Preharvest hematopoietic progenitor cell counts predict CD34+ cell yields in granulocyte–colony‐stimulating factor–mobilized peripheral blood stem cell harvest in healthy donors

Abstract

The hematopoietic progenitor cell (HPC) count measured by the Sysmex hematology analyzer can determine the timing for leukapheresis in autologous peripheral blood stem cell (PBSC) harvest. We evaluated whether a HPC count could predict CD34+ cell yield in healthy, unrelated donors after granulocyte-colony-stimulating factor mobilization. A total of 117 healthy donors underwent 161 PBSC leukapheresis procedures in our institution. The HPCs and CD34+ cells were identified by an automated hematology analyzer and flow cytometry, respectively. Using Spearman's rank test, we evaluated the relationships between preharvest HPCs, CD34+ cell counts, and CD34+ cell yields in the apheresis product. A receiver operating characteristic (ROC) curve analysis was used to identify the cutoff value of HPC for adequate mobilization and harvest yield. The HPC count had a moderate correlation with the preharvest CD34+ cell count (r = 0.502, p < 0.001), and an HPC count of more than 21.3 x 10(6)/L could exclude poor mobilization (<20 x 10(6) CD34+ cells/L) with sensitivity and specificity of 89.2 and 83.3%. However, the relationship between HPC count and CD34+ cell yield was not marked (r = 0.321, p < 0.001). The area under the curve for HPCs was significantly smaller than the preharvest CD34+ cell count on the ROC curve for predicting adequate harvest yield (>10 x 10(6) CD34+ cells/L of processed blood volume, 0.678 vs. 0.850, p = 0.001). Although the preapheresis HPC count could predict mobilization in healthy donors before leukapheresis, it may not be a superior index for predicting CD34+ cell yield compared with the preharvest CD34+ cell count.