[Show abstract][Hide abstract] ABSTRACT: Background:
An inefficient immune response against Epstein-Barr virus (EBV) infection is related to the pathogenesis of a subgroup of classical Hodgkin lymphomas (cHL). Some EBV immune-evasion mechanisms target HLA presentation, including the non-classical HLA-E molecule. HLA-E can be recognized by T cells via the TCR, and it also regulates natural killer (NK) cell signaling through the inhibitory CD94/NKG2A receptor. Some evidences indicate that EBV-infected B-cells promote the proliferation of NK subsets bearing CD94/NKG2A, suggesting a relevant function of these cells in EBV control. Variations in CD94/NKG2A-HLA-E interactions could affect NK cell-mediated immunity and, consequently, play a role in EBV-driven transformation and lymphomagenesis. The two most common HLA-E alleles, E*01:01 and E*01:03, differ by a single amino acid change that modifies the molecule function. We hypothesized that the functional differences in these variants might participate in the pathogenicity of EBV.
We studied two series of cHL patients, both with EBV-positive and-negative cases, and a cohort of unrelated controls, to assess the impact of HLA-E variants on EBV-related cHL susceptibility.
We found that the genotypes with at least one copy of E*01:01 (i.e., E*01:01 homozygous and heterozygous) were underrepresented among cHL patients from both series compared to controls (72.6% and 71.6% vs 83%, p = 0.001). After stratification by EBV status, we found low rates of E*01:01-carriers mainly among EBV-positive cases (67.6%). These reduced frequencies are seen independently of other factors such as age, gender, HLA-A*01 and HLA-A*02, HLA alleles positively and negatively associated with the disease (adjusted OR = 0.4, p = 0.001). Furthermore, alleles from both HLA loci exert a cumulative effect on EBV-associated cHL susceptibility.
These results indicate that E*01:01 is a novel protective genetic factor in EBV-associated cHL and support a role for HLA-E recognition on the control of EBV infection and lymphomagenesis.
PLoS ONE 08/2015; 10(8-8):e0135512-. DOI:10.1371/journal.pone.0135512 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Natural killer (NK) cells, a cytotoxic lymphocyte lineage, are able to kill tumor cells in vitro and in mouse models. However, whether these cells display an anti-tumor activity in cancer patients has not been demonstrated. Here we have addressed this issue in patients with several hematological cancers. We found a population of highly activated CD56dimCD16+ NK cells that have recently degranulated, evidence of killing activity, and it is absent in healthy donors. A high percentage of these cells expressed natural killer cell p46-related protein (NKp46), natural-killer group 2, member D (NKG2D) and killer inhibitory receptors (KIRs) and a low percentage expressed NKG2A and CD94. They are also characterized by a high metabolic activity and active proliferation. Notably, we found that activated NK cells from hematological cancer patients have non-NK tumor cell antigens on their surface, evidence of trogocytosis during tumor cell killing. Finally, we found that these activated NK cells are distinguished by their CD45RA+RO+ phenotype, as opposed to non-activated cells in patients or in healthy donors displaying a CD45RA+RO− phenotype similar to naïve T cells. In summary, we show that CD45RA+RO+ cells, which resemble a unique NK population, have recognized tumor cells and degranulate in patients with hematological neoplasias.
