysis using MABs VEP13 (CD16) and B1 (CD20). The My4+ cells coexpress the CD16 antigen and comprise a unique monocyte subset. The My4(+) cells coexpress the B1 antigen, characteristic of B cells. In addition, the My4(+) cells are depleted after treatment of mononuclear cells with the anti-B cell MAB BA-1 plus complement. Finally, leukemic cells from patients with B cell type chronic lymphocytic leukemia are stained in 18/20 cases. Hence, the MAB My4 identifies regular monocytes and in addition, with lower intensity of staining a new monocyte subset and a subset of B cells in human peripheral blood.
Dendritic cells (DC) are the major APC capable of stimulating resting T cells in human peripheral blood (PB). Recent evidence suggested that various subsets of DC and monocytes might circulate in human PB, but their exact phenotype and function had not been delineated. We have previously characterized a population of human PB DC precursors that express the myeloid marker CD33, but not the monocyte marker CD14. To identify and characterize further functional myeloid APC subsets, triple color FACS analysis and sorting was used. A CD33dimCD14dimCD16+ monocyte subset, with similar APC function but less efficient accessory function than CD14bright monocytes, was isolated. In addition to the CD33+CD14dimCD16- DC precursors, a smaller population (0.1 to 0.2% of PBMC) of CD33brightCD14dimCD16- cells with potent APC function was identified. This DC population expressed greater amounts of MHC class II, adhesion, and accessory molecules, and demonstrated a greater costimulatory capacity when freshly isolated than CD33dimCD14dim DC precursors, and therefore had the characteristics of mature, possibly tissue-derived DC. When freshly isolated, however, these DC did not express B7, and up-regulation of accessory function occurred after in vitro differentiation. These data demonstrate multiple circulating myeloid accessory and APC subsets in human PB. Phenotypic and functional differences suggest that they are at different stages of differentiation, and have specialized roles in Ag presentation in vivo. Furthermore, full functional DC differentiation, associated with B7 expression and the capacity to activate T cells maximally, is likely to occur only in specific physiologic circumstances.
Airway macrophages are activated in asthmatic subjects. Peripheral blood monocytes from these subjects present some functional features of activation, but their membrane markers are not known. Recently a new subtype of blood monocytes, CD14+/CD16+, has been identified which possesses the characteristics of tissue macrophages. A study was carried out on nine normal subjects and 11 untreated asthmatics having variable severities of the disease to examine the phenotypic characteristics of monocytes. CD14, CD16, HLA-DR, CD11a, CD11b, CD44 and CD54 were studied using double fluorescence flow cytometry since these antigens have been defined in the CD14+/CD16+ monocytes. The functional activation of monocytes was examined using the release of superoxide anion. The co-expression of CD14 and CD16 by monocytes in terms of percentage and mean fluorescence intensity was significantly higher in asthmatics (P < 0.002 and P < 0.0001, respectively, Mann-Whitney U-test). There was no difference for the other membrane markers between asthmatics and normal subjects. Superoxide anion release was significantly increased in asthmatic subjects (P < 0.01). This study shows that most blood monocytes of asthmatics are CD14+/CD16+ and are likely to present features of tissue macrophages.
The CD14+/CD16+ cells account for about 10 % of all blood monocytes. They are characterized by a low level expression of the CD14 molecule and a high level expression of the CD16 (FcγR III) molecule. Polymerase chain reaction analysis of mRNA prevalence in CD14+/CD16+ cells (compared to the regular CD14++ blood monocytes) demonstrates low levels of CD14 transcripts and high levels of CD16 transcripts, suggestive of a transcriptional control for both of these proteins. Analysis of additional cell surface molecules in three-color immunofluorescence reveals that CD14+/CD16+ cells express the FcγR II in all, and FcγR I and ICAM-1 in some donors. Furthermore, class II antigens are expressed at fourfold higher levels, while both, CD11b and CD33 cell surface proteins, are decreased by a factor of two. Transcript levels were reduced in CD14+/CD16+ cells for all three cell surface molecules. Since these phenotypic markers of the CD14+/CD16+ blood monocytes are reminiscent of tissue macrophages, we performed a comparative analysis with alveolar macrophages (AM). These cells are similar to the CD14+/CD16+ monocytes in that they show low levels of CD14 and strong expression of CD16. Furthermore, similar to the CD14+/CD16+ cells, the AM also exhibit higher levels of class II and lower levels of CD11b and CD33 when compared to the regular CD14++ blood monocytes.
