Abstract des Autors

Immunophenotyping by dual parameter flow cytometry was used to compare the expression of interleukin-2 receptor alpha and beta chains on lymphocyte subsets in the peripheral blood of 7 trained and 6 untrained volunteers (respective VO2max 57.0+/-6.1 and 39.0+/-4.5 ml/kg/min). Venous blood samples were collected at least 36 h after the most recent exercise session. The trained subjects had higher circulating counts of total leukocytes, granulocytes, and NK cells but lower lymphocyte counts than their sedentary peers. Counts for T cells (CD3+) and B cells (CD19+), and the CD4+/CD8+ ratio did not differ between the two subject groups. The p55-IL-2 receptor alpha expression was unrelated to training, but the p70-75-IL-2 receptor beta expression was higher in the active group. Beta chain co-expression was also higher on NK cell subsets in trained than in sedentary subjects. Aerobic power was strongly correlated with IL-2R-beta expression. We conclude that physical conditioning is associated with an increase in IL-2 receptor beta expression on lymphocytes as assessed by the proportion of circulating p70-75-IL-2R-beta positive NK cells. Such changes could enhance protection against both infectious diseases and cancer. Longitudinal studies are now needed to explore the causal nature of this association. Verf.-Referat