Autoimmune antibody positivity Anti-mitochondrial M2 antibody positivity 2018-05-19T15:34:03Z The presence of M2 anti-mitochondrial antibody (immunoglobulins) in the serum. AMA-M2 positive Anti-mitochondrial antibody (AMA) can be tested via indirect immunofluorescence. AMAs are biomarkers of primary biliary cirrhosis (PBC) and can also be found in patients with idiopathic inflammatory myopathies. The auto-antigens of AMA have been identified as pyruvate dehydrogenase complex-E2 (PDC-E2), branched-chain 2-oxo acid dehydrogenase complex and 2-oxoglutaric acid dehydrogenase complex. The antibody to these antigens is known as AMA-M2. AMA-M2 is more specific to PBC than AMA, and the determination of its titer is feasible Anti-pyruvate dehydrogenase antibody positivity