Stress system activity, innate and T helper cytokines, and susceptibility to immune-related diseases.

Associations between stress and health outcomes have now been carefully documented, but the mechanisms by which stress specifically influences disease susceptibility and outcome remain poorly understood. Recent evidence indicates that glucocorticoids (GCs) and catecholamines (CAs), the major stress hormones, inhibit systemically IL-12, TNF-alpha, and INF-gamma, but upregulate IL-10, IL-4, and TGF-beta production. Thus, during an immune and inflammatory response, the activation of the stress system, through induction of a Th2 shift may protect the organism from systemic "overshooting" with T helper lymphocyte 1 (Th1)/proinflammatory cytokines.