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].

Interferons (IFNs) are glycoproteins known as cytokines.

The body’s reaction to infections involves the orchestration of multiple systems to effectively initiate, execute and resolve the immune response.

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

The immune and nervous systems are anatomically and functionally interconnected, this cross-talk is evidenced by the dense innervation – mainly sympathetic – of the primary (bone marrow and thymus) and secondary (spleen and lymph nodes) lymphoid organs [1, 2].

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.