Natural history of hepatitis C and the impact of anti-viral therapy.

The hepatitis C virus (HCV) infects some 170 million people worldwide and is responsible for approximately 20% of cases of acute hepatitis and 70% of cases of chronic hepatitis. Acute hepatitis is icteric in only 20% of patients and is rarely severe. Eighty five per cent of the infected patients develop chronic infection which is generally asymptomatic. Among the HCV chronic carriers, 25% have persistently normal serum alanine aminotransferase (ALT) levels despite having detectable HCV-ribonucleic acid in serum, 75% have elevated ALT levels. While the majority of patients with mild chronic hepatitis have a slowly progressive liver disease, the patients with moderate or severe chronic hepatitis may develop cirrhosis within a few years. In patients with HCV-related cirrhosis, the incidence of hepatocellular carcinoma is 2-5% per year. HCV-related end-stage cirrhosis is currently the first cause of liver transplantation. Treatment with the combination of interferon-alpha and ribavirin induces a sustained virological response in roughly 40% of the patients. The virological response is associated with a biochemical response and histological improvement. It is believed that the decrease of necroinflammatory liver lesions induced by anti-viral therapy in responders, is associated with a decreased risk of development of cirrhosis and hepatocellular carcinoma