AT-406 decreases the expression of XIAP in donor T cells and host nonhematopoietic target cells after allo-BMT. (A-B) BALB/c animals received 8.5 Gy on day −1 and received transplants of 0.5 × 10⁶ CD90.2⁺ splenic T cells along with 5 × 10⁶ TCD-BM cells from either syngeneic BALB/c or allogeneic MHC-mismatched B6 donors. Recipient animals received either AT-406 (10 mg/kg) or its diluent subcutaneously on days −1, +1, +3, +5, and +7 after BMT. (A) Schema of experiment. (B) XIAP expression of donor CD3⁺ T cells in the spleen and CD326⁺ epithelial cells of the small intestine was evaluated by FACS staining on day 8. Representative figure (left) and pooled data (right) from 5 to 8 animals are shown. *P < .05, **P < .01. The bar shows the mean ± standard error of the mean (SEM).