Characteristics of CD11c+CD5+ chronic B-cell leukemias and the identification of novel peripheral blood B-cell subsets with chronic lymphoid leukemia immunophenotypes.
Previous studies have indicated that chronic lymphocytic leukemias (CLL) are characterized by the coexpression of CD5 and B-cell antigens, while hairy cell leukemias (HCL) typically express CD11c+CD5- B-cell immunophenotypes. In this report we describe the features of B-cell leukemias with CD11c+CD5+ immunophenotypes and the identification of novel circulating B-cell subsets defined by the expression of CD20, CD5, and CD11c antigens. Morphologic evaluation of 14CD11c+CD5+ B-cell leukemias showed that they generally had larger cellular diameters (14 to 21 microns) and lower nuclear:cytoplasm ratios than typical small lymphocyte CLL. These cases did not exhibit the well-defined nucleoli characteristic of prolymphocytic leukemia (PLL). The presenting clinical features of CD11c+CD5+ B-cell leukemias were most consistent with CLL or PLL, and none of the evaluated cases had pancytopenia, splenomegaly, and cytoplasmic villi characteristic of HCL. Examination of normal peripheral blood (n = 6) by three-color flow cytometry identified four novel B-cell subsets with the following immunophenotypes (mean percent of total CD20+ B cells +/- SE): CD20+CD5+CD11c+ (8.0 +/- 1.6); CD20+CD5-CD11c+ (12.0 +/- 2.0); CD20+CD5+CD11c- (35.0 +/- 4.9); and CD20+CD5-CD11c- (44.0 +/- 5.0). Our findings suggest that CD11c+CD5+ B-cell leukemias with atypical morphologic features represent forms of CLL or PLL rather than HCL. In addition, we have identified novel subsets of circulating B cells defined by patterns of CD20, CD5, and CD11c expression that correspond to the immunophenotypes of chronic B-cell leukemias.
Cytometrics, Inc., San Diego, CA 92121.
S B
SB
Wormsley
S M
SM
Baird
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N
Gadol
K R
KR
Rai
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RE
Sobol
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018951:Antigens, CD20; D000943:Antigens, Differentiation / Q000276:immunology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000473:pathology; D018956:CD5 Antigens; D002455:Cell Division; D005260:Female; D006801:Humans; D016167:Integrin alphaXbeta2; D007943:Leukemia, Hairy Cell / Q000276:immunology / Q000473:pathology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D015463:Leukemia, Prolymphocytic / Q000276:immunology / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D016028:Receptors, Leukocyte-Adhesion / Q000276:immunology*
D018951:Antigens, CD20; D000943:Antigens, Differentiation; D000944:Antigens, Differentiation, B-Lymphocyte; D018956:CD5 Antigens; D016167:Integrin alphaXbeta2; D016028:Receptors, Leukocyte-Adhesion