THE EFFECTS OF PSYCHOLOGICAL STRESS ON HUMANS - INCREASED PRODUCTION OF PRO-INFLAMMATORY CYTOKINES AND A TH1-LIKE RESPONSE IN STRESS-INDUCED ANXIETY

There is some evidence that, in humans and experimental animals, psych ological stress may suppress or enhance immune functions, depending on the nature of the stressor and the immune variables under considerati on, The possibility that psychological stress may affect the productio n of pro-inflammatory and immunoregulatory cytokines was investigated in 38 medical students, who had blood samplings a few weeks before and after as well as one day before an academic examination. Psychologica l stress significantly increased the stimulated production of tumour n ecrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), IL-1 receptor antagonist (IL-1Ra), interferon gamma (IFN-gamma) and IL-10. Students with high stress perception during the stressful condition had a signi ficantly higher production of TNF-alpha, IL-6, IL-1Ra and IFN-gamma th an students with a low-stress perception. Students with a high anxiety response had a significantly higher production of IFN-gamma and a low er production of the negative immunoregulatory cytokines, IL-10 and IL -4, than students without anxiety. These findings suggest that, in hum ans, changes in the production of the pro-inflammatory cytokines, TNF- alpha, IL-6 and IFN-gamma, and negative immunoregulatory cytokines, IL -10 and IL-4, take part in the homeostatic responses to psychological stress and that stress-induced anxiety is related to a T-helper-1-like response. (C) 1998 Academic Press Limited.