In vitro immunosuppressive potency of deflazacort, a new bone-sparing corticosteroid on T lymphocytes, NK and K cells.

The in vitro immunosuppressive effect of deflazacort, a new bone-sparing glucocorticoid, and its biologically active metabolite, 21-deacetyl-deflazacort, was examined on phytohaemagglutinin (PHA) stimulated human peripheral blood lymphocytes (PBL) as well as on natural killer (NK) and killer (K) cell activity. Deflazacort and the 21-deacetyl metabolite were as potent as prednisolone and hydrocortisone in suppressing PHA stimulated lymphocytes in a dose dependent way, but all were less potent than methylprednisolone. The physiological metabolites of hydrocortisone, dihydrocortisol and tetrahydrocortisol were without any immunosuppressive effects in vitro. Deflazacort, 21-deacetyl-deflazacort, and methylprednisolone suppressed NK cell activity, while hydrocortisone and aldosterone had no effect on NK cells. K cell activity was resistent to all tested glucocorticoids except methylprednisolone at high concentrations. The present results indicate that deflazacort and 21-deacetyl-deflazacort are potent immunosuppressive drugs in vitro and, on a molar basis, equally as potent as prednisolone.