Viral infections are common complications after allo-HSCT. With wide use of HLA-mismatch, unrelated and cord blood donors as alternative sources of hematopoietic stem cells, and anti-thymocyte globulin (ATG) as the standard prophylaxis of graft versus host disease (GVHD) in HLA-mismatch and unrelated donor transplantation, allo-HSCT recipients are at increasing risk for viral infections.~Till now, CMV remains one of the most important viruses and causes of death in the recipients of allo-HSCT. Approximately 75% of CMV-seropositive recipients develop CMV reactivation, and 20-30% of these patients develop CMV disease without intervention. Ganciclovir is the first-line treatment of CMV diseases. However, bone marrow suppression, which is the main and common side effect, limits the utility of ganciclovir in allo-HSCT recipients. Besides, ganciclovir and other antiviral agents resistance has been reported up to 28%. Since it has been known that specific immune response to CMV is important to control reactivation, CMV-specific CTL has been used in prophylaxis and treatment of CMV viremia in several studies. However, the production of CTL requires time. Mesenchymal stem cells (MSC) are a form of multipotent adult stem cells that can be isolated from bone marrow (BM), adipose tissue, and cord blood. In vivo experiment showed that MSCs have antimicrobial activity.~In this trial, we will use MSCs in the recipients with refractory CMV infections.
The purpose of this study is to evaluate the efficacy of mesenchymal stem cells (MSC) in the treatment of refractory cytomegalovirus (CMV) infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT).