Interaction in vitro between myocardial cells and autologous lymphocytes and sera from patients with rheumatic carditis.

The cytotoxicity of antimyocardial antibodies and peripheral blood lymphocytes from patients with rheumatic carditis on autologous myocardial cells was investigated. Although sera obtained after open-heart surgery from seven out of eight patients with rheumatic carditis were bound to cultures of autologous myocardial cells, they were not cytotoxic. Peripheral blood leukocytes obtained both before and after surgery from one of these eight patients aggregated around and underwent blast transformation when exposed to autologous myocardial cells in vitro, but not after exposure to autologous skin fibroblasts. Only the postoperative leukocytes from another of these eight patients aggregated around autologous myocardial cells in vitro; however, these lymphocytes were also not cytotoxic to autologous myocardium. To investigate the effect of antimyocardial antibodies on myocardial function, antimyocardial antibodies were added to the culture medium of pulsating cultures of mouse myocardial explants. Although antimyocardial antibody from 27 patients with chronic rheumatic carditis and seven postcardiotomy patients had no effect on the pulsation of the mouse myocardial cultures, serum gamma-globulin from a patient suffering from acute rheumatic fever with myocardial involvement first accelerated and then gradually stopped the pulsation of mouse myocardial explants.