Mahmoud Sadeghi

Tongji Hospital, Wu-han-shih, Hubei, China

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Publications (60)177.75 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Human corneal endothelial cells (HCEC) are a potential target of immune attack after corneal transplantation. The aim of this in vitro study was to investigate the role of HCEC during the allo-immune response of T-cells by examining cytokine profiles, function of the immunosuppressive enzyme indoleamine 2,3-dioxigenase (IDO), major histocompatibility complex (MHC -I/ -II), T-cell proliferation, and the induction of cell death. Methods: Real time-PCR and RP-HPLC were used to determine IDO expression and activity. Multiplex assay was performed for quantification of cytokine levels. T-cell proliferation was assessed by thymidine incorporation and HCEC cell death was measured by flow cytometry. Results: HCEC induce strong proliferation of allogeneic T-cells and an increase of pro-inflammatory cytokines such as interleukin-1 α (IL-1α), IL-1ß, IL-6, interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). TNF-α (and to a lesser extent IFN-γ) induces apoptosis. Moreover, IFN-γ strongly upregulates MHC-II molecules and IDO activity in HCEC as reflected by high kynurenine (Kyn) concentrations. Interestingly, the T-cell response was not affected by increased IDO activity, since blocking of IDO did not affect the proliferation rate. IDO-induced Kyn levels did not exceed concentrations of 175 ± 20 µM. Concentrations of ≥ 400 µM Kyn were required to suppress T-cell proliferation. Conclusions: Our data show that T-cell attack on HCEC leads to increased concentrations of pro-inflammatory cytokines. Inflammatory cytokines induce apoptosis and upregulate MHC-II molecules and IDO in HCEC. Although increased IDO activity does not influence the T-cell response, it constitutes an inflammatory marker of the allo-immune response towards HCEC.
    Investigative ophthalmology & visual science 12/2013; · 3.43 Impact Factor
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    ABSTRACT: Hemophilia patients infected with human immunodeficiency virus (HIV) 30 years ago show increased proportions of activated CD8(+)DR(+) blood lymphocytes. We hypothesized that this might indicate a cellular immune response directed against HIV and might be the reason for long-term clinical stability of these patients. CD8(+) peripheral blood lymphocytes (PBL) reactive with six HIV and two cytomegalovirus (CMV) pentamers were determined in heparinized whole blood. Additional lymphocyte subsets as well as plasma cytokines and HIV-1 load were studied. Long-term HIV-infected hemophilia patients with (n=15) or without (n=33) currently detectable HIV-1 load in the plasma showed higher proportions of CD8(+) lymphocytes reactive with HIV (p<0.001) and CMV pentamers (p=0.010) than healthy individuals. The cellular anti-HIV response tended to be stronger and more polyclonal in patients during periods of viral replication than in patients with retroviral quiescence (p=0.077). Anti-HIV CD8(+) lymphocyte responses were strongest in patients with high counts of activated CD8(+)DR(+) T (r=0.353; p=0.014) and low CD19(+) B lymphocyte counts (r=-0.472; p=0.001). Patients with or without HIV-1 viral load showed normal Th1 and Th2 plasma cytokine levels and high plasma interleukin-6 (versus healthy controls, p=0.001) and tumor necrosis factor-α (p=0.020). Hemophilia patients who have been living with HIV for more than 30 years showed a polyclonal CD8(+) T-cell response against HIV and CMV. This cellular antiviral immune response was strongest during periods of HIV-1 replication and remained detectable during periods of HIV-1 quiescence. We hypothesize that the consistent cellular anti-HIV-1 response in combination with highly active antiretroviral therapy ensures stability and survival of these chronically HIV-1-infected hemophilia patients.
    BioResearch open access. 12/2013; 2(6):399-411.
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    ABSTRACT: There is increasing evidence that IFNg plays a major role in both induction of Tregs as well as immunosuppression mediated by IFNg-producing Tregs. The present review focuses on a small subset of iTregs that produces IFNg, comprises only 0.04% of all CD4(+) T lymphocytes in the blood of healthy individuals, and increases strongly during an immune response. IFNg(+) Tregs are induced by IFNg and IL12, making them sensors for inflammatory cytokines. They develop rapidly during inflammation and represent the first line of Tregs that suppress initial immune responses. The pool of IFNg(+) Tregs consists of activated stable immunosuppressive thymus-derived nTregs as well as peripherally proliferating iTregs with in part only transient immunosuppressive function, which limits their diagnostic and therapeutic usefulness in organ transplantation. Apparently, a part of IFNg(+) Tregs dies during the immune response, whereas others, after efficient immunosuppression with resolution of the immune response, differentiate toward Th1 lymphocytes. Goals of further research are the development of appropriate diagnostic tests for rapid and exact determinination of immunosuppressive IFNg(+) iTregs, as well as the induction and propagation of stable immunosuppressive IFNg(+) Tregs that establish and maintain good long-term graft function in transplant recipients.
