Efficacy and Safety of UCBT With TMI -Based Conditioning Regimen for Adults With Refractory/Relapsed Aplastic Anemia

Inclusion criteria

• ✓. Age ≥18 years and \<50 years, regardless of gender.
• ✓. Diagnosis of AA according to the guidelines of the British Society for Haematology. The bone marrow shows hypocellularity, without infiltration of abnormal cells or marrow fibrosis. The peripheral blood must meet at least two of the following three criteria: absolute neutrophil count (ANC) \<1.5×10⁹/L; platelet count \<50×10⁹/L; hemoglobin \<100 g/L. Based on the severity of the disease, AA is classified into severe aplastic anemia (SAA) and non-severe aplastic anemia (NSAA).
• ✓. Meet the criteria for refractory AA: ①SAA: no response to first-line ATG + CSA treatment for more than 6 months; ②NSAA: ①persistent transfusion dependence of two or more blood cell lines, ②meet any of the following criteria: no response to immunosuppressive therapy with cyclosporine for more than 12 months, or no response to androgen and/or TPO receptor agonist therapy for more than 6 months, ④or progression to SAA; Meet the criteria for relapsed AA: initially effective to first-line immunosuppressive therapy, but pancytopenia recurs after reduction or discontinuation of immunosuppressive therapy, meeting the criteria for SAA.
• ✓. Karnofsky score ≥60, ECOG score ≤2, HCT-CI index ≤2.
• ✓. No HLA-identical sibling donor or no HLA-identical unrelated donor available.
• ✓. Understanding of the study procedures and voluntary written informed consent.

Exclusion criteria