The implication of alterations in leukocyte subset counts on immune function

Changes elicited by physical exercise in the numbers or the activity of blood T lymphocytes, NK cells and neutrophils are sometimes considered as indicators of altered immunocompetence. By comparing the pathological conditions, in which the changes in the numbers of cells resemble observations in the exercise studies, however, we notice large discrepancies in the clinical manifestations. Supplementary information regarding the differences in cytokines and mediators responsible for altered distributions helps to explain this difference and the significance of altered distribution of the cells for immunocompetence. Alterations in the numbers and activities of T lymphocytes, NK cells and neutrophils may serve as markers of sympathetic and glucocorticoid activities, which per se may influence immunocompetence not necessarily deterioration.