NEUROIMMUNE MECHANISMS IN HEALTH AND DISEASE .2. DISEASE

In the second part of their article on the emerging field of neuroimmu nology, the authors present an overview of the role of neuroimmune mec hanisms in defence against infectious diseases and in immune disorders . During acute febrile illness, immune-derived cytokines initiate an a cute phase response, which is characterized by fever, inactivity, fati gue, anorexia and catabolism. Profound neuroendocrine and metabolic ch anges take place: acute phase proteins,are produced in the liver, bone marrow function and the metabolic activity of leukocytes are greatly increased, and specific immune reactivity is suppressed. Defects in re gulatory processes, which are fundamental to immune disorders land inf lammatory diseases, may lie in the immune system, the neuroendocrine s ystem or both. Defects in the hypothalamus-pituitary-adrenal axis have been observed in autoimmune and rheumatic diseases, chronic inflammat ory disease, chronic fatigue syndrome and fibromyalgia. Prolactin leve ls are often elevated in patients with systemic lupus erythematosus an d other autoimmune diseases, whereas the bioactivity of prolactin is d ecreased in patients with rheumatoid arthritis. Levels of sex hormones and thyroid hormone are decreased during severe inflammatory disease. Defective neural regulation of inflammation likely plays a pathogenic role in allergy and asthma, in the symmetrical form of rheumatoid art hritis and in gastrointestinal inflammatory disease. A better understa nding of neuroimmunoregulation holds the promise of neu approaches to the treatment of immune and inflammatory diseases with the use of horm ones, neurotransmitters, neuropeptides and drugs that modulate these n ewly recognized immune regulators.