Type 2 autoimmune hepatitis and hepatitis C virus infection.

The prevalence of serum antibodies to hepatitis C virus (HCV) was assessed by an enzyme-linked immunosorbent assay in 46 patients seropositive for liver-kidney microsomal antibody (anti-LKM1), the marker of autoimmune hepatitis type 2. 43 had chronic hepatitis (with histological confirmation in 34) and 3 were seropositive for anti-LKM1 without clinical or biochemical evidence of liver damage. The overall prevalence of anti-HCV was 78.2% or 86.1% in patients with chronic hepatitis--a similar prevalence to that reported in patients with chronic non A, non B posttransfusion hepatitis. HCV infection may lead to altered expression of the hepatocellullar LKM1 target antigen, with loss of tolerance and appearance of anti-LKM1 in serum.