Relation between lymphocyte subpopulations and pineal function in patients with early or metastatic cancer

It has been demonstrated that melatonin and other pineal hormones play a role in the neuroendocrine control of immunity. Anomalies of both pineal and immune functions have been reported in cancer. Pineal and lymphocyte functions, however, have never been simultaneously evaluated in oncologic patients. This preliminary study was carried out in order to analyze the melatonin-lymphocyte relationship in human neoplasms. In a first investigation, we evaluated melatonin serum levels and lymphocyte subpopulations on venous blood samples collected during the morning from 46 healthy controls and from 27 cancer patients, 13 of whom had metastases, while the other 14 were without metastases. Moreover, melatonin levels were high in 10 oncological patients and within the normal range in the other 17 cases. B lymphocyte (B), total T lymphocyte (T3), T helper/inducer (T4) and T suppressor/cytotoxic (T8) mean percentages and T4/T8 mean ratios did not significantly differ, either between patients with high and normal melatonin levels, or between metastatic and nonmetastatic cancer patients. In a second study, we evaluated the effects of a prolonged treatment with melatonin (20 mg/daily intramuscularly at 3:00 p.m. for 2 months) on 8 patients with advanced cancer, in whom conventional antitumor therapies had failed. Mean percentages of B, T3, T4, T8 lymphocytes and T4/T8 mean ratios were not significantly different before or after melatonin treatment. In only one patient did the T4/T8 ratio decrease after therapy; in this case only, a stabilization of the disease was obtained, while in all 7 other patients the neoplastic disease progressed also during melatonin treatment, even if an evident improvement of the performance status was seen as it was in most cases. These results seem to exclude that melatonin may influence lymphocyte functions in cancer. Longitudinal studies and further data, however, will be needed to clarify this question.