Characteristics of CD11c+CD5+ chronic B-cell leukemias and the
identification of novel peripheral blood B-cell subsets with chronic
lymphoid leukemia immunophenotypes [see comments]
SB Wormsley, SM Baird, N Gadol, KR Rai and RE Sobol
Cytometrics, Inc., San Diego, CA 92121.
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.
Volume 76,
Issue 1,
pp. 123-130,
07/01/1990
Copyright © 1990 by The American Society of Hematology
