Macrophage depletion ameliorates BM failure. (A) Macrophages from CByB6F1 recipient mice were depleted with Clodrosome before induction of BM failure; Encapsome was used as vehicle control. Severity of BM failure was evaluated at day 13. (B) Macrophage depletion with Clodrosome (n = 9) attenuated immune-mediated BM failure in CByB6F1 mice with improved BM structure, and increased numbers of BM cells, RBCs, and platelets, when compared with mice treated with Encapsome as vehicle control (n = 5) without macrophage depletion (original magnification ×200; hematoxylin and eosin stain). (C) Macrophage depletion by Clodrosome suppressed expansion of T cells, especially CD8⁺ T cells, in the BM relative to vehicle control without macrophage depletion. (D) Macrophage depletion by Clodrosome reduced plasma levels of IFN-γ and TNF-α. (E) Macrophage depletion by Clodrosome suppressed IFN-γ levels in both CD8⁺ and CD4⁺ T cells in the BM. *P < .05; **P < .01; ***P < .001; ****P < .0001.