Erfe-deficient mice exhibited a more severe AI than WT mice. Hemoglobin (A), hematocrit (B), and MCH (C) were compared between WT and Erfe-deficient mice at t = 0, 7, 13, 21, and 28 days after injection of BA. Erfe^−/− mice had lower hemoglobin concentration and lower hematocrit on day 21 than WT mice. MCH was also lower at days 7, 13, 21, and 28 in Erfe^−/− mice compared with WT mice. Erfe-deficient mice had higher hepcidin levels 13 days after injection of BA compared with WT mice (D) (see also supplemental Figure 3A). Expression ratios ± SEM of Rpl4-normalized Hamp transcripts in Erfe^−/− mice relative to WT controls were calculated using REST. Statistical significance was determined using randomization. Data shown for hemoglobin, hematocrit, and MCH are means ± SEM and were compared between WT and Erfe^−/− mice (n = 6-7 per time point) by 2-tailed Student t test at each time point (***P < .001, **P < .01, *P < .05).