Glutathione S-Transferase T1 Mismatch Is a Risk Factor for Chronic Ductopenic Rejection of Liver Allografts.

The underlying causes of chronic rejection (CR) after liver transplantation (LT) are not completely known. The main aim of this study was to explore the involvement of the minor histocompatibility antigen glutathione S-transferase T1 (GSTT1) in CR. We retrospectively studied 611 patients who underwent LTs at University Hospital Virgen del Rocío between 2003 and 2016 with a median follow-up of 7.4 ± 4.2 years. The GSTT1 genotype was determined by polymerase chain reaction. We defined GSTT1 mismatch as a specific donor/recipient combination in which a recipient who was homozygous for the deletion allele received a transplant from a positive donor. The prevalence of CR in our whole cohort was 11.6% (71/611), and the prevalence in the GSTT1-mismatched group was 18.8% (16/85) versus 10.5% (55/526) in the GSTT1-matched group. In the cyclosporine A (CsA) group, the prevalence was 26.3% (26/99), much higher than the 8.8% (45/512) observed in the tacrolimus (Tac) group. For statistical analysis, the patients were distributed into 2 groups: group 1, regarded as GSTT1 mismatched, which included the donor (D)+/recipient (R)- allelic combination; and group 2, regarded as GSTT1 matched, which included the other allelic combinations of D+/R+, D-/R-, and D-/R+. All relevant clinical information was collected, and a diagnosis of CR was always confirmed by liver biopsy. GSTT1 mismatch (hazard ratio [HR], 1.99; 95% confidence interval [CI], 1.08-3.66; P = 0.03) and use of CsA/Tac (P < 0.001) were independent risk factors for CR. CR increased the risk of mortality (HR, 2; 95% CI, 1.2-3.6; P = 0.01). Out of the 71 CR patients, 12 (16.9%) needed retransplantation. In conclusion, the GSTT1 D+/R- allelic mismatch is an independent risk factor for CR. A long follow-up of LT patients is recommended because the incidence of CR in adults seems to be underestimated.

Computer-Assisted Definition of the Inflammatory Infiltrates in Patients With Different Categories of Banff Kidney Allograft Rejection.

Currently, the diagnosis of kidney allograft rejection relies on individual histological assessments made by expert pathologists according to the Banff classification. In this study, we applied new Computer-Assisted System Technology (newCAST™) by Visiopharm® with the aim of identifying and quantifying the immune cells in inflammatory infiltrates. We searched for distinctive cellular profiles that could be assigned to each rejection category of the Banff schema: antibody-mediated rejection (active and chronic active), borderline, T cell-mediated rejection (TCMR), and mixed rejection. This study was performed with 49 biopsy samples, 42 from patients with rejection and 7 from patients with clinical signs of dysfunction but an absence of histological findings of rejection. Plasma cells, B and T lymphocytes, natural killer cells, and macrophages, with a special focus on the M1 and M2 subsets, were studied. A major difference among the Banff rejection groups was in the total amount of cells/mm2 tissue. Principal component analysis identified some distinctive associations. The borderline category grouped with CD4+ lymphocytes and M1 macrophages, and active antibody-mediated rejection (aAMR) clustered with natural killer cells. Despite these findings, the search for characteristic profiles linked to the rejection types proved to be a very difficult task since the cellular composition varied significantly among individuals within the same diagnostic category. The results of this study will be analyzed from the perspective of reconciling the classic way of diagnosing rejection and the immune situation "in situ" at the time of diagnosis.

Rethinking de novo immune hepatitis, an old concept for liver allograft rejection: Relevance of glutathione S-transferase T1 mismatch.

Antibody-mediated rejection (AMR) in liver transplantation has long been underestimated. The concept of the liver as an organ susceptible to AMR has emerged in recent years, not only in the context of the major histocompatibility complex with the presence of HLA donor-specific antibodies, but also with antigens regarded as "minor", whose role in AMR has been demonstrated. Among them, antibodies against glutathione S-transferase T1 have been found in 100% of patients with de novo autoimmune hepatitis (dnAIH) when studied. In its latest update, the Banff Working Group for liver allograft pathology proposed replacing the term dnAIH with plasma cell (PC)-rich rejection. Antibodies to glutathione S-transferase T1 (GSTT1) in null recipients of GSTT1 positive donors have been included as a contributory but nonessential feature of the diagnosis of PC-rich rejection. Also in this update, non-organ-specific anti-nuclear or smooth muscle autoantibodies are no longer included as diagnostic criteria. Although initially found in a proportion of patients with PC-rich rejection, the presence of autoantibodies is misleading since they are not disease-specific and appear in many different contexts as bystanders. The cellular types and proportions of the inflammatory infiltrates in diagnostic biopsies have been studied in detail very recently. PC-rich rejection biopsies present a characteristic cellular profile with a predominance of T lymphocytes and a high proportion of PCs, close to 30%, of which 16.48% are IgG4+. New data on the relevance of GSTT1-specific T lymphocytes to PC-rich rejection will be discussed in this review.

