Optimizing the CD34+ and CD34+Thy-1+ stem cell content of peripheral blood collections

A. K. Stewart, K. Imrie, A. Keating, S. Anania, R. Nayar, D. R. Sutherland

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

We have previously described a sensitive and specific CD34 enumeration assay and report here a prospective analysis of 25 myeloma patients undergoing PBSC mobilization using this assay to determine the optimal days for collection of CD34+ and CD34+Thy-1+ cells after chemotherapy and growth factor mobilization. Correlations between frequency of peripheral blood CD34+ cells, circulating white blood cell (WBC) count, apheresis CD34+ cell count, nucleated cell count (NCC), and numbers of apheresis colony-forming units granulocyte/macrophage (CFU-GM) were determined. To assess levels of the more primitive subsets of CD34+ cells in the PBSC collections, coexpression of the Thy-1 antigen (CDw90) on CD34+ cells was also assessed. Marked heterogeneity was noted between patients with apheresis samples containing a median NCC of 4.2 x 108/kg (range 1.3-8.1), median CFU-GM 17 x 104/kg (range 0.15-32 x 104/kg), and median CD34+ cell count of 1.39 x 106/kg (range 0.02-6.6). The frequency of CD34+ cells in PBSC collections coexpressing Thy-1 was also heterogeneous (6.2-50% of CD34+ cells), median 21.6%, mean 24.7 ± 2%. The apheresis CD34+ cell count correlated with the peripheral blood CD34+ cell percentage (r = 0.71, p < 0.0001) but only weakly with the peripheral WBC. Apheresis CD34+Thy-1+ cell numbers correlated strongly with the circulating CD34+ cell numbers (r = 0.80), but no correlation was noted between these candidate stem cells and the peripheral WBC. In contrast, apheresis CFU-GM levels correlated most strongly with the peripheral WBC count (r = 0.61, p < 0.0001). The apheresis CD34+ cell count correlated with apheresis CFU-GM (r = 0.75, p < 0.0001) but not with the apheresis NCC. Apheresis CD34+Thy-1+ counts significantly correlated only with the apheresis CD34+ cell count and not with the apheresis CFU-GM or NCC. A higher percentage of circulating and apheresis CD34+ cells expressing Thy-1 were found on day 1 of collection, and the percentage of CD34+ cells expressing Thy-1 decreased on each subsequent day of measurement: median of 22% day 1 vs. 16.6% day 4, p = 0.04. This study therefore confirms that accurate quantitation of circulating CD34+ cells best predicts the optimal day for apheresis collection of CD34+ and CD34+Thy-1+ cells and is superior to the WBC count in this regard. Furthermore, the candidate stem cell (CD34+Thy-1+) subset is most prevalent during the earliest phases of CD34+ cell mobilization.

Original languageEnglish (US)
Pages (from-to)1619-1627
Number of pages9
JournalExperimental Hematology
Volume23
Issue number14
StatePublished - Dec 1 1995

Keywords

  • Blood
  • CD34
  • Flow cytometry
  • Myeloma
  • Thy-1

ASJC Scopus subject areas

  • Molecular Biology
  • Hematology
  • Genetics
  • Cell Biology
  • Cancer Research

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    Stewart, A. K., Imrie, K., Keating, A., Anania, S., Nayar, R., & Sutherland, D. R. (1995). Optimizing the CD34+ and CD34+Thy-1+ stem cell content of peripheral blood collections. Experimental Hematology, 23(14), 1619-1627.