Primary Biliary Cirrhosis

Anti-Mitochondrial M2 (AMA) Antibodies

Primary Biliary Cirrhosis (PBC) and autoimmune hepatitis are chronic disorders of the liver with debilitating effects on the patient. Early diagnosis helps in patient management and significantly improves quality of life. Anti-mitochondrial antibodies (AMA) occur in over 90% of PBC cases, 3-11% of chronic active hepatitis patients and are absent in patients with extrahepatic biliary obstruction as well as other liver diseases.

The presence of AMA in greater than 95% of patients with PBC and their virtual absence in extrahepatic jaundice makes detection of these antibodies extremely valuable in establishing a differential diagnosis.

AMA can be detected by IF on mouse kidney/stomach substrate.

In addition to AMA, patients with PBC have autoantibodies to two other nuclear antigens: Gp-210 and Sp-100. 28% to 52% of PBC patients have antibodies to nuclear pore complex protein Gp-210, characterised by peripheral staining of the nucleus by indirect IFA.

Anti -Sp-100 antibodies are characterised by multiple nuclear dot staining of the nucleus. These antibodies are present in approximately 30% of patients with PBC. Approximately one half of AMA negative PBC patients are positive for antibodies to Gp-210 and Sp-100.