The fact that HCV-specific IL-21 responses correlated with HCV viral control in acute HIV/HCV coinfection is consistent with previous findings from HIV, HBV and HCV monoinfections in which virus-specific IL-21 production was associated with viral control [11, 13, 15, 25] and suggests that HCV-specific IL-21 secretion may rescue HCV-specific CD8+ T cell responses, leading to viral decline. This evidence concerns the gene IL21 and coinfection.