Stressor-induced alterations of immune function: mechanisms and issues.

This paper reviews the role of catecholamines and the hypothalamic-pituitary-adrenal system in the mediation of stress-induced immune changes in both human and animal subjects. There is evidence to support the importance of these factors in mediating stressor effects on certain immune parameters, but further research is needed to define the specific circumstances in which they are relevant. Therefore, discussion of such issues as sex, genotype, stress history, environment, and stressor characteristics is provided to suggest possible ways to increase our understanding of stressor effects on immune function. Since the imposition of a stressor disrupts physiological homeostasis, understanding the capacity of the immune system to function under such conditions is of prime importance in predicting disease onset and outcome.