Prospective flow cytometric evaluation of nucleated red blood cells in cord blood units and relationship with nucleated and CD34(+) cell quantification.
BACKGROUND
Cord blood (CB) represents an alternate source of stem cells in transplantation. Nucleated red blood cells (NRBCs) are a physiological subset of CB population. Although it is important to have an accurate estimate of CD34(+) cell number, NRBCs could compromise white blood cell count and interfere with CD34(+) cell quantification.


METHODS
A total of 826 CB units were analyzed for total nucleated cells (TNCs), NRBCs, and CD34(+) cells by flow cytometry. NRBCs were also counted conventionally by manual microscopy. Percentages of CD34(+) cells corrected by NRBC count (CD34+c) were determined as follows: %CD34+c = CD34(+)/CD45(+) (x10(6))/(TNCs (x10(8)) - NRBCs (x10(8))).


RESULTS
The mean percentages of CD34+ cells and NRBCs were 0.27 percent (range, 0.01%-1.25%) and 7.64 percent (range, 0.13%-84%), respectively. Comparison between flow cytometric and microscopic NRBC count showed a regression of y = 0.685 + 0.719x and a coefficient of determination of r(2) = 0.721. When corrected with NRBC count, the mean percentage of CD34(+) c cells was 0.295 percent (p = 0.0008 compared with CD34(+)%) and mean TNCc count was 14.8 x 10(8) (p < 10(-4) compared to TNC count).


CONCLUSIONS
The determination of NRBCs with a flow cytometric method might represent a new strategy for providing satisfactory quality assurance controls of CB products.
Cell Therapy Unit and Bone Marrow Transplant Department, Saint-Louis Hospital, Paris, France.
Jerome
J
Larghero
Delphine
D
Rea
Yves
Y
Brossard
Jacqueline
J
Van Nifterik
Veronique
V
Delasse
Isabelle
I
Robert
Nicole
N
Biscay
Elisabeth
E
Chantre
Emmanuel
E
Raffoux
Gerard
G
Socié
Eliane
E
Gluckman
Marc
M
Benbunan
Jean-Pierre
JP
Marolleau
D018952:Antigens, CD34; D041905:Erythroid Cells / Q000166:cytology*; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D007231:Infant, Newborn; D007958:Leukocyte Count / Q000379:methods; D008297:Male
D018952:Antigens, CD34