Although the effects on the recruitment and activation of donor‐derived monocytes and dendritic cells, which are important in GVHD exacerbations [17], have not been analyzed, we have shown that Chb‐M' decreased the production of GM‐CSF expression in both in vitro experiments using primary human T cells and in an in vivo model of xenogeneic‐GVHD. Here, CSF2 is linked to graft versus host disease.