Erfe mRNA expression in erythroid cell populations. Erythroid cells from proerythroblasts (Pro-E) through basophilic (Baso) and polychromatic (Poly) to orthochromatic (Ortho) erythroblasts were isolated from the marrow of 3 WT and 3 Th3/+ mice at 12 weeks of age. (A) The percentage of each cell type (means ± SEM) in the total (Ter119+) erythroid cell population was compared between WT and Th3/+ mice by 2-tailed Student t-test. (B) Erfe mRNA expression (means ± SEM) was compared for each cell type between WT and Th3/+ mice by 2-tailed Student t-test. Erfe mRNA expression was greatly increased in all erythroid cell types. (C) Treatment of WT marrow-derived macrophages with EPO did not influence Erfe mRNA expression. Means ± SEM of 3 independent experiments were compared between controls and EPO-treated cells by 2-tailed Student t-test. ***P < .001, *P < .05.