Pretreatment of BMT recipients with FL reduces acute GVHD lethality.

B6D2F1 mice were injected subcutaneously with 10 μg FL for 8 consecutive days (days −9 to −2) and received transplants of BM and splenic T cells from B6 donor mice after 12 Gy TBI on day 0. (A) Survival in control-treated (n = 17, closed circle) and FL-treated (n = 22, open circle; P < .01) animals after allogeneic BMT and syngeneic BMT (n = 4, closed square). (B) GVHD clinical score was significantly lower in FL-treated animals (n = 22, open circle) than in controls (n = 17, closed circle) at all time points (P < .05) and was significantly higher than in syngeneic BMT recipients (n = 4, closed square; P < .01). Data represent mean ± SE from 2 similar experiments. (C) Liver disease 2 weeks after BMT. Liver GVHD was significantly less in FL-treated animals (P < .05) but was higher than in syngeneic controls (P < .05). Randomized coded slides were scored semiquantitatively, as described in “Materials and methods,” and results compared to allogeneic controls represent the mean ± SE of 3 mice per group.