[Viral myocarditis and autoimmunity]

The pathogenesis of viral myocarditis has not been clarified yet especially in the subacute and chronic stages. Recent reports have shown that myocarditis may be caused by autoimmune reactions. Autoantigens and autoantibodies have recently been reported in myocarditis and cardiomyopathy, and most of them may be induced by the cross-reaction between virus and cardiac tissue, molecular mimicry, or by the destruction of immune tolerance. However it is not clear how autoimmune reactions affect viral myocarditis. We have reported that cytokines are increased in the blood of patients with myocarditis and cardiomyopathy. Many kinds of cytokines modulate viral myocarditis in different ways in murine models. Nitric oxide is also recognized as an important factor in viral myocarditis. We have reported that drugs for heart failure modulate cytokine production. Classifying drugs from this point of view may be helpful for developing new therapeutic strategy for patients with myocarditis and cardiomyopathy.