[Impact of the infused CD34(+) cell dose on hematopoietic reconstitution and transplant-related outcomes in newly diagnosed multiple myeloma patients undergoing autologous peripheral blood stem cell transplantation].

Abstract

Objective: To investigate the impact of different infused CD34(+) cell doses on hematopoietic reconstitution and transplant-related outcomes in patients with multiple myeloma (MM) undergoing autologous peripheral blood stem cell transplantation (auto-PBSCT) . Methods: We retrospectively analyzed 57 newly diagnosed MM patients who underwent first auto-PBSCT at the Second Affiliated Hospital of Anhui Medical University between July 27, 2020 and August 29, 2025. Patients were stratified by infused CD34(+) cell dose into a low-dose group (<4×10(6)/kg, n=19) and a high-dose group (≥4×10(6)/kg, n=38). The primary endpoints were time to neutrophil engraftment and time to platelet engraftment. Secondary endpoints included the duration of grade 3-4 neutropenia, duration of grade 3-4 thrombocytopenia, duration of febrile neutropenia, and platelet transfusion requirements. Secondary endpoints were adjusted for multiple comparisons using the Benjamini-Hochberg false discovery rate (FDR) procedure. Logistic regression was used to identify factors associated with neutrophil and platelet engraftment within 10 days. Survival outcomes, including progression-free survival (PFS) and overall survival (OS), were analyzed using the Kaplan-Meier method and Cox regression analysis. Results: The median infused CD34(+) cell dose was 5.30 (3.49, 9.35) ×10(6)/kg, and all patients achieved hematopoietic reconstitution. Compared with the low-dose group, the high-dose group had shorter time to neutrophil engraftment (median: 10.00 d vs 11.00 d, P=0.014) and platelet engraftment (median: 10.00 d vs 12.00 d, P=0.009). The high-dose group also had shorter duration of severe cytopenia, shorter febrile neutropenia duration, and lower platelet transfusion requirements (all P value<0.05). Multivariable analysis showed that an infused CD34(+) cell dose ≥4×10(6)/kg was independently associated with neutrophil engraftment within 10 days (OR=4.661, 95% CI: 1.322-16.435, P=0.017), whereas ISS stage Ⅲ (OR=0.217, 95% CI: 0.060-0.781, P=0.019) and a higher number of pre-transplant chemotherapy cycles (OR=0.706, 95% CI: 0.520-0.958, P=0.025) were associated with failure to achieve platelet engraftment within 10 days. Survival analysis showed that the high-dose group had superior PFS and OS compared with the low-dose group (median PFS time: not reached vs 773 d, P=0.040; median OS time: not reached vs 812 d, P=0.009), and that an infused CD34(+) cell dose ≥4×10(6)/kg might be independently associated with a lower risk of relapse or disease progression (HR=0.212, 95% CI: 0.052-0.870, P=0.031) . Conclusion: In patients with newly diagnosed MM undergoing auto-PBSCT, an infused CD34(+) cell dose ≥4×10(6)/kg was associated with faster neutrophil engraftment, shorter duration of severe myelosuppression, reduced time of febrile neutropenia, and decreased need for platelet transfusions, and may improve long-term survival outcomes.