Stress-induced suppression of the cellular immune reactions: on the neuroendocrine control of the immune system

Immune competence is considered as a state of equilibrium between humoral and cellular immunity. This notion fits well with the functionally antagonistic cytokine profiles in cell groups of CD4(+)-helper cells as described by Mosmann and Coffman. The Th-1 cells release mainly IL-2, IL-12 and IFN gamma and thereby stimulate the cellular immune reactions. Conversely, the Th-2 cells produce predominantly IL-4, IL-6 and IL-10, thus enhancing humoral immune reactions. Recently, it has been shown that the lymphokine profiles in Th-2 are linked to changes of the humoral balance between cortisol and dehydroepiandrosterone. These studies show that there exist states of equilibrium between T- and B-cell-mediated immune reactions, which may selectively be altered to the disadvantage of the T-cellular immunity by a stress-induced enhancement of cortisol release. In an attempt to restitute stress-induced immunosuppression, a dampening of the cortisol release hormone in the hypothalamus should, therefore, be of primary importance.