An antigen detected frequently in human sera with elevated levels of alanine aminotransferase: a potential marker for non-A, non-B hepatitis.

In a search for additional antigens associated with virus-induced human liver disease a radioimmunoassay (RIA) was developed using IgG from sera of a multiply transfused person. Polystyrene beads coated with IgG F(ab)'2 fragments, dinitrophenylated F(ab)'2 fragments and 125I-labelled anti-2,4-dinitrophenyl antibodies (Neurath & Strick, 1979) were used in the RIA. An apparently new antigen or the corresponding antibodies were detected in 155 serum specimens from 35/37 (94%)individuals who developed non-A, non-B hepatitis. The antigen was also present in hepatitis B surface antigen-negative sera of blood donors with normal (13.2%) and elevated levels of alanine aminotransferase (34%). The antigen has an approximate mol. wt. of 45,000, a buoyant density of 1.23 g/ml and an isoelectric point of 7.