Pathogenic relevance of autoantibodies in dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a heart muscle disease of unknown origin characterized by progressive cardiac dilatation and loss of contractile function in the absence of coronary artery disease. Genetic causes and cardiotoxic substances account for about one third of the cases, but the etiology of the two other thirds is still poorly understood. However, within the past two decades evidence has grown continuously that autoimmunity to certain cardiac antigens may play an important role in the development of DCM. Recent experiments in rodents even indicate that autoantibodies targeting the cardiac β1 (catecholamine) receptor can actually cause the disease. Dependent on the individual genetic predisposition, such harmful autoimmune reactions most likely occur as a result of heart muscle damage induced by viral triggers, ischemia, and/or exposure to cardiotoxins leading to myocyte apoptosis or necrosis, and subsequent liberation of self antigens previously hidden to the immune system. The following article reviews current evidence and recent experimental and clinical findings focusing on the possible role of autoantibodies against a confined number of cardiac self antigens in the pathogenesis of DCM.