LACK OF INTERLEUKIN-2 (IL-2) EXPRESSION AND SELECTIVE EXPRESSION OF IL-10 MESSENGER-RNA IN HUMAN RENAL-CELL CARCINOMA

Freshly isolated tumor-infiltrating lymphocytes (TIL) are often functi onally deficient. Since one of the key functional parameters of an imm une response is the local production of cytokines, we studied the expr ession of cytokine genes in freshly isolated renal cancer tissue. Usin g a PCR-assisted mRNA amplification assay, the constitutive expression of mRNA for 10 different cytokines was assessed in renal cancer tissu e. We compared the cytokine mRNA expression in freshly isolated sample s of renal carcinomas, renal cancer cell lines established from the tu mor samples, peripheral blood mononuclear cells (PBMC) and non-tumor k idney tissue isolated from the same patients. IL-10 mRNA expression wa s detected only in tumor samples, while renal cancer lines, PBMC and n on-tumorous kidney tissues were devoid of this cytokine. One-third of the tumor samples but none of the normal kidney samples also expressed G-CSF mRNA. IL-6, TNF-alpha and IFN-gamma mRNA were expressed non-sel ectively in tumors, PBMC and normal renal tissue. Expression of IL-2, IL-3 and IL-4 mRNA was not detected in any of the tissues analyzed. Es tablished renal cancer lines exhibited expression of IL-1 alpha IL-6, TNF-alpha and GM-CSF. Culture of tumor-derived T cells with anti-CD3 m onoclonal antibody (MAb) resulted in expression of IL-2, IL-3 and IL-4 mRNA. In contrast, none of these cytokines was detected in culture wi th recombinant human IL-2 alone. Since IL-10 is known to suppress anti gen presentation, these findings have important implications for the p ossible in vivo role of IL-10 as a suppressor of local anti-tumor resp onse. (C) 1995 Wiley-Liss, Inc.