Erythropoiesis is severely impaired in BA-treated mice. FACS analysis of BM and spleen of WT, IL-6-KO, and Hamp-KO mice 1 week after BA injection. CD71 (Tf receptor), Ter119 (erythroid-specific), and CD44 (adhesion molecule that exhibits a progressive decrease from pro-erythroblast to reticulocyte) costaining was used. CD71⁺/Ter119⁺ and CD71⁻/Ter119⁺, characterizing erythroid precursor and mature RBCs, respectively, were selected and plotted as CD44 vs forward scatter, to show the different stages of erythroid maturation. Maturation stages occur as indicated by the arrow and include (I) pro-erythroblast, (II) basophilic, (III) polychromatic, (IV) orthochromatic reticulocytes, and (V) mature erythrocytes. The percentage of cells constituting each population is shown. Three mice per each group were analyzed; 1 representative mouse per each group is shown.