exMito aggravate GVHD-induced mortality. HSCs from the BM (5 × 10⁶ cells) and splenocyte (4 × 10⁶ cells) from C57BL6/J congenic mice expressing CD45.1⁺ allele were transplanted into BALB/c CD45.2⁺ mice after TBI conditioning to model aGVHD. At the time of transplantation, the indicated doses of mitochondria were given along with the BM. (A) Graphical representation of the experimental setup. (B) Isolated recipient CD45.2⁺ cells from the spleen and mesenteric lymph nodes (MLNs) were analyzed for the expression of MHC-II. Donor cells were excluded from analysis using an antibody against CD45.1 Representative dot plots (left) and MFI (right) shown as bar graphs (Mito: mitochondria, 100 μg). (C) Survival curve and (D) illness severity, including weight loss, and GVHD scores. ∗P < .05, ∗∗P < .01, ∗∗∗P < .001, and ∗∗∗∗P < .0001; n, number of animals.