Estimation of the Progenitor Cell Yield in a Leukapheresis Product by Previous Measurement of CD34+ Cells in the Peripheral Blood

Abstract

To assess whether measurement of CD34+ cells in the peripheral blood allows one to estimate the progenitor cell yields of subsequent leukapheresis procedures, 733 corresponding blood and leukapheresis samples were analyzed. Peripheral blood progenitor cells of cancer patients were mobilized with hematopoietic growth factors alone or postchemotherapy, and harvested processing 10 liters of blood for each leukapheresis product. The CD34+ cell count (CD34+ cells/microliter blood) correlated most closely with the progenitor cell yield in the corresponding leukapheresis product (CD34+ cells/kg bodyweight, r = 0.80), while the proportion of circulating CD34+ cells to the white blood and mononuclear cells predicted the yield less reliably (r = 0.74 and r = 0.60). The CD34+ cell yield was independent of the white blood count (r = 0.04), whereas a weak correlation was found between the mononuclear cell count and the number of CD34+ cells/kg collected (r = 0.42). It was unlikely to obtain the threshold quantity of 2.5 x 10(6) CD34+ cells/kg required for rapid engraftment when counts below 10 CD34+ cells/microliter blood were detected. At levels between 10 and 30 CD34+ cells/microliter sufficient autografts could be harvested, whereas 30-100 CD34+ cells/microliter were required to achieve this by a single leukapheresis. A surplus of CD34+ cells was likely above 100 CD34+ cells/microliter which could be useful for progenitor cell enrichment techniques. The correlation between the CD34+ cell count and progenitor cell yield was independent of the mobilizing regimen and whether leukaphereses had been performed previously. In conclusion, the number of CD34+ cells/microliter blood allows a reliable prediction of the CD34+ progenitor cell yield in subsequent leukapheresis procedures. However, rare cases of unexpectedly sufficient progenitor cell yields may be observed even at CD34+ cell levels below detection limit.

Collection Efficiencies of CD34+ Progenitor Cells and Mononuclear Cells in Leukapheresis Products Quantified by Flow Cytometry and Calculated on the Basis of a New Formula

“…Our results demonstrate a very strong correlation between the number of CD34+ progenitor cells circulating in the peripheral blood and their yield in leukapheresis products, and are in accordance with recently published data; however, the minimum threshold of CD34+ cells in the peripheral circulation prior to initiating apheresis is still controversial [8, 9, 10, 11, 12, 13]]. Schots et al [8]showed that 10 CD34+ cells/µl peripheral blood can result in a harvest of at least 0.5×10 6 CD34+ cells/kg BW, whereas Chapple et al [12]demonstrated a threshold of 5 CD34+ cells/µl to obtain a minimum of 0.5×10 6 CD34+ cells/kg BW.…”

“…Taking all of this together, however, our finding reinforces the extreme importance of the flow cytometric monitoring of CD34+ cells for clinical decision making. The MNC count showed only a weak correlation (r = 0.374) with the collected CD34+ cells/kg BW, whereas the WBC count failed to predict the harvest of progenitor cells (r = 0.005), confirming previously published data [9, 10, 12]. Thus, the determination of WBC number is not suitable to replace the monitoring of CD34+ cells, which is still to be recommended for collecting stem cells efficiently and optimizing the use of financial and economic resources.…”

“…The advantages of PBSCT include the absence of a need for general anesthesia and operative aspiration of bone marrow, as well as a more rapid engraftment of neutrophil granulocytes and platelets [6, 7]. Conflicting data have been published with respect to the predictive significance of preapheresis parameters for a sufficient stem cell harvest [8, 9, 10, 11, 12, 13, 14]. …”

Estimation of haemopoietic progenitor cells in peripheral blood by the Advia 120 and BD vantage flow cytometer: a direct comparison for the prediction of adequate collections

“…Centres advocating its use recommend commencing apheresis when the total WCC rises to between 3-10 · 10 6 /l (Watts et al, 1997). Most groups, however, demonstrate poor correlation between WCC and harvest CD34 (Möhle et al, 1996;Schots et al, 1996;Yu et al, 1999) and do not recommend basing a decision to commence apheresis on this value alone. In our group of patients the total WCC did not predict the timing of a successful apheresis.…”

Harvesting, processing and inventory management of peripheral blood stem cells

“…Mohle et al . [48] found a strong linear correlation between the blood CD34+ cell count and the yield of CD34+ cells in the apheresis product. Moreover, they showed that 1 × 10 6 /kg CD34+ cells were collected in less than 5% harvests done with the blood CD34+ cells of < 10 µL.…”