[CD34(+) selected donor hematopoietic stem cell infusion for poor graft function after allogeneic hematopoietic stem cell transplantation: a retrospective cohort study].

Objective: To evaluate the efficacy of purified donor CD34 positive hematopoietic stem cell (CD34(+) cell) infusion in patients with poor graft function (PGF) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: The clinical data of 25 patients with PGF who underwent donor CD34(+) cell sorting and infusion at the Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences between September 2019 and March 2023, were retrospectively analyzed. The cohort included 19 haploidentical and 6 HLA-matched cases. CD34(+) cells were purified using immunomagnetic beads for therapeutic infusion. The purification efficiency was evaluated based on the purity and recovery rate of CD34(+) cells. Clinical outcomes were assessed by hematopoietic recovery, overall survival (OS) rate, and the incidence of graft-versus-host disease (GVHD) . Results: The median total number of CD34(+) cells was 2.64 (0.82-6.53) × 10(8) before purification and 2.22 (0.48-5.68) ×10(8) after purification, with a median recovery rate of 78.37% (58.48%-115.72%) . After infusion of purified CD34(+) cells, 8 of 10 patients (80.0%) with poor neutrophil engraftment achieved recovery (absolute neutrophil count ≥ 0.5×10(9)/L) , with a median time to recovery of 21 (10-40) days. And 15 of 21 patients (71.4%) with poor platelet engraftment achieved recovery (platelet count ≥ 20×10(9)/L) , with a median time to recovery of 15 (13-38) days. Only 3 patients (12.0%) developed GVHD after the infusion of purified CD34(+) cells, including 2 cases of grade I acute GVHD and 1 case of limited chronic GVHD. With a median follow-up of 14.47 (0.23-41.63) months, the overall OS rate after CD34(+) cell infusion was (65.63± 8.28) %. Seventeen patients survived, with a median survival time of 19.07 (0.23-41.63) months. Conclusion: Purification of CD34(+) cells using immunomagnetic beads is effective, and the infusion of these purified donor CD34(+) cells can safely and effectively improve PGF after allo-HSCT.