HYPOTHALAMIC-PITUITARY-ADRENAL AXIS FUNCTION, PSYCHOPATHOLOGICAL TRAITS, AND NATURAL-KILLER (NK) CELL-ACTIVITY IN ANOREXIA-NERVOSA

To evaluate the role of Hypothalamic-Pituitary-Adrenal (HPA) hormones and psychoneuroendocrine modulation on NK cell activity in Anorexia Ne rvosa (AN) we studied in 24 patients and 20 sex-and age-matched health y controls, the spontaneous NK activity of peripheral blood mononuclea r (PBM) cells and the susceptibility in vitro to cortisol or immune in terferon or interleukin-2. NK cytotoxicity of PBM cells was measured i n a direct non-radiometric 4h cytolytic assay using K562 cells as targ ets. HPA axis function was evaluated by IV ovine Corticotropin Releasi ng Hormone (o-CRH) administration. We did not find clear-cut abnormali ties of NK cytotoxicities either in basal conditions or after exposure to challengers. The extent of cortisol-dependent inhibition was compa rable in patients and controls. Significant inverse and direct correla tions were found respectively between the spontaneous NK cell activity and baseline serum cortisol at 0800h (r = -0.5; p < .02), and between IL-2 dependent boosting of NK cell cytotoxicity and ACTH, beta-endorp hin or cortisol responses after o-CRH, expressed as areas under the cu rve (AUC) (r = 0.46, p < .05; r = 0.46, p < .05; and r = -0.48, p < .0 5, respectively). Correlations observed with AUC ratios yielded more s ignificant results (r = 0.62; p < .01 and r = 0.51; p < .05 respective ly). These data suggest a role for Proopiomelanocortin (POMC) derived peptides in the regulation of NK cell activity in AN, and multifaceted relationships between this particular immune function, on the one han d, and certain patterns of HPA axis function on the other. (C) 1997 El sevier Science Ltd. All rights reserved.