Mechanisms of glucocorticosteroid activity in patients with the preleukemic syndrome (hemopoietic dysplasia)

We have analyzed mechanisms of glucocorticosteroid activity in patients with the preleukemic syndrome by culturing in agar and methylcellulose bone marrow cells from 5 glucocorticosteroid-responsive patients with the preleukemic syndrome. We have found that methylprednisolone and cortisol are equally effective in enhancing colony growth in these patients, that enhancement occurs in either methylcellulose or agar matrix and in RPMI 1640, McCoy's 5a, and alpha medium. In 4 patients, glucocorticosteroids inhibited the activity of T-lymphocyte inhibitors of granulopoiesis in vitro. In one patient, these agents stimulated the immediate proliferation of CFU-C and in the presence of LCM enhanced CFU-C survival in suspension culture. These effects were blocked by progesterone and not due to enhancement of CSA production or inhibition of inhibitory T-cell function. Our results document the involvement of cortisol sensitive T-lymphocytes in the suppression of granulopoiesis in a small number of patients with the preleukemic syndrome and indicate that the mechanisms of glucocorticosteroid responses among patients with this syndrome are heterogeneous.