A novel scientific discipline that examines the complex inter-dependence of the neural, endocrine and immune systems in health and disease has emerged in recent years. In health, the neuroimmunoregulatory network is fundamental to host defence and to the transfer of immunity to offspring; the network also plays important roles in intestinal physiology and in tissue regeneration, healing and reproduction. The proliferation of lymphocytes in primary lymphoid organs (bone marrow, bursas of Fabricius [in birds] and thymus) and in secondary lymphoid organs (spleen, lymph nodes and mucosal lymphoid tissue) depends on prolactin and growth hormone. These hormones allow immune cells to respond to antigen and to soluble mediators, called cytokines. Immune-derived cytokines are capable of inducing fever and of altering neurotransmitter activity in the brain and hormone secretion by the pituitary gland. The activation of hypothalamus-pituitary-adrenal axis by cytokines leads to immunosuppression. Lymphoid organs are innervated, and tissue mast cells respond to neurologic stimuli. In general, acetylcholine and substance P exert immunostimulating and proinflammatory effects, whereas epinephrine and somatostatin immunosuppressive and anti-inflammatory. In this article, the authors predict that novel approaches to immunomodulation will be possible by altering the level of efficacy of immunoregulatory hormones and neurotransmitters.

Department of Psychology

Anisman, H, Baines, M.G. (Malcolm G.), Berczi, I. (Istvan), Bernstein, C.N. (Charles N.), Blennerhassett, M.G. (Michael G.), Gorczynski, R.M. (Reginald M.), … Warrington, R.J. (Richard J.). (1996). Neuroimmune mechanisms in health and disease: 1. Health. CMAJ, 155(7), 867–874.