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.
OBJECTIVE
Optimal mobilization and harvest of hematopoietic progenitors are essential for peripheral blood stem cell transplantation after myeloablative high-dose chemotherapy. Conflicting data have been published concerning the most useful, cost-effective collection strategy which is also convenient for patients.


METHODS
A total of 66 leukaphereses in 20 patients were retrospectively evaluated. We assessed the predictive value of the number of white blood cells, mononuclear cells (MNCs) and CD34+ cells in peripheral blood for the yield of CD34+ cells in leukapheresis products. The concentrations of MNCs and CD34+ cells were quantified simultaneously by a flow cytometric procedure using fluorescent microparticles. Their collection efficiencies were calculated based on a newly developed formula.


RESULTS
The collected hematopoietic progenitor concentration could be predicted only by the number of peripheral blood CD34+ cells prior to apheresis (r = 0.902; p<0.01). Furthermore, the mobilization of at least 30 CD34+ cells/microl peripheral blood was a good predictor that a single leukapheresis would yield a minimum of 2.0x10(6) CD34+ cells/kg body weight. The collection efficiencies calculated by the new formula were 55.2+/-10.7% and 57.7+/-11.2% for MNCs and CD34+ cells, respectively.


CONCLUSIONS
The precise quantification of MNCs and CD34+ cells by a direct flow cytometric assay, as well as the new formula to determine the collection efficiencies, has an impact on optimizing high-quality stem cell products.
Schlenke
P
P
Institute of Immunology and Transfusion Medicine, Section Hematology/Oncology, University of Lübeck School of Medicine, Lübeck, Germany. schlenke@immu.mu-luebeck.de
Frohn
C
C
Hennig
H
H
Weber
K
K
Kisro
J
J
Saballus
M
M
Kirchner
H
H
Klüter
H
H
D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000097:blood*; D001810:Blood Volume; D002648:Child; D005260:Female; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000276:immunology; D006801:Humans; D007937:Leukapheresis / Q000191:economics / Q000379:methods* / Q000592:standards; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D012189:Retrospective Studies
D018952:Antigens, CD34