Effect of corticosteroids on exercise-induced lymphocytosis.

Eight subjects ran on a treadmill at 8 miles per hr for 10 min. All developed lymphocytosis with predominant effect on the B cells. This was repeated 5 hr after receiving 60 mg of Prednisone. The lymphocytosis of both T and B cells were suppressed. When this was repeated 2 hr after receiving Prednisone, only lymphocytosis of the T subpopulation was suppressed. It was concluded that corticosteroid administration could suppress entry of lymphocytes into the circulation, with preponderant effect on the T subpopulation.