Immunopathology of primary biliary cirrhosis

A major advance in the study of primary biliary cirrhosis was identification of the major B-cell auto-antigen as the mitochondrial enzyme pyruvate dehydrogenase dihydrolipoamide acetyltransferase (PDC-E2), Subsequent studies revealed that PDC-E2 also contained epitopes recognized by patients' T cells, Furthermore, aberrant expression of MHC class ii, intercellular adhesion molecules, lymphocyte co-stimulatory molecules and B-cell epitopes of PDC-E2 was observed on patients' biliary epithelium, supporting the concept that biliary epithelial cells are the target of a focused autoimmune reaction. Changes in distribution of auto-antigen on biliary epithelium and the presence of auto-antibody in patient's serum have both been shown to occur very early in the natural history of primary biliary cirrhosis, suggesting an intimate role for these molecules in immunopathogenetic mechanisms. Eur J Gastroenterol Hepatol 11:587-593 (C) 1999 Lippincott Williams & Wilkins.