Consistent with imaging data, FTY decreases GVHD scores in spleen and colon, but not in liver or lung. Lethally irradiated B6 mice were given BALB/c BM and splenocytes (25 × 10⁶) and administered sterile water or FTY by oral gavage from day −1 to time of tissue harvest. Control mice received only BM. On day 7 after transplantation, 5 per group were electively killed, and indicated GVHD target tissues were harvested, sectioned, and stained with hematoxylin and eosin and scored for GVHD histopathology. Shown is average score (± 1 SD). *P ≤ .01 versus BM-only control; ^P ≤ .006, water- versus FTY-treated mice.