Natural history and predictors of severity of chronic hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co-infection.

Co-infection by the hepatitis C virus (HCV) is observed in up to 30% of HIV-infected individuals. In studies conducted in the 'pre-HAART era', the late consequences of HCV-related chronic liver disease were overshadowed by extra-hepatic causes of deaths, related to severe immune deficiency, and the impact of HCV infection on mortality of HIV-infected patients was low. While the development of HAART has resulted in a significant decrease in morbidity and mortality amongst HIV-infected patients, this clear benefit allowed the expression of liver-related complications associated with HCV chronic infection. The impact of HCV on HIV remains debated but HIV infection significantly modifies the natural history of HCV infection. HIV infection increases levels of HCV viraemia by 2- to 8-fold, resulting in a significant decrease in spontaneous recovery of acute hepatitis. HIV co-infection also worsens the histological course of HCV infection by increasing and accelerating the risk of cirrhosis or leading to rare but lethal fibrosing cholestatic hepatitis. Liver disease is now one of the leading causes of morbidity and mortality in co-infected patients, even if HAART and especially protease inhibitors, may decrease the severity of the liver disease and the liver-related mortality. Several non-exclusive pathogenic processes explain the increasing rate of liver complications associated with HCV-related liver disease.