Antiphase signalling in the neuroendocrine-immune system in healthy humans

Background: Any quantity varying in the spatial-temporal dimension may be considered as a signal. Human lymphocyte cell surface molecules and subsets present circadian variation and this variation may represent a kind of signalling in the neuroendocrine-immune system. We have analyzed the dynamics of variation of specific lymphocyte subsets in healthy humans. Subjects and methods: In our study, lymphocyte subpopulation analyses were performed and cortisol, melatonin, GH and TSH serum levels were measured on blood samples collected every 4 h for 24 hours from eleven healthy men, ages 35-53 years (mean = 44 +/- 6 SD). Results: A clear circadian rhythm was validated for CD8 and cortisol with acrophase during the day and for CD3, CD4, melatonin, GH and TSH with acrophase at night. Cross-correlation showed that CD3 correlated positively with CD4 (rho = 0.67, P < 0.05) and negatively with CD8 (rho = -0.41, P < 0.05), CD4 correlated positively with melatonin (rho = 0.90, P < 0.05), GH (rho = 0.92, P < 0.05) and TSH (rho = 0.71, P < 0.05), negatively with CD8 (rho = -0.90, P < 0.05) and cortisol (rho = -0.18, P < 0.05), CD8 correlated positively with cortisol (rho = 0.38, P < 0.05). Discussion: The different profiles of nyctohemeral changes of lymphocyte cell surface molecules and specific lymphocyte subsets realize different relationships with the neuroendocrine hormones and might represent a way of signal transmission among the multiple components of the neuroendocrine-immune system. (C) 2011 Elsevier Masson SAS. All rights reserved.