[Show abstract][Hide abstract] ABSTRACT: Natural killer (NK) cells recognize and eliminate transformed or infected cells that have downregulated MHC class-I and express specific activating ligands. Recent evidence indicates that allogeneic NK cells are useful to eliminate haematological cancer cells independently of MHC-I expression. However, it is unclear if transformed cells expressing mutations that confer anti-apoptotic properties and chemoresistance will be susceptible to NK cells. Allogeneic primary human NK cells were activated using different protocols and prospectively tested for their ability to eliminate diverse mutant haematological and apoptotic-resistant cancer cell lines as well as patient-derived B-cell chronic lymphocytic leukemia cells with chemotherapy multiresistance. Here, we show that human NK cells from healthy donors activated in vitro with Epstein Barr virus positive (EBV(+))-lymphoblastoid cells display an enhanced cytotoxic and proliferative potential in comparison to other protocols of activation such a K562 cells plus interleukin (IL)2. This enhancement enables them to kill more efficiently a variety of haematological cancer cell lines, including a panel of transfectants that mimic natural mutations leading to oncogenic transformation and chemoresistance (e.g., overexpression of Bcl-2, Bcl-XL and Mcl-1 or downregulation of p53, Bak/Bax or caspase activity). The effect was also observed against blasts from B-cell chronic lymphocytic leukemia patients showing multi-resistance to chemotherapy. Our findings demonstrate that particular in vitro activated NK cells may overcome anti-apoptotic mechanisms and oncogenic alterations frequently occurring in transformed cells, pointing toward the use of EBV(+)-lymphoblastoid cells as a desirable strategy to activate NK cells in vitro for the purpose of treating haematological neoplasia with poor prognosis.
[Show abstract][Hide abstract] ABSTRACT: New-onset diabetes mellitus after transplantation (NODAT) in patients undergoing liver transplantation (LT) for hepatitis C virus (HCV)-related cirrhosis is associated with more aggressive HCV recurrence on the graft, rapid progression of fibrosis, and lower rate of sustained viral response to antiviral therapy. The CC genotype at rs12979860 of the IL28B is associated with greater rates of spontaneous clearance of HCV and response to antiviral therapy. IL28B acts on the interferon-stimulated genes through the JAK-STAT pathway, which is related to the development of insulin resistance. The aim of this study was to investigate whether IL28B rs12979860 polymorphism is associated with the development of NODAT after LT for cirrhosis owing to HCV infection.
We analyzed 99 patients (age, 52.7 ± 9.4 years; 70% male) who underwent LT for HCV-related cirrhosis, with ≥1 year of follow-up and with available DNA sample. NODAT was defined starting from the sixth month after LT, according to the international consensus guidelines. Genotyping was carried out by real-time polymerase chain reaction and analysis of the melting temperature with the LightCycler 480 system.
Twenty-eight patients (28.3%) developed NODAT. CC genotype at rs12979860 of IL28B was associated with a lesser incidence of NODAT versus non-CC genotypes (P = .05; odds ratio, 0.31; 95% CI, 0.11-0.92). We did not find any association between NODAT and age at transplantation, gender, pretransplant body mass index, presence of hepatocellular carcinoma, type of initial immunosuppression (cyclosporine, tacrolimus or corticosteroids) or acute rejection treated with steroids.
The CC genotype at rs12979860 of IL28B is a protective factor for NODAT in patients with LT for HCV-related cirrhosis.
[Show abstract][Hide abstract] ABSTRACT: Among the strategies to optimize engraftment of cord blood (CB) stem cell transplantation (SCT), single CB with the co-infusion of CD34+ stem cells from a HLA-mismatched auxiliary donor (haplo-cord) provides a valid alternative for adult patients without a suitable donor. 132 high-risk adult patients with hematological malignancies from 3 Spanish institutions underwent myeloablative haplo-cord SCT. Median age was 37 years; weight 70 kg and 37% had active disease. The median number of post-processing CB total nucleated and CD34+ cells was 2.4 x 107/kg (IQR 1.8-2.9) and 1.4 x 105/kg (IQR 0.9-2), respectively. Neutrophil engraftment occurred in a median of 11.5 days (IQR 10.5-16.5) and platelet engraftment at 36 days (IQR 25.5-77). Graft failure was 2% overall and only 9% for CB. Cumulative incidence of aGVHD grades II-IV was 21% and cGVHD 21%. Median follow-up was 60 months (range 3.5-163). OS was 43.5%, EFS 38.3%, NRM 35% and relapse 20% at 5 years. Myeloablative haplo-cord SCT results in fast engraftment of neutrophils and platelets, low incidences of acute and chronic GVHD, and favorable long term outcomes using single CB units with relatively low cell content. Moreover, CB cell dose had no impact on CB engratment and survival in this study. Therefore, haplo-cord SCT expands donor availability reducing CB cell dose requirements.