Identification of the cellular components involved in de novo immune hepatitis: a quantitative immunohistochemical analysis.

BACKGROUND: Diagnosis of de novo immune hepatitis (dnIH) after liver transplantation relies on biopsy findings, with an abundance of plasma cells (PCs) in the inflammatory infiltrates a hallmark of the disease. Very little is known about what other types of immune cells exist in the infiltrates mainly located in the portal areas of the liver tissue. METHODS: We analyzed the composition of T cells, B cells, PCs, and macrophages in the liver biopsies of 12 patients with dnIH, 9 of them obtained at the time of diagnosis. For comparison, biopsies from 9 patients with chronic rejection (CR) were included in the study. The results were analyzed by a computer-assisted stereology quantification method. RESULTS: The major components of the infiltrates in the portal areas were CD3+ T lymphocytes in both groups, with 36.6% in the dnIH group versus 49.4% in the CR group. CD20+ B lymphocytes represented 14.9% in the dnIH group and 29.1% in the CR group. Macrophage levels were very similar in the dnIH and CR group (19.7% versus 16.8%, respectively). PCs were much less represented in CR biopsies than those from the dnIH group (mean value of 4.7% versus 28.8%). CONCLUSION: In conclusion, the determination of a characteristic cellular profile could be an important tool for a more reliable diagnosis of dnIH, in support of the histological evaluation made by the pathologist, which in most cases is challenging. Recognition of this condition is crucial because it leads to graft failure if left untreated.

De novo recipient-specific Glutathione S-transferase T1 antibody development after HLA-identical hematopoietic cell transplantation.

Donor-specific antibodies against Glutathione S-transferase T1 (GSTT1) have been associated with de novo immune hepatitis after liver transplantation. These antibodies have also been found very early in allo-HCT associated with acute hepatic GvHD but in all the cases the donor cells had experienced previous priming through pregnancies. It remained to be explored whether or not primary recognition of the antigen occurs after HCT and what could be the consequences in the long term outcome. We genotyped a cohort of 68 HCT patients and found 11 with the GSTT1 null donor/positive recipient mismatch. After testing 114 serum samples, we found a unique case of a 33-year-old patient transplanted from his HLA-identical sibling donor in which IgG GSTT1 antibodies were detected for the first time on day +178. After stimulation of peripheral blood mononuclear cells with GSTT1 peptides we could demonstrate that this patient also had GSTT1-specific T lymphocytes that became activated upon exposure to the GSTT1 antigen. In this report, we describe the first case in which simultaneous T and B cell response against GSTT1 is developed in HCT although the clinical consequences in GvHD are still unclear.

T-cell allorecognition of donor glutathione S-transferase T1 in plasma cell-rich rejection.

AIM: To investigate the role of glutathione S-transferase T1 donor-specific T lymphocytes in plasma cell-rich rejection of liver allografts. METHODS: The study group included 22 liver transplant patients. Among them, 18 patients were mismatched for the glutathione S-transferase T1 (GSTT1) alleles (don+/rec-), and 4 were matched (don+/rec+). Seven of the mismatched patients produced anti-GSTT1 antibodies and developed plasma cell-rich rejection (former de novo immune hepatitis). For the detection of specific T lymphocytes, peripheral blood mononuclear cells were collected and stored in liquid nitrogen. The memory T cell response was studied by adding to the cell cultures to a mix of 39 custom-made, 15-mer overlapping peptides, which covered the entire GSTT1 amino acid sequence. The specific cellular response to peptides was analyzed by flow cytometry using the markers CD8, CD4, IL-4 and IFNγ. RESULTS: Activation of CD8+ T cells with different peptides was observed exclusively in the group of patients with plasma-cell rich rejection (3 out of 7), with production of IL-4 and/or IFNγ at a rate of 1%-4.92% depending on the peptides. The CD4+ response was most common and not exclusive for patients with the disease, where 5 out of 7 showed percentages of activated cells from 1.24% to 31.34%. Additionally, two patients without the disease but with the mismatch had cells that became stimulated with some peptides (1.45%-5.18%). Highly unexpected was the finding of a double positive CD4+CD8low T cell population that showed the highest degree of activation with some of the peptides in 7 patients with the mismatch, in 4 patients with plasma cell-rich rejection and in 3 patients without the disease. Unfortunately, CD4+CD8low cells represent 1% of the total number of lymphocytes, and stimulation could not be analyzed in 9 patients due to the low number of gated cells. Cells from the 4 patients included as controls did not show activation with any of the peptides. CONCLUSION: Patients with GSTT1 mismatch can develop a specific T-cell response, but the potential role of this response in the pathogenesis of plasma cell-rich rejection is unknown.

