Causes

It's not clear what causes primary biliary cholangitis. Many experts consider it an autoimmune disease in which the body turns against its own cells. Researchers believe this autoimmune response may be triggered by environmental and genetic factors.

The liver inflammation seen in primary biliary cholangitis starts when certain types of white blood cells called T cells (T lymphocytes) start to collect in the liver. Normally, these immune cells detect and help defend against germs, such as bacteria and viruses. But in primary biliary cholangitis, they mistakenly destroy the healthy cells lining the small bile ducts in the liver.

Inflammation in the smallest ducts spreads and eventually damages other cells in the liver. As the cells die, they're replaced by scar tissue (fibrosis) that can lead to cirrhosis. Cirrhosis is scarring of liver tissue that makes it difficult for your liver to work properly.