Neuroimmune Regulation in Health: Acute Febrile Illness and Healing

Adaptive Immunity (ADIM) is maintained by Growth hormone (GH), Prolactin (PRL), and during fetal life Placental lactones (PL) fulfill this role. Vasopressin (VP) is also an ADIM regulator. ADIM is also regulated by antigens and by cytokines and chemokines. Innate immunity (INIM) is the second part of our Immune System. This system is with us for life, capable of responding instantaneously and it is with us in acute febrile illness and in other pathological situations. It protects us till the last second of life. The Hypothalamic-Pituitary –Adrenal (HPA) axis and catecholamine’s regulate INIM.The acute phase response (APR), or acute febrile illness, is an emergency defence reaction against infectious disease and towards other pathogens. Here the ADIM system is suppressed and INIM function is significantly amplified. Cytokines, I l -1 beta, Tumor necrosis factor (TNF)-alpha and IL-6 stimulate corticotrophin releasing hormone (CRH), VP secretion and cause “sympathetic outflow”. Colony stimulating factors activate leukocytes. CRH is a powerful activator of the HPA-axis, and elevates glucocorticoid (GC) levels. Cytokines, GC and catecholamine’s (CAT) play fundamental role of INIM amplification. VP supports the APR at this stage, however when the disease turns to chronic, it is VP that will regulate, and not CRH, the chronic disease and proceed to recovery and healing. VP is able to cause recovery as it stimulates the HPA axis and also Prolactin. The ACTHadrenal axis stimulates NATIM and suppressor regulatory (T sr), which suppresses ADIM. It is concluded that VP regulates healing and recovery from disease.