The immunopathogenesis of primary biliary cirrhosis

There have been several recent advances in our understanding of primary bil iary cirrhosis. Foremost amongst these has been the cloning and identificat ion of the mitochondrial autoantigens as members of the 2-oxo-dehydrogenase complex. These include the E2 components of PBC, BCKD and OGDC. The immuno dominant autoepitopes of the autoantigens have been mapped and, in all case s, correspond to the inner lipoyl domain. Limited progress has also been ma de on T cells, particularly the CD4 response. However, the fundamental mech anisms and the role, if any, of CD8 cells are unknown. Finally, at least 2 groups have identified a molecule that cross-reacts with PDC-E2, i.e., a mi mic, on the luminal surface of biliary epithelium in PBC but not controls. The identification of this molecule will be critical in further understandi ng the immune response of this disease.