IgG subclass profile among anti-Glutathione S-transferase T1 antibodies in post-transplant de novo immune hepatitis.

Although the pathogenic pathways leading to de novo immune hepatitis (IH) are not completely understood, we have shown strong evidences of an antidonor response against Glutathione S-transferase T1 (GSTT1), an antigen exclusively expressed in the donor liver. The first sign of this process is the production of GSTT1 antibodies that, in 25% of the cases, will precede de novo IH. Because the presence of the antibodies is not sufficient to trigger the disease, we aimed to study GSTT1 IgG subclasses in a group of 18 liver transplant patients, 12 that developed de novo IH and 6 that remained free of disease. Surprisingly, the predominant subclasses were IgG1-GSTT 1 and IgG4-GSTT 1. The presence of IgG4-expressing plasma cells was also investigated in 10 available liver biopsies. Six biopsies coinciding with diagnosis showed a mean value of 32.8 IgG4+ plasma cells/hpf vs. 5.55 in patients without the disease. We have not found a distinctive GSTT1-IgG profile in patients with de novo IH, but the ratio IgG1-GSTT 1 /IgG4-GSTT 1 in samples from close to the time of diagnosis seemed to be important. The novel finding of abundant IgG4-GSTT 1 in liver transplantation is intriguing, but their possible role in pathogenesis of de novo IH remains unknown.

Variants of the IFI16 gene affecting the levels of expression of mRNA are associated with susceptibility to Behçet disease.

OBJECTIVE: Behçet disease (BD) is a multifactorial disease in which infectious agents have been proposed as triggers in genetically predisposed individuals. The aim of our study was to investigate the role of innate immunity receptors, specifically the nucleic acid sensors, in susceptibility to BD. METHODS: Seventy-four tag single nucleotide polymorphisms (tSNP) selected in 9 candidate genes (DDX58, IFIH1, TLR3, TLR7, TLR8, AIM2, IFI16, ZBP1, and TLR9) were genotyped in 371 patients and 854 controls. Assays of mRNA expression and allele-specific transcript quantification (ASTQ) were performed in 110 and 50 controls, respectively. RESULTS: Patients and controls were genotyped and 2 tSNP (rs6940 in IFI16 and rs855873 in AIM2) were associated with BD. To confirm this association, these tSNP were genotyped in 850 additional controls, and the total cohort was randomly divided into 2 cohorts. The association of these 2 tSNP with the disease remained in both cohorts. One haplotype (rs6940T-rs855873G) was identified as a risk factor (OR 1.41, 95% CI 1.06-1.86, p = 0.015), and another (rs6940A-rs855873A) as a protective factor (OR 0.65, 95% CI 0.47-0.90, p = 0.009). Samples with the risk haplotype had lower IFI16 expression levels than samples with the protective (0.99 ± 0.29 vs 1.23 ± 0.50, p = 0.022). Consistently, in the ASTQ assays performed with the nonsynonymous rs6940 SNP, the risk allele had lower IFI16 expression levels than the protective (p = 0.027). CONCLUSION: Our findings suggest association of IFI16, a cytosolic sensor of dsDNA and mediator of the AIM2 inflammasome-dependent pathway, in susceptibility to BD. Differences genetically determined in the levels of this molecule could be the cause of this association.

Mismatch on glutathione S-transferase T1 increases the risk of graft-versus-host disease and mortality after allogeneic stem cell transplantation.

