An open-label, randomized, controlled clinical trial to explore the efficacy and safety of iMSC in preventing the development of acute graft-versus-host disease of degree III-IV in patients after allogeneic hematopoietic stem cell transplantation.
Subjects with malignant or nonmalignant hematologic diseases 7-21 days after allogeneic hematopoietic stem cell transplantation;
No gender restrictions and age between 14-70 years old；
Patients received aGVHD prophylaxis regimen of a calcium-modulated phosphatase inhibitor combined with mycophenolate mofetil wtih or without short-course methotrexate and rabbit anti-human thymocyte globulin (CNI+MMF± short-course MTX +ATG)；
Patients had a MAGIC algorithm probability (MAP) score ≥ 0.14 at +7d or +14d after allogeneic hematopoietic stem cell transplantation(HSCT) (if patients had a MAP< 0.14 at +7d, another test was performed at +14d)；
Serious organ dysfunction such as organ failure after allogeneic HSCT;
Received more than once HSCT (including autologous transplants);
Positive for Hepatitis B Surface Antigen (HBsAg) or Hepatitis B Core Antibody (HBcAb) and have Hepatitis B Virus (HBV) DNA titers above the normal range ; positive for Hepatitis C Virus (HCV) antibodies and have positive peripheral blood HCV RNA; positive for Human Immunodeficiency Virus (HIV) antibodies; positive for syphilis;
Subjects with severe hepatic veno-occlusive disease or sinus veno-occlusive syndrome;