Dhh^−/− mice recover more quickly during stress-induced anemia that WT. Anemia was induced in Dhh^−/− and WT mice by PHZ treatment, and the kinetics of stress-induced erythropoiesis and recovery was monitored over time. (A) Photographs represent typical WT and Dhh spleen size at 5, 9, and 14 days after PHZ treatment. Top bar chart represents time course of RBC concentration in WT (filled bars) and Dhh^−/− (open bars) blood, after PHZ treatment. The difference in mean RBC concentration between WT and Dhh^−/− was statistically significant on day 7 (P = .011). Bottom bar chart represents the percentage of reticulocytes in RBCs in blood. The difference in mean percentage between WT and Dhh^−/− was statistically significant before treatment (day 0, P = .015) and on day 9 (P = .045). (B) Kinetics of recovery of the erythroblast populations after PHZ treatment was measured in the spleen (left panel) and BM (right panel) at 5 days (top row), 9 days (second row), and 14 days (third row) after treatment. Dot plots represent erythroblast populations I to IV, defined by CD71 and Ter119 expression, and regions used and percentage of cells in each population are shown. (C) The relative percentage of MEP (measured by FACS, staining Lin⁻ cells with antibodies against CD34 and FcγRII/III) in spleen (left) and BM (right) in WT (filled bars) and Dhh^−/− (open bars), 7 days after PHZ treatment. The difference in mean was statistically significant for spleen (P = .017) and BM (P = .033). (D) The relative percentage of neutrophils (measured by FACS, staining with antibodies against Ly6g) in BM in WT (filled bars) and Dhh^−/− (open bars), 7 days after PHZ treatment. The difference in means was statistically significant (P < .001).