Several drug-metabolizing enzymes, preferentially expressed in the liver, have the potential to act as minor histocompatibility antigens. In the present study, we analyzed the impact of glutathione S-transferase T1 (GSTT1), glutathione S-transferase M1, glutathione S-transferase P1, and UDP glucuronosyl transferase 2B17 (UGT2B17) disparities on the outcome of 125 patients undergoing allogeneic hematopoietic stem cell transplantation. Grades 2 to 4 acute graft-versus-host disease (aGVHD) developed in 56.2% versus 73.3% of GSTT1-matched versus mismatched patients (P = .048). Remarkably, 8.6% GSTT1-matched patients developed grades 2 to 4 liver aGVHD, compared with 36.8% among GSTT1-mismatched recipients (P < .001). Regarding chronic graft-versus-host disease (cGVHD), 34.8% versus 70.7% matched versus mismatched patients developed overall cGVHD (P = .038) and 16.3% versus 48% developed hepatic cGVHD (P = .006). We also found a strong association between the UGT2B17 mismatch and the risk of severe aGVHD (P = .001), especially with gut involvement (P < .001). Most striking was the influence of the GSTT1 mismatch on nonrelapse mortality (26.8% versus 52.6%, P = .031) and overall survival (62% versus 36.9%, P = .045). In summary, UGT2B17 and GSTT1 mismatch are risk factors for the development of GVHD and the latter also influences on mortality and survival after allogeneic transplantation from HLA-identical donors.

Hepatitis C virus-specific cellular immune responses in sustained virological responders with viral persistence in peripheral blood mononuclear cells.

BACKGROUND & AIMS: Hepatitis C virus (HCV)-RNA detection in peripheral blood mononuclear cells (PBMCs) after recovery from HCV infection, is a type of occult HCV infection although is unclear how the viral persistence in PBMCs affects HCV-specific T-cell responses. The aim of this study was to investigate if cellular immune responses are modified by HCV persistence in PBMCs. METHODS: HCV-specific CD4(+) and CD8(+) T-cell responses against six HCV peptides, situated within the non-structural (NS) proteins NS3, NS4b and NS5b, were measured by flow cytometry-through intracellular detection of gamma interferon (IFN-γ) or interleukin 4 (IL-4) and CD69 expression- in 27 sustained virological responders (SVR): 13 with and 14 without occult HCV infection in PBMCs, detected by strand-specific real-time PCR. Ten healthy individuals and 14 chronically infected patients with viraemia, were included as controls. RESULTS: SVR without occult infection showed a higher percentage of activated CD4(+) cells against peptides belonging to NS3 (p124, p153) and NS5b (p257, p294), activated CD8(+) cells against NS3 (p124, p153, p158) and NS5b-p294, as well as an elevated percentage of CD4(+) cells releasing IFN-γ + IL-4 against NS3-p153, and by CD8(+) cells against NS3 (p124, p153). SVR without occult infection showed a higher percentage of activation and release of IFN-γ + IL-4 by both cell subpopulations than the two group of controls, in contrast to SVR with occult infection. CONCLUSION: The lower HCV-specific T-cell response found in SVR with occult infection indicates that the immune response may be impaired when the virus persists in PBMCs.

HLA and non-HLA genes in Behçet's disease: a multicentric study in the Spanish population.

INTRODUCTION: According to genome wide association (GWA) studies as well as candidate gene approaches, Behçet's disease (BD) is associated with human leukocyte antigen (HLA)-A and HLA-B gene regions. The HLA-B51 has been consistently associated with the disease, but the role of other HLA class I molecules remains controversial. Recently, variants in non-HLA genes have also been associated with BD. The aims of this study were to further investigate the influence of the HLA region in BD and to explore the relationship with non-HLA genes recently described to be associated in other populations. METHODS: This study included 304 BD patients and 313 ethnically matched controls. HLA-A and HLA-B low resolution typing was carried out by PCR-SSOP Luminex. Eleven tag single nucleotide polymorphisms (SNPs) located outside of the HLA-region, previously described associated with the disease in GWA studies and having a minor allele frequency in Caucasians greater than 0.15 were genotyped using TaqMan assays. Phenotypic and genotypic frequencies were estimated by direct counting and distributions were compared using the χ(2) test. RESULTS: In addition to HLA-B*51, HLA-B*57 was found as a risk factor in BD, whereas, B*35 was found to be protective. Other HLA-A and B specificities were suggestive of association with the disease as risk (A*02 and A*24) or protective factors (A*03 and B*58). Regarding the non-HLA genes, the three SNPs located in IL23R and one of the SNPs in IL10 were found to be significantly associated with susceptibility to BD in our population. CONCLUSION: Different HLA specificities are associated with Behçet's disease in addition to B*51. Other non-HLA genes, such as IL23R and IL-10, play a role in the susceptibility to the disease.

