Effect of IL-18 on GVHD-related mortality. (A) Recipient bm12 mice were irradiated with 13 Gy TBI and injected with 5 × 106 TCD BM and 2 × 106 purified CD4+ T cells from either allogeneic B6 (□ and ▪) or syngeneic bm12 (▾; n = 9) donors, as described in “Materials and methods.” Allogeneic bm12 recipients were injected intraperitoneally with 1 μg/d rmIL-18 per mouse (▪, n = 17) or diluent (□, n = 17) from days -2 to +2. Syngeneic recipients also received the same dose and schedule of IL-18. Data from 3 similar experiments are combined. Percentage survival after BMT. Percentage survival, ▪ vs □; P < .0001 by Wilcoxon rank test. (B) bm1 mice underwent irradiation and transplantation with 5 × 106 TCD BM and 2 × 106 purified CD8+ T cells from allogeneic B6 or syngeneic bm1 donors. Allogeneic recipients were injected with rmIL-18 (•, n = 17) or diluent (○, n = 17), as described. Syngeneic animals (▴, n = 9) were treated with IL-18 in a similar manner. Data from 3 similar experiments are combined. Percentage survival, • vs ○; P < .0001 by Wilcoxon rank test. (C) B6 recipients were injected with IL-18 or the diluent and underwent transplantation with TCD BM and 2 × 106 CD8+ T cells from allogeneic C3H.SW (•, n = 8; ○, n = 9) or syngeneic B6 donors (▴, n = 4) as described. Percentage survival after BMT, • vs ○; P = .01 by Wilcoxon rank test.
