Alterations in serum cortisol, CD4+ CD8+ lymphocyte sub-population ration and T cell mediated suppression of immune responses in the malnutrition of anorexia nervosa

Serum cortisol and T lymphocyte sub-populations (CD3+, 4+ and 8+) were studied in 22 consecutively admitted patients with anorexia nervosa (AN) who had a mean weight loss of 30%. In addition Concanavalin A (Con A) mitogen induced T cell suppression of lymphocyte response to PPD (purified protein derivative of tuberculin antigen) was analysed. Increased serum cortisol concentrations were found in the AN-patients compared to the control group, with mean levels 654 and 418 nmol/l respectively. The relative numbers of CD4+ lymphocytes (mean 36.2%) and the CD4+ CD8+ ratio (mean 1.54) were significantly reduced (p < 0.05) in the AN-patients compared to the control group (mean 41.6% and 2.14 respectively). T cell mediated, Con A induced suppression of lymphocyte response to PPD was increased in AN-patients compared to the control group with low (1mug/ml) Con A concentration, but unchanged with high (5 mug/ml) Con A concentration. There was no correlation between serum cortisol concentrations and the numbers of T lymphocyte subpopulations or T cell suppressor activity. In contrast, a highly significant correlation existed between serum cortisol and the duration of AN (p < 0.002), but not with relative weight loss or anthropometric variables: triceps skin-fold (TSF) and arm muscle circumference (AMC). Immunological variables were not correlated with duration of disease. Thus, immunological alterations of the T cell system are detectable in AN, but are subtle and their clinical importance is not well known.