HLA class II genes determine the natural variance of hepatitis C viral load

The aim of this study was to investigate the relationship between human leu kocyte antigen (HLA) class II genes and the natural fluctuations in hepatit is C viral load in a homogeneous patient population. The study group consis ted of 57 viremic (hepatitis C virus [HCV] 1b) women for whom HLA class II DRB1 and DQB1 haplotyping, virologic, histologic, and biochemical markers o f disease activity were available. All patients were infected with HCV 1b f rom the same source of hepatitis C-contaminated anti-D immunoglobulin durin g the period from May 1977 to November 1978, The mean slope of change of vi ral load was 0.34 (SD +/- 0.73) log(10) viral copies/mL/year, which is sign ificantly different from zero, P < 10(-9). Analysis of the relationship bet ween the slope of change of viral load and HLA class II haplotype indicated a significantly different slope of change of viral load between the allele s of (1) DRB1"15 and DRB1*0701, and (2) DQB1*0602 and DQB1*0201, P-c = .036 and P-c = .026 after Bonferroni correction for multiple comparisons, respe ctively. Significant differences for grade and stage of disease at liver bi opsy were observed for DQB1*0501 and DQB1*0201 alleles; P = .019, r(s) = .6 4, and P = .047, r(s) = .57, respectively. In addition, significant differe nces in stage of disease were found to exist between DRB1*13 and DRB1*0701, P = .031, r(s) = -.71. Our results define an association between the slope of change of viral load and HLA class II haplotype in patients infected wi th genotype Ib of HCV, This suggests a role for host immunogenetic factors in HCV infection in this homogeneous group.