In vitro inhibition of interleukin-2 production by peripheral blood lymphocytes from stage III melanoma patients by prostaglandin E₂: Enhancement of lymphocyte proliferation by exogenous interleukin-2 plus indomethacin

Interleukin-2 (IL-2) production following concanavalin A stimulation and the response of peripheral blood mononuclear cells (PBMC) to both IL-2 alone and IL-2 plus indomethacin, a prostaglandin synthetase inhibitor, were examined in 16 melanoma patients and 12 healthy controls. Mean IL-2 production by PBMC in 11 melanoma patients with metastatic disease (Stage III) was significantly decreased compared with controls and was moderately decreased compared with five patients with resected nodal disease (Stage II). Indomethacin restored IL-2 production in Stage III PBMC to levels equivalent to that produced by control PBMC. The PBMC of stage III patients also produced 40 times more prostaglandin E₂ than PBMC from controls or Stage II patients. Indomethacin plus IL-2, but not IL-2 alone, was capable of restoring the low blastogenic response of PBMC of Stage III patients to normal levels. Hence, these data emphasize the importance for using IL-2 along with indomethacin for in vivo immunorestoration in disseminated melanoma.