Nursing Research: Depression, Obesity and High Blood Pressure Weakens the Immune Response

Depression is associated with an increased risk for both disability and death. One possible way that depression may adversely affect physical health is by altering immune function, and depressed individuals have been shown to have signs of both decreased immune cell activity and elevated markers of systemic inflammation. From a group of 79 pre- or perimenopausal women participating in the multisite Study of Women's Health Across the Nation, researchers studied the links between depressive symptoms and the presence of a class of compounds called proinflammatory cytokines, which serve as cellular messengers to activate the immune response. The women averaged 48 years of age, 61% were white and 39% were black, 72% were married, and 23% were current smokers. In addition, 29% reported recent sleep problems. The women completed the Center for Epidemiologic Studies-Depression (CES-D) scale.

Based on a cut-off score of 10 on this scale, 60% of the women had low depression scores, and 40% had high scores. Using blood samples, mononuclear immune cells were isolated from each of the women and exposed to mitogens that stimulate immune compound production. The immune cells from women with high depression scores displayed significantly lower production of 3 types of proinflammatory cytokines than women with low depression scores. In addition, reduced cytokine production was related to higher body mass index and a history of HBP. In a smaller subgroup of 62 of the participants, no association was found between depressive symptoms and baseline circulating serum levels of these cytokines. The findings of this study suggest that depression, as well as obesity and HBP, may suppress the ability of immune cells to produce cytokines that activate the immune response.

Depression May Suppress Activation of the Immune Response
Cyranowski JM, Marsland AL, Bromberger JT, Whiteside TL, Chang Y, Matthews KA. Depressive symptoms and production of proinflammatory cytokines by peripheral blood mononuclear cells stimulated in vitro. Brain, Behavior, and Immunity. 2007;21:229-237.