• CD8;
  • cytotoxic T lymphocytes;
  • cytotoxicity;
  • interferon-alpha;
  • ribavirin;
  • viral load

Summary.  This report describes an association between intrahepatic and peripheral blood cytotoxic T lymphocytes (CTL) activity present prior to receiving treatment, and a response to combination interferon-α (IFN-α) and ribavirin therapy for chronic hepatitis C virus (HCV) infection. Recombinant vaccinia virus constructs were used to expand and detect cytotoxic effectors against the entire genotype 1a HCV polyprotein. Six patients with a sustained response to therapy were significantly more likely to display intrahepatic and peripheral blood HCV-specific CTL activity than patients who relapsed or had no treatment response. Limited longitudinal data suggested that rather than combination therapy acting to enhance the CTL response to achieve viral clearance, detectable CTL prior to treatment increases the likehood of the host responding to the direct antiviral activity of IFN-α and ribavirin.