Retinoic acid modulation of induced basophil differentiation.

Current models of the regulation of hematopoiesis postulate a combination of both factor-directed cell differentiation/survival acting through intracellular signaling pathways, and factor-independent differentiation along intrinsically set, default pathways. Recent reports have indicated that eosinophil/basophil (Eo-Baso) differentiation may represent one default pathway. Because of the strong modulating effect of all trans-retinoic acid (ATRA) on hematopoietic differentiation, we have investigated the role of ATRA in regulating Eo-Baso differentiation from pluripotent progenitors. Our results indicate that ATRA inhibits Eo-Baso maturation at early stages of lineage commitment. Because allergic responses may depend on the continued recruitment and differentiation of such inflammatory mediators, the ability to modulate this pathway may eventually prove to have a therapeutic role in allergic inflammation.