Sleep supports immune defense. In the first half of nocturnal sleep, slow wave sleep (SWS) and the circadian system act in concert to induce a pro-inflammatory milieu, while immunosuppressive mediators are at lowest levels.

The sexual dimorphism in immune responses in humans is well known; females have more vigorous cellular and humoral immune responses, they are more resistant to many infections, and they suffer a higher incidence of autoimmune diseases as compared with males [reviewed in Reference 1].

Homeostatic control of the immune system is dependent on CD4, FoxP3+, NKT or antigen-specific CD4+ or CD8+ regulatory T cells.

The nervous and immune systems share common functions: both are involved in adapting the body to the environment and in maintaining homeostasis.

Glucocorticoids, steroid hormones secreted from the adrenal cortex, play essential roles in the maintenance of internal homeostasis by influencing virtually all organs and tissues.

During immune responses a tight balance between proinflammatory and regulatory mechanisms is key in order to restore homeostasis and avoid excessive tissue damage.

Leukocytes are key components of the body’s defense system and the major subsets of leukocytes are granulocytes and lymphocytes.

Vasopressin (VP) has emerged in recent years as a very important immunoregulatory peptide of the hypothalamus.