Pathogenesis of hepatitis C virus infection.

The hepatitis C virus (HCV) is a single stranded RNA virus. In 60-80% of patients, it is able to escape innate and adaptive immune surveillance. Thus it establishes itself as an agent of chronic hepatitis. Cytotoxic lymphocytes then contribute to liver injury in an attempt to eradicate the virus. On the other hand, strong multispecific T-lymphocyte reaction against HCV proteins is associated with viral clearance. Both CD4+ and CD8+ lymphocyte functions are important to effect this outcome. In chronic infection, genetic and environmental factors determine the progression of inflammation and fibrosis in individual patients. Of these factors, age, gender, race and alcohol use are the most established ones. The development of hepatocellular carcinoma is mainly restricted to patients with cirrhosis.