This group received treatment of matched sibling donor - hematopoietic stem cell transplantation (MSD-HSCT).

This group received treatment of haploid family donor - hematopoietic stem cell transplantation (HFD-HSCT).

1. Conditioning regimens: (A) Patients had SAA and PNH, or heavy transfusion (RBC≥25U), or failed rabbit ATG therapy, and received 0.8 mg/kg/6h busulfan (days -7 to -6), 30mg/m2/day fludarabine (days -5 to -2), 25 mg/kg/day cyclophosphamide (days -5 to -2) and 2.5 mg/kg/day r-ATG (days -5 to -2). (B) The other patients with SAA or VSAA received same procedure but without busulfan;
2. Allogeneic HSC infusion: Doner BM cells were harvested to achieve a target mononuclear cell count (MNC) of 2-4 × 108 per kilogram of recipient weight. The target MNC from PB was 4-6× 108 per kilogram of recipient weight;
3. Prophylaxis and treatment of GVHD: GVHD prophylaxis consisted of intravenous CSP 2-3 mg/kg/day in divided doses beginning on the day before transplantation (day -5) and the target concentration was adjusted to 150-250 ng/ml. The oral MMF dose was 20 mg/kg/day from day -1 and was tapered off after 1 months if no aGVHD was observed.

Neutrophil engraftment was defined as the first of three consecutive days in which the neutrophil counts (ANC) exceeded 0.50 × 109/L, and platelet engraftment was defined as the first of five consecutive days in which the platelet count exceeded 20 × 109/L without transfusion. GF was classified as follows: (1) primary non-engraftment (failure to reach a neutrophil count of 0.5×109/L after transplant); (2) rejection (decrease in blood counts to < 0.5×109/L neutrophils, after achieving a neutrophil count of 0.5×109/L); (3) late graft failure (decrease of blood counts after day 100 to < 1.0×109/L neutrophils and < 30×109/L platelets).

The transplantation-related toxicity (TRT) was graded using the National Cancer Institute Common Toxicity Criteria for Adverse Events version 4.0. Organ damage due to GVHD or infectious complications were excluded.

Chimerism would be evaluated in recipient BM cells usually on days +30 after HSCT using cytogenetic G-banding or fluorescence in situ hybridization. Sex-matched donor-recipient chimerism was assessed using PCR-based analyses of polymorphic minisatellite or microsatellite regions. HLA typing was performed for patients with HLA-haploidentical donors.

Chimerism would be evaluated in recipient BM cells usually on days +180 after HSCT using cytogenetic G-banding or fluorescence in situ hybridization. Sex-matched donor-recipient chimerism was assessed using PCR-based analyses of polymorphic minisatellite or microsatellite regions. HLA typing was performed for patients with HLA-haploidentical donors.