Modified Transplantation Regimen and aGVHD Prophylaxis for Severe Aplastic Anemia in the Setting of Allogeneic HSCT.

Inclusion Criteria: 1. Patients who were diagnosed with severe aplastic anemia by NCCN guidelines, and has received HSCT with this transplantation preconditioning and aGVHD prophylaxis regimen; 2. Age 3-65 years old; 3. Weight 10Kg-100Kg; 4. Eastern Cooperative Oncology Group (ECOG) score ≤3; 5. No major organ injury (ECG ejection fraction \>45%; bilirubin \< 2 times the upper limit of normal value; AST and ALT \< 3 times the upper limit of normal value; serum creatinine \< 2 times the upper limit of normal value); 6. No severe infection; 7. Subjects voluntarily participated in this clinical trial and signed the informed consent. Exclusion Criteria: 1. Patients with other hematologic diseases who are not eligible for transplantation or who do not wish to receive transplantation; 2. Patients with an expected survival of less than 1 month; 3. Patients with previous autologous or allogeneic hematopoietic stem cell transplantation; 4. pregnant patients; 5. Patients with severe mental or neurological disorders that would affect the ability to provide informed consent and/or to report or observe adverse events; 6. Other conditions that the investigator determines to be inappropriate for enrollment.