Hepatitis C viraemia in adults with type 2 autoimmune hepatitis.

Sera from 14 patients with type 2 autoimmune hepatitis (anti-LKM1 positive) were investigated for evidence of hepatitis C virus (HCV) infection. Antibodies to HCV were detected in 13 patients by both commercial and "in-house" ELISAs and also by a second generation recombinant immunoblot assay. Nine of the 13 (69%) anti-HCV positive patients were shown to be viraemic by a polymerase chain reaction-based assay for serum HCV RNA. Neither anti-HCV nor serum HCV RNA were detected in any of 6 controls with primary biliary cirrhosis or in 39 healthy blood donors. These findings strongly suggest a role for HCV in the pathogenesis of type 2 autoimmune hepatitis.