The effects of psychological stress on humans: Increased production of pro-inflammatory cytokines and a Th1-like response in stress-induced anxiety
ABSTRACT There is some evidence that, in humans and experimental animals, psychological stress may suppress or enhance immune functions, depending on the nature of the stressor and the immune variables under consideration. The possibility that psychological stress may affect the production 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. Psychological stress significantly increased the stimulated production of tumour necrosis 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 significantly higher production of TNF-alpha, IL-6, IL-1Ra and IFN-gamma than students with a low-stress perception. Students with a high anxiety response had a significantly higher production of IFN-gamma and a lower production of the negative immunoregulatory cytokines, IL-10 and IL-4, than students without anxiety. These findings suggest that, in humans, 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.
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ABSTRACT: The use of relaxation and guided imagery to reduce stress and improve immune function has great potential benefits for patients with breast cancer. This pilot study used a pretest-posttest experimental design with 28 breast cancer patients, aged 25 to 75 years, with the diagnosis of stage 0, 1, or 2 breast cancer. The experimental group received a relaxation and guided imagery intervention and the control group received standard care. The effects of the intervention on immune function were measured by natural killer (NK) cell cytotoxicity and IL-2-activated NK cell activity prior to surgery and 4 weeks postsurgery. NK cell activity was measured using a 15-hr incubation chromium release assay. Cytotoxicity of NK cells was measured against chromium-labeled K-562 target cells. IL-2 was used to enhance reactivity of NK cells against tumor cells. After incubation for 15 hr, cytotoxicity was measured through the release of radioactive chromium. Significant differences between groups were found at 4 weeks postsurgery. T-tests showed increased NK cell cytotoxicity for the intervention group at 100:1, 50:1, and 25:1 effector cell: target cell ratios (E:T) (p < .01 to p < .05) and increased activation for IL-2 at 100:1, 50:1, 25:1, and 12.5:1 (E:T) (p < .01 to p < .05) for the intervention group as compared to the control group. These findings suggest that a relaxation intervention such as guided imagery could have an effect on NK cell cytotoxicity and NK cell cytotoxicity after activation with IL-2 in patients undergoing surgery for breast cancer.Biological Research for Nursing 02/2008; 9(3):205-14. DOI:10.1177/1099800407309374 · 1.34 Impact Factor
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ABSTRACT: Psychological stress can influence the immune system, which may result in stress-related illnesses. In this study, we investigated the effect of psychological stress and the coping skill on plasma cytokine levels. One hundred eighty-three students, at different stages of an academic year, participated in this study. Plasma tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-2 soluble receptor alpha, and IL-4 were measured and examined in relation to the measures of anxiety [State Anxiety Inventory (SAI)] and Bell Adjustment Inventory (BAI) score. SAI scores were significantly higher in both midterm students (MTS) and examination-taking students (ETS), compared with the freshly admitted students (FAS). In addition, TNF-alpha levels were significantly different between the high- and the low-anxiety groups of ETS but not in MTS or FAS. The correlation between SAI scores and the BAI emotional scores was highest in the ETS group. TNF-alpha level was significantly lower in the ETS group with high anxiety scores, and it is situation specific.Journal of Psychosomatic Research 08/2007; 63(1):65-9. DOI:10.1016/j.jpsychores.2007.03.001 · 2.84 Impact Factor
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ABSTRACT: One potential pathway by which depression may impact health is through modulation of immune function. Depressed individuals have been shown to display reductions in measures of cellular immune competence as well as elevated markers of systemic inflammation. The current study assessed the in vitro production of proinflammatory cytokines IL-6, IL-1beta, and TNF-alpha by peripheral blood mononuclear cells (PBMCs) in response to mitogen stimulation within a community-based sample of 79 midlife women. Results indicate that midlife women with higher levels of depressive symptoms (as assessed with the Center for Epidemiologic Studies Depression scale) and greater body mass index (BMI) displayed diminished production of IL-6, IL-1beta, and TNF-alpha by stimulated PBMCs, as compared with their less-depressed counterparts. These relationships remained after controlling for such health-related variables as age, recent sleep disruption, physical activity level, and self-reported medical history. In contrast, depressive symptoms were not significantly associated with circulating levels of the same proinflammatory cytokines (IL-6, IL-1beta, and TNF-alpha) obtained from serum samples available for a subset of 62 of the study participants. Moreover, circulating proinflammatory cytokine levels were not significantly associated with the in vitro proinflammatory cytokine production outcomes. Further research is needed to clarify the clinical significance of the current study findings, and the extent to which in vitro tests of stimulated proinflammatory cytokine production are associated with other measures of cellular immune function and/or circulating markers of systemic inflammation obtained across various study populations.Brain Behavior and Immunity 03/2007; 21(2):229-37. DOI:10.1016/j.bbi.2006.07.005 · 6.13 Impact Factor