A novel variant marking HLA-DP expression levels predicts recovery from hepatitis B virus infection.

Variants near the HLA-DP gene show the strongest genome-wide association with chronic hepatitis B virus (HBV) infection and HBV recovery/persistence in Asians. To test the effect of the HLA-DP region on outcomes to HBV infection, we sequenced the polymorphic HLA-DPB1 and DPA1 coding exons and the corresponding 3' untranslated regions (3'UTRs) in 662 individuals of European-American and African-American ancestry. The genome-wide association study (GWAS) variant (rs9277535; 550A/G) in the 3'UTR of the HLA-DPB1 gene that associated most significantly with chronic hepatitis B and outcomes to HBV infection in Asians had a marginal effect on HBV recovery in our European- and African-American samples (odds ratio [OR] = 0.39, P = 0.01, combined ethnic groups). However, we identified a novel variant in the HLA-DPB1 3'UTR region, 496A/G (rs9277534), which associated very significantly with HBV recovery in both European and African-American populations (OR = 0.37, P = 0.0001, combined ethnic groups). The 496A/G variant distinguishes the most protective HLA-DPB1 allele (DPB1*04:01) from the most susceptible (DPB1*01:01), whereas 550A/G does not. 496A/G has a stronger effect than any individual HLA-DPB1 or DPA1 allele and any other HLA alleles that showed an association with HBV recovery in our European-American cohort. The 496GG genotype, which confers recessive susceptibility to HBV persistence, also associates in a recessive manner with significantly higher levels of HLA-DP surface protein and transcript level expression in healthy donors, suggesting that differences in expression of HLA-DP may increase the risk of persistent HBV infection.

Human leukocyte antigen genotype and risk of HIV disease progression before and after initiation of antiretroviral therapy.

While the human leukocyte antigen (HLA) genotype has been associated with the rate of HIV disease progression in untreated patients, little is known regarding these relationships in patients using highly active antiretroviral therapy (HAART). The limited data reported to date identified few HLA-HIV disease associations in patients using HAART and even occasional associations that were opposite of those found in untreated patients. We conducted high-resolution HLA class I and II genotyping in a random sample (n = 860) of HIV-seropositive women enrolled in a long-term cohort initiated in 1994. HLA-HIV disease associations before and after initiation of HAART were examined using multivariate analyses. In untreated HIV-seropositive patients, we observed many of the predicted associations, consistent with prior studies. For example, HLA-B*57 (ß = -0.7; 95% confidence interval [CI] = -0.9 to -0.5; P = 5 × 10⁻¹¹) and Bw4 (ß = -0.2; 95% CI = -0.4 to -0.1; P = 0.009) were inversely associated with baseline HIV viral load, and B*57 was associated with a low risk of rapid CD4+ decline (odds ratio [OR] = 0.2; 95% CI = 0.1 to 0.6; P = 0.002). Conversely, in treated patients, the odds of a virological response to HAART were lower for B*57:01 (OR = 0.2; 95% CI = 0.0 to 0.9; P = 0.03), and Bw4 (OR = 0.4; 95% CI = 0.1 to 1.0; P = 0.04) was associated with low odds of an immunological response. The associations of HLA genotype with HIV disease are different and sometimes even opposite in treated and untreated patients.

The relation of HLA genotype to hepatitis C viral load and markers of liver fibrosis in HIV-infected and HIV-uninfected women.

BACKGROUND: Human leukocyte antigen (HLA) class I and II genotype is associated with clearance of hepatitis C virus (HCV) infection, but little is known regarding its relation with HCV viral load or risk of liver disease in patients with persistent HCV infection. METHODS: High-resolution HLA class I and II genotyping was conducted in a prospective cohort of 519 human immunodeficiency virus (HIV)-seropositive and 100 HIV-seronegative women with persistent HCV infection. The end points were baseline HCV viral load and 2 noninvasive indexes of liver disease, fibrosis-4 (FIB-4), and the aspartate aminotransferase to platelet ratio index (APRI), measured at baseline and prospectively. RESULTS: DQB1*0301 was associated with low baseline HCV load (ß = -.4; 95% confidence interval [CI], -.6 to -.3; P < .00001), as well as with low odds of FIB-4-defined (odds ratio [OR], .5; 95% CI, .2-.9; P = .02) and APRI-defined liver fibrosis (OR, .5; 95% CI, .3-1.0; P = .06) at baseline and/or during follow-up. Most additional associations with HCV viral load also involved HLA class II alleles. Additional associations with FIB-4 and APRI primarily involved class I alleles, for example, the relation of B*1503 with APRI-defined fibrosis had an OR of 2.0 (95% CI, 1.0-3.7; P = .04). CONCLUSIONS: HLA genotype may influence HCV viral load and risk of liver disease, including DQB1*0301, which was associated with HCV clearance in prior studies.

