Antimitochondrial Antibodies

Serum antimitochondrial autoantibodies (AMA) are specific to the autoimmune cholestatic disease primary biliary cirrhosis (PBC), with 90-95% of affected individuals being positive at indirect immunofluorescence. Indeed, AMA are one of the three diagnostic criteria for the disease and may precede its onset by several years. AMA autoantigens include the lipoilated domains of the 2-oxoacid dehydrogenase complexes. More specifically, AMA most commonly are directed against the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2). Animal models and other experimental studies failed to prove a direct or indirect pathogenic role for AMA. From a clinical standpoint, AMA titers or specificity do not correlate or predict the clinical course of the disease. Novel methods for the detection of serum AMA are being developed that are increasing the sensitivity of the test, particularly since the introduction of recombinant antigens.