Cardiac contractile proteins and autoimmune myocarditis.

Concerning cardiac contractile proteins, antigenicity and myocardiotogenicity were discussed. In normal states, these proteins are immunologically tolerant, and can not provoke any heart-specific disease. Why the proteins can provoke such lethal autoimmune myocarditis has not been completely elucidated. Shortly after cardiac infection or myocardial ischemia, these proteins may work as the antigen for the autoimmune myocarditis. First of all, the role of cardiac myosin has been strongly emphasized. But, the antigen determinants: epitope proteins remain unclear. Either cross-activity to the streptococcal M protein and/or the alpha-helical coiled-coil protein may be an important factor to determine antigenicity. In this autoimmune myocarditis, the roles of T-lymphocyte and cardiac dendritic cell are noticeable. Through further study on the relation between antigen epitope and the infectious agents in the heart; on cardio-cytotoxicity of the T-lymphocyte and on the precise contribution of cardiac dendritic cells, this autoimmune myocarditis will be more clarified.