An assessment of the immunological environment based on intratumoral cytokine production in renal cell carcinoma

OBJECTIVE: To assess the immunological relationship between tumour and host, focusing on the production of T-cell helper (Th) subset-derived cytokines in patients with renal cell carcinoma (RCC). PATIENTS AND METHODS: The study comprised 35 patients (19 men and 16 women, mean age 56.9 years, range 39-78) with RCC, who had undergone nephrectomy. Using enzyme-linked immunosorbent assays, the levels of Th1-derived cytokines were measured, including interleukin (IL)-2 and interferon (IFN)-gamma, and Th2-derived cytokines, including IL-4, IL-5, IL-6, IL-10 and others. RESULTS: There was no detectable IL-2 or IFN-gamma production (below the detection limit) except in two patients; IL-4 was produced in 18 patients (51%) and of these, 15 (43%) showed a higher level than the mean. IL-5 was produced in 12 patients (34%), all of whom showed a higher level than the mean, and IL-6 was produced in 32 (91%) of whom 10 (29%) showed a higher level than the mean. IL-10 was detected in 28 patients (80%) of whom 14 (40%) showed a higher level than the mean. The production of these cytokines was closely related to the stage and grade of malignancy. Furthermore, there were significant correlations between the levels of production of IL-4 and IL-5 (r2=0.92), IL-4 and IL-10 (r2=0.91), and IL-5 and IL-10 (r2=0.85). CONCLUSION: The intratumoral immunological environment in patients with RCC shows a tendency to produce Th2-related cytokines in accordance with the stage and grade; this suggests a role in humoral but not in cellular immunity.