Hematopoietic progenitor cell counting can optimize peripheral blood stem cell apheresis process

Abstract

Introduction: Monitoring of stem cell concentration in transplantation settings is crucial to determine the optimal time of apheresis and is currently based on enumeration of CD34+ cells by flow cytometry. No surrogate marker has replaced CD34+ cell enumeration to date. The aim of this study was the evaluation of the hematopoietic progenitor cell (HPC) parameter of the Sysmex XN-1000 analyzer in terms of optimizing the peripheral blood stem cell apheresis process.Materials and Methods: Results of flow cytometric CD34+ cell and Sysmex HPC count were compared in 208 preharvest samples and 139 apheresis products.Results: HPC and CD34+ cell counts showed significant differences in the multiple myeloma (MM) group. The correlation between preharvest HPC and CD34+ cell counts was good in the MM group (rho = .613) and strong in the lymphoma group (rho = .802), allogeneic donors (rho = .923), and other group of samples (rho = .816). The HPC positive cutoff demonstrating 100% specificity and positive predictive value for MM patients was high for ≥20/μL and ≥10/μL CD34+ cell counts, and therefore of limited value. The HPC negative cutoff demonstrating 100% sensitivity and negative predictive value was approximately <4/μL, irrespective of diagnosis.Conclusions: Based on proposed HPC positive cutoffs (≥31/μL in the lymphoma group and ≥11/μL in the other group of samples), routine HPC enumeration could improve the workflow by replacing CD34+ cell counting in allogeneic donors as well as non-MM patients. Furthermore, based on proposed HPC negative cutoff (<4/μL), CD34+ cell counting could be fully omitted in donors and patients that are not adequately mobilized.

Hematopoietic progenitor cell count as a potential quantitative marker in apheresis products during allogeneic stem cell transplantation

“…XN‐HPC count can quickly and accurately predict the starting time point for apheresis, according to the research done previously 10,26 . Our ROC analysis, however, shows that the XN‐HPC count in autologous samples is not as good a predictor as it is in allogeneic samples.…”

“…XN-HPC count can quickly and accurately predict the starting time point for apheresis, according to the research done previously. 10,26 Our ROC analysis, however, shows that the XN-HPC count in autologous samples is not as good a predictor as it is in allogeneic samples. Therefore, considering the differences in transplant types, disease diagnosis, chemotherapy, and/or mobilization regimens, the exact clinical application of XN-HPC to guide the timing of apheresis remains to be explored.…”