Sleep is a process that occupies a third of the life of the human being and is essential for the individual to maintain the homeostasis of the body. It emerges as an important regulator of the immune system, since the functions necessary to maintain its balance are carried out during sleep. On the other hand, the reduction of sleep has adverse effects that alter the metabolism and produces an increase in the secretion of C-reactive protein, interleukin (IL) -6 and tumor necrosis factor (TNF). These cytokines activate NF-κB, so sleep disturbance can be a risk factor for developing chronic and metabolic inflammatory diseases. Proinflammatory cytokines IL-1, IL-6, and TNF increase non-rapid eye movement sleep, and anti-inflammatory cytokines such as IL-4 and IL-10 decrease it.
Sleep can modify the function of the immune system by inducing changes in the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. In turn, the circadian rhythm of hormones such as cortisol and adrenaline, which decrease at night, favors different activities of the immune system. The objective of this review is to address various aspects of sleep and its relationship with the immune system.