Hepatitis B virus (HBV) infection is a major health issue worldwide which may lead to hepatic dysfunction, liver cirrhosis and hepatocellular carcinoma. To identify host genetic factors that are associated with chronic hepatitis B (CHB) susceptibility, we previously conducted a two-stage genome-wide association study (GWAS) and identified the association of HLA-DP variants with CHB in Asians; however, only 179 cases and 934 controls were genotyped using genome-wide single nucleotide polymorphism (SNP) arrays. Here, we performed a second GWAS of 519 747 SNPs in 458 Japanese CHB cases and 2056 controls. After adjustment with the previously identified variants in the HLA-DP locus (rs9277535), we detected strong associations at 16 loci with P-value of <5 × 10⁻⁵. We analyzed these loci in three independent Japanese cohorts (2209 CHB cases and 4440 controls) and found significant association of two SNPs (rs2856718 and rs7453920) within the HLA-DQ locus (overall P-value of 5.98 × 10⁻²⁸ and 3.99 × 10⁻³⁷). Association of CHB with SNPs rs2856718 and rs7453920 remains significant even after stratification with rs3077 and rs9277535, indicating independent effect of HLA-DQ variants on CHB susceptibility (P-value of 1.52 × 10⁻²¹– 2.38 × 10⁻³⁰). Subsequent analyses revealed DQA1*0102-DQB1*0604 and DQA1*0101-DQB1*0501 [odds ratios (OR) =0.16, and 0.39, respectively] as protective haplotypes and DQA1*0102-DQB1*0303 and DQA1*0301-DQB1*0601 (OR = 19.03 and 5.02, respectively) as risk haplotypes. These findings indicated that variants in antigen-binding regions of HLA-DP and HLA-DQ contribute to the risk of persistent HBV infection.

Background. Pegylated interferon, ribavirin, and telaprevir triple therapy is a new strategy expected to eradicate the hepatitis C virus (HCV) even in patients infected with difficult-to-treat genotype 1 strains, although adverse effects, such as anemia and rash, are frequent. Methods. We assessed efficacy and predictive factors for sustained virological response (SVR) for triple therapy in 94 Japanese patients with HCV genotype 1. We included recently identified predictive factors, such as IL28B and ITPA polymorphism, and substitutions in the HCV core and NS5A proteins. Results. Patients treated with triple therapy achieved comparatively high SVR rates (73%), especially among treatment-naive patients (80%). Of note, however, patients who experienced relapse during prior pegylated interferon plus ribavirin combination therapy were highly likely to achieve SVR while receiving triple therapy (93%); conversely, prior nonresponders were much less likely to respond to triple therapy (32%). In addition to prior treatment response, IL28B SNP genotype and rapid viral response were significant independent predictors for SVR. Patients with the anemia-susceptible ITPA SNP rs1127354 genotype typically required ribavirin dose reduction earlier than did patients with other genotypes. Conclusions. Analysis of predictive factors identified IL28B SNP, rapid viral response, and transient response to previous therapy as significant independent predictors of SVR after triple therapy.