Psychological and biological effects of stress on human immune system

Stress is a broad concept that comprises challenging to such circumstances (stress responses). In humans one of the systems that respond to challenging circumstances is the immune system. broadly, the immune system comprises cells, proteins, organs, and tissues that work together to provide protection against bodily disease and damage. Several facets of the human immune system have been empirically associated with stress. Acute stress also increases blood levels of pro-inflammatory cytokines. We have proposed that short term stress is one of the nature‘s fundamental but under-appreciated survival mechanisms that could be clinically harnessed to enhance immune protection. Short-term (i.e., lasting for minutes to hours) stress experienced during immune activation enhances innate/primary and adaptive/secondary immune responses. Mechanisms of immuno-enhancement include changes in dendritic cell, neutrophil, macrophage, and lymphocyte trafficking, maturation, and function as well as local and systemic production of cytokines. In contrast, long-term stress suppresses or dysregulates innate and adaptive immune responses by altering the Type 1-Type 2 cytokine balance, inducing low-grade chronic inflammation, and suppressing numbers, trafficking, and function of immunoprotective cells. Chronic stress may also increase susceptibility to some types of cancer by suppressing Type 1 cytokines and protective T cells and increasing regulatory/suppressor T cell function.