To reduce regimen-related toxicity we transplanted three children with refractory SAA after conditioning with radiotherapy-free regimens.

Patients with refractory SAA are at risk of later clonal evolution to myelodysplastic syndrome and acute leukemia.

We show that haploHSCT can successfully rescue refractory SAA patients who lack donor-directed HLA antibodies but not in the presence of donor-directed HLA antibodies.

Fludarabine-based conditioning is powerfully immunosuppressive and may be used for children with refractory SAA undergoing HCT from alternative donors even after rejection following previous HCT.