Autoreactive CD8-specific T-cell response in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune liver disease of unknown etiology. Autoimmune attack in PBC is predominantly organ‐specific, despite the presence of mitochondrial autoantigens, the major targets of autoimmunity in PBC, in all nucleated cells. Cytotoxic T lymphocytes are thought to be directly involved in the tissue injury in PBC. The major histocompatibility complex (MHC) class I‐restricted epitope for E2 components of pyruvate dehydrogenase complexes, namely amino acid 159–167, a region very close to the epitoperecognized by MHC class II‐restricted CD4 cells and by antibody, has been characterized. In addition, there was a 10‐fold increase in the frequency of autoreactive cytotoxic T lymphocytes in the liver as compared to the blood in PBC patients using tetramer technology.