Genetic factors and autoimmunity in viral hepatitis.

Whether a patient develops the HBsAg carrier state may depend on his genome. HBsAg subtypes may reflect the viral genome and may be of prognostic significance. Different subtypes predominate in different populations throughout the world. Altered immune response, as in patients with Down's syndrome, may increase the HBsAg carrier rate. Autoantibodies have been used to differentiate various types of hepatitis. There is an increased incidence of histocompatibility antigen HL-A1 and HL-A8 in patients who have chronic aggressive hepatitis. In primary hepatic carcinoma, the HBsAg carrier rate is increased. Because of the suggestion that neonatal hepatitis, biliary atresia and choledochal cyst may all result from infantile obstructive cholangiopathy, with the precise outcome depending on whether other conditions such as alpha 1-antitrypsin deficiency are also present, we have determined HBsAg in 166 children with a variety of diseases, among them Reye's syndrome, alpha 1-antitrypsin deficiency, and renal disorders. The HBsAg carrier rate in the sera of these patients was normal.