SEPSECS

Autoimmune hepatitis (AIH) is a chronic progressive liver disease of unknown origin that responds well to immunosuppressive therapy, but has a poor prognosis if untreated. Early and accurate diagnosis is therefore of great importance. AIH is characterized by histological features of periportal hepatitis in the absense of viral markers, by hypergammaglobulinemia and, in the majority of patients, by the presence of autoantibodies in serum. 70% of all patients have significant titres of anti-nuclear antibodies (ANA), smooth-muscle autoantibodies (SMA) or liver-kidney microsomal autoantibodies (LKM). These antibodies are of diagnostic value for AIH, but not specific for the disease since they also occur in 10-15% of patients with viral hepatitis and other immune-mediated diseases. In contrast, antibodies to soluble liver antigen (SLA) and antibodies to a liver and pancreas antigen (LP) are the only to be specific for autoimmune hepatitis and are present in 20% of all AIH-patients, many of whom are negative for other autoantibodies. It was shown that anti-SLA and anti-LP are directed against the same antigen and thus are identical. The SLA/LP antigen cloned and sequenced in 2000 is a protein of unknown function, suggested to be an UGA-suppressor tRNA-associated protein. ANA/SMA and anti-SLA positive patients share most clinical, biochemical, histological and prognostic features. Distinction of different subgroups according to autoantibody status is therefore clinically not helpful. However, testing for anti-SLA autoantibodies is very important for the diagnosis of AIH in many patients who are negative for other autoantibodies and may otherwise be misdiagnosed.

SEPSECS;Sep (O-phosphoserine) tRNA:Sec (selenocysteine) tRNA synthase;