The Absolute Number of Circulating CD34+ Cells as the Best Predictor of Peripheral Hematopoietic Stem Cell Yield

Abstract

Many controversies still exist about the timing of leukapheresis procedures for PBSC transplantation. Thirty-nine patients were followed daily by monitoring the absolute PB WBC count and CD34+ cell enumeration prior to apheresis. These determinations were compared with the apheresis cell content (nucleated cells and CD34+ cells yield). There was a highly significant correlation between PB CD34+ cells and apheresis CD34+ cell yield (r = 0.921, p < 0.001). A small but significant correlation was found between the PB WBC count and the apheresis nucleated cell content (r = 0.383, p < 0.001), but no correlation was found between PB WBC count and apheresis CD34+ cell yield (r = -0.065, p = 0.460). A target value of 20 x 10(6) CD34+ cells/L was determined to be the most reliable predictor to collect at least 1.0 x 10(6) CD34+ cells/kg in a single apheresis. Of the 39 patients, 20 could be followed after transplantation, and a good correlation was found for total number of CD34+ cells reinfused and platelet and neutrophil engraftment. No correlation was found for nucleated cells infused and engraftment. CD34+ cell determination is a better predictor than WBC count for timing leukapheresis and is thus recommended for monitoring the quality of the product.

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.…”

“…[23][24][25][26] During the time period of our study, 28 patients (unpublished data) received disease-specific chemotherapy primes with G-CSF and the median time to first harvest was 13 days (range [11][12][13][14][15][16][17][18]. Stem cell recovery is more rapid however following low-dose cyclophosphamide/G-CSF.…”

Flow cytometric CD34+ stem cell enumeration: Lessons from nine years' external quality assessment within the Benelux countries

“…Each send-out, from Spring 1996 to Autumn 2004 was chronologically assigned with a unique number (i.e., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. In this way, we analyzed any effect of the EQA program on the results of the participants as a function of time.…”

“…This emphasizes the need for an adequate prediction of engraftment potency of HSCs in patients after receiving myeloablative therapy followed by HSC transplantation (8)(9)(10)(11). Furthermore, enumeration of CD34þ cells has been shown to be useful in con-siderations of peripheral blood stem cell harvesting (12)(13)(14)(15)(16) and in comparing the efficacy of various PB stem cell mobilization strategies (reviewed by Fruehauf and Kessinger and Sharp) (17,18). Furthermore, CD34þ cell enumeration is useful for monitoring the stem cell yield during graft manipulations, such as immunomagnetic selections, ex vivo expansion, or genetic modifications of HSCs.…”