In vitro induction of maturation of blood monocytes by 5 day culture of peripheral blood mononuclear cells in 10 % human serum will result in decreased CD14 and increased CD16 cell surface expression on the monocyte derived macrophages. At the same time, these cells acquire increased levels of class II and decreased levels of CD11b and CD33. Taken together, these data show that CD14+/CD16+ monocytes, while still in circulation, have acquired features in common with mature tissue macrophages.
Expression of CD43 (leukosialin, sialophorin) by rat blood monocytes was analyzed by flow cytometric, microscopic, and biochemical techniques. Monocytes were identified cytometrically using a combination of light-scatter parameters and binding of the anti-monocyte/macrophage monoclonal antibody (mAb) OX-41. Two-color flow cytometry studies with W3/13 and HIS 17, two anti-CD43 mAb that react with different antigenic epitopes, revealed two subpopulations of monocytes expressing disparate levels of CD43 (referred to hereafter as hi-CD43 MO and lo-CD43 MO). In three-color flow cytometry studies, hi-CD43 MO were found to express higher levels of CD4 than lo-CD43 MO; in contrast, lo-CD43 MO bound higher levels of RP-3, a mAb raised against rat neutrophils. Hi- and lo-CD43 MO expressed comparable amounts of CD14, CD45, and intercellular adhesion molecule-1 (CD54); hi-CD43 MO expressed somewhat more lymphocyte function-associated antigen-1 alpha chain (CD11a) and CD18 than their lo-CD43 MO counterparts. A minority of cells in both subpopulations expressed class II histocompatibility antigens. Hi- and lo-CD43 MO isolated by fluorescence-activated cell sorting had features typical of monocytes as assessed by light and electron microscopy. In Western blotting experiments, lo-CD43 MO and elicited peritoneal macrophages were found to express a less heavily sialylated form of CD43 than hi-CD43 MO.
The expression and co-expression profiles of functionally important monocyte surface markers were compared between control and HIV+ individuals using combined physical gating and dim CD4 expression to delineate the monocytes. The Fc gamma RII (CD32), the MHC class II antigen HLA-DR and the adhesion molecules CD11a (LFA-1 alpha), CD18 and CD54 (ICAM-1) showed an unimodal distribution. Of these markers, CD11a and HLA-DR were up-regulated in the HIV+ subjects compared with controls. The expression levels of the adhesion molecules correlated with each other in both patients and controls. The CD11b (CR3-alpha), CD14, Fc gamma RI, and Fc gamma RIII markers were bimodally distributed. Compared with controls, monocytes from seropositives contained fewer CD14bright+ cells, an equal proportion of Fc gamma RIbright+ cells, but twice as many Fc gamma RIII+ cells. The expression level of Fc gamma RI and CD11b within their brightly positive subset increased as CD4 T cells decreased. Both in patients and controls, co-expression of bright CD11b, CD14 and Fc gamma RI was shown, whereas the Fc gamma RIII+ cells were negative or dim positive for the former triad. We conclude that the expression of two Fc gamma R (I and III), of the adhesion molecules CD11a and CD11b and of HLA-DR showed particular alterations on monocytes from HIV+ subjects. The relationship of these phenotypic observations with altered cytokine profiles and altered monocyte function is discussed.
