Corticosteroid effects on circulating lymphocyte subset levels in normal humans

Abstract
The effects ofin vivo corticosteroid administration on levels of lymphocyte subsets in normal humans require further definition. Using monoclonal antibodies, we carried out a double-blind, placebo-controlled study of oral and intravenous methylprednisolone in 10 normal volunteers. Four hours after a 7-day oral course of 0.5 mg/kg/day, there was modest lymphopenia but no significant selective alteration in lymphocyte subsets. In contrast, 4 hr after a single intravenous injection of 1.0 mg/kg, there was more pronounced lymphopenia (PP<0.001), and a more modest decrease in the percentage of T3 cells. The possible mechanisms and implication of these changes are discussed.