IL-33 conditioning peri-alloHCT protects against acute GVHD. (A) Indicated combinations of WT mice were administered IL-33 (1.0 μg per mouse per day) starting on day −10 prior to alloHCT. On day −1, recipient mice received lethal TBI (B-D, 700 cGy to BALB/c recipients; E, 1100 cGy to B6 recipients) followed by 1 × 107 WT allogeneic TCD-BM (B-D, B6; E, BALB/c) alone or with 2 × 106 allogeneic pan T cells (B-D, B6; E, BALB/c) on day 0. IL-33 was continued through day +4 posttransplant. PBS vehicle-treated mice were used as BM + T only controls. (B,E) Survival curves with statistical significances calculated by log-rank (Mantel-Cox) test (*P < .05, **P < .01). For panels B-C, n = 4 (BM only), 10 (BM + T cells), and 10 (BM + T cells + IL-33) and the depicted experiment is representative of 2 independent experiments completed. For panel E, n = 5 (BM only), 10 (BM + T cells), and (10 BM + T cells + IL-33). (C) Group means with SEM are depicted for clinical GVHD scores. Significant differences for each point with ≥3 mice per group were calculated between BM + T cells vs BM + T cells + IL-33 using an unpaired Student t test (*P < .05). (D) Average frequency and standard deviation (SD) of indicated colon LPL population. Three to 4 mice per group with statistical significance calculated between groups using an unpaired Student t test (*P < .05). d, day; ns, not significant.
