FTY inhibits GVHD; irradiation does not limit efficacy. (A) Lethally irradiated B6 mice were infused with BALB/c BM. Cohorts received 15 × 106 (15S) or 25 × 106 (25S) BALB/c splenocytes. Mice were administered sterile water or FTY (3.0 mg/kg) by oral gavage daily from days −1 to 28. Survival is indicated (n = 3 experiments pooled for a total of 24 mice per group for 15S; n = 8 per group for 25S; P < .001 for 15S, P = .006 for 25S, FTY vs water). (B) B6 RAG2-deficient mice were lethally irradiated or not irradiated and given 3 × 106 BALB/c purified CD25-depleted T cells. Lethally irradiated mice received BALB/c BM. FTY or water was given as for panel A. Survival is indicated (n = 7-8 per group; P = .003 for no TBI, P = .006 for TBI, FTY vs water).