    International Reviews Of Immunology 11/2013; · 5.73 Impact Factor
  • H Wang, V Daniel, M Sadeghi, G Opelz
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    ABSTRACT: CD4(+) CD25(+) FoxP3(+) T-regulatory cells (Treg) and CD3(+) CD8(+) CD28(-) T-suppressor cells (Ts) were shown to have immunosuppressive function in vivo and in vitro. However, the in vitro inducibility of Ts subsets is rather unclear. We investigated the induction of Treg and Ts subsets in peripheral blood mononuclear cells of 5 healthy control individuals during stimulation with phorbol 12-myristate 13-acetate (PMA)/ionomycin or phytohemagglutinin (PHA). Phenotypes were analyzed 0, 4, 8, 16, and 24 hours after initiation of cell culture using 4-color fluorescence flow-cytometry. Number of CD4(+) CD25(+) FoxP3(+) CD127(-) Treg increased during PMA/ionomycin or PHA stimulation (P < .01). CD4(+) CD25(+) FoxP3(+) Treg coexpressed the phenotypes interleukin (IL)-2(-), IL-10(+), and/or transforming growth factor (TGF)-β(+) after stimulation (all P < .01). Interferon (IFN)-γ production was induced only by PMA/ionomycin (P < .01) but not by PHA (P = NS). IFN-γ-secreting Treg were detectable at 4 hours whereas IL-2(-), IL-10(+) and/or TGF-β(+) Treg required 16 hours of stimulation. In contrast, CD3(+) CD8(+) CD28(-) Ts phenotypes were not inducible during 24-hour PMA/ionomycin or PHA stimulation (all P = NS). However, Ts coexpressed IL-10 and/or TGF-β during polyclonal stimulation (all P < .01), whereas the proportion of IL-2(-) Ts remained stable during the cell culture period (P = NS). Similar to Treg, IFN-γ-secreting Ts were detected only during PMA/ionomycin stimulation (P < .01), but not during PHA stimulation (P = NS). We conclude that the proportion of CD3(+) CD8(+) CD28(-) Ts remains stable during polyclonal stimulation. They modify only the cytokine pattern indicating activation of the Ts. In contrast, CD4(+) CD25(+) FoxP3(+) CD127(-) Treg are inducible by PMA/ionomycin and PHA stimulation. IFN-γ- secreting Treg form the first line of immunoregulatory T cells during an initiated immune response followed by IL-2(-), IL-10(+), and/or TGF-β(+) Treg.
    Transplantation Proceedings 06/2013; 45(5):1822-31. · 0.95 Impact Factor
  • H Wang, V Daniel, M Sadeghi, G Opelz
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    ABSTRACT: Induced regulatory T cells (iTreg) are a heterogeneous T-cell subset that is induced during an allo-response and down-regulates the immune response. iTreg are commonly characterized as CD4(+)CD25(high), CD4(+)CD25(high)FoxP3(+), CD4(+)CD25(high)CD127(-), or CD4(+)CD25(high)FoxP3(+)CD127(-) peripheral blood lymphocytes (PBL). In the present study, we investigated the overlap of these 4 phenotypically determined iTreg subsets in normal human individuals. PBL of 8 healthy individuals were incubated for 0 hours (Group 1) or for 16 hours in medium without (Group 2) or with phorbol 12-myristate 13-acetate (PMA)/Ionomycin (Group 3). Thereafter, proportions of PBL with Treg phenotypes were determined using 4-color flow-cytometry. All 4 Treg subsets increased strongly during polyclonal stimulation (P < .001). After stimulation, combining 2 iTreg markers, 24% of stimulated CD4(+) PBL were CD25(high)FoxP3(+), 18% CD25(high)CD127(-), and 61% FoxP3(+)CD127(-). Combining 3 iTreg markers, only 18% of the polyclonally stimulated CD4(+) PBL were CD25(high)FoxP3(+)CD127(-). Importantly, the proportion of FoxP3(+)CD127(-) PBL increased with the quantity of CD25 on stimulated CD4(+) PBL and was highest in CD25(high) PBL (P = .002), emphasizing the relevance of CD25(high) as iTreg marker. Different iTreg phenotypes should not be used interchangeably because they define different iTreg subsets that overlap only in part. CD25(high) is the most relevant iTreg marker. These conclusions should be considered when studies and experiments involving iTreg phenotypes are compared.