Biology of Blood and Marrow Transplantation 09/2014; 20(12). DOI:10.1016/j.bbmt.2014.08.024 · 3.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Human cytomegalovirus (HCMV) causes a highly prevalent and lifelong infection, with a multifaceted impact in human health. NK cells play an important role in the immune response to HCMV and the virus has reciprocally developed a variety of immune evasion strategies. We originally reported that HCMV infection promotes, to a variable degree in healthy individuals, a redistribution of the NK-cell receptor (NKR) repertoire which persists under steady-state conditions. Its hallmark is an expansion of a mature NK-cell subset displaying high surface levels of the CD94/NKG2C activating receptor, with additional distinctive phenotypic and functional features. Such adaptation of host NK cells to HCMV infection, confirmed in different clinical settings, is particularly magnified in immunocompromised patients and influenced by NKG2C gene copy number. The mechanism(s) underlying the differentiation and proliferation of NKG2C+ NK cells, the basis for the individual differences in the magnitude of their expansion, and their precise role in anti-viral defence remain open issues. Moreover, the possibility that the impact of HCMV infection on the NK-cell compartment may exert a broader influence on immunity deserves further attention.
Seminars in Immunology 04/2014; 26(2). DOI:10.1016/j.smim.2014.03.002 · 5.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The interaction between clonally distributed inhibitory receptors and their activating counterparts on NK cells and HLA class I molecules defines NK cell functions, but the role of HLA class I ligands in the acquisition of their receptors during NK development is still unclear. Although some studies demonstrated that HLA-C affects the expression of killer Ig-like receptors (KIR), other studies showed that NK cells acquire their KIR repertoire in a stochastic manner. Only when infected with human CMV is an expansion of self-specific KIR(+) NKG2C(+) NK cells detected. To gain more insight into this question, we compared the coexpression of different KIR molecules, NKG2A, CD8, and CD57, on NK cells in healthy donors and seven patients with deficient HLA class I expression due to mutations in one of the TAP genes. Our results show a correlation between the presence/absence of HLA class I molecules and the coexpression of their receptors. In an HLA class I low-expression context, an increase in KIR molecules' coexpression is detected on the NKG2A(+) CD8(+) subset. In functional assays, hyporesponsiveness was observed for TAP-deficient NK cells derived from four patients. In contrast, NK cells from patient five were functional, whereas CD107a(+) and IFN-γ(+) CD56(dim) NK cells presented a different pattern of HLA class I receptors compared with healthy donors. Taken together, our results provide strong evidence for the role of HLA class I molecules in NK cell maturation and KIR repertoire acquisition.
The Journal of Immunology 02/2014; 192(6). DOI:10.4049/jimmunol.1302843 · 4.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Human Cytomegalovirus (HCMV) infection promotes a persistent expansion of a functionally competent NK-cell subset expressing the activating CD94/NKG2C receptor. Factors underlying the wide variability of this effect observed in HCMV-seropositive healthy individuals and exacerbated in immunocompromised patients are uncertain. A deletion of the NKG2C gene has been reported, and an apparent relation of NKG2C zygosis with circulating NKG2C(+) NK-cell numbers was observed in HCMV(+) children. We have assessed the influence of NKG2C gene dose on the NK-cell repertoire in a cohort of young healthy adults (N = 130, median age 19 years). Our results revealed a relation of NKG2C copy number with surface receptor levels and with NKG2C(+) NK-cell numbers in HCMV(+) subjects, independently of HLA-E dimorphism. Functional studies showed quantitative differences in signalling (i.e. iCa(2+) influx), degranulation and IL-15-dependent proliferation, in response to NKG2C engagement, between NK cells from NKG2C(+/+) and hemizygous subjects. These observations provide a mechanistic interpretation on the way the NKG2C genotype influences steady state NKG2C(+) NK-cell numbers, further supporting an active involvement of the receptor in the HCMV-induced reconfiguration of the NK-cell compartment. The putative implications of NKG2C zygosity over viral control and other clinical variables deserve attention This article is protected by copyright. All rights reserved.