Clinical relevance of GSTT1 mismatch in solid organ and hematopoietic stem cell transplantation.

Since 2001, year in which Glutathione S-transferase theta class 1 (GSTT1) gene appeared to be related to the occurrence of de novo immune hepatitis after liver transplantation, this gene with two allelic variants, GSTT1(∗)A (wild type copy) and GSTT1(∗)0 (deletion copy), has emerged as a potent histocompatibility antigen. Namely, a donor-recipient liver graft combination of a GSTT1-negative recipient (homozygous for GSTT1(∗)0) and a GSTT1-positive donor results, very frequently, in the appearance of a severe immune-related graft hepatitis with production of IgG anti-GSTT1 antibodies. In kidney transplantation, GSTT1 donor-recipient mismatch is also associated with production of anti-GSTT1 antibodies and antibody-related rejection episodes with C4d deposition in graft biopsy. The more recent discovery of anti-GSTT1 antibodies in hematopoietic stem cell transplantation, clearly confirms a role of GSTT1 as histocompatibility antigen in this setting. Interestingly, the consequences of GSTT1 mismatch might be either rejection or graft-versus-host disease, depending on the GSTT1 mismatch's sense of direction. The involvement of GSTT1 in immunological allo-recognition is unquestionable although there are still many aspects that remain to be explored.

Association of the AIRE gene with susceptibility to rheumatoid arthritis in a European population: a case control study.

INTRODUCTION: AIRE is a transcriptional regulator playing a functional role in thymocyte education and negative selection by controlling the expression of peripheral antigens in the thymus. Recently, the AIRE gene was identified as a genetic risk factor for rheumatoid arthritis (RA) in genome wide association (GWA) studies performed in the Japanese population. According to the available data this association is restricted to the Asian population. However, different facts could influence the lack of association in Caucasian populations. The aim of this study was to further investigate the possible role of the AIRE gene in susceptibility to RA in a Caucasian population. METHODS: A total of 472 Spanish Caucasian RA patients and 475 ethnically matched controls were included in the study. Three single-nucleotide polymorphisms (SNPs) (rs2776377, rs878081 and rs1055311) with a minor allele frequency>0.05 in the Caucasian population which were not included in the high-throughput platforms used in the GWA studies performed in susceptibility to RA, and two SNPs (rs2075876 and rs1800520) associated with RA in the Japanese population, were selected and genotyped using TaqMan assays. RESULTS: No significant differences in the distribution of the alleles of rs2776377, rs2075876, rs1055311 and rs1800520 SNPs between RA patients and controls were observed. Nevertheless, the frequency of the C allele of rs878081 was significantly higher among RA patients (80.5% vs. 74.6% in the control group, pc=0.012, OR=1.41, 95%CI 1.13-1.75). Regarding the distribution of the rs878081 genotypes, a higher frequency of CC homozygous individuals was found in the RA patient group (65.56% vs. 56.47% in the control group, pc=0.013, OR=1.47, 95%CI 1.12-1.93). The in silico analysis predicted lower affinity to the binding-site of a motif of the transcription NF-κB family and lower transcription levels of AIRE gene for the rs878081C risk variant CONCLUSIONS: Our findings suggest that the AIRE gene is associated with susceptibility to RA in the Spanish population. Probably, this association has not been detected in the European population in the GWA studies because the earliest high-throughput platforms did not include SNP suitable markers (e.g. rs878081).

Expression of CD81, SR-BI and LDLR in lymphocytes and monocytes from patients with classic and occult hepatitis C virus infection.

