Human basophils express CD22 without expression of CD19.
BACKGROUND
Even modern automatic cell counters cannot count basophils precisely. Therefore, we need a rapid, accurate, precise, and easy method for counting basophils.


METHODS
Using flow cytometry, basophils (CD22+/CD19-) and B cells (CD22+/CD19+) were counted. Within a large lymphocyte light scatter gate, % basophils (G%baso) and % B cells (G%B) were determined from the total count. Another method of analysis was to make two regions (R1 for basophils and R2 for B cells) and to determine in those the % basophils (R1%baso) and % B cells (R2%B) without gating. The flow cytometric basophil counts of the blood of 21 normal controls and 43 chronic myelogenous leukemia (CML) patients were compared with manual basophil count (Ma%baso) and basophil count by Coulter electronic cell counter (Hialeah, FL) (Auto%baso). CD22+/CD19- cells were sorted by a FACSCalibur (Becton Dickinson, San Jose, CA).


RESULTS
The G%baso of all samples was 4.66 +/- 5.35%, and R1%baso was 4.23 +/- 4.88%, and they were well-correlated (r = 0.996, P < 0.001). The G%B of all samples was 1.55 +/- 1.68%, and R2%B was 1.59 +/- 1.67%, and they were also well-correlated (r = 0.993, P < 0.001). Their correlation was better in normal controls than in CML. G%baso was well-correlated to Ma%baso (r = 0.827) and Auto%baso (r = 0.806), and R1%baso was well-correlated to Ma%baso (r = 0.831) but showed poor correlation to Auto%baso (r = 0.734). Auto%baso revealed the poorest correlation to Ma%baso (r = 0.692). The sorted CD22+/CD19- cells were all basophils (99.48 +/- 0.30%), and they revealed CD13, CD33, and dim CD45 expression, whereas CD3, CD14, CD16, and HLA-DR were not detected on them.


CONCLUSIONS
We discovered a specific marker combination to identify basophils (CD22+/CD19-), and we suggest that flow cytometric analysis using these markers is an easy, reliable, and accurate method of basophil counting.
Han
K
K
Department of Clinical Pathology, Catholic University Medical College, Seoul, Korea. hankja@cmc.cuk.ac.kr
Kim
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Lee
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Lim
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Lee
K Y
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Kang
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Kim
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WI
Kim
B K
BK
Shim
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Kim
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D015703:Antigens, CD / Q000378:metabolism*; D018941:Antigens, CD19 / Q000378:metabolism*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D001402:B-Lymphocytes / Q000166:cytology; D001491:Basophils / Q000166:cytology / Q000378:metabolism*; D015815:Cell Adhesion Molecules; D002469:Cell Separation; D005434:Flow Cytometry / Q000379:methods; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D037102:Lectins; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood / Q000378:metabolism; D007958:Leukocyte Count / Q000379:methods; D051918:Sialic Acid Binding Ig-like Lectin 2
D015703:Antigens, CD; D018941:Antigens, CD19; D000944:Antigens, Differentiation, B-Lymphocyte; C497867:CD22 protein, human; D015815:Cell Adhesion Molecules; D037102:Lectins; D051918:Sialic Acid Binding Ig-like Lectin 2