SERUM LEVELS OF CYTOKINES AND SOLUBLE CYTOKINE RECEPTORS IN PATIENTS WITH METASTATIC RENAL-CELL CARCINOMA OR MALIGNANT-MELANOMA RECEIVING IL-2 INTERFERON-ALPHA COMBINATION THERAPY

Elevated serum levels of soluble tumour necrosis factor receptor (sTNF R-55) and (at a lesser degree) of sTNFR-75 were found in most of the p atients with metastatic renal cell carcinoma (RCC) or malignant melano ma (MM) before immunotherapy and with further increase during treatmen t (intravenous infusions of interleukin-2 [IL-2] and subcutaneous inte rferon-alpha [IFN-alpha]). In the majority of the patients with MM the pretreatment serum levels of IL-2 and soluble IL-2 receptor (sIL-2R) were increased, whereas fewer patients with RCC presented with increas ed serum levels of IL2 and sIL-2R. Twelve days' treatment with IL-2/IF N-alpha, with a rest on days 6 and 7, resulted in a consistent further increase in the serum levels of sIL-2R and sTNFRs. In most patients t he increase of slL-2R and sTNFRs lasted for at least 3 weeks after tre atment discontinuation. The clinical significance of the increase rema ins unknown.