IMMUNOSUPPRESSIVE DRUGS INHIBIT THE PRODUCTION OF INTERLEUKIN-6 AND INTERLEUKIN-8 IN CULTURED CARDIAC MYXOMA CELLS

Cardiac myxoma cells produce large amounts of interleukin (IL)-6 and I L-8. To determine whether immunosuppressive agents could be used to tr eat cardiac myxoma, we tested the effects of dexamethasone and three o f the newer second-generation immunosuppressive drugs, cyclosporin A, tacrolimus, and deoxyspergualin, on the production of IL-6 and IL-8 in these cells. Cultured cardiac myxoma cells were used as in vitro mode l of cardiac myxoma. Cells were tested for 24 hours with 10(-7) M dexa methasone, 10(-6) M cyclosporin A, 10(-8) M tacrolimus, and 10(-6) M 1 5-deoxyspergualin, with aliquots of conditioned medium being assayed f or cytokine levels at 0, 6, 12, and 24 hours. Cardiac myxoma cells iso lated from 4 patients all produced quantities of IL-6 and IL-8. The co ncentrations of IL-6 in the medium after 7 days in culture ranged from 79,000 to 2,740,000 pg/ml, and the concentrations of IL-8 ranged from 40,000 to 1,000,000 pg/ml. Exposure of cyclosporin A and dexamethason e almost completely inhibited the production of IL-6 and IL-8 after 24 hours of treatment. Tacrolimus inhibited the production of both cytok ines by 55%, while 15-deoxyspergualin reduced IL-6 levels by 24% and I L-8 levels by 48% after separate 24 hour treatments. These results sug gest that these newer immunosuppressive agents may be useful in reduci ng the production of IL-6 and IL-8 in patients with cardiac myxoma.