Association between an MHC class II allele and clearance of hepatitis B virus in the Gambia.

BACKGROUND: The course of hepatitis B virus (HBV) infection does not appear to be determined by variations in viral virulence and may be influenced by the host immune response. We studied the distribution of human leukocyte antigens in children and adult men in the Gambia who spontaneously recovered from HBV infection as compared with the distribution of these antigens in subjects with persistent infection. METHODS: In a two-stage, case-control study, we analyzed the frequency of MHC class I antigens and class II haplotypes in people with either transient or persistent HBV infection. MHC class I typing was performed by microlymphocytotoxicity assays. MHC class II typing was performed with analysis of restriction-fragment-length polymorphisms (RFLPs), supplemented by other techniques. RESULTS: In the first stage (the study of children up to the age of 10 years), the RFLP pattern 25-1, which includes the class II allele HLA-DRB1*1302, was found in 58 of 218 subjects with transient HBV infection (26.6 percent) and 30 of 185 subjects with persistent infection (16.2 percent) (relative risk of carrying the 25-1 pattern in the persistently infected group as compared with the transiently infected group, 0.53; 95 percent confidence interval, 0.32 to 0.90; P = 0.012). In the second stage (the study of adults), HLA-DRB1*1302 was found in 50 of 195 subjects with transient HBV infection (25.6 percent) and in 3 of 40 subjects with persistent infection (7.5 percent) (relative risk, 0.24; 95 percent confidence interval, 0.04 to 0.80; P = 0.012). The RFLP pattern 13-2, which includes the class II allele DRB1*1301, was less frequent in children with persistent infection than in those with transient infection, an association that was neither confirmed nor excluded by the data on adults. Possible associations with HLA class I antigens found in children were not supported by the data on adults. CONCLUSIONS: The MHC class II allele DRB1*1302 was associated with protection against persistent HBV infection among both children and adults in the Gambia.