CD81, the scavenger receptor-BI (SR-BI) and the low-density lipoprotein receptor (LDLR) are involved in peripheral blood mononuclear cells (PBMCs) hepatitis C virus (HCV) entry. To investigate if these molecules are altered by HCV, 20 controls and 66 patients: 37 untreated and 29 sustained virological responders, were studied. CD81 and LDLR expression, measured the percentage of cells expressing the HCV-receptors and their mean fluorescence intensity (MFI), was analyzed on lymphocytes and monocytes, as well as SR-BI on monocytes by flow cytometry. RNA was extracted from PBMCs and detection of the HCV-RNA positive and negative strands was performed by strand-specific RT-PCR. A statistically significant increase of CD81 expression was observed on lymphocytes, a higher percentage of LDLR on lymphocytes and monocytes, as well as SR-BI on monocytes was found in the patients as compared to the controls (P < 0.05 in all cases). Untreated patients showed a higher percentage of LDLR(+) lymphocytes than sustained virological responders (P = 0.025). Nineteen sustained virological responders bore the HCV-RNA positive strand in PBMCs; nine of them the negative strand too. Sustained virological responders with occult infection and viral replication, showed a higher expression of LDLR on lymphocytes (P < 0.05) and a higher LDLR MFI on monocytes (P = 0.011) than those without viral replication. In conclusion, HCV exposure modifies expression levels of the receptors studied, being LDLR related with HCV replication, not only in the classic but also in the occult infection.

Clinical relevance of anti-HLA donor-specific antibodies detected by Luminex assay in the development of rejection after renal transplantation.

BACKGROUND: The role of anti-human leukocyte antigen (HLA) donor-specific antibodies (DSA) detected by Luminex in the development of rejection is not fully understood. METHODS: A study including 369 patients who received transplants from deceased donors with a negative complement-dependent cytotoxicity crossmatch (XM) was performed. From the total of patients, 151 underwent a renal biopsy because of renal dysfunction, whereas the 218 remaining showed a stable renal function, and no rejection was assumed. Diagnosis and type of rejection was based in biopsy data. RESULTS: Patients with a positive virtual XMs showed more rejection episodes of any types when comparing with patients with negative virtual XMs (P<0.0001). Nevertheless, there were no significant differences between patients without anti-HLA antibodies and patients with anti-HLA no DSA. Allograft impairment was caused by a rejection episode in 84% (32/38) of patients with anti-HLA-DSA but only in 30% (34/113) of patients without anti-HLA-DSA. Regarding the type of rejection detected in the biopsy, all the patients with de novo (after transplantation) anti-HLA-DSA were diagnosed as antibody-mediated rejection (AMR) or AMR+T-cell-mediated rejection, whereas most of the patients without anti-HLA-DSA (68%) were diagnosed with T-cell-mediated rejection, and patients with preexistent anti-HLA-DSA showed a more homogeneous distribution of the different types of rejection. CONCLUSIONS: According to our results, patients with preformed or de novo anti-HLA-DSA showed the highest likelihood to suffer rejection episodes. Transplantation with preformed anti-HLA-DSA should be avoided, and an early detection of de novo HLA antibodies is important to treat patients before damage occurs in the graft.

HAVCR1 gene haplotypes and infection by different viral hepatitis C virus genotypes.

The hepatitis A virus cellular receptor 1 (HAVCR1) gene is highly polymorphic, and several variants have been associated with susceptibility to allergic and autoimmune diseases. The HAVCR1 gene region was identified as a candidate for hepatitis C virus (HCV) natural clearance in a genotyping study of selected immune response genes in both European-American and African-American populations. The aim of the present study was to explore the influence of HAVCR1 in the outcome of HCV infection in the Spanish population. Three cohorts, consisting of 354 subjects with persistent HCV infection (285 with persistent HCV monoinfection and 69 with natural clearance), 182 coinfected HIV/HCV patients, and 320 controls, were included. Samples were genotyped in several polymorphic positions, insertion/deletion variants in exon 4 and tag single nucleotide polymorphisms (SNPs), in order to define previously described HAVCR1 haplotypes (haplotypes A to D). No statistically significant differences were observed with spontaneous resolution of infection or with viral clearance after treatment. Nevertheless, different rates of infection by viral genotypes (G's) were observed among the HAVCR1 haplotypes. Individuals bearing haplotype C had the highest viral G1 infection rate when compared to individuals bearing other haplotypes (75.82% versus 57.72%, respectively; corrected P value [P(c)], 3.2 × 10(-4); odds ratio [OR], 2.30; 95% confidence interval [CI], 1.51 to 3.47). Thus, HAVCR1 could be involved in susceptibility or resistance to infection by a particular HCV genotype.

Clinical relevance of HLA donor-specific antibodies detected by single antigen assay in kidney transplantation.

