The immunopathogenesis of hepatitis C virus infection.

The outcome of HCV infection is determined by the interaction between the virus and the host immune system. The persistence of infection in most HCV-infected individuals, despite the presence of HCV-directed antibodies, suggests that such antibodies fail to induce viral clearance. Patients with self-limited hepatitis C have evidence of a polyclonal, multispecific CD8+ T-cell response along with a coordinated CD4+ T-cell response that is associated with eradication of HCV infection. Cytokines are produced both locally within the liver and systemically and may play an important role in controlling viral replication and contributing to hepatocellular damage through amplification of a nonspecific immune response. In most patients, the humoral, cellular immune, and cytokine response seem insufficient to eradicate infection. In its attempt to clear the virus from the liver, the immune system contributes to the hepatocellular injury seem in most chronically infected patients. A better understanding of the host's immune response may provide further insight on the pathogenetic mechanisms involved in development of chronic hepatitis and aid the development of better therapeutic strategies.