European Journal of Immunology 12/2013; 43(12). DOI:10.1002/eji.201343773 · 4.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A variety of strategies have been designed for sequence-based HLA typing (SBT) and for the isolation of new human leucocyte antigen (HLA) alleles, but unambiguous characterization of complete genomic sequences remains a challenge. We recently reported a simple method for the group-specific amplification (GSA) and sequencing of a full-length C*04 genomic sequence in isolation from the accompanying allele. Here we build on this strategy and present homologous methods that enable the isolation of HLA-C alleles belonging to another two allele groups. Using this approach, which can be applied to sequence-based typing in some clinical settings, we have successfully characterized three novel HLA-C alleles (C*04:128, C*07:01:01:02, and C*08:62).
[Show abstract][Hide abstract] ABSTRACT: As discussed in this review, human cytomegalovirus (HCMV) infection in healthy individuals is associated with a variable and persistent increase of NK cells expressing the CD94/NKG2C activating receptor. The expansion of NKG2C(+) NK cells reported in other infectious diseases is systematically associated with HCMV co-infection. The functionally mature NKG2C(bright) NK-cell subset expanding in HCMV(+) individuals displays inhibitory Ig-like receptors (KIR and LILRB1) specific for self HLA class I, and low levels of NKp46 and NKp30 activating receptors. Such reconfiguration of the NK-cell compartment appears particularly marked in immunocompromised patients and in children with symptomatic congenital infection, thus suggesting that its magnitude may be inversely related with the efficiency of the T-cell-mediated response. This effect of HCMV infection is reminiscent of the pattern of response of murine Ly49H(+) NK cells against murine CMV (MCMV), and it has been hypothesized that a cognate interaction of the CD94/NKG2C receptor with HCMV-infected cells may drive the expansion of the corresponding NK-cell subset. Yet, the precise role of NKG2C(+) cells in the control of HCMV infection, the molecular mechanisms underlying the NK-cell compartment redistribution, as well as its putative influence in the response to other pathogens and tumors remain open issues.
European Journal of Immunology 05/2013; 43(5). DOI:10.1002/eji.201243117 · 4.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Human cytomegalovirus (HCMV) has been reported to reshape the NK-cell receptor (NKR) distribution, promoting an expansion of CD94/NKG2C(+) NK and T cells. The role of NK cells in congenital HCMV infection is ill-defined. Here we studied the expression of NKR (i.e. NKG2C, NKG2A, LILRB1, CD161) and the frequency of the NKG2C gene deletion in children with past congenital infection, both symptomatic (n = 15) and asymptomatic (n = 11), including as controls children with postnatal infection (n = 11) and non-infected (n = 20). The expansion of NKG2C(+) NK cells in HCMV-infected individuals appeared particularly marked and was associated with an increased number of LILRB1(+) NK cells in cases with symptomatic congenital infection. Increased numbers of NKG2C(+) , NKG2A(+) and CD161(+) T cells were also associated to HCMV infection. The NKG2C deletion frequency was comparable in children with congenital HCMV infection and controls. Remarkably, the homozygous NKG2C(+/+) genotype appeared associated with increased absolute numbers of NKG2C(+) NK cells. Moreover, HCMV-infected NKG2C(+/+) children displayed higher absolute numbers of NKG2A(+) and total NK cells than NKG2C(+/-) individuals. Our study provides novel insights on the impact of HCMV infection on the homeostasis of the NK-cell compartment in children, revealing a modulatory influence of NKG2C copy number.
