After irradiation, bm 1 mice underwent transplantation from B6. Ly-5a (CD45.1⁺) donors and were treated with IL-18 or the diluent, as described in “Materials and methods.” Splenocytes were pooled from 3 mice per group and were analyzed on day 5 after BMT by 3-color flow cytometry for expression of annexin, CD45.1⁺, and CD8⁺ cells. Gates were set for CD45.1⁺CD8⁺ (donor) cells, and the percentage of cells expressing annexin was determined. Data are from 1 of 2 similar experiments and represent mean ± SE. P = .84, allogeneic plus IL-18 vs allogeneic plus PBS.