The immunosuppressive potency in vitro of physiological and synthetic steroids on lymphocyte cultures.

The immunosuppressive potency of five natural and seven synthetic steroids were tested in vitro on phytohemagglutinin (PHA) stimulated peripheral lymphocytes (PBL) and T-lymphocytes and compared to their anti-inflammatory potencies. The physiological glucocorticoid, hydrocortisone, was of intermediate immunosuppressive potency in vitro, whereas the metabolites of hydrocortisone (cortisone, dihydrocortisol, and tetrahydrocortisol) and aldosterone were without effect. The synthetic steroids, methylprednisolone and fluorohydrocortisone were both highly potent in suppressing the PHA responses of both lymphocyte subsets. Prednisolone and dexamethasone were of intermediate potency and ranked similar to hydrocortisone which is in contrast to their anti-inflammatory properties. Prednisone, the biologically inactive metabolite of prednisolone, was without immunosuppressive properties. Deoxy-deflazacort, the biologically active metabolite of deflazacort (a new oxazoline derivative of prednisolone) was comparable to prednisolone and hydrocortisone in suppressing lymphocyte proliferation but again there was a large discrepancy between the in vitro immunosuppressive effect and the anti-inflammatory potency. In conclusion, the present assay may therefore separate the immunosuppressive properties from the anti-inflammatory properties of glucocorticoids. These findings may be useful for comparison of new synthetic steroids.