The natural killer cell response to exercise in spinal cord injured individuals

In order to evaluate exercise-induced changes in natural killer (NK) and ot her immunocompetent cells in spinal cord injured individuals, immunological competent blood cells and stress hormones were followed in five paraplegic and six quadriplegic subjects in relation to 30 min electrically stimulate d cycling exercise. The leukocyte and lymphocyte concentrations increased d uring exercise. In the recovery period, the concentration of neutrophils in creased, whereas the lymphocytes decreased. The percentage and concentratio n of NK cells increased during exercise in the paraplegic group and returne d to pre-exercise level 2 h after, whereas no changes were seen in these me asures for the quadriplegic group. No changes in activated CD38(+) NK cells appeared. Unstimulated and interferon-a or interleukin-2 stimulated NK cel l activity increased during exercise and returned to pre-exercise level 2 h after with no distinction between paraplegics and quadriplegics. The conce ntrations of plasma growth hormone and catecholamines increased during exer cise, with the rise in epinephrine being more pronounced in paraplegic than in quadriplegic subjects, indicating a difference between the groups in sy mpathetic nervous system integrity. The sympathoadrenal activity is conclud ed to be responsible for recruitment of NK cells to the blood during exerci se.