Mesenchymal stem cell has been described to shift macrophages to M2‐like subsets,47, 48 and MSC‐educated macrophages possess the therapeutic potential for GVHD.48 Furthermore, as demonstrated previously, TGF‐β1 can increase the differentiation of M2‐like macrophages which function in wound healing and immunoregulation.49, 50 Taken together, these studies partially explain why infusion of MSC‐TGF‐β1 increased the M2‐like macrophages in our murine aGVHD models. Here, TGFB1 is linked to graft versus host disease.