BACKGROUND: Clinical relevance of donor-specific antibodies (DSAs) detected by a single antigen Luminex virtual crossmatch in pre-transplant serum samples from patients with a negative cytotoxicity-dependent complement crossmatch is controversial. The aim of this study was to analyse the influence of a pre-transplant positive virtual crossmatch in the outcome of kidney transplantation. METHODS: A total of 892 patients who received a graft from deceased donors after a negative cytotoxicity crossmatch were included. Presence of anti-human leucocyte antigen (HLA) antibodies was investigated using a Luminex screening assay and anti-HLA specificities were assigned performing a Luminex single antigen assay. RESULTS: Graft survival was significantly worse among patients with anti-HLA DSA compared to both patients with anti-HLA with no DSA (P = 0.001) and patients without HLA antibodies (P < 0.001) using a log-rank test. No graft survival differences between anti-HLA with no DSA and no HLA antibodies patient groups were observed (P = 0.595). Influence of both anti-Class I and anti-Class II DSA was detected (P < 0.0001 in both cases). When the fluorescence values were stratified in four groups, no significant differences in graft survival were observed among the groups with fluorescence levels >1500 (global P > 0.05). CONCLUSIONS: The presence of preformed HLA DSA in transplanted patients with a negative cytotoxicity crossmatch is associated with a lower allograft survival. The detection of anti-HLA with no DSA has no influence in the graft outcome. Finally, there were no demonstrable effects of mean fluorescence intensity (MFI) values >1500 on graft survival.

Influence of glutathione S-transferase T1 donor/recipient mismatch and anti-GSTT1 antibodies in hepatic graft-versus-host-disease.

B cell responses to minor histocompatibility antigens (mHags) have not been extensively studied after allogeneic hematopoietic stem cell transplantation (HSCT). Glutathione S-transferase T1 (GSTT1) is a drug metabolizing enzyme encoded by a single gene that is highly expressed in liver and kidney. Anti-GSTT1 antibodies have been described in the context of antibody-mediated rejection in kidney and liver transplantation, due to a mismatch between donor and recipient. The aim of the present study was to investigate the specific immune response against GSTT1 in HSCT with production of antibodies and their influence in the development of hepatic graft-versus-host-disease (GVHD). Forty patients and their respective donors were included in the study. The median follow-up time was 35.6 months (range 0.6-76 months) and a total of 349 serum samples were tested for the presence of anti-GSTT1 antibodies by ELISA test. Statistical analysis was performed by defining the GSTT1 null donor/positive recipient as mismatch compared with the other three genetic combinations regarded as GSTT1-matched. Antibodies were found in three patients within the group of null donor/positive recipient and one within the null/null group. Development of liver GVHD, particularly its acute form, was highly associated with the GSTT1-mismatch (P=0.0178) and with the presence of post-transplant anti-GSTT1 antibodies (P=0.0076). We conclude that GSTT1 could be considered as a new mHag in hepatic GVHD. The fact that three donors were parous females and the rapid production of antibodies after HSCT suggests the existence in the graft of memory B-cells specific for the GSTT1 antigen.

Antibodies against heterogeneous nuclear ribonucleoprotein K in patients with cardiac allograft vasculopathy.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is the most serious long-term complication after cardiac transplantation. T-cell-mediated immune response has been implicated as the central mechanism for this form of graft rejection, but the role of humoral immunity is still controversial. METHODS: This study investigated whether human leukocyte antigen (HLA) and non-HLA antibodies are associated with CAV and if their presence can be used to identify patients at high risk of developing CAV. Diagnosis of CAV was made by angiography and intravascular ultrasound (IVUS) technology. Sera from 48 heart transplant recipients were assessed for the presence of antibodies. RESULTS: Although anti-HLA or anti-major histocompatibility complex class I chain-related gene A (MICA) antibodies in patients with or without CAV were not statistically different, heterogeneous nuclear ribonucleoprotein K (hnRNP-K) was identified as a new antigenic target after the screening of a human coronary artery smooth muscle cells complementary DNA (cDNA) expression library with a serum sample from a CAV patient. Four years after transplantation, presence of anti-hnRNP-K antibodies was significantly higher in the IVUS-defined CAV group (85.3%) and angiography-defined CAV patients (90.5%) compared with the non-CAV group (p < 0.0001 and p = 0.0023 respectively). CONCLUSIONS: The presence of anti-hnRNP-K antibodies 4 years after the transplant is statistically associated with CAV disease, regardless of the diagnostic technique. Therefore, prospective detection of these antibodies could be proposed as a helpful biomarker in CAV diagnosis.