Influence of HCV genotype and co-infection with human immunodeficiency virus on CD4(+) and CD8(+) T-cell responses to hepatitis C virus.

The role of T-cells in clearance of hepatitis C virus (HCV) during acute infection is critical. The relevance of the immunological response in the control of HCV replication is less clear in chronic HCV infection. HCV-specific T-cell responses were examined in 92 interferon-naive individuals with chronic hepatitis C. A panel of 441 overlapping peptides spanning all expressed HCV proteins was used to measure HCV-specific T-cell responses, using flow cytometry after stimulating peripheral blood mononuclear cells (PBMCs) with different pools of these peptides. Most patients showed responses to at least one HCV protein, with NS5B for CD8(+) responses and E2 for CD4(+) responses identified most frequently. Both the prevalence and breadth of CD4(+) and CD8(+) responses were lower in co-infected patients, independently of the HCV genotype.