Specific human leukocyte antigen class I and II alleles associated with hepatitis C virus viremia.

UNLABELLED: Studies of human leukocyte antigen (HLA) alleles and their relation with hepatitis C virus (HCV) viremia have had conflicting results. However, these studies have varied in size and methods, and few large studies assessed HLA class I alleles. Only one study conducted high-resolution class I genotyping. The current investigation therefore involved high-resolution HLA class I and II genotyping of a large multiracial cohort of U.S. women with a high prevalence of HCV and HIV. Our primary analyses evaluated associations between 12 HLA alleles identified through a critical review of the literature and HCV viremia in 758 HCV-seropositive women. Other alleles with >5% prevalence were also assessed; previously unreported associations were corrected for multiple comparisons. DRB1*0101 (prevalence ratio [PR] = 1.7; 95% confidence interval [CI] = 1.1-2.6), B*5701 (PR=2.0; 95% CI = 1.0-3.1), B*5703 (PR = 1.7; 95% CI = 1.0-2.5), and Cw*0102 (PR = 1.9; 95% CI = 1.0-3.0) were associated with the absence of HCV RNA (i.e., HCV clearance), whereas DRB1*0301 (PR = 0.4; 95% CI = 0.2-0.7) was associated with HCV RNA positivity. DQB1*0301 was also associated with the absence of HCV RNA but only among HIV-seronegative women (PR = 3.4; 95% CI = 1.2-11.8). Each of these associations was among those predicted. We additionally studied the relation of HLA alleles with HCV infection (serostatus) in women at high risk of HCV from injection drug use (N = 838), but no significant relationships were observed. CONCLUSION: HLA genotype influences the host capacity to clear HCV viremia. The specific HLA associations observed in the current study are unlikely to be due to chance because they were a priori hypothesized.

Diversity of MICA and linkage disequilibrium with HLA-B in two North American populations.

The MICA gene has a high degree of polymorphism. Allelic variation of MICA may influence binding of these ligands to the NK cell receptor NKG2D and may affect organ transplantation and/or disease pathogenesis. Knowledge of the population distribution of MICA alleles and their linkage disequilibrium (LD) with class I human leukocyte antigen (HLA) will enhance our understanding of the potential functional significance of the MICA polymorphism. In the present study, we characterized the MICA and HLA-B polymorphisms in two North American populations: European and African. The individual racial groups showed rather limited variation at the MICA locus, where the same set of three most common alleles, MICA*00201, *004, and *00801, account for 64 and 71% of the allele frequency in European-Americans and African-Americans, respectively. Other common alleles (allele frequency >5% in a population) include MICA*00901 and *010. MICA alleles showed strong linkage disequilibrium with HLA-B. Typically, a common MICA allele has strong LD with several HLA-B alleles, whereas most HLA-B alleles and their related serological groups are associated with a single MICA allele. The lack of evidence for an active diversification of the MICA gene after racial separation indicates an evolutionary history distinct from that of the classical HLA genes.

HLA-B alleles associate consistently with HIV heterosexual transmission, viral load, and progression to AIDS, but not susceptibility to infection.

