Multiple infusions of third-party ILC2s reduce aGVHD incidence. Lethally irradiated B6D2 mice received B6 TCD BM (BM only), B6 BM plus total splenic B6 T cells (BM + T cells), or BM plus T cells with activated ILC2s (BM, T cells + B10.BR ILC2). (A) Kaplan-Meier plot of male recipient survival following allo-HSCT; red arrows indicate time points for B10.BR ILC2 injections, 1 representative of 2 experiments shown (n = 5 each experiment), log-rank (Mantel-Cox) test. (B) Clinical score of recipients from panel A, analyzed by using a two-way analysis of variance, with Bonferroni correction for repeated measures of multiple comparisons. (C) Diagram for B10.BR into B6 transplantation. Each B6 recipient received WT B10.BR BM and B10.BR splenic T cells, with one group of B6 recipients also being given BALB/c ILC2s. Lethally irradiated B6 mice received TCD BM (BM only), BM plus total splenic T cells (BM + B10.BR T cells), or BM plus T cells with activated B10.BR ILC2s (BM, B10.BR T cells + BALB/c ILC2s). (D) Kaplan-Meier plot of survival after allo-HSCT; white arrows indicate time points for BALB/c ILC2 injections for those receiving infusions beginning at the time of transplant; 1 representative of 2 experiments shown (n = 5 each experiment), log-rank (Mantel-Cox) test. (E) Clinical score posttransplantation, analyzed by using a two-way analysis of variance, with Bonferroni correction for repeated measures of multiple comparisons. *P < .05, **P < .01, ***P < .001. Flow cytometry analysis of donor B10.BR (H-2K^k) ILC2 12 days’ posttransplant following ILC2 infusions on day 0 and day 7 in the small intestine (F) and lung (G).