The immune system defends us against attacks from foreign cells and organisms, such as bacteria and viruses. But it often goes haywire and sees some of its own tissues as foreign. The production of antibodies against the body’s own tissues is the cause of a large number of autoimmune diseases, such as rheumatoid arthritis, lupus and juvenile diabetes. When the body produces antibodies against its own mitochondria, a component of cells, this can lead to primary biliary cholangitis (PBC). PBC causes inflammation and bile duct lesions leading to liver damage and preventing the normal flow of bile.
Over 90% of people with PBC will have high anti-mitochondrial antibody levels. Slighter increases can be seen in other liver conditions (autoimmune hepatitis, primary sclerosing cholangitis, etc.).
Anti-mitochondrial antibody tests are often positive even before the onset of PBC symptoms (itchiness, jaundice, fatigue, swollen and painful liver). Testing is ordered with several other tests when the physician is looking for the causes of an abnormal liver profile (high bilirubin, alkaline phosphatase, ALT, GGT, etc.). A PBC diagnosis is confirmed by biopsy or imaging (scan, ultrasound, etc.).