Comprehensive longitudinal analysis of hepatitis C virus (HCV)‐specific T cell responses during acute HCV infection in the presence of existing HIV‐1 infection

Summary. The aim of this study was to study the development of HCV‐specific T cell immunity during acute HCV infection in the presence of an existing HIV‐1 infection in four HIV‐1 infected men having sex with men. A comprehensive analysis of HCV‐specific T cell responses was performed at two time points during acute HCV infection using a T cell expansion assay with overlapping peptide pools spanning the entire HCV genome Three patients with (near) normal CD4+ T cell counts (range 400–970 × 10⁶/L) either resolved (n = 1) or temporary suppressed HCV RNA. In contrast, one patient with low CD4+ T cell counts (330 × 10⁶/L), had sustained high HCV RNA levels. All four patients had low HCV‐specific CD8+ T cell responses, and similar magnitudes of CD4+ T cell responses. Interestingly, individuals with resolved infection or temporary suppression of HCV‐RNA had HCV‐specific CD4+ T cell responses predominantly against nonstructural (NS) proteins. While the individual with high HCV RNA plasma concentrations had CD4+ T cell responses predominantly directed against Core. Our data show that an acute HCV infection in an HIV‐1 infected person can be suppressed in the presence of HCV‐specific CD4+ T cell response targeting non‐structural proteins. However further research is needed in a larger group of patients to evaluate the role of HIV‐1 on HCV‐specific T cell responses in relation to outcome of acute HCV infection.