What is the role of chronic cholestasis in the pathogenesis of primary biliary cholangitis (PBC)?

Updated: Nov 08, 2017
  • Author: Nikolaos T Pyrsopoulos, MD, PhD, MBA, FACP, AGAF; Chief Editor: BS Anand, MD  more...
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Answer

A continuous destruction of small and medium bile ducts occurs, which is mediated by activated CD4 and CD8 lymphocytes. As a result, chronic cholestasis is the prominent clinical and laboratory finding. Once destroyed, it is well established that regeneration of bile ducts is either not possible or inefficient.

Subsequent to the loss of the intrahepatic bile ducts, a disruption of the normal bile flow occurs with retention and deposition of toxic substances, which are normally excreted into bile. The retention of toxic substances, such as bile acids and copper, can cause a further secondary destruction of the bile ducts and the hepatocytes. In addition, increased expression of the HLA class II antigens in the liver occurs, rendering the hepatocytes and bile duct epithelial cells more susceptible to activated T lymphocytes and perhaps exacerbating immunologically mediated cytotoxicity. An association has been suggested between primary biliary cholangitis and haplotype HLA-DR8 and, for some populations, HLA-DPB1.


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