Distinct BM abnormalities in T-bet tg mice. (A) H&E staining of BM sections (femur) prepared from 30-week-old mice with the indicated genotypes. Arrows indicate yellowish-brown macrophages extensively engulfed erythrocytes. Bar = 100 µm. (B) Total numbers of cells in BM from mice with the indicated genotypes. Results are means ± SD; n = 3, 3, and 6. (C) Percentages of myeloid cells, B cells, and T cells in total living BMCs from 30- to 50-week-old mice with the indicated genotypes. Results are means ± SD; n = 8, 4, and 7. *P < .05 (1-way ANOVA, followed by Tukey’s multiple comparisons tests). (D) Percentages of each hematopoietic stem and progenitor compartment in BM from 30- to 50-week-old mice with the indicated genotypes. Results are means ± SD; n = 3 each. CMP, common myeloid progenitors; GMP, granulocyte-macrophage progenitors; MDP, macrophage and dendritic cell progenitors; MEP, megakaryocyte-erythroid progenitors; MMP, multipotent progenitors.