Antibodies to soluble liver antigen (SLA) appear to be directed against the UGA-suppressor tRNA associated protein. These antibodies are highly specific for autoimmune hepatitis (AIH) and may, rarely, be the only autoantibodies detected in serum from such patients. Antibodies to SLA are most closely associated with AIH type1; the presence of these antibodies in patients with cryptogenic hepatitis suggests that these patients may have AIH type 1. Anti-SLA antibodies may be detected in some patients with the primary biliary cirrhosis-AIH overlap syndrome, but not in healthy controls.