OBJECTIVE: HLA class I polymorphism is known to affect the rate of progression to AIDS after infection with HIV-1. Here we test the consistency of HLA-B allelic effects on progression to AIDS, heterosexual HIV transmission, and 'set point' viral levels. METHODS: We used adjusted Cox proportional hazard models in previously published relative hazard values for the effect of HLA-B alleles on progression to AIDS (n = 1089). The transmission study included 303 HIV-1-infected men with hemophilia and their 323 female sex partners (Multicenter Hemophilia Cohort Study cohort). Among 259 HIV-1 seroconverters (Multicenter AIDS Cohort Study cohort), HIV RNA levels at 'set point' were determined in stored plasma samples by a reverse-transcription polymerase chain reaction assay. HLA-B genotyping was performed by sequence-specific oligonucleotide hybridization and DNA sequencing. RESULTS: Several HLA-B alleles showed consistent associations for AIDS risk, infectivity, and 'set point' HIV RNA. HLA-B*35 was associated with more rapid progression to AIDS (relative hazard 1.39; P = 0.008), greater infectivity (odds ratio 3.14; P = 0.002), and higher HIV RNA (P = 0.01), whereas the presence of either B*27 or B*57 associated with slower progression to AIDS (B*27: relative hazard 0.49, P < 0.001; B*57: relative hazard 0.40, P < 0.0001), less infectivity (odds ratio 0.22 and 0.31, respectively, though not significant), and lower viral levels (P < 0.0001). Importantly, HLA-B polymorphism in female partners was not associated with susceptibility to HIV-1 infection. CONCLUSION: HLA-B polymorphisms that affect the risk of AIDS may also alter HIV-1 infectivity, probably through the common mechanism of viral control, but they do not appear to protect against infection in our cohort.

Association of human leukocyte antigens with nasopharyngeal carcinoma in high-risk multiplex families in Taiwan.

An association between specific human leukocyte antigens (HLA) alleles and nasopharyngeal carcinoma (NPC) has been reported for sporadic NPC, but studies of familial NPC are lacking. We evaluated this association with familial NPC in a study of 301 NPC cases and 1010 family and community controls from Taiwan. Class I HLA alleles were characterized using a sequence-based typing protocol. Allele frequencies between case and control groups were compared by chi(2) or exact tests. For alleles associated with NPC, odds ratios (OR) and 95% confidence intervals (CI) were calculated. Similar allelic frequency distribution and HLA associations were found as those previously reported for sporadic NPC: protective effect for HLA-A*1101 and increased risk for HLA-A*0207, HLA-A*3303, HLA-B*3802, and HLA-B*5801. Overall, the magnitude of observed associations was weakest when cases were compared with sibling controls and strongest when compared with unrelated community controls. Evaluating the joint effect of HLA-A*0207 and HLA-B*4601, individuals who were carriers of HLA-A*0207 with or without the presence of HLA-B*4601 had a 1.9-fold (95% CI = 1.0-3.4) and 2.1-fold (95% CI = 0.83-5.3) risk of NPC, respectively. Conversely, carriers of HLA-B*4601 in the absence of HLA-A*0207 had a 50% reduction in NPC risk (95% CI = 0.27-0.93). Comparable findings from our family study and those from previous sporadic studies were found with the notable exception of a lack of positive association between HLA-B*4601 and familial NPC in the absence of HLA-A*0207. This finding requires replication in larger studies.

Comprehensive analysis of class I and class II HLA antigens and chronic hepatitis B virus infection.

Following an acute hepatitis B virus (HBV) infection, clearance or persistence is determined in part by the vigor and breadth of the host immune response. Since the human leukocyte antigen system (HLA) is an integral component of the immune response, we hypothesized that the highly polymorphic HLA genes are key determinants of viral clearance. HLA class I and II genes were molecularly typed in 194 Caucasian individuals with viral persistence and 342 matched controls who had cleared the virus. A single class I allele, A*0301 (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.30 to 0.72; P = 0.0005) was associated with viral clearance. The class II allele DRB1*1302 was also associated with clearance (OR, 0.42; 95% CI, 0.19 to 0.93; P = 0.03), but its significance decreased in a multivariate model that included other alleles associated with disease outcome as covariates. B*08 was associated with viral persistence both independently (OR, 1.59; 95% CI, 1.04 to 2.43; P = 0.03) and as part of the conserved Caucasian haplotype A*01-B*08-DRB1*03. The B*44-Cw*1601 (OR, 2.23; 95% CI, 1.13 to 4.42; P = 0.02) and B*44-Cw*0501 (OR, 1.99; 95% CI, 1.22 to 3.24; P = 0.006) haplotypes were also associated with viral persistence. Interestingly, both the B*08 haplotype and DR7, which forms a haplotype with B*44-Cw*1601, have been associated with nonresponse to the HBV vaccine. The associations with class I alleles are consistent with a previously implicated role for CD8-mediated cytolytic-T-cell response in determining the outcome of an acute HBV infection.