Association between HLA class II alleles and protection from or susceptibility to chronic hepatitis C

Background/Aims: Recent studies have suggested that the course of chronic hepatitis C may be influenced by the immunogenetic background of the host. Specifically, HLA-DR11 (5) has been associated with less advanced hepatitis C virus (HCV)-related liver disease. The aim of the present study was to investigate whether HLA-DRB1*11 subtypes or HLA-DQA1 and DQB1 genes might be associated with protection from or susceptibility to chronic HCV infection, histological severity of HCV-induced liver disease and infecting HCV genotype. Methods: Ninety-nine unrelated outpatients with histologically documented chronic hepatitis C were studied and their allele frequencies were compared with those of 179 ethnically matched controls and with those of 41 HCV RNA-positive patients with persistently normal aminotransferase levels (HCV carriers). HLA-DQ types and HLA-DRB1*11 subtypes were determined by polymerase chain reaction gene amplification with sequence specific primers. Results: None of 10 DQA1 or 12 DQB1 alleles was significantly associated with susceptibility to or protection from chronic HCV infection or with histological staging or with HCV genotype. However, analysis of DQA1-DQB1 combinations showed that DQA1*0201-DQB1*0201 combination was significantly more frequent in patients compared to controls, both in cis (26.3% vs 16.2%, p=0.04, odds ratio 1.8, 95% confidence interval, 0.96-3.5) and in trans (12.1% vs. 1.1%, p=0.0001, OR=12.2, 95% CI, 2.6-113.7). HCV carriers did not differ from controls or from patients in the frequency of DQA1-DQB1 combinations. The extended haplotype DRB1*1104, DQA1*0501, DQB1*0301 was seen significantly less frequently in patients than in controls (8% vs 22.3%, p=0.0025, OR=0.31, 95% CI, 0.12-0.7) or HCV-RNA carriers (8% vs 26.8%, p=0.003, OR=0.24, 95% CI, 0.08-0.73). Conclusions: Immunogenetic factors may play a role in determining both protection from and susceptibility to chronic hepatitis C, the trans-dimer DQA1*0201-DQB1*0201 predisposing to and the DRB1*1104, DQA1*0501, DQB1*0301 haplotype protecting from chronic hepatitis C.