Parameters of immune activation/differentiation were studied in a group of newly diagnosed HIV- and HIV+ pulmonary tuberculosis (TB) patients. Compared with controls, HLA-DR expression on both CD4 and CD8 T cells from the HIV- TB patients was approximately doubled; HLA-DR on T cells from the HIV+ group was tripled. The monocytes from both groups of patients expressed abnormally high levels of the Fc gamma receptors I and III. Serum levels of tumour necrosis factor-alpha (TNF-alpha), neopterin and beta 2-microglobulin were increased in HIV- and even more so in HIV+ TB patients. The expression of HLA-DR on T cell subsets and of Fc gamma R on monocytes correlated with each other, but not with serum activation markers. This pattern of non-specific activation during TB infection may be associated with enhanced susceptibility to HIV infection.
Mononuclear phagocytes play a major role in the development of vascular lesions in atherogenesis. The goal of our study was to characterize circulating blood monocyte subpopulations as potential cellular markers of systemic immunological abnormalities in hypercholesterolemia. In normal subjects, three-parameter immunophenotyping of whole blood revealed that 61.3 +/- 6.0% of monocytes showed "bright" expression of the lipopolysaccharide receptor (LPSR: CD14) and Fc gamma receptor I (RI: CD64) without expression of Fc gamma-RIII (CD16). Other monocyte subsets (populations 2, 3, 4, and 5) were characterized by the simultaneous expression of both Fc gamma-R's (25.6 +/- 5.0%), isolated expression of Fc gamma-RIII (9.4 +/- 1.7%), or high expression of CD33 (3.7 +/- 1.1%) with only dim expression of CD14, respectively. The smallest subset of monocytes (population 5: 2.1 +/- 0.8%) differed from the predominant population of CD14brightCD64+CD16- monocytes by additional expression of neural cell adhesion molecule (N-CAM: CD56). In a group of hypercholesterolemic patients (n = 19), high density lipoprotein cholesterol levels were negatively correlated to the population size of CD64-CD16+ monocytes. In both healthy subjects (n = 55) and hypercholesterolemic patients, the rare apolipoprotein E3/E4 and E4/E4 phenotypes were associated with a tendency toward a larger population of CD64-CD16+ monocytes. Expression of the variant activation antigen CD45RA by peripheral blood mononuclear phagocytes showed a positive correlation to plasma levels of the atherogenic lipoproteins low density lipoprotein and lipoprotein(a). These data suggest that systemic abnormalities in mononuclear phagocyte subpopulations may play a role in the pathogenesis of atherosclerosis.
15-30% of patients infected with HIV will develop a debilitating dementia. Whilst HIV enters the brain soon after infection, presumably within monocyte-derived macrophages, not all patients with HIV become demented. Blood monocytes probably cross the blood-brain barrier and give rise ultimately to parenchyma macrophages. We looked for a specific monocyte subset in AIDS patients with dementia.
Peripheral blood monocytes from three groups were compared: AIDS patients with (n = 12) and without (n = 11) dementia, and ten HIV seronegative healthy controls. We used flow cytometry to analyse monocytes, and cell lysis and apoptosis assays to examine monocyte effects on human brain cells in vitro.
We found a unique subset of monocytes in patients with AIDS dementia. These monocytes were more dense and granular and expressed CD14/CD16 and CD14/CD69. Means (SD) for CD14/CD16 in HIV-negative controls and in AIDS non-dementia and AIDS dementia patients were 6.5% (4), 16% (13), and 37% (21), respectively (p = 0.008 between the two groups of patients). The corresponding means for CD14/CD69 were 7% (6), 8% (10), and 69% (18) (p < 0.0001).
CD69 is a member of the natural-killer-cell gene complex that is expressed after activation. Supernatants from cultures containing these dense cells can trigger apoptosis of human brain cells in vitro. The monocyte subset we found in patients with AIDS dementia might enter the brain and expose neural cells to toxic factors.
