[Hepatitis C, awakening of a giant]

Cloning of the hepatitis C virus (HCV) was reported in 1989. By now, the entire viral genome has been sequence. It consists of a single-stranded positive RNA, with relationship to the Flaviviridae. The envelope region shows considerable variability. 6 major genotypes have been described. HCV is transmitted via the parenteral route, mainly blood, rarely by sexual contact. Hepatitis C occurs worldwide and is found in 0.01 to 1.5% of blood donors. The immune response is unable to clear the virus in 80% of infected subjects, probably because of the hypervariability. In the acute phase the hepatitis has only mild symptoms and the chronic hepatitis usually also runs a mild course. After many years liver cirrhosis may develop in 20% of cases; in these subjects there is a high incidence of hepatocellular carcinoma. The diagnosis can be made by detection of anti-HCV antibodies in the blood and an immunoblot confirmation test. The viral genome can be detected by the HCV-RNA (PCR) test. Immunisation against hepatitis C is not possible yet. Therapy with interferon results in an initial response in 45% and a sustained response in < 20% of the patients. Interferon therapy reduces the incidence of hepatocellular carcinoma.