An ultrastructural study on experimental autoimmune myocarditis with special reference to effector cells.

The previously described animal model of autoimmune myocarditis induced by immunization of Lewis rats with cardiac myosin was investigated pathologically, ultrastructurally and immunohistologically. Cardiac dendritic cells and infiltrating macrophages were dominantly encamped at the front of the myocarditis. The macrophages accompanied by neutrophils infested cardiocytes, forming rosette figures as a sign of active cardiocytolysis. The dendritic cells reached into intact muscle at a short distance from the inflammation. T cells, the most important candidate for effector cells in this animal model, were generally found at a distance from active muscle necrosis.