抗线粒体抗体是一种免疫球蛋白，是针对线粒体，尤其是肝细胞中的线粒体的自身抗体。若在人体血液或血浆中检出该抗体，则意味着此人可能患有严重的自身免疫疾病，如原发性胆汁性肝硬化（一种对肝脏，尤其是胆管造成伤害的疾病），大约95%的病例会检出该类型抗体。

原发性胆汁性肝硬化是一种自身性免疫疾病，主要见于中年妇女，以及患有其它自身免疫疾病的病人。所谓自身性免疫疾病，是指人体免疫系统错误的将自身的细胞或其中一部分视为攻击目标的疾病，其中原发性胆汁性肝硬化属于后一种情况。

关于为何会产生抗线粒体抗体，有假说认为，异生诱导或氧化修饰所导致的对线粒体抗原的修改，是导致机体不能忽略线粒体抗原的关键步骤。在前述急性肝硬化病症中，该抗体被发现会对几乎所有肝脏抗原起作用 ，包括：

Anti-mitochondrial antibodies (AMA) are autoantibodies, consisting of immunoglobulins formed against mitochondria, primarily the mitochondria in cells of the liver.

The presence of AMA in the blood or serum of a person may be indicative of the presence of, or the potential to develop, the autoimmune disease primary biliary cirrhosis (PBC; also known as primary biliary cholangitis). PBC causes scarring of liver tissue, confined primarily to the bile duct drainage system. AMA is present in about 95% of cases. PBC is seen primarily in middle-aged women, and in those afflicted with other autoimmune diseases.