We describe a patient with self-induced disease who presented with repeated urinary tract infection and sepsis due to intravesical and intravenous injection of feces. Sepsis occurred repeatedly such that the patient exhibited 10 bouts of fever > 40 degrees C in a single month. This bacterial challenge led to massive activation of the monocyte system with high levels of TNF-alpha, IL-6, and monocyte colony-stimulating factor (M-CSF). This cytokine response was followed by strong expansion of the novel CD14+CD16+ monocyte subset. These results suggest that cytokines induce the development of CD14+CD16+ cells in human septicemia and that CD14+CD16+ cells may serve as indicator for previous bouts of excessive inflammation.
LEW rats were treated intravenously with recombinant rat interferon-gamma (IFN-gamma) for 3 days to achieve intravascular accumulation, proliferation, and activation of monocytes. Monocytes, defined by their expression of the ED1, ED9, and Ox41 antigens, were recovered from the vasculature by perfusion with PBS/EDTA, subsequently depleted of erythrocytes and granulocytes by Percoll density gradient centrifugation, and analyzed by flow cytometry and immunocytology. In untreated and control-infused specified pathogen-free (SPF) rats, lymphocytes and monocytes formed overlapping cell populations with respect to size and internal granularity. At least two intravascular monocyte subsets, probably central and marginating cells, were distinguished by their size and differential expression of CD43, CD4, CD11a, CD18, and L-selectin. It is interesting to note that a fraction of the monocytes in normal and control-infused animals carried the NKR-P1A molecule. IFN-gamma treatment provoked a duplication of monocyte size and granularity. Both the number of positive monocytes and the level of expression of NKR-P1A strongly increased after IFN-gamma infusion, whereas CD43 (leukosialin) and CD4 were impressively down-regulated. NKR-P1A+ L-selectin+ CD43low CD4- monocytes also occur in the vasculature of rats during immune reactions in vivo. We speculate that these cells are involved in organ damage and that their number is controlled by activation-induced cell death within the vessels.
The phenotypic alterations between blood monocytes from 11 patients with end-stage renal disease, who had been on peritoneal dialysis for less than one week, and blood monocytes from 10 healthy controls, were analyzed. In addition, peritoneal macrophages in the dialysate effluent were enclosed. Analysis of functional receptor density was performed using immunostaining and flow cytometry. The phenotypic characterization was selected to represent various biological functions such as adhesion, phagocytosis (CD11b/CD18, CD11c/CD18, CD16), antigen-presentation (HLA-DR, ICAM-1), differentiation (transferrin receptor, CD71), receptor for LPS (CD14) and initiation of the coagulation cascade (Tissue factor, CD142). The proportion of CD16-positive blood monocytes and the quantitative level of ICAM-1 were higher in the patient group, compared to healthy controls. A significant increase in the quantitative level of CD11b/CD18, CD11c/CD18, HLA-DR and ICAM-1, transferrin receptor, CD14 and CD16, was found on peritoneal macrophages, compared to monocytes, harvested both from the corresponding patients, as well as from healthy donors. In contrast, we did not find any significant differences in the expression of tissue factor between monocytes and peritoneal macrophages. In conclusion, phenotypic differences exist between monocyte populations in the blood circulation of CAPD patients, and healthy individuals. We also show that transmigration of monocytes into the peritoneal cavity implies a selective up-regulation of functional receptors, preferentially related to adhesion, and antigen-presentation in a steady-state situation in non-infected CAPD patients.
To determine the relative contribution of alveolar macrophages, peripheral blood monocytes (PBM) and peripheral blood lymphocytes (PBL) from HIV-infected individuals to HIV-1 viral load.
Alveolar macrophages were obtained by flexible bronchoscopy, and PBM and PBL by venipuncture from HIV-1-infected individuals. Alveolar macrophages and PBM were purified using immunomagnetic bead selection to deplete CD3+ and CD19+ cells from bronchoalveolar lavage and peripheral blood mononuclear cells, respectively. DNA and mRNA were extracted and gag copy number quantified using polymerase chain reaction (PCR) and reverse transcriptase PCR. The titres of infectious cell-associated HIV-1 in cells were determined by the endpoint dilution coculture technique for alveolar macrophages and PBM.
