Immunofluorescence studies of florid rheumatic Aschoff lesions

We studied cardiac tissues of a patient who died of severe rheumatic myocarditis. Multiple Aschoff lesions were present throughout both ventricles and auricles. Immunofluorescence studies showed large monocytoid cells staining with OKM1 and anti-Leu M-3 as well as anti-Ia. Scattered T cells in areas of focal myocarditis stained with OKT3. Parallel staining for cardiac myosin-heavy chain antigens showed patchy dissolution of cardiac muscle fibers and traces of cardiac myosin within large monocytoid Aschoff cells.