Psychoneuroendocrine influences on immunocompetence and neoplasia.

Emotional, psychosocial, or anxiety-stimulated stress produces increased plasma concentrations of adrenal corticoids and other hormones though well-known neuroendocrine pathways. A direct consequence of these increased corticoid concentrations is injury to elements of the immunological apparatus, which may leve the subject vulnerable to the action of latent oncogenic viruses, newly transformed cancer cells, or other incipient pathological processes that are normally held in check by an intact immunological apparatus. This article describes studies that examine the adverse effects of increased plasma concentrations of adrenal corticoids on the thymus and thymus-dependent T cells, inasmuch as these elements constitute a major defense system against various neoplastic processes and other pathologies. The studies demonstrate that anxiety-stress can be quantitatively induced and the consequences measured through specific biochemical and cellular parameters, providing that authentic quiescent baselines of these conditions are obtained in the experimental animals by the use of low-stress protective housing and handling techniques.