What causes destruction of the bile ducts in PBC?
AMA are tremendously important as a diagnostic marker in patients with PBC. Despite that, no evidence exists that the AMA itself causes the destruction of the biliary epithelial cells lining the small bile ducts. Neither the presence nor the amount (titer) of AMA in the blood appears to be related to the inflammatory destruction of the bile ducts. Indeed, immunization of animals with PDC-E2 antigen results in production of AMA without any liver or bile duct damage (pathology). What, then, causes the destruction of the bile ducts in PBC? Inspection of liver biopsies from patients with PBC indicates that T-lymphocytes surround and invade the small bile ducts. Thus, T-lymphocytes appear to be responsible for the death of the biliary epithelial cells lining the ducts and the destruction of the bile ducts. T-lymphocytes capable of directly killing target-cells (for example, biliary epithelial cells) are called cytotoxic T-lymphocytes, meaning that these T-cells are toxic to the target cells
