Antimyocardial antibodies in heart diseases. II. Immunofluorescent patterns in rheumatic fever and rheumatic heart disease.

Antibodies against rat myocardium were studied by means of histoimmunfluorescence (indirect technique) in 32 rheumatic fever patients. Antibodies were found in 54% of the cases without carditis or active rheumatic valvulitis and in 83% of those with carditis. The fluorescent patterns observed were : sarcolemmal, sarcoplasmic (intermyofibrillar) and smooth muscle of vessels. The sarcolemmal pattern was more frequently observed in rheumatic carditis while the intermyofibrillar one was more common in rheumatic fever without evidence of carditis as well as rheumatic valvulitis. The serum factors involved in the sarcolemmal fluorescence were inhibitied by the insoluble saline myocardium extract.