Dexamethasone enhances ‘CSA’ release and depresses ‘BPA’ release

Dexamethasone 10(-7) M enhanced the release of granulocyte-macrophage colony stimulating activity (GM-CSA) by peripheral blood cells from 15 normals. In 16 patients with hypoplastic marrow failure this effect was more prominent, the release of GM-CSA being increased up to 10-fold by dexamethasone. Dose-response curves of patient cell supernatants indicate that dexamethasone acts by abrogation of an inhibitor on CSA-production. Dexamethasone decreased the release of burst promoting activity (BPA) in all normals and most patients. We conclude that the interaction of glucocorticoid hormones with lymphocyte function results in positive and negative effects on haemopoiesis in vitro. Preliminary experiments in one patient suggest that the steroid effect in vivo correlates with GM-CSA enhancement in vitro.