Itpkb-deficient donor T cells have impaired survival in aGVHD recipients. BALB/c recipients were lethally irradiated and infused with B6 BM+B6 CD45.1 WT and CD45.2 Itpkb^−/− purified T cells (0.75 × 10⁶ each). (A-B) Spleens (SPLs) and mesenteric lymph nodes (MLNs) were harvested on day 6 after transplantation to quantify donor T-cell frequencies (H2^b+ CD4⁺ and CD8⁺ T cells) by flow cytometry. (C-D) Donor T-cell frequencies in small intestines (SIs) and large intestines (LIs) of recipients on posttransplantation day 14. (E) Percentages of active caspase-8 in donor T cells isolated from spleens of recipients on posttransplantation day 6 (n = 5). One experiment was performed. Data are shown as the mean ± SEM. ***P < .001 and ****P < .0001.