Idiopathic myocarditis associated with T-cell subset changes and depressed natural killer activity

A 65-year-old man with idiopathic myocarditis is described. He was admitted with symptoms of acute heart failure. Examination revealed left ventricular hypokinesis. Results of an endomyocardial biopsy showed "resolving myocarditis". Immunological studies of the peripheral blood showed a low helper-suppressor (CD4/CD8) ratio on admission and depressed natural killer (NK) cell activity coincident with the onset of myocarditis. We considered that this immunological imbalance may have occurred during the progression of myocarditis to dilated cardiomyopathy.