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Protective effect of HLA‐B57 on HCV genotype 2 infection in a West African population

Recovery from Hepatitis C virus (HCV) infection is considered infrequent (<20%) in western populations but reaches 50% in West Africa where genotype 2 infection is predominant. To investigate the role of cellular immune responses and host genetics in this phenomenon, samples from 104 Ghanaian blood donors reactive with anti‐HCV assays were collected between 2000 and 2005. HCV antibody was confirmed by Western blot using genotype 2 recombinant core, E2 and NS3 proteins. Viral load and genotype were determined. Samples were stratified into 37 chronic, 35 recovered infections and 32 false positive. Eighty‐one percentage of subjects with chronic infection (RNA positive) carried genotype 2 HCV. Cellular immune response was investigated in 35 frozen peripheral blood mononuclear cell (PBMC) samples suitable for interferon‐gamma ELISPOT assay. Twelve out of 24 confirmed recovered, 1 out of 5 chronically infected and none of the 6 false‐positive controls reacted to recombinant proteins. HLA‐A, ‐B and ‐DR types were determined by DNA methodology. HLA‐B*57 was significantly more frequent in the group which had recovered from HCV infection compared with chronically infected subjects (P = 0.0053, OR = 8.02). In conclusion, it is hypothesized that the dominance of genotype 2 HCV strains may be an important factor explaining the high rate of recovery from HCV infections in Ghana via an efficient contribution of HLA‐B*57 which is relatively frequent in the population. J. Med. Virol. 79: 724–733, 2007. © 2007 Wiley‐Liss, Inc.