Identification of hepatitis A virus as a trigger for autoimmune chronic hepatitis type 1 in susceptible individuals.

To identify factors contributing to the pathogenesis of autoimmune chronic active hepatitis (CAH) healthy relatives of 13 patients with the disorder were followed prospectively for 4 years. 58 relatives were monitored for various serological markers and for T-lymphocyte migration inhibitory activity every 2 months. 3 cases of subclinical acute hepatitis A occurred during the study. In 2 of the 3 subjects, before hepatitis A virus (HAV) infection, there was a defect in suppressor-inducer T lymphocytes specifically controlling immune responses to the asialoglycoprotein receptor, an antigen expressed on the hepatocyte surface. In these 2 subjects, specific helper T cells and antibodies to the asialoglycoprotein receptor persisted and increased after acute hepatitis A, and autoimmune CAH type 1 developed within 5 months. Thus, in susceptible individuals HAV is a trigger for autoimmune CAH.