Altered terminal erythroid differentiation of Hbb^th1/th1 mice and normalization after thansferrin therapy. (A) Representative erythropoiesis profiles of bone marrow and spleen of Hbb^th1/th1 mice. (Top panel) The representative erythropoiesis profiles of bone marrow. A decrease in fraction I (proerythroblast) and fraction VI (mature red cells) is clearly seen in PBS-treated thalassemia bone marrow and is restored in transferrin-treated bone marrow. (Bottom panel) Representative erythropoiesis profiles of spleen. There are very few erythroblasts in WT spleen, but the spleen of thalassemia mouse is highly erythropoietic and is restored in transferrin-treated spleen. (B) Western blot revealed an increase in soluble serum TfR1 in Hbb^th1/th1 relative to WT mice and is normalized after transferrin treatment.