Treatment of donor mice with CpG and incomplete Freund’s adjuvant (IFA), G-CSF, or recombinant G-CSF/Flt-3 ligand + G-CSF results in increase of splenic CD11b+Gr1+ cells preventing GVHD after cotransplantation with allogeneic T cells (14–16). This evidence concerns the gene CSF3 and graft versus host disease.