Age-Stratified Conditioning Regimen Efficacy for MDS Haplo-HSCT

This study plan aims to enroll adult patients diagnosed with myelodysplastic syndrome (MDS) who are scheduled to receive T-cell-replete haploidentical hematopoietic stem cell transplantation. After obtaining written informed consent, participants will receive either reduced-toxicity Bu/Flu/Cy/ATG conditioning regimen (for patients aged ≥55 years) or standard myeloablative modified Bu/Cy+ATG conditioning regimen (for patients aged \<55 years) followed by unified post-transplant immunosuppression and supportive care. The objective is to prospectively characterize the 1-year transplant-related mortality and comprehensively evaluate hematopoietic engraftment, graft-versus-host disease, infection, relapse, survival outcomes and conditioning-related organ toxicity among all enrolled patients undergoing haploidentical transplantation.