title: Expression of lymphocyte subsets after exercise and dexamethasone in high and low stress responders.
abstract: OBJECTIVE
  Recent work indicates that among the normal population, persons can be classified as low (LR) or high (HR) stress responders based on hypothalamic-pituitary-adrenal (HPA) axis responses to high-intensity exercise. We studied whether differential activation of the HPA axis affected cytokine production and expression of selected lymphocyte subsets in HR and LR in response to high-intensity exercise after placebo and dexamethasone (DEX; 4 mg).
  
  
  METHODS
  Healthy HR (N = 12) and LR (N = 10) underwent two exercise tests at 90% of VO2max, 8 h after placebo or DEX. Expression of lymphocyte surface markers (CD3+, CD4+, CD8+, CD56+), adhesion molecule markers (intercellular adhesion molecule-1/ICAM-1: CD54+ and L-selectin: CD62L+), and concentrations of plasma interleukin 6 (IL-6) were examined before and after exercise.
  
  
  RESULTS
  Baseline percentages of CD8+ and CD56+ cells were significantly higher, and concentrations of IL-6 and percentages of CD4+ cells were significantly lower in HR as compared with LR. The percentage of CD54+ and CD62L+ cells was not significantly different in HR and LR. DEX significantly reduced the percentage of CD3+ and CD4+ and increased the percentage of CD8+ and CD56+ subsets; the percent of cells expressing CD54+ increased, whereas CD62L+ decreased. Exercise-induced changes in the percentage of lymphocyte subsets were similar to those induced by DEX.
  
  
  CONCLUSIONS
  In summary, HR and LR have different baseline patterns of IL-6 and lymphocyte subsets, which may reflect differential sensitivity to endogenous glucocorticoids. However, exogenous glucocorticoids induced similar patterns of lymphocyte expression in HR and LR.
authors.affiliation: Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814-4799, USA. pdeuster@usuhs.mil
authors.forename: P A
authors.initials: PA
authors.lastname: Deuster
authors.forename: E B
authors.initials: EB
authors.lastname: Zelazowska
authors.forename: A
authors.initials: A
authors.lastname: Singh
authors.forename: E M
authors.initials: EM
authors.lastname: Sternberg
mesh_terms: D015815:Cell Adhesion Molecules / Q000032:analysis; D003907:Dexamethasone / Q000494:pharmacology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D016131:Lymphocyte Subsets / Q000502:physiology*; D008297:Male; D010913:Pituitary-Adrenal System / Q000502:physiology*
chemical_list: D015815:Cell Adhesion Molecules; D003907:Dexamethasone