Low CXCR4 membrane expression on CD34(+) cells characterizes cells mobilized to blood.
In this work, association between the presence and membrane density of CXCR4 and the effectiveness of mobilization was studied. Ninety G-CSF mobilized PBPC and 28 native BM (nBM) preparations obtained from healthy individuals for transplantation and BM obtained after G-CSF mobilized PBPC collection in 10 donors were investigated. Positivity for CD34, HLA-DR and CXCR4 were analysed in the three colour fluorescence. The cellular profile of PBPC differed from nBM preparations with respect to lower: (i) proportion of CD34(+) cells (0.64%+/-0.04 vs 0.92+/-0.07) and CD34(+)CXCR4(+) cells (0.30%+/-0.02 vs 0.61+/-0.07); (ii) contribution of CXCR4(+) cells to CD34(+) cells (52.2%+/-2.5 vs 62.2%+/-4.2); (iii) CXCR4 epitope density in CD34(+) cells (48.9+/-5.5 vs 94.7+/-10.4). PBPC yield for CD34(+) cells was correlated with the content of CD34(+) cells lacking CXCR4 in the leukapheresis product (R=0.38). In contrast, nBM harvested for transplantation was poor in CD34(+) cells if these cells were frequently CXCR4- (R=-0.49). The present study shows that CD34(+) cells mobilized to blood were characterized with a low proportion of CXCR4 and this associated with CD34(+) cell content in PBPC.
Dlubek
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L. Hirszfeld Institute of Immunology and Experimental Therapy, Lower Silesian Centre for Cellular Transplantation and National Bone Marrow Donor Registry, Wroclaw, Poland.
Drabczak-Skrzypek
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Lange
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D018952:Antigens, CD34 / Q000096:biosynthesis*; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage; D019650:Hematopoietic Stem Cell Mobilization; D006801:Humans; D007937:Leukapheresis; D007962:Leukocytes / Q000166:cytology / Q000378:metabolism*; D019718:Receptors, CXCR4 / Q000096:biosynthesis*
D018952:Antigens, CD34; D019718:Receptors, CXCR4; D016179:Granulocyte Colony-Stimulating Factor