Which antibody is typically associated with primary biliary cirrhosis?

The association of AMA subgroup M2 with primary biliary cirrhosis (PBC) is well established in medical literature. Primary biliary cirrhosis is an autoimmune disease that primarily affects the liver, leading to progressive destruction of the small bile ducts. The presence of antimitochondrial antibodies, specifically the M2 subgroup, serves as a hallmark for diagnosing PBC. These antibodies target the E2 component of the pyruvate dehydrogenase complex, which is found in the mitochondria of liver cells.

Identifying AMA in patients with symptoms suggestive of PBC can help confirm the diagnosis and is often a critical component of the laboratory workup. The specificity of AMA subtype M2 for PBC distinguishes it from other autoimmune conditions, where different antibodies might be present but do not correlate with this particular liver disease.

In contrast, the other antibodies mentioned are linked with other autoimmune diseases. Anti-DNA antibodies are primarily associated with systemic lupus erythematosus. Anti-Smith antibodies are also specific for lupus, while anti-cardiolipin antibodies are typically associated with antiphospholipid syndrome. Thus, AMA M2 remains unique in its strong correlation with PBC, making it the correct answer for this