Abstract: Objective To observe the clinical efficacy of plasma exchange in desensitization treatment of DSA (donor-specific antibody) positive patients undergoing hematopoietic stem cell transplantation (HSCT). Methods A retrospective analysis was carried out of 30 DSA positive patients desensitized with plasma exchange and combined with anti-B cell therapy in our hospital from July 2021 to July 2023. We primarily investigated the changes in the average fluorescence intensity of DSA before and after plasma exchange therapy, its impact on the incidence of cell implantation during transplantation and GVHD (graft-versus-host disease) after transplantation, and the adverse reactions during plasma exchange therapy. Results Totally 64 plasma exchanges were performed on 30 patients, with 24 mild adverse reactions including hypocalcemia and allergies. These reactions were relieved after treatment and did not didrupt the plasma exchange process. The average fluorescence intensity of DSA before and after plasma exchange was 7 182.9±5 535.3 and 2 311.8±2 835.9, respectively (P<0.001). Among the 30 patients, 25 underwent allo-HSCT (umbilical cord blood transplantation in 19 and Haplo HSCT in 6), with 23 (92%) achieving hematopoietic reconstruction. The median engraftment times were 14 (9~60) days for neutrophils and and 31 (10~64) days for platelets. Two patients underwent secondary transplantation due to failed engraftment. Five patients were not transplanted or their data was deleted. The cumulative incidence of Ⅱ~Ⅳ aGVHD within 30 days after transplantation in 23 patients was 41%. Conclusion Plasma exchange combined with anti B cell therapy is an effective desensitization therapy for DSA positive patients subjected to hematopoietic stem cell transplantation.

Key words: Hematopoietic stem cell transplantation, Donor-specific antibody, Plasma exchange