In vivo administration of an Itpkb inhibitor (GNF362) attenuated aGVHD lethality. (A) Survival and weight curves are shown for irradiated B10.BR recipients that were given B6 BM, with or without B6 purified T cells (3 M is 3 × 10⁶ cells) and given vehicle or GNF632 twice daily by gavage from days 0 to 42 (n = 5 mice/BM group; n = 8 mice/BM+T group). (B-C) Lethally irradiated BALB/c recipients were infused with B6 BM, with or without B6 purified T cells (panel B, 1 M is 1 × 10⁶; panel C, 2M is 2 × 10⁶ cells) and treated with either vehicle or Itpkb inhibitor, GNF362 as in panel A. Survival and weight curves are shown (n = 5 mice/BM group; n = 8-16 mice/BM+T group). Data are presented as the mean ± SEM. *P < .05, **P < .01, ***P < .001, and ****P < .0001.