Effect of methylprednisolone on human lymphocytes primed to alloantigens.

Human lymphocytes were primed in mixed lymphocyte cultures (MLC) in the presence of the corticosteroid methylprednisolone (MP). The generation of proliferative-, cytotoxic- and suppressor cells after specific restimulation of the cultures was studied. Low doses of MP strongly inhibited the generation of secondary proliferative and cytotoxic cells. MP did not render these cells permanently unresponsive, as lymphocytes primed in the presence of MP as were still able to respond to the original stimulators in a primary fashion. In contrast, doses of MP as high as 10 micrograms/ml which are well above clinical levels, had no inhibitory effect on the induction of suppressor cells in these cultures. Our results indicate therefore, that steroids may prevent priming of specific cytotoxic and proliferative T cells, without inhibiting the induction of suppressor lymphocytes in secondary allogeneic cultures.