Neuroimmunomodulation in cancer patients: correlations between melatonin and beta-endorphin blood levels and T helper/suppressor ratio.

The pineal gland and opioid peptides play roles in the neuroendocrine control of immunity. Both neuroendocrine and immune dysfunctions have been observed in cancer but the importance of the altered secretion of neurohormones in the immunoincompetence of cancer patients has never been investigated. This study concomitantly evaluated neuroendocrine and immune functions in 40 patients with early or advanced neoplastic disease. In each patient, melatonin and beta-endorphin blood levels and lymphocyte subtypes were determined on venous blood samples collected during the morning. Metastatic patients had lower melatonin levels and a lower T4/T8 ratio than patients without metastases but no significant correlation was found between melatonin and the T4/T8 ratio. beta-endorphin levels appeared to be normal in all patients. These results suggest that melatonin and beta-endorphin secretion have no role in determining immune dysfunctions in cancer.