Haploidentical Transplantation for Pediatric Patients with Acquired Severe Aplastic Anemia

Techniques for haploidentical hematopoietic stem cell transplantation (haplo-HSCT) to treat severe aplastic anemia (SAA) have recently improved, but no protocol has been evaluated in a large number of pediatric patients. Fifty-two children with SAA received haplo-HSCT in our center. The treatment protocol used G-CSF-primed bone marrow with G-CSF-mobilized PBSCs without in vitro T-cell depletion. The conditioning regimen included busulfan/cyclophosphamide and antithymocyte globulin. Fifty-one patients achieved primary engraftment; one child died of regimen-related toxicity on the day +1. Secondary graft failure occurred in three patients. The cumulative incidences of aGVHD grade II-IV and grade III-IV were 39.2±0.5 and 13.7±0.2%, respectively. The cumulative incidence of cGVHD was 34.2±0.5%. The 3-year overall and failure-free survival rates were 84.5±5.0 and 82.7±5.2%, respectively, with a median follow-up time of 744.5 days (100-3294) for surviving patients. The Eastern Cooperative Oncology Group score was the only predictor of overall and failure-free survival rates. Clinical outcomes were similar between the upfront and salvage group. This result suggests that both newly diagnosed and refractory pediatric SAA patients benefit from haplo-HSCT, especially when patients are in good general condition. Therefore, haplo-HSCT might be an alternative therapy for pediatric SAA patients without HLA-matched sibling donors.