As a well‐characterized immunosuppressive molecule, it can down‐regulate multiple immune responses and participate in the pathological process of immune disorders.21 TGF‐β1 can be secreted by MSC and plays a non‐redundant role in the immunomodulatory function of MSC.22, 23 Sławomira KyrczKrzemień showed that low level of TGF‐β1 probably being one of the factors contributing to the development of acute GVHD. Here, TGFB1 is linked to immune system disorder.