There is indirect evidence for T-cell control from genetic studies, which demonstrated an association between HCV clearance and specific class-I and class-II HLAs, which present HCV peptides to CD8+ and CD4+ T cells, respectively.48, 49 A vigorous and multispecific proliferative CD4+ T-cell response against HCV proteins has been correlated with spontaneous control of acute HCV infection.50, 51, 52, 53 Schulze zur Wiesch et al50 demonstrated that broadly directed HCV-specific CD4+ T cells are detectable during early stages of infection, regardless of outcome. This evidence concerns the gene CD4 and infection.