    Transplantation Proceedings 06/2013; 45(5):1816-21. · 0.95 Impact Factor
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    ABSTRACT: BACKGROUND: Plasmapheresis (PP) has been used in the treatment of various immunologic disorders, and its efficacy has mainly been attributed to the removal of humoral factors and autoantibodies. Besides these effects, PP may induce modifications of the cellular immunologic status, contributing to the restoration of impaired immunologic function. The effect of PP on lymphocyte subpopulations, plasma neopterin, and cytokines in renal transplant recipients was investigated in this study. METHODS: We compared pre-PP and post-PP lymphocyte subpopulations and plasma neopterin in 37, and cytokine plasma levels in 30, potential renal transplant recipients. Plasma neopterin and cytokines were measured by enzyme-linked immunosorbent assay kits, lymphocyte subsets were determined using four-color fluorescence flow cytometry. RESULTS: Lymphocyte subpopulation counts and ratios including CD45:μL (P=0.005), CD3:μL (P=0.02), CD4DR:μL (P=0.002), CD8:μL (P=0.01), and CD8DR:μL (P=0.005) T cells; CD4DR:CD4 (P=0.009) and CD8DR:CD8 (P=0.0004) ratios; DR cells:μL (P=0.003); CD19 B lymphocytes:μL (P=0.001); and plasma levels of neopterin (P<;0.0001), soluble interleukin-1 receptor antagonist (P<;0.0001), IL-8 (P=0.0001), and tumor necrosis factor-α (P=0.008) were significantly decreased after PP as compared with before PP. The results indicate a decrease of activated DR, CD4, and CD8 T lymphocytes and B lymphocytes, and a decrease of monocyte and macrophage activation as a result of PP. CONCLUSION: Based on these results, we conclude that PP not only removes antibodies from the plasma but, in addition, modulates T-lymphocyte activation and the inflammatory response by decreasing plasma proinflammatory cytokines.
    Transplantation 04/2013; 95(8):1021-1029. · 3.78 Impact Factor
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    ABSTRACT: BACKGROUND: The Model for End-Stage Liver Disease (MELD) score is a tool for assessment of the degree of hepatic insufficiency/failure. Quinolinic acid (QuinA) is a tryptophan metabolite produced by activated macrophages. Here we investigate whether the degree of systemic inflammation (QuinA, neopterin, CRP and IL-6) correlates with clinical liver dysfunction according to the MELD Score. METHOD: Ninety-four patients with liver cirrhosis were categorized into 2 groups according to baseline MELD score (group I, MELD <20, n=61, and group II, MELD ⩾20, n=33). RESULTS: Serum levels of QuinA, neopterin, CRP, and IL-6 significantly correlated with MELD score (r=0.77, 0.75, 0.57, and 0.50; p<0.0001, respectively). Patients of group II had significantly higher serum levels of QuinA, neopterin, CRP, and IL-6 than group I (p⩽0.0001). ROC curve analysis showed that QuinA and neopterin are more sensitive markers for severity of liver disease than established markers of inflammation such as CRP and IL-6 (sensitivity=86% and 79%, respectively) (AUC=0.89 and 0.89, respectively). QuinA provided the most sensitive index with regard to the identification of patients with hepatic encephalopathy. CONCLUSION: Serum levels of QuinA reflect the degree of liver dysfunction. Moreover, high levels of QuinA may serve as a sensitive indicator of hepatic encephalopathy.
