ABSTRACT

Melatonin has a number of immunomodulatory properties. The pineal hormone seemed to restore the effects of aging on the proliferative index of submaxillary lymph nodes and spleen, as measured by the activity of ornithine descarboxylase (ODC). In aging thymus, melatonin increased number of T cells, but was without effects on percentage of CD4+ or CD8+ cells. The effect of melatonin on immune parameters could be direct, by an effect on local innervation of lymphoid organs or through its general effects as a synchronizer.