The contribution of sleep to the neuroendocrine regulation of rhythms in human leukocyte traffic
The first cooperative paper between the Social Neuroscience Lab and Psychoneuroimmunology (Prof. Tanja Lange; Department of Rheumatology & Clinical Immunology) is out!
In our review, we summarize how 24-h rhythms in leukocyte traffic are regulated by neuroendocrine mediators and how this is supported by sleep. We delineate the molecular setups of different leukocyte subsets and specify how these contribute to opposing rhythms in blood counts of those subsets: Namely, by being differentially affected by epinephrine and cortisol, neutrophils together with highly differentiated cytotoxic T cells are mobilized into the circulation in the morning (epinephrine effect), while eosinophils together with less differentiated T cells are simultaneously redirected out of the circulation (cortisol effect). By suppressing epinephrine and cortisol at night, sleep supports this rhythmicity. We explain why this leads to immunosupportive (commonly “pro-inflammatory”) action at a systemic level during sleep at night (suited for recognition of and response to antigens), while daytime acts as a phase of immune regulation and resolution and thus homeostasis. While this might seem to be counterintuitive since the active phase of the 24-h rhythm (day) is associated with a higher rate of pathogen encounters, we believe that these rhythms support an anti-inflammatory state during daytime to counteract a locally highly active innate immune system ready to fight invading pathogens, and to restrict resulting potentially dangerous inflammatory processes in time and space. Since the more sophisticated and slower responses by the adaptive immune system do not have to occur immediately, they can occur during sleep when energy can be reallocated to these processes. We summarize potential methodological pitfalls including differences between research on humans and animal models and conclude that disruption of this leukocyte rhythmicity can exacerbate disease, which can lead into a vicious circle when sleep gets further impaired by higher symptom load. We close with recommendations for time-dependent medication and behavioral interventions to support and strengthen sleep and rhythmicity.
Lange T, Luebber F, Grasshoff H & Besedovsky L (2022). The contribution of sleep to the neuroendocrine regulation of rhythms in human leukocyte traffic. Semin Immunopathol. doi: 10.1007/s00281-021-00904-6. Online ahead of print.