Hepatitis C virus infection in individuals with or without human immunodeficiency virus type 1 infection.

Serum specimens from 111 human immunodeficiency virus type 1 (HIV-1) infected and 183 HIV-1 seronegative patients were analysed for antibodies to hepatitis C virus (HCV), hepatitis B virus (HBV) and hepatitis A virus (HAV) by enzyme linked immunoassay (ELISA) and radioimmunoassay. Anti-HCV and anti-HBV antibodies were found in the vast majority (89 and 83%, respectively) of intravenous drug addicts (IVDA), independent of the type of drug abuse or whether the patients were HIV-1 infected or not. Anti-HAV antibodies were found in 60% of the IVDA. Anti-HCV antibodies were found in anti-HIV-1 positive homosexual men (14%) and anti-HIV-1 negative heterosexual persons (8%), but not in HIV-1 seronegative homosexual men. Also anti-HAV antibodies were found to a small extent in these groups. In contrast, anti-HBV antibodies were common in the homosexual men. The absorbance values of the positive reactions in the anti-HCV ELISA were lower for HIV-1 seropositive patients than those for HIV-1 seronegative subjects, particularly in the late stages of HIV-1 infection. These data suggest that HCV infection is transmitted as readily as HBV infection by intravenous drug abuse and that all three types of hepatitis virus infection are common in IVDA. Although transmission of HCV is primarily mediated by blood, sexual transmission may also occur. HIV-1 infection seems to be associated with unusually low levels of anti-HCV antibodies, especially in the late stages of HIV-1 infection.