title: Nocturnal sleep uniformly reduces numbers of different T-cell subsets in the blood of healthy men.
abstract: In humans, numbers of circulating T cells show a circadian rhythm with peak counts during the night and a steep decline in the morning. Sleep per se appears to counter this rhythm by acutely reducing the total number of T cells. The T-cell population, however, is rather heterogeneous, comprising various subpopulations with different features and functions and also different circadian rhythms. Therefore, we examined here whether sleep likewise differentially affects these subsets. We measured eight different T-cell subsets (naïve, central memory, effector memory, and effector CD4+and CD8+T cells) over a 24-h period under conditions of sustained wakefulness compared with a regular sleep-wake cycle in 14 healthy young men. Sleep reduced the number of all T-cell subsets during nighttime with this effect reaching the P < 0.05 level of significance in all but one subpopulation, i.e., effector CD4+T cells, where it only approached significance. Furthermore, sleep was associated with an increase in growth hormone, prolactin, and aldosterone levels, whereas concentrations of catecholamines tended to be lower than during nocturnal wakefulness. The effect of sleep uniformly decreasing the different T-cell subsets is surprising considering their differential function and circadian rhythms, and even more so, since the sleep-induced decreases in these subsets are probably conveyed by different hormonal mediators. Although the reductions in cell numbers are rather small, they are comparable to changes seen, for example, after vaccination and are, therefore, likely to be of physiological relevance.
authors.affiliation: Department of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
authors.forename: Luciana
authors.initials: L
authors.lastname: Besedovsky
authors.affiliation: Department of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.|German Center for Diabetes Research, München-Neuherberg, Germany.|Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.|Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany.
authors.forename: Stoyan
authors.initials: S
authors.lastname: Dimitrov
authors.affiliation: Department of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.|German Center for Diabetes Research, München-Neuherberg, Germany.|Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.|Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany; and.
authors.forename: Jan
authors.initials: J
authors.lastname: Born
authors.affiliation: Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany; tanja.lange@uksh.de.|Clinic for Rheumatology, University of Lübeck, Lübeck, Germany.
authors.forename: Tanja
authors.identifier: 0000-0001-8309-2112
authors.initials: T
authors.lastname: Lange
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D012016:Reference Values; D012890:Sleep / Q000502:physiology*; D013601:T-Lymphocytes / Q000145:classification / Q000166:cytology* / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*
keywords: T-cell subsets; migration; sleep