European Journal of Immunology 12/2012; 42(12). DOI:10.1002/eji.201242752 · 4.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A recently developed anti-KIR2DL5 (CD158f) antibody has demonstrated KIR2DL5 expression on the surface of NK and T lymphocytes, making it the last functional KIR identified in the human genome. KIR2DL5 belongs to an ancestral lineage of KIR with Ig-like domains of the D0-D2 type, of which KIR2DL4, an HLA-G receptor, is the only other human member. Despite KIR2DL4 and KIR2DL5 being encoded by genes with similar domain usage, several KIR2DL5 functions resemble more closely those of KIR recognizing classical HLA class I molecules - surface-expressed KIR2DL5 inhibits NK cells through the SHP-2 phosphatase and displays a clonal distribution on NK and T lymphocytes. No activating homolog of KIR2DL5 has been described in any species. The genetics of KIR2DL5 is complicated by duplication of its gene in an ancestor of modern humans living ∼1.7 million years ago. Both KIR2DL5 paralogs have undergone allelic diversification; the centromeric gene is most often represented by alleles whose expression is silenced epigenetically through DNA methylation, thus providing a natural system to investigate the regulation of KIR transcription. The role of KIR2DL5 in immunity is not completely understood, in spite of different attempts to define its ligand. Here we revisit the most relevant characteristics of KIR2DL5, an NK-cell receptor possessing a unique combination of genetic, structural, and functional features.
Frontiers in Immunology 09/2012; 3:289. DOI:10.3389/fimmu.2012.00289
[Show abstract][Hide abstract] ABSTRACT: Polymorphisms of the IL28B gene (encoding interferon-λ3) determine the spontaneous course of hepatitis C virus (HCV) infection and its response to antiviral therapy. We investigated the influence of the IL28B rs12979860 (C>T) polymorphism on the risk of severe HCV recurrence after liver transplantation.
Ninety patients who underwent transplantation because of HCV cirrhosis were retrospectively analyzed; forty-one (45.6%) of them with severe HCV recurrence. Forty-eight of their paired donors were available and were also analyzed. IL28B rs12979860 was genotyped by real-time polymerase chain reaction, and evaluated for association with severe HCV recurrence, along with other variables, by univariate and multivariate analyses.
The risk allele rs12979860-T was more common in transplanted patients (66.7%) than reported in healthy whites, and it was significantly overrepresented among patients with severe HCV recurrence, in comparison with patients without it (82.9% vs. 53.1%, odds ratio [OR]=4.30, etiologic fraction=63.6%; P=0.0028). Furthermore, separate analysis of the recipients' genotypes indicated that the risk of severe HCV recurrence increased with the dose of the T allele (linear trend, P=0.0068). Multiple logistic regression analysis confirmed the contribution of the IL28B genotype to the risk of severe HCV recurrence (OR=4.27; P=0.014), independently of other associated factors. Allele IL28B T in the donor seemed to have an opposite effect than that in the recipient (OR=0.46), but the study was underpowered to demonstrate this unforeseen effect (P=0.1995).
The recipient IL28B rs12979860 genotype has a major influence on the posttransplantation course of HCV infection, being a valuable biomarker for patient care in liver transplantation.
[Show abstract][Hide abstract] ABSTRACT: Natural killer (NK) and T-lymphocytes monitor human leukocyte antigen (HLA)-E expression through CD94:NKG2 heterodimers. Structural polymorphism is not a hallmark for NK-complex genes on chromosome 12, except for complete NKG2C deletion in some humans. We present a method for fast, simple and accurate assessment of NKG2C copy-number variation - presence or absence in the genome of an NKG2C gene, in homo- or heterozygosis, is detected by a single conventional polymerase chain reaction that yields amplicons of different lengths in each genotype. We have also determined the NKG2C genotypes of a reference cell panel comprising 13 NK- and tumour-cell lines and 39 Epstein-Barr virus transformed cells from the International Histocompatibility Workshop. Our results should facilitate research on the importance of NKG2C and its deletion for immunity.
[Show abstract][Hide abstract] ABSTRACT: The killer-cell immunoglobulin-like receptors (KIR), which enable NK cells to detect allogeneic target cells and abnormalities in the expression of self-HLA molecules, are encoded by genes that display extensive copy number variation. These variations in the KIR genotype are relevant for multiple aspects of human health, including therapy of cancer. PCR with sequence-specific primers (SSP) is simplest and most widely used among techniques for studying KIR genotypes. Here, we present a protocol that details the critical steps of a method for KIR genotyping by PCR-SSP.
Methods Mol Biol. Immunogenetics., 06/2012: pages 415-30; Humana Press-Springer 2012..