Correlations between hematopoietic progenitor cell counts as measured by Sysmex and CD34+ cell harvest yields following mobilization with different regimens.
OBJECTIVE
The Sysmex SE-9000 cell counter provides an estimate of immature cells referred to as hematopoietic progenitor cells (HPC). HPC counts should correlate with CD34+ counts in mobilized peripheral blood and apheresis to allow optimization of apheresis timing.


METHODS
We correlated the HPC counts as measured in the immature information channel with CD34+ cell levels as determined by FACS (HPCA-2 antibody, Becton Dickinson) from mobilized peripheral blood in 40 samples (27 patients and three healthy donors) and in aphereses ( n=113, 41 patients and 20 healthy donors).


RESULTS
In mobilized blood, HPC counts were correlated with CD34+ cells ( r=0.78, P<0.0001, n=40). The HPC counts were about 1.5-fold higher than CD34+ cell counts with a median (range) of 84 (1-747)/microl and 57 (1-370)/microl, respectively. In CD34+ selected cell preparations ( n=8), HPC counts were about fourfold lower than CD34+ cell counts with a median (range) of 179 (67-693)/microl and 760 (191-4309)/microl, respectively. In apheresis preparations, linear regression analyses were performed for the group of stem cell donors ( n=44), the group of lymphoma patients ( n=23), the multiple myeloma group ( n=21), and the group of solid tumors ( n=25). Interestingly, no correlation between HPC counts and CD34+ cell counts was found in the G-CSF-mobilized healthy donor group ( r=0.23, P=0.13). Pairing of HPC counts and CD34+ counts was effective in the group of patients receiving chemotherapy + G-CSF for stem cell mobilization: lymphoma group ( r=0.67, P=0.0005), multiple myeloma group ( r=0.56, P=0.008), and the group of solid tumors ( r=0.52, P=0.007).


CONCLUSIONS
Lymphoma and multiple myeloma patients who were moderately pretreated and mobilized with chemotherapy and G-CSF showed the best results in correlation analyses even at low HPC counts. Therefore, HPC measurement can be used for timing of apheresis in these patients.
Department of Hematology, Oncology, Rheumatology, and Immunology, Medical Center II, Eberhard Karls University, Otfried-Müller-Str. 10, 72076 Tübingen, Germany.
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Vogel
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Kopp
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Kanz
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Einsele
D000293:Adolescent; D000328:Adult; D018952:Antigens, CD34 / Q000097:blood*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002452:Cell Count; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use*; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000473:pathology; D006801:Humans; D000078224:Lenograstim; D008223:Lymphoma / Q000097:blood* / Q000188:drug therapy; D008875:Middle Aged; D009101:Multiple Myeloma / Q000097:blood* / Q000188:drug therapy; D009369:Neoplasms / Q000097:blood* / Q000188:drug therapy; D011237:Predictive Value of Tests; D011994:Recombinant Proteins / Q000627:therapeutic use*; D012016:Reference Values; D012044:Regression Analysis
D018952:Antigens, CD34; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D000078224:Lenograstim