Changes in cytokine profile during local IL-2 therapy in cancer patients

Background: Exogenous interleukin 2 (IL-2) can influence the complex cytokine network in vivo. This study investigated the cytokine profile of patients with different malignancies before and after local IL-2 administration. Patients and Methods: The human TH1 / TH2 cytometric bead array (CBA) kit was used to investigate IL-2, IFN gamma, TNF alpha. IL-4, IL-5 and IL- 10 in a control group and in 13 patients. Results: The baseline serum IL-4 levels in patients were lower than in healthy controls, while the baseline ascitic IL-10 levels in patients was higher than in serum. The IL-2 applications induced a strong serum increase in IL-2 and IL-5 and even more in ascites, while IL-10 increased weakly and mainly locally. One month after the start of therapy, the serum IFN gamma had increased in patients, reaching the level of the control group. Conclusion: After local injection, IL-2 probably leaks into the blood circulation. The higher increases of IL-2, IL-5 and IL-10 in ascites compared to the serum suggests that the injected cytokines and their effects are mainly local. The minor increase of the immunosuppressive IL-10 could explain the therapeutic difference between local and systemic IL-2 therapy since IL-10 levels markedly increase after systemic IL-2 therapy. IL-5 was always increased after IL-2 therapy and, consequently, may be a downstream mediator of antitumour responses.