Primary biliary cirrhosis is an autoimmune isease of the liver marked by the slow progressive destruction of the small bile ducts (bile canaliculi) within the liver. When these ducts are damaged bile builds up in the liver (cholestasis) and over time damages the tissue. This can lead to scarring, fibrosis, cirrhosis, and ultimately liver failure. It was previously thought to be a rare disease, but more recent studies have shown that it may affect up to 1 in 3-4,000 people; the sex ratio is not less than 9 to 1, women to men (reference: Medical care of the Liver Transplant Patient, 3rd Edition published 2006, editied by Paul G. Killenberg, page 155).