Immune outcomes of sleep disorders: the hypothalamic- pituitary-adrenal axis as a modulatory factor Repercussões imunológicas dos distúrbios do sono: o eixo hipotálamo-pituitária-adrenal como fator modulador

Abst rac t Objective: To review the literature on the interaction between sleep and the immune system. Method: A search on Web of Science and Pubmed database including the keywords sleep, sleep deprivation, stress, hypothalamic-pituitary-adrenal axis, immune system, and autoimmune diseases. Results: On Web of Science, 588 publications were retrieved; 61 references, more significant and closer to our objective, were used, including original articles and review papers. Conclusion: Sleep deprivation and immune system exert a bidirectional influence on each other. Since sleep deprivation is considered a stressor, inasmuch as it induces elevation of cortisol or corticosterone levels in humans and rodents, respectively, and given the well-known immunosuppressive effect of glucocorticoids, we propose that increased activation of the hypothalamic-pituitary-adrenal axis is a major mediator of the immune alterations observed in patients with insomnia or in sleep deprived subjects.