A Phase-2 Study on the Kinetics of the Improvement in Lymphocyte-toMonocyte Ratio by High-Dose Pineal Hormone Melatonin in Lymphocytopenic Untreatable Metastatic Cancer Patients

It is known that lymphocytopenia is one of the most negative biomarkers in cancer patients, being an expression of cancer-related immunosuppression. Today it is known that, despite its complexity, the antitumor immunity is mainly mediated by dendritic cell-T lymphocyte system and suppressed by the macrophage-regulatory T lymphocyte system. Then, lymphocyte-to-monocyte ratio (LMR) has been proven to represent a more appropriate prognostic clinical index than the simple lyphocytopenia alone. Because of the fundamental role of lymphocytes in mediating tumor cell destruction, the correction of cancer-related lymphocytopenia could influence the clinical history of the neoplastic disease. At present, the only cytokine able to induce a clear in vivo lymphocytosisis IL-2. However, it has been demonstrated that the immune system is physiologically under a neuroendocrine control, and that the pineal hormone MLT may stimulate T lymphocyte proliferation and activation. On these bases, we have evaluated the effect of highdose MLT therapy in metastatic solid tumor patients with persistent lymphocytopenia and abnormally low values of LMR. The study included 14 patients, and the results were compared to those found in a control group of 20 lymphocytopenic untreatable metastatic cancer patients treated with the only best supportive care alone. Patients received MLT at a dose of 100 mg/day orally in the evening for 3 consecutive months. Lymphocyte mean count increases on MLT therapy, and the values observed after two months of therapy were significantly higher than the pretreatment ones, with a normalization of lymphocyte number in 4/14 (29%) patients, whereas no spontaneous lymphocyte rise occurred in the control group. On the other hand, monocyte count rapidly diminished on MLT therapy, and LMR mean values observed after only one month of treatment was significantly higher than that found prior to therapy, whereas it significantly decreases in controls. This preliminary study shows that high-dose MLT may improve the immune status of cancer patients, and be effective in the treatment of disseminated cancer-related lymphocytopenia.