Alveolar macrophages and PBM from HIV-1-infected subjects (n=11) contained equivalent concentrations of HIV-1 DNA and HIV-1 mRNA as determined by PCR and reverse transcriptase PCR, respectively. Antiretroviral therapy was associated with reduced viral DNA concentrations in alveolar macrophages but not in PBM. PBL had a significantly higher level of proviral DNA and mRNA than alveolar macrophages or PBM.
Although alveolar macrophages infected in vitro are more permissive for HIV-1 replication than PBM, this difference could not be demonstrated in vivo.
Glucocorticoids (GC) are potent anti-inflammatory and immunosuppressive agents that act on many cells of the body, including monocytes. Here we show that a 5-day course of high dose GC therapy differentially affected the CD14++ and the CD14+ CD16+ monocyte subpopulations in 10 patients treated for multiple sclerosis. While the classical (CD14++) monocytes exhibited a substantial increase from 495 +/- 132 to 755 +/- 337 cells/microl, the CD14+ CD16+ monocytes responded with a pronounced decrease from 36 +/- 15 to 2 +/- 3 cells/microl (P < 0.001). In 4/10 patients the CD14+ CD16+ monocytes fell below detection limits (<0.2 cells/microl). This observation was confirmed when the CD14+ CD16+ monocytes were identified by virtue of their low CD33 expression as these cells decreased as well. After discontinuation of GC therapy the CD14+ CD16+ monocytes reappeared and reached normal levels after 1 week. The profound depletion of CD14+ CD16+ monocytes by GC as described here is a novel effect of GC action in vivo and may contribute to GC-mediated immunosuppression. Determination of the number of this monocyte subset may also serve to monitor the effectiveness of GC therapy in patients requiring immunosuppressive treatment.
The quantitative and phenotypic changes of peripheral blood monocytes during the acute stage of simian immunodeficiency virus infection were investigated. We inoculated intravenously three cynomolgus monkeys (Macaca fascicularis) with 100 TCID50 of SIVmac239 and collected whole blood twice a week until 35 days postinoculation. We found that the relative number of monocytes in peripheral blood leukocytes significantly increased at 7-17 days postinoculation. This increase was concomitant with the peak of primary SIV antigenemia. To determine if the monocytes observed during the acute stage were phenotypically altered, they were periodically examined for the expression of surface markers (i.e., CD11b, CD14, CD16, CD29, D32, CD56, CD62L, CD64, CD80, and MHC-II-DR) by flow cytometry. The results showed that the expression levels of CD14 and CD56 on most of the monocytes were remarkably reduced at 7-17 days postinoculation, and a new subpopulation, CD14lowCD16+CD80+ monocytes, was clearly detected at 10 days postinoculation. These results indicate that the phenotypic alteration of peripheral blood monocytes occurs during the primary SIV infection.
The mAb 2A10 recognizes a 120-kDa protein with sequence homology to the human CD163 and whose expression is restricted to the cells of the porcine monocyte/macrophage lineage. While most of tissue macrophages express high levels of 2A10 Ag, bone marrow cells and a subset of blood monocytes are negative for this marker. The percentage of 2A10+ blood monocytes ranges between 5-50% depending on the donor. The phenotypic analysis indicates that these cells are more similar to mature macrophages than 2A10- monocytes. 2A10+ monocytes express higher levels of swine histocompatibility leukocyte Ag II, CD16, and the adhesion molecules very late Ag-4 (CD49d) and LFA-1 (CD11a) than 2A10- monocytes, while CD14 and SWC1 expression is lower. Both monocyte subsets also differ in their functional capabilities. 2A10+ monocytes induce a greater allogeneic response on T lymphocytes than 2A10- cells. LPS-stimulated 2A10+ and 2A10- monocytes both produce proinflammatory cytokines (TNF-alpha and IL-1alpha), but antiinflammatory IL-10 is only detected on the latter population. When 2A10- monocytes were cultured in medium containing pig serum, they acquired some phenotypic features of 2A10+ cells, expressing the 2A10 Ag. In contrast, when they were cultured in the presence of L929 supernatant as a source of GM-CSF, the 2A10 Ag expression remained low, scarcely increasing over basal levels. 2A10+ cells cultured with pig serum developed features that resemble monocyte-derived dendritic cells. These results indicate that 2A10+ monocytes could constitute a cell population in a more advanced maturation stage than 2A10- circulating monocytes.
