The Relationship of Stress-Induced Hypothalamic-Pituitary-Adrenal Axis Function with Cell-mediated Immunity

Koh, Kyung Bong

Abstract

The objective of this study was to examine the relationship between stress-induced hy-pothalamic-pituitary-adrenal(HPA) axis function and cell-mediated immunity in healthy individuals. Thirty-three medical students participated in the study 5 weeks before an academic examination period and then during the exam period. Cell-mediated immune function was measured by lymphocyte proliferative response to phytohemagglutinin(PHA) and interleukin-2(IL-2) production. Plasma adrenocorticotropic hormone(ACTH) and cortisol as well as plasma prolactin were assessed by radioimmunoassay. Global assessment of recent stress(GARS) scale and symptom checklist-90-revised(SCL-90-R) were used to measure the level of subjective stress and distress. The total scores of the GARS scale were significantly higher during the exam period than during the nonexam period, but no significant differences were found in scores of each SCL-90-R subscale between the two periods. Plasma ACTH levels, lymphocyte proliferation and IL-2 production were significantly higher during the exam period than during the nonexam period. Subjects with higher perceived stress were found to have significantly higher IL-2 production during the exam period than those with lower perceived stress. However, plasma cortisol and prolactin levels showed no significant differences between the two periods. Also, regression analyses showed no significant relationships between each of the endocrine and immune parameters. These results suggested that mild stressors such as examination may activate some HPA axis function and cell-mediated immunity. However, it was found that there was no significant relationship between ACTH or cortisol levels and stress-induced immune activation.