ALTERATIONS IN LYMPHOCYTE SUBSETS AND PITUITARY-ADRENAL GLAND-RELATEDHORMONES DURING FASTING

We investigated changes in the immunoendocrine system during fasting. Ten hospitalized patients aged 14-46 y with psychosomatic disorders fa sted for 7 or 10 d. Blood samples were collected before and on days 3 and 7 of the 7-d fasts. When fasting continued to 10 d, an additional sample was taken on day 10. We measured blood cellularity (white blood cells and total lymphocytes), the total number and percentage of lymp hocyte subsets (CD2, CD3, CD4, CD8, and CD19), natural killer (NK) cel l activity, cytokines (interleukin 1 beta, interleukin 2, interleukin 6, granulocyte-macrophage colony stimulating factor, tumor necrosis fa ctor alpha, and interferon gamma), and soluble interleukin 2 receptors . Corticotropin, cortisol, and dehydroepiandrosterone sulfate (DHEAS) concentrations were also determined. Although the total number of lymp hocytes decreased during fasting, NK cell activity increased significa ntly. Plasma cortisol and DHEAS concentrations also increased signific antly whereas changes in corticotropin concentrations were not signifi cant. The total number and percentage of CD4 cells decreased significa ntly during fasting but no other lymphocyte subsets changed significan tly. The percentage of CD4 cells was negatively correlated with cortis ol concentrations during fasting. No detectable changes occurred in cy tokines or soluble interleukin 2 receptors during the study. All measu red immunoendocrine values that changed during fasting returned to pre fasting values during the refeeding period. These findings indicate th at fasting affects immune variables such as T cell subsets and NK cell activity at least in part through changes in adrenal gland-related ho rmones.