    Human immunology 10/2012; · 2.55 Impact Factor
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    ABSTRACT: Induced Treg with the phenotype CD4(+)CD25(+)Foxp3(+)IFNΥ(+) were shown to be associated with good long-term graft outcome in renal transplant recipients and inhibition of allogeneic T-cell responses in-vitro. In the present study, we investigated whether apoptosis and Fas/FasL-dependent pathways contribute to the inhibition of T-cell activation. Early apoptosis and necrosis rates as well as co-expression of immunostimulatory and immunosuppressive proteins in/on CD4(+)CD25(+)Foxp3(+), CD4(+)IFNΥ(+)Foxp3(+) and CD4(+)CD25(+)IFNΥ(+) PBL were analyzed using cells from healthy controls and four-color flow cytometry, PMA/Ionomycin-stimulated PBL, and MLC. 16h PMA/Ionomycin stimulation induced iTreg subsets with the phenotype CD4(+)CD25(+)Foxp3(+), CD4(+)IFNΥ(+)Foxp3(+) and CD4(+)CD25(+)IFNΥ(+) co-expressing CD95, CD152, CD178, CD279, Granzyme A, Granzyme B, Perforin, IL-10, and TGFß(1). CD178(+) iTreg increased within 3h after PMA/Ionomycin stimulation in parallel to early apoptotic Annexin(+)/PI(-) PBL, suggesting CD178-mediated apoptosis of responder cells by CD4(+)CD25(+)Foxp3(+)IFNΥ(+)CD178(+) iTreg. CD4(+)CD25(+)IFNΥ(+) and CD4(+)CD25(+)CD178(+) PBL separated from primary cell cultures and added to autologous PMA/Ionomycin stimulated secondary cell cultures induced apoptosis immediately. Early apoptosis was not antigen-specific as shown in secondary MLC with separated CD4(+)CD25(+)IFNΥ(+) and CD4(+)CD25(+)CD178(+) PBL and third-party cells as stimulator. CD4(+)CD25(+)Foxp3(+)IFNΥ(+)CD178(+) iTreg differentiate after cell stimulation and induce antigen-unspecific apoptosis of activated CD95(+) responder/effector cells in vitro that might contribute to iTreg-mediated inhibition of T-cell activation.
    Human immunology 09/2012; · 2.55 Impact Factor
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    ABSTRACT: IFNγ-producing CD3(+)CD4(+)CD25(+)Foxp3(+) induced Treg are more frequently detectable in patients with good than in patients with impaired long-term kidney graft function. We investigated the in-vitro function of separated CD3(+)CD4(+)CD25(+)Foxp3(+)IFNγ(+) PBL that were induced by phorbol-12-myristate-13-acetate(PMA)/Ionomycin or alloantigenic stimulation. Additionally, we studied iTreg induction and cell proliferation in MLC with pretransplant obtained PBL. CD4(+)CD25(+)IFNγ(+) PBL separated from PMA/Ionomycin-stimulated PBL of healthy controls inhibited secondary cell cultures of autologous PBL. Furthermore, CD4(+)CD25(+)IFNγ(+) PBL separated from primary MLC and added to secondary MLC suppressed allogeneic T-cell activation in secondary MLC unspecifically, irrespective of the stimulator cell. However, the strongest suppression was observed in specific MLC. Patients with poor long-term graft outcome were able to form IFNγ(+) iTreg in pretransplant MLC. Eight patients with a serum creatinine level ranging from 0.9 to 14mg/dl 18-29years posttransplant were studied. In MLC with pretransplant obtained recipient and donor cells, strong IFNγ(+) iTreg (p=0.007) and strong blast induction (p=0.047) were associated with impaired long-term graft outcome. Long-term graft outcome was not associated with cell proliferation and iTreg induction in unspecific MLC with third-party cells as stimulator. The data indicate that patients with impaired long-term graft outcome are able to form high numbers of IFNγ(+) iTreg in specific pretransplant MLC. Quantity of induced IFNγ(+) iTreg depends on the strength of the alloresponse and both parameters are inversely associated with long-term graft outcome.
