ERFE does not affect hepcidin in PV. (A) Serum ERFE; control, n = 4; Erfe-KO, n = 4; PV, n = 5; and PV × Erfe-KO, n = 11. (B) Liver Hamp1 mRNA expression relative to Hprt; control, n = 15; Erfe-KO, n = 15; PV, n = 15; and PV × Erfe-KO, n = 13. (C) Serum hepcidin; control, n = 4; Erfe-KO, n = 4; PV, n = 12; and PV × Erfe-KO, n = 12. (D) Liver and (E) spleen nonheme iron content; control, n = 6; Erfe-KO, n = 6; PV × Erfe-KO, n = 6; and PV, n = 8. (F-H) RBCs (F), HCT (G), and HGB (H); control, n = 9; Erfe-KO, n = 8; PV, n = 15; and PV × Erfe-KO, n = 14. (I) Terminal erythropoiesis in the BM determined by flow cytometry. Based on CD44 expression and FSC-A, Ter119⁺ cells were gated into 5 distinct populations: I, proerythroblast (Pro-E); II, basophilic erythroblasts (Baso); III, polychromatic erythroblasts (Poly); IV, orthochromatic erythroblasts and reticulocytes (Ortho/Retic); and V, RBCs; control, n = 9; Erfe-KO, n = 8; PV, n = 13; and PV × Erfe-KO, n = 12. One-way ANOVA for panels A,C,E-H, Kruskal-Wallis test for panels B,D, or two-way ANOVA with Dunnett correction for multiple comparisons for panel I. ∗P < .05; ∗∗P < .01; In panel I, “∗” represents control vs PV, and “^” represents PV vs PV × Erfe-KO.