Differential sensitivity of lymphocyte subsets to corticosteroid treatment.

Corticosteroid treatment of SJL mice produced a marked decrease in the number of viable lymphocytes obtained 48 hr later from the thymus, spleen and lymph node but no change in peripheral blood. Within the residual lymphocyte population there was a fall in the relative number of splenic B cells with increasing dose; in contrast the proportion of B cells increased in the lymph nodes. The most marked change however was a dose-related increase inthe Lyt-2+ population in all of the lymphoid organs examined including the thymus though, in this organ alone, the lowest dose caused a pronounced reduction in the Lyt-2+ population, since most immature thymocytes are Lyt-2+. These findings support the concept that mature thymocytes have phenotypic identity with peripheral T cells and provide a basis for the immunosuppressive action of corticosteroids.