HLA class II alleles and chronic hepatitis C virus infection

The aim of this study was to investigate association of human leucocyte antigens (HLA)-DRB1 and DQB1 polymorphisms with hepatitis C virus (HCV) infection and with the occurrence of severe liver fibrosis/cirrhosis in chronically infected patients. Ninety-nine white patients, from southeast Brazil, with confirmed HCV chronic infection were included in the study. Severe fibrosis/cirrhosis (METAVIR scores F3-F4) was present in 49 patients. HLA-DRB1 specificities and DRB1*11 and DQB1* alleles were determined by PCR-SSP, and their frequencies were compared between patients and a control group of 103 healthy white Brazilian individuals. The results confirmed previous reports of the association of DRB1*11 and DQB1*03 with protection from chronic HCV infection, but did not confirm their association with protection from severe fibrosis/cirrhosis. Furthermore, the results suggested that the polymorphic sites on HLA molecules responsible for protection from chronic HCV infection are encoded not only by the DRB1*1101 and DQB1*0301, as suggested in the literature, but also by other DRB1*11 and DQB1*03 alleles. Thus, we hypothesized that the common polymorphic residues shared by different DRB1*11 and/or DQB1*03 alleles might be responsible for selection of viral epitopes for presentation to CD4(+) T cells, leading to an efficient immune response against the virus.