    Transplant Immunology 08/2012; · 1.52 Impact Factor
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    ABSTRACT: BACKGROUND: IFNgamma-producing CD4+CD25+Foxp3+ PBL represent a subtype of iTreg that are associated with good long-term graft outcome in renal transplant recipients and suppress alloresponses in-vitro. To study the mechanism of immunosuppression, we attempted to block cell surface receptors and thereby inhibited the function of this iTreg subset in-vitro using monoclonal antibodies and recombinant proteins. METHODS: PBL of healthy control individuals were stimulated polyclonally in-vitro in the presence of monoclonal antibodies or recombinant proteins against/of CD178, CD152, CD279, CD28, CD95, and HLA-DR. Induction of IFNgamma+ iTreg and proliferation of effector cells was determined using four-color fluorescence flow cytometry. Blockade of iTreg function was analyzed using polyclonally stimulated co-cultures with separated CD4+CD25+CD127-IFNgamma+ PBL. RESULTS: High monoclonal antibody concentrations inhibited the induction of CD4+CD25+Foxp3+IFNgamma+ PBL (anti-CD152, anti-CD279, anti-CD95: p < 0.05) and CD4+CD25+CD127-IFNgamma+ PBL (anti-CD178, anti-CD152, anti-CD279, anti-CD95: p < 0.05). Effector cell proliferation increased with increasing antibody concentrations in culture medium (anti-CD178 and anti-CD279: p < 0.05). Conversely, high concentrations of recombinant proteins induced formation of CD4+CD25+Foxp3+IFNgamma+ PBL (rCD152 and rCD95: p < 0.05) and decreased cell proliferation dose-dependently (rCD178 and rCD95: p < 0.05). Our data suggest an inverse association of iTreg induction with effector cell proliferation in cell culture which is dependent on the concentration of monoclonal antibodies against iTreg surface determinants. 3-day co-cultures of polyclonally stimulated PBL with separated CD4+CD25+CD127-IFNgamma+ PBL showed lower cell proliferation than co-cultures with CD4+CD25+CD127-IFNgamma- PBL (p < 0.05). Cell proliferation increased strongly in CD4+CD25+CD127-IFNgamma- PBL-containing co-cultures in the presence of monoclonal antibody (anti-CD28, anti-CD152, anti-CD279: p < 0.05) but remained low in co-cultures with CD4+CD25+CD127-IFNgamma+ PBL (with the exception anti-CD28 monoclonal antibody: p < 0.05). Monoclonal antibodies prevent iTreg induction in co-cultures with CD4+CD25+CD127-IFNgamma- PBL but do not efficiently block suppressive iTreg function in co-cultures with CD4+CD25+CD127-IFNgamma+ PBL. CONCLUSIONS: CD178, CD152, CD279, CD28, CD95, and HLA-DR determinants are important for induction and suppressive function of IFNgamma+ iTreg.
    BMC Immunology 08/2012; 13(1):47. · 2.61 Impact Factor
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    ABSTRACT: Infection-induced inflammation triggers catabolism of proteins and amino acids. Phenylalanine and tryptophan are 2 amino acids related to infections that regulate immune responses. Polyomavirus BK (BKV) and cytomegalovirus (CMV) are important pathogens after kidney transplantation. We investigated the clinical relevance of phenylalanine, tryptophan, and tryptophan metabolites (kynurenine and quinolinic acid) plasma levels in kidney transplant recipients with active CMV (BKV(-)CMV(+), n = 12) or BK virus infection (BKV(+)CMV(-), n = 37). Recipients without active viral infections (CMV(-)BKV(-), n = 28) and CMV(-)BKV(-) healthy individuals (HCs, n = 50) served as controls. In contrast to BKV infection, activated CMV infection is tightly linked to increased phenylalanine and tryptophan metabolite plasma levels (p ≤ 0.002). The association of phenylalanine (cutoff 50 μmol/L) with CMV infection demonstrates high sensitivity (100%) and specificity (94%). By contrast, kynurenine (p = 0.029) and quinolinic acid (p = 0.003) values reflect the severity of CMV infection. In this early proof-of-concept trial, evidence indicates that activated CMV infection is strongly associated with increased phenylalanine as well as kynurenine and quinolinic acid plasma levels. Moreover, tryptophan metabolite levels correlate with disease severity. Measurement of these amino acids is an inexpensive and fast method expected to complete conventional diagnostic assays.
