Wt mice transplanted with Hfe-KO BM respond better to erythropoietic stress. Recovery of Hb values in wt → wt versus Hfe → wt (A) and wt → Hfe-KO versus Hfe → Hfe-KO (B) mice after phlebotomy, as in Figure 1. Phlebotomies were performed 2-3 months after BM transplantation. Data are mean ± SEM of 5-10 mice. *P ≤ .05 relative to controls.