To investigate the regulation of Fc gamma receptor (Fc gamma R) expression on circulating phagocytes in Kawasaki disease (KD), we analysed the expressions of Fc gamma RI, II and III on neutrophils and monocytes in 20 patients with KD, 10 with a bacterial infection (BI), 10 with a viral infection (VI), and 10 healthy controls (HC) using flow cytometric analysis. The KD patients had a significantly higher level of Fc gamma RI expression on neutrophils, but not on monocytes, than the BI, VI and HC patients. Fc gamma RII expression on neutrophils was significantly higher in KD, BI and VI than HC, but there was no significant difference in Fc gamma RII expression among KD, BI and VI. Fc gamma RIII expression on neutrophils in KD was significantly lower than in VI and HC, but was higher on monocytes. A kinetic analysis of Fc gamma R expression in KD demonstrated the expression of Fc gamma RI and II on neutrophils to decline, but no remarkable change was observed in the monocytes, from the subacute phase through the convalescent phase. In addition, Fc gamma RIII expression on neutrophils increased, while Fc gamma RIII expression on monocytes decreased during the time course of KD. Fc gamma R expression in the acute phase of KD is thus characterized by markedly increased expression of Fc gamma RI on neutrophils, followed by a subsequent decrease, and decreased expression of Fc gamma RIII on neutrophils and increased expression of Fc gamma RIII on monocytes followed by a reverse kinetics during the clinical course. These findings are thus considered to reflect the functional up-regulation of neutrophils and monocytes in KD.
The existence of a reservoir of resting CD4+ T cells harboring latent replication-competent HIV has been demonstrated in patients on prolonged highly active antiretroviral therapy (HAART). Latently infected tissue macrophages may constitute a second HIV reservoir. The pool of these cells may be maintained by incoming infected monocytes from blood and/or by in situ viral replication. In this study, the presence of infectious HIV was investigated in highly purified monocytes from 5 patients receiving HAART with undetectable plasma viral load for up to 16 months. HIV was detected in freshly isolated monocytes and recovered following Staphylococcus aureus Cowan strain 1 (SAC) or lipopolysaccharide (LPS) activation. No new drug resistance-associated mutation was found in monocyte-associated HIV. These results demonstrate the long-term persistence of infectious virus in cells of the monocyte-macrophage lineage in patients receiving HAART. These cells are capable of releasing infectious virus under appropriate stimulations.
HIV infection is associated with cytokine production by monocytes and expansion of a monocyte subset that expresses high levels of CD16. Our study was designed to investigate the effects of anti-retroviral therapies on these immune parameters. Four groups of HIV+ patients were included in the study. The first group comprised drug-naive patients (n = 20); the second included patients who received two inhibitors of HIV reverse transcriptase (n = 45); the third group received a therapy combining these two inhibitors and one inhibitor of HIV protease (HAART) (n = 35); the fourth consisted of patients who had stopped their treatment (n = 20). The release of inflammatory cytokines (tumour necrosis factor, IL-1beta, IL-6) and immunoregulatory cytokines such as IL-10 by monocytes was determined by ELISA. The monocyte subsets expressing low or high levels of CD16 were studied by flow cytometry. Monocytes from patients naive of treatment released higher amounts of inflammatory cytokines and IL-10 than HIV- individuals. Each anti-retroviral therapy restored a normal pattern of cytokine secretion. Nevertheless, the release of cytokines increased again after the arrest of the treatment. The expansion of the monocyte subset that expresses high levels of CD16 was significantly decreased by HAART but not by the treatment including two inhibitors of reverse transcriptase. These results suggest that only HAART controls monocyte activation in the treatment of HIV infection.