    Human immunology 11/2011; 73(2):186-92. · 2.55 Impact Factor
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    ABSTRACT: Hantaviruses of the family Bunyaviridae are emerging zoonotic pathogens which cause hemorrhagic fever with renal syndrome (HFRS) in the Old World and hantavirus pulmonary syndrome (HPS) in the New World. An immune-mediated pathogenesis is discussed for both syndromes. The aim of our study was to investigate cytokine expression during the course of acute Puumala hantavirus infection. We retrospectively studied 64 patients hospitalised with acute Puumala hantavirus infection in 2010 during a hantavirus epidemic in Germany. Hantavirus infection was confirmed by positive anti-hantavirus IgG/IgM. Cytokine expression of IL-2, IL-5, IL-6, IL-8, IL-10, IFN-γ, TNF-α and TGF-β1 was analysed by ELISA during the early and late phase of acute hantavirus infection (average 6 and 12 days after onset of symptoms, respectively). A detailed description of the demographic and clinical presentation of severe hantavirus infection requiring hospitalization during the 2010 hantavirus epidemic in Germany is given. Acute hantavirus infection was characterized by significantly elevated levels of IL-2, IL-6, IL-8, TGF-β1 and TNF-α in both early and late phase compared to healthy controls. From early to late phase of disease, IL-6, IL-10 and TNF-α significantly decreased whereas TGF-β1 levels increased. Disease severity characterized by elevated creatinine and low platelet counts was correlated with high pro-inflammatory IL-6 and TNF-α but low immunosuppressive TGF-β1 levels and vice versa . High expression of cytokines activating T-lymphocytes, monocytes and macrophages in the early phase of disease supports the hypothesis of an immune-mediated pathogenesis. In the late phase of disease, immunosuppressive TGF-β1 level increase significantly. We suggest that delayed induction of a protective immune mechanism to downregulate a massive early pro-inflammatory immune response might contribute to the pathologies characteristic of human hantavirus infection.
    BMC Immunology 11/2011; 12:65. · 2.61 Impact Factor
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    ABSTRACT: Reliable markers for assessing the biological effect of immunosuppressive drugs and identification of transplant recipients at risk of developing rejection are not available. In a prospective multicenter study, we investigated whether posttransplant measurement of the T-cell activation marker soluble CD30 (sCD30) can be used for estimating the risk of graft loss in kidney transplant recipients. Pre- and posttransplant sera of 2322 adult deceased-donor kidney recipients were tested for serum sCD30 content using a commercial enzyme-linked immunosorbent assay. sCD30 decreased posttransplant and reached a nadir on day 30. Patients with a high sCD30 of more than or equal to 40 U/mL on day 30 showed a subsequent graft survival rate after 3 years of 78.3±4.1%, significantly lower than the 90.3±1.0% rate in recipients with a low sCD30 on day 30 of less than 40 U/mL (log-rank P<0.001; Cox hazard ratio 2.02, P<0.001). Although an association was found between pre- and posttransplant sCD30 levels, patients with high sCD30 on posttransplant day 30 demonstrated significantly lower 3-year graft survival irrespective of the pretransplant level. Our data suggest that posttransplant measurement of sCD30 on day 30 is a predictor of subsequent graft loss in kidney transplant recipients and that sCD30 may potentially serve as an indicator for adjustment of immunosuppressive medication.
    Transplantation 06/2011; 91(12):1364-9. · 3.78 Impact Factor
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    ABSTRACT: Interferon-γ (IFN-γ)-producing CD3(+)CD4(+)CD25(+)Foxp3(+) peripheral blood lymphocytes (PBL) are more frequently detectable in patients with good than in patients with impaired long-term kidney graft function, suggesting an immunoregulatory role of this induced T regulatory (iTreg) subtype. Herein, the in vitro function of separated CD3(+)CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL that were induced by phorbol 12-myristate 13-acetate (PMA)/ionomycin or alloantigenic stimulation was investigated using cell coculture techniques and flow cytometry. CD4(+)CD25(+)Foxp3(+) PBL with intracellular IFN-γ production increased to 26% in cell cultures stimulated with PMA/ionomycin for 6 hours. Recombinant IFN-γ augmented and anti-IFN-γ monoclonal antibody blocked induction of CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL, suggesting their IFN-γ-dependent induction. In addition, CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL produced immunosuppressive interleukin (IL)-10, transforming growth factor-β, and IL-4 intracellularly and expressed both IFN-γ and IFN-γ receptors (CD119) on the cell surface, allowing separation of CD4(+)CD25(+)IFN-γ(+) PBL with 98% purity. Addition of enriched CD4(+)CD25(+)IFN-γ(+) PBL to autologous PMA/ionomycin stimulated PBL decreased blast formation (p < 0.05), indicating suppression of cell proliferation by CD4(+)CD25(+)IFN-γ(+) PBL. CD4(+)CD25(+)IFN-γ(+) PBL separated from primary mixed leukocyte cultures (MLC) and added to autologous or third-party secondary MLC suppressed allogeneic T-cell activation nonspecifically (p < 0.05). We conclude that CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL are induced by IFN-γ, making them sensors for IFN-γ and initial immune responses. Circulating CD4(+)CD25(+)Foxp3(+)IFN-γ(+) PBL could suppress allogeneic T-cell responses in patients and may be involved in inhibition of the posttransplant alloresponse.
