Objective: To evaluate the efficacy and safety of bone marrow-derived mesenchymal stem cells (MSC) from a third party donor for secondary poor graft function (PGF) following allogeneic hematopoietic stem cell transplantation(allo-HSCT).
Methods: Five patients with secondary PGF were treated with MSC at a dose of 1 x 10(6)/kg body weight at a median of 47 days (35 to 61) after secondary PGF. MSC were derived from bone marrow (BM) of HLA-disparate third party donors, cultured in vitro and infused without HSC. If absolute neutrophil cell (ANC) and platelet counts (PLT) did not reach the standardization of > 1.5 x 10(9)/L and > 50.0 x 10(9)/L, respectively, within 28-30 days after the first MSC treatment, a second MSC treatment was required.
Results: MSC were infused once in one patient and twice in four patients with an interval of 28 to 30 days. All patients obtained ANC and PLT recovery at a median of 34 (25 to 49) days and 47 (26 to 54) days, respectively, without toxic side effects within follow-up periods of median 761 (204-1491) days. Three patients developed Epstein-Barr virus (EBV) reactivation at 42, 48, 108 days after MSC infusion, respectively and two of the three coverted to posttransplant lymphoproliferative disorders (PTLD).
Conclusion: MSC from a third party donor are effective to patients with secondary PGF following allo-HSCT, whether it might increase the risk of EBV reactivation and EBV-associated PTLD need further observation.