Immunohistological characterization of infiltrating lymphocytes in biopsies of patients with clinically suspected dilated cardiomyopathy.

Experimental and clinical data suggest a relationship between myocarditis and dilated cardiomyopathy. One postulated mechanism is a viral infection triggering a host response with autoimmune features directed against the heart, resulting in an initial myocarditis which is followed by dilated cardiomyopathy. Until now, the importance of myocarditis as an aetiological factor in the pathogenesis of isiopathic cardiomyopathy has been unknown. This investigation was undertaken to determine immunohistologically the frequency of lymphocytic infiltrations in endomyocardial biopsies of patients with clinically suspected dilated cardiomyopathy. T-lymphocytic subsets and other immunological features were also analysed to explore possible relationships between immunohistologically documented myocarditis and dilated cardiomyopathy.