    Human immunology 05/2011; 72(9):699-707. · 2.55 Impact Factor
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    ABSTRACT: BACKGROUND AND INTRODUCTION: Without adequate prophylaxis, liver transplantation (LTx) is frequently followed by hepatitis B virus (HBV) reinfection, which results in rapidly progressing liver disease and significantly decreased overall survival. In the last two decades, significant progress has been made in the prophylaxis and treatment of HBV. DISCUSSION: We present an overview of different protocols and regimens used for prophylaxis of HBV reinfection after LTx and describe the protocol implemented at our center. Following LTx, HBV reinfection can be effectively prevented by administration of anti-hepatitis B immunoglobulin (HBIg) alone or more recently in combination with antiviral nucleoside/nucleotide analogs (NUCs). Several studies reported good results with the use of HBIg alone, but combination treatment with HBIg and NUCs has proven to be a superior prophylactic regimen for HBV recurrence. At present, combination therapy (HBIg and a nucleoside or nucleotide analog) is the gold standard used in many transplantation centers. This preventive regimen reduces the risk of a recurrence of HBV infection and thereby the need for re-transplantation. Future and ongoing studies will show how long HBIg must be given after transplantation, especially when used in combination with potent antivirals, such as entecavir or tenofovir.
    Langenbeck s Archives of Surgery 05/2011; 397(5):697-710. · 1.89 Impact Factor
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    ABSTRACT: Indoleamine 2,3-dioxygenase (IDO), an enzyme expressed in many cell types, catalyses degradation of tryptophan (Trp) to kynurenine (Kyn) and may exert immunosuppressive functions, mediated mainly by kynurenines. Therefore, increased Kyn concentrations would be expected to protect allografts from rejection. We conducted this study to examine whether Kyn has predictive value for kidney graft outcome. End-stage renal disease patients (n = 210) demonstrated an increased Kyn/Trp ratio compared with healthy controls (n = 30). Both Kyn and Trp levels were significantly higher in patients who subsequently developed acute rejection than in patients who did not (p < 0.001 and p < 0.001, respectively). Furthermore, pretransplantation Kyn and Trp plasma concentrations were significantly different in patients who went on to develop acute rejection (high values) or acute tubular necrosis (low values) (p = 0.007 and p = 0.021, respectively). After transplantation Kyn levels decreased. Approximately 3 days before biopsy-confirmed rejection, Kyn was significantly increased in patients with rejection compared with those without rejection (p < 0.001). Contrary to expectation, high Kyn plasma levels before transplantation were not predictive of low rejection risk. Although informative in overall terms, at the present stage, Kyn levels do not allow the concise risk differentiation of individual patients.
    Human immunology 11/2010; 71(11):1067-72. · 2.55 Impact Factor
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    ABSTRACT: Borderline rejection (Bord-R) is a frequent diagnosis in renal transplantation, and there is increasing evidence that regulatory T lymphocytes are involved in its pathogenesis. Current histopathologic practice does not differentiate between graft-protecting and -damaging T lymphocytes, and patients with Bord-R routinely receive rejection treatment. We analyzed Treg-associated forkhead box P3 (Foxp3) gene expression in Bord-R and more severe forms of acute rejection episodes (ARE). Foxp3 transcripts were measured in 520 serial peripheral blood samples from 177 kidney graft recipients obtained during the first 20 days posttransplantation. The highest Foxp3 transcripts were observed in patients with Bord-R or without rejection and the lowest in patients with ARE. Patients with Bord-R on posttransplant days 5 to 7 showed an increased Foxp3 transcript level of 156%, which increased to 302% by posttransplant days 14 to 16. In contrast, patients with ARE demonstrated significantly lower Foxp3 gene expression than that observed in Bord-R, nonrejectors, or acute tubular necrosis patients (P=0.001, P<0.001, and P=0.005, respectively, on days 11-13). Acute tubular necrosis patients demonstrated intermediately high Foxp3 gene expression. Our data indicate that increased Treg activity in peripheral blood is a frequent feature of Bord-R. This finding questions the appropriateness of rejection treatment in all patients with the histopathologic diagnosis "Bord-R".
