EFFECTS OF MELATONIN ADMINISTRATION ON CYTOKINE PRODUCTION IN PATIENTS WITH ADVANCED SOLID TUMORS

There is growing evidence that the pineal gland has antineoplastic pro perties, which include the action of melatonin (MLT) on the immune sys tem through the release of cytokines by activated T-cells and monocyte s. Despite these intriguing preliminary findings, only few studies hav e been undertaken to date on MLT's action in cancer patients. The pres ent study was carried out on 23 patients (15 males and 8 females, rang e 48-71 years), with advanced solid tumors, who received MLT (10 mg/da y orally for a month) after conventional therapy. Blood was assayed fo r tumor necrosis factor alpha (TNF-alpha), Interleukin-2 (IL-2) and hu man interferon gamma (IFN-gamma). Blood samples were taken immediately before the start of MLT administration and 30 days after therapy. Pla sma was collected in EDTA tubes on ice, centrifuged immediately at 4-d egrees-C and stored frozen at -80-degrees-C until assayed. Cytokines w ere quantified by immunoradiometric assays. Circulating levels of TNF- alpha, IL-2 and IFN-gamma increased by 28%, 51% and 41% respectively a fter MLT administration. These increments were statistically significa nt (paired Student's t-test, p<0.01). These findings are consistent wi th the hypothesis that MLT modulates immune functions in cancer patien ts by activating the cytokine system.