Clinical Study of Super Transplantation in the Treatment of Severe β-thalassemia

Patient screening: 1. Two months before transplantation, pediatric patients are evaluated by our center, and the patients meeting the inclusion criteria will be screened into the group. 2. Investigators and doctors will give detailed information about the benefits and risks of participating in the study, and the informed consents are further signed. Transplant conduction: 1. Donor mobilization: HLA-fully matched or haplo-identical donors are mobilized subcutaneously for five days with human granulocyte colony-stimulating factor (G-CSF) and the peripheral blood mononuclear cells (PBMCs) that contain a certain numbers of CD34+ stem cells and CD3+ lymphocytes will be extracted by blood cell separators. 2. Transplant regimen: Hydroxycarbamide will be used to reduce the total white blood cells before transplant. However, no traditional transplantation conditioning will be performed, including but not limited to busulfan, fludarabine, Cyclophosphamide, ATG, and irradiation. Splenectomy should be performed if the longitudinal diameter of the spleen exceeds the normal value by 4 cm. 3. Cell infusion: Pediatric patients will be infused with the PBMCs intravenously at day 0. 4. GVHD prophylaxis: The dosage of immunosuppressants is half of the conventional post-transplantation level, but adjustments to the dosage may be necessary based on specific circumstances. 5. Infection management: Antibacterial, antifungal medications, and anti-Pneumocystis medications need to be administered during the period of granulocytopenia. The preemptive treatment for cytomegalovirus will be performed when the virus serological test is positive.