 Rationale: Chronic HCV infection is characterised by a weak HCV specific CD8 T cell response, due to continuous pressure of high viral load. Treatment of chronic HCV patients with ASV and DCV will result in a significant drop in HCV viral load. At present, no information is available on the immunological effects of treatment with ASV and DCV, nor on the early effects of viral load reduction caused by a compound that is thought not to possess direct immunomodulatory effects. This information will be crucial for a better understanding of the mechanisms that may limit the effectiveness of treatment, occurrence of viral rebound or relapses during, at the end of treatment or during the follow up period. 