Donor treatment with G-CSF prevents aGVHD in a TGF-β- and IL-10-dependent manner. (A) Survival curves by Kaplan-Meier analysis, pooled from 3 experiments. B6 wild-type (wt) or B6 IL-10^-/- donors and B6D2F1 donors were treated for 6 days with human G-CSF or control diluent, and splenocytes were transplanted into lethally irradiated B6D2F1 mice. Recipients received anti-TGF-β or control antibody at day 0 and then 3 times weekly. ^**P < .01; allogeneic recipients of G-CSF-pretreated wild-type splenocytes plus anti-TGF-β antibody (n = 17) compared with control antibody (n = 16) and IL-10^-/- splenocytes treated with anti-TGF-β (n = 11). All allogeneic recipients of control pretreated B6 spleens treated after transplantation with control antibody died by day 14 (n = 5). All control allogeneic recipients of TCD IL-10^-/- splenocytes (n = 5) and control syngeneic recipients of B6D2F1 splenocytes (n = 4) treated with anti-TGF-β antibody survived the period of observation. (B) GVHD clinical scores were determined as a measure of GVHD severity in animals, as described in “Materials and methods.” ^*P < .05 and ^**P < .01; allogeneic G-CSF wt and IL-10^-/- recipients plus anti-TGF-β compared with control antibody. ▾ indicates control wt allo plus control Ab; ○, G-CSF wt allo plus control Ab; ♦, G-CSF IL-10^-/- allo plus anti-TGFβ; □, G-CSF wt allo plus anti-TGFβ; •, G-CSF allo TCD plus anti-TGF-β; and ▿, control syn wt plus anti-TGFβ.