A BIOLOGICAL STUDY ON THE EFFICACY OF LOW-DOSE SUBCUTANEOUS INTERLEUKIN-2 PLUS MELATONIN IN THE TREATMENT OF CANCER-RELATED THROMBOCYTOPENIA

The production of cytokines involved in platelet generation, including interleukin (IL)-3, IL-6 and IL-11, is stimulated by IL-2. However, t he platelet number has been shown to decrease on IL-2 cancer therapy, and this side effect depends on the enhanced peripheral platelet destr uction following the activation of the macrophage system by IL-2 itsel f. Our previous studies showed that IL-2-induced macrophage activation may be counteracted by the pineal hormone melatonin (MLT). On this ba sis, a pilot study with IL-2 plus MLT was performed to evaluate its in fluence on the platelet number in cancer patients with persistent thro mbocytopenia. The study included 20 advanced solid tumor patients, who received IL-2 at 3 million IU/day s.c. for 6 days/week for 4 weeks in association with MLT (40 mg/day orally). A normalization of the plate let number was achieved in 14/20 (70%) patients. This pilot study show s that the therapy with low-dose IL-2 plus MLT, in addition to its pre viously described antitumor activity, may also be effective in the tre atment of cancer-related thrombocytopenia.