The predictive value of white cell or CD34+ cell count in the peripheral blood for timing apheresis and maximizing yield

Abstract

The number of CD34+ cells, but not WBCs, in the peripheral blood can be used as a predictor for timing of apheresis and estimating PBPC yield. This is a robust relationship not affected by a variety of patient and collection factors except the diagnosis of acute myeloid leukemia. Patients who undergo mobilization with chemotherapy and filgrastim also should undergo monitoring of peripheral blood CD34+ cell counts, beginning when the WBC count in the blood exceeds 1.0 to 5.0 x 10(9) per L.

An analysis of the optimal timing of peripheral blood stem cell harvesting following priming with cyclophosphamide and G-CSF

“…[11][12][13][14][15][16] Recommendations for the level of PB CD34 þ cell count that should be used to initiate apheresis has varied from 8 to 20/ml. [16][17][18][19] If harvesting is initiated at a lower PB CD34 þ count, daily yield will be lower and more apheresis days are required to achieve an adequate harvest. If too high a target is set, fewer patients will reach the target count thereby increasing the failure rate.…”

“…The lack of correlation between WBC count and harvest yield (r ¼ 0.0117) is supported by previous studies, in which r-values ranged from À0.065 to 0.43. [12][13][14]16,17 WBC count is therefore less reliable than PB CD34 þ count for initiating apheresis. If the WBC count is low, the PB CD34 þ count is also likely to be low 14,16,19 leading some to suggest that monitoring CD34 þ counts should begin when the WBC count exceeds 1-5 Â 10 9 /l.…”

“…[12][13][14]16,17 WBC count is therefore less reliable than PB CD34 þ count for initiating apheresis. If the WBC count is low, the PB CD34 þ count is also likely to be low 14,16,19 leading some to suggest that monitoring CD34 þ counts should begin when the WBC count exceeds 1-5 Â 10 9 /l. 14,16 Analysing the utility of WBC in predicting yield is problematic when another variable, that is PB CD34 þ count is being used to select patients for harvesting.…”

“…If the WBC count is low, the PB CD34 þ count is also likely to be low 14,16,19 leading some to suggest that monitoring CD34 þ counts should begin when the WBC count exceeds 1-5 Â 10 9 /l. 14,16 Analysing the utility of WBC in predicting yield is problematic when another variable, that is PB CD34 þ count is being used to select patients for harvesting. Our data show that until WBC count recovers to 41 Â 10 9 /l, the PB CD34 þ count is unlikely to be greater than 10/ml and this may inform units where a PB CD34 þ count is not immediately available.…”

Immature granulocyte fraction in the peripheral blood is a practical indicator for mobilization of CD34+ cells

“…Apheresis failures can be reduced if reliable indicators are available for measuring adequate mobilization of CD34 + cells. The WBC count during the recovery phase following the chemotherapy-induced nadir is widely used as the practical indicator of time to initiate apheresis, but the counts do not correlate well with the number of mobilized CD34 + cells [18][19][20]30,31]. Several previous studies reported that the rate of WBC recovery could be used to predict the most effective time for apheresis [5,9,27,32,33], but in our experience, the correlation between WBC recovery rate and the CD34 + cell number was moderate, indicating that this parameter is not useful in clinical practice.…”