Allogeneic peripheral blood hematopoietic stem cell transplantation for severe aplastic anemia

Objective To evaluate the efficacy of allogeneic peripheral blood hematopoietic stem cell transplantation (allo-PBSCT) for severe aplastic anemia (SAA). Methods Ten patients with SAA (three were diagnosed as SAA-Ⅰand seven as SAA-Ⅱ,with two complicated with severe infection) received allo-HSCT,including eight receiving from related and two from unrelated donors. The patients included five men and five women,with a median age of 27 years old (range:18-42). Most of patients in our group were treated with CsA and other treatments but were all proven to be ineffective before transplant. The period from diagnosis to transplantation was 1-240 months,with a median time of 12 months. PBSC were mobilized with G-CSF for 5 days. Conditioning regimens included ATG-Fresenius 4-5 μg·kg-1·d-1×4 d plus CTX 60 mg·kg-1·d-1×2 d. CsA and MTX were given to prevent acute graft-versus-host disease (aGVHD). The effectiveness and complications were analyzed retrospectively. Results Hematopoiesis reconstitution was achieved in 9 patients and graft rejection occurred in 1 patient.The median periods for neutrophils to reach 0.5×109/L and platelets to reach 20×109/L were 13.2 (11-15) and 14.3 (13-15) days,respectively. Eight patients were full donor chimerism and two were in mixed chimerism status. One patient with related donor was transferred to full donor chimerism after infusion of frozen peripheral blood hematopoietic stem cells. Another patient with unrelated donor had decreased peripheral white blood cells,red blood cells and platelets three months after transplantation; STR-PCR indicated graft rejection; second transplantation was performed with the same donor and hematopoiesis of the patient origin was achieved gradually. One case developed grade Ⅱ aGVHD and two developed limited cGVHD.Three patients had pure red cell aplasia and achieved hematopoiesis reconstitution after plasma replacement. All the patients survived with a median period of 33 months (3-92) at the end of follow-up. Conclusion Allo-PBSCT with ATG plus CTX as reduced intensity conditioning regimens is an effective therapy for patients with SAA; it has less complication and is worth popularizing in clinical practice.