    Transplantation 08/2010; 90(4):427-32. · 3.78 Impact Factor
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    Transplantation 07/2010; 90(2):227-228. · 3.78 Impact Factor
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    ABSTRACT: Leukemia stem cells are known to exhibit multidrug resistance by expression of ATP-binding cassette (ABC) transporters which constitute transmembrane proteins capable of exporting a wide variety of chemotherapeutic drugs from the cytosol. We show here that human promyeloblastic leukemia KG-1a cells exposed to the histone deacetylase inhibitor phenylbutyrate resemble many characteristics of leukemia stem cells, including expression of functional ABC transporters such as P-glycoprotein, BCRP and MRP8. Consequently, KG-1a cells display resistance to the induction of apoptosis by various chemotherapeutic drugs. Resistance to apoptosis induction by chemotherapeutic drugs can be reversed by cyclosporine A, which effectively inhibits the activity of P-glycoprotein and BCRP, thus demonstrating ABC transporter-mediated drug resistance in KG-1a cells. However, KG-1a are highly sensitive to apoptosis induction by salinomycin, a polyether ionophore antibiotic that has recently been shown to kill human breast cancer stem cell-like cells and to induce apoptosis in human cancer cells displaying multiple mechanisms of drug and apoptosis resistance. Whereas KG-1a cells can be adapted to proliferate in the presence of apoptosis-inducing concentrations of bortezomib and doxorubicin, salinomycin does not permit long-term adaptation of the cells to apoptosis-inducing concentrations. Thus, salinomycin should be regarded as a novel and effective agent for the elimination of leukemia stem cells and other tumor cells exhibiting ABC transporter-mediated multidrug resistance.
    Biochemical and Biophysical Research Communications 03/2010; 394(4):1098-104. · 2.41 Impact Factor
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    ABSTRACT: After initiation of highly-active antiretroviral therapy (HAART), long-term HIV-infected hemophilia patients have been shown to lose autoantibodies against CD4(+) peripheral blood leukocytes (PBL), suggesting that HAART induces autoimmunity-blocking mechanisms. We compared cytokine levels and subpopulations of lymphocytes and dendritic cells (DC) in the blood of 40 long-term HIV(+) patients with those of 13 long-term HIV(-) hemophilia patients; 23 HIV(+) patients had a detectable retroviral load. Cell subsets were determined using flow cytometry and cytokine levels were measured using ELISA. HIV(+) patients showed higher proportions of DC subpopulations with immunostimulatory phenotypes (p < 0.01), CD8(+) PBL (p < 0.001), and IL-2 (p < 0.001) and sIL-2R plasma levels (p = 0.002) than HIV(-) patients. They also exhibited increased proportions of T PBL with immunosuppressive phenotypes such as CD3(+)CD4(+)CD25(+)Foxp3(+) (p = 0.001), and CD3(+)CD8(+)CD28(-)Foxp3(+) PBL (p < 0.001), and a decreased IL-7R expression on CD3(+)CD8(+) PBL (p = 0.001) compared to HIV(-) patients. Frequencies of CD3(+)CD4(+)CD25(+) PBL producing IL-2, IL-4, IL-10, IL-12, and/or IFN-gamma, and of CD3(+)CD4(+)CD28(-) PBL secreting IL-2 and/or IL-4 were lower in HIV(+) than in HIV(-) patients (p <or= 0.02). Proportions of CD4(+) PBL coated with IgG, IgM, and C3d were similar in HIV(+) and HIV(-) patients (p = n.s.). However, the proportion of CD4(+)gp120(+) PBL was higher in HIV(+) patients (p = 0.002), and associated with low CD3(+)CD4(+)CD25(+)Foxp3(+) PBL (p = 0.012). We conclude that long-term HIV-infected hemophilia patients on HAART show an adaptive immune response, presumably against HIV, in the presence of upregulated immunosuppressive T PBL, downregulated cytokine-producing CD4(+) PBL, and downregulated IL-7R expression on CD8(+) PBL. Increased immunoregulatory T PBL might decrease autoimmunity, thereby contributing to immunological reconstitution and stabilization of long-term HIV-infected hemophilia patients on HAART.
    Viral immunology 02/2010; 23(1):87-97. · 1.78 Impact Factor

Publication Stats

530 Citations
177.75 Total Impact Points

Institutions

  • 2013
    • Tongji Hospital
      Wu-han-shih, Hubei, China
  • 2003–2013
    • Universität Heidelberg
      • • Department of Transplantation Immunology
      • • Department of General, Visceral and Transplantation Surgery
      Heidelberg, Baden-Wuerttemberg, Germany
  • 2010
    • German Cancer Research Center
      Heidelburg, Baden-Württemberg, Germany