Circadian variations of melatonin concentration in saliva and blood content of immunocompetent cells in healthy individuals.

Salivary content of melatonin and parameters of the immune status were studied in young healthy individuals. Morning and evening levels of melatonin showed different correlations with some immunity parameters. It was assumed that the degree and type of correlation between the immune system and melatonin depend on the phase of circadian cycle, which should be considered during evaluation of immunoendocrine status.