Psychoneuroimmunology Updated by Dr: Mohamed Adel El-Hadidy Definition: Psychoneuroimmunology is the field concerned with relationships among the mind (psycho), the nervous and endocrine systems (neur) and the immune system (immunology). The central idea is that psychosocial factors can influence immune responses through the brain as a master regulator for bodily system.

Communication between the brain and immune system The immune system for the body like an army to the nation Stimulation of brain sites (The hypothalamus, locus ceruleus, and the limbic system) Enhancing immune system inhibiting immune system The autonomic nervous system: the sympathetic nervous system fibers provide a direct link between the brain and the lymphocytes, spleen and thymus. Lymphocytes have receptor sites on their surfaces for certain hormones and the neurotransmitter catecholamine Immune cells produce cytokines that act on the CNS

Antigens ( threaten health ) Body Activation of immune system to defeat the body (from bone marrow) humoral branch like navy because it operates through B cell (from bone marrow) that circulates in the blood (From thymus gland) The cellular branch like foot army because it operates through T cell (From thymus gland) that can leave the blood stream and more through the tissues Memory B cells Memory T cells Memory T cells remain to provide immunity against further attach with same antigen

The immune has also two responses: according to type of lymphocyte Non-specific Response: Non-specific Response: (by non-specific lymphocytes): Both Natural Killers (NK- cells) that destroy tumors and viruses. Macrophages that attack bacteria and pass information about the antigen to specific Helper T cells. Specific Response: Where specific lymphocytes using the information from macrophages to produce T Killer cells and B cells become plasma cells that secrete antibodies.

Communication between neuroendocrine and immune system response to stress Activation of the hypothalamic-pituitary- adrenal connection Glucocorticoids and catecholamines influence immune cells Endorphins from pituitary & adrenal medulla act on immune system Activity of the immune system is correlated with neuroendocrine activity of brain cells Feedback from hormones and other chemicals produced by lymphocytes and macrophages.

Increase apoptosis. Connections between glucocorticoids and immune system Anti-inflammatory hormones that enhance the organisms response to a stressor Prevent the overreaction of the body's own defense system. Regulators of the immune system Cause immunosuppression through Affect cell growth, proliferation & differentiation. Suppress cell adhesion, antigen presentation, chemotaxis & cytotoxicity. Corticosteroid

Other psychological Factors affecting immune system Stress and personal control Stress produces “down-regulation” of the immune system when associated with lack of personal control interfere with leukocyte function and antibody production is mediated through the release of cortecosteroids Patients taught relaxation techniques Patients taught relaxation techniques significantly fewer stress-related symptom significantly fewer stress-related symptom had increase in nature killer cell (NK-cell) activity

2) Depression and bereavement: Depression decrease immune system. bereavement show 1.significant reduction in NK cell activity. 2.A significant reduction of lymphocyte response has been found during the first two months following death of spouse with a return to normal by five months post bereavement.

Pharmaceutical advances based on psychoneuroimmunology: Antidepressants (SSRIs, SNRIs and tricyclic) acting on serotonin, norepinephrine and dopamine receptors Immunomodulator anti-inflammatory against pro- inflammatory cytokine processes Tricyclic and (SNRIs) have analgesic properties Many investigation for antidepressants for use in Psychiatric (Anxiety, OCD, impulse control) non-psychiatric illness ( autoimmune neuritis )