Nonmyeloablative stem cell transplantation followed by donor stem cell infusion for the treatment of nonmalignant haematologic diseases

Objective To evaluate the efficacy and complications of nonmyeloablative stem cell transplantation(NST) for the treatment of nonmalignant haematologic diseases with high-risk rejection.Methods NST was performed for two patients with severe aplastic anemia(SAA) and one with beta-thalassemia major(TM).The protocal was designed on transplantation of granulocyte colony-stimulating factor(G-CSF) primed allogeneic bone marrow cells combined with perpheral blood stem cells(PBSCs) for two SAA patients,with conditioning regimen based on anti-lymphocyte globulin and reduced dose of cyclophosphamide(CTX).One TM patient was performed transplantation of PBSCs with conditioning regimen of anti-T-lymphocyte globulin(ATG),fludarabine and reduced dose of busulfan.Cyclosporin A combined with methylprednisone was used for graft-versus-host disease(GVHD) prophylaxis.Donor stem cells infusion(DSI) were underwent for three patients at 78,99 and 44 days post transplant respectively.Results Three patients achieved engraftment successfully with mixed chimera and the lowest white blood cell(WBC) of 0.26×10~9/L,0.5×10~9/L and 1.26×10~9/L respectively.The absolute neutrophil count achieved more than 0.5×10~9/L and platelet count achieved more than 20×10~9/L at days of 12d,3d,0d and 1d,5d,0d post transplant in three patients,respectively.The haematopoiesis and chimera were improved after DSI without complications of infection and GVHD in three patients.Conclusion The stem cells engraftment is achieved successfully with donor stem cell infusion followed NST for the treatment of nonmalignant haematologic disease patients with high-risk rejection.