POSSIBLE MYOCARDIAL TOXICITY ASSOCIATED WITH INTERLEUKIN-4 THERAPY

Interleukin (IL)-4 is a cytokine produced by T lymphocytes, which may play a role in allergic inflammatory processes through its stimulatory effects on immunoglobulin E production and mast cells. In this report , we describe a patient with metastatic melanoma involving the heart w ho had biopsy-proven myocarditis after treatment with high-dose IL-4. Because of the uncharacteristic predominance of polymorphonuclear and mast cells in the inflammatory infiltrate of this patient's myocardium , we postulate a unique mechanism of IL-4-associated myocarditis. Thre e other patients treated with IL-4 had less well-defined cardiac abnor malities, suggesting that patients receiving IL-4 may be at risk for c ardiac toxicity. Additional studies will be necessary to confirm such an association.