The correlation of mononuclear cell phenotype in endomyocardial biopsies with clinical history and cardiac dysfunction

Endomyocardial biopsy specimens from 96 patients with unexplained congestive heart failure or dysrhythmia were evaluated by standard histologic techniques and by direct immunofluorescence and immunoperoxidase cell marker analysis for mononuclear cell infiltration. Control specimens derived from normal autopsy hearts (n = 8) and autopsy hearts with severe coronary artery disease (n = 9) were analyzed in a similar fashion. The results were correlated with functional data obtained from cardiac catheterizations as well as the clinical history. The objectives of the study were to assess the sensitivity and specificity of immunoperoxidase identification of lymphocytes for the diagnosis of myocarditis and to correlate clinical parameters such as degree of cardiac dysfunction and symptom duration with the extent of inflammatory changes. No control biopsies (neither normal nor ischemic) had a T-cell concentration of one or more cells per high-power field (HPF:200x), whereas 32% of the study cases had more than one T-cell per HPF. Heavy T-cell infiltration (≥3 per HPF) was present in 7% of the study cases and occurred most commonly when the symptoms were of recent onset. The results demonstrate that lymphocytes are not present (<1 per HPF) in normal myocardium, in viable myocardium from hearts with generalized coronary artery disease, and in most endomyocardial biopsies (68%) from patients with unexplained heart failure or dysrhythmia. Thus, lymphocyte infiltration is not a nonspecific response to cardiac dysfunction. Immunoperoxidase identification of lymphocytes provides a quantitative assessment of inflammatory cell infiltration that is useful in the detection of myocarditis.