Primary Biliary Cholangitis (PBC) is a chronic, progressive autoimmune liver disease that affects the small bile ducts in the liver. It is caused by an immune system attack on the bile ducts, leading to inflammation, scarring, and eventual destruction of the ducts. Symptoms of PBC include fatigue, itching, jaundice, and abdominal pain. Treatment typically involves medications to reduce inflammation and slow the progression of the disease.