Elevation of IgE-binding factors in serum of patients with B cell- derived
chronic lymphocytic leukemia
M Sarfati, D Bron, L Lagneaux, C Fonteyn, H Frost and G Delespesse
University of Montreal, Notre-Dame Hospital, Quebec, Canada.
One hundred nineteen sera from patients with various lymphoproliferative
diseases and normal sera were tested by a solid- phase radioimmunoassay
(RIA) for their content in IgE-binding factor (IgE-BF), a soluble
glycoprotein binding to IgE and derived from low- affinity IgE receptors
(Fc epsilon R). Fc epsilon R, recently identified as CD23, are known to be
expressed on the surface of B cells at the intermediate stage of
differentiation. The results indicate that in all cases of chronic
lymphocytic leukemia (CLL) tested (n = 40), IgE- BF levels (45 to 8,656
U/mL) were 3-fold to 500-fold higher than in 24 controls (15.5 +/- 2 U/mL).
With a few exceptions, serum IgE-BF levels could differentiate patients
with CLL from those with other leukemias or lymphomas. In vitro studies
indicated that B lymphocytes isolated from CLL patients produced 8 to 50
times more IgE-BF than did normal B cells (P less than 0.001). IgE-BF level
was correlated with the Rai stage of the disease (P = 0.002) and the
lymphocyte count (P = 0.041). IgE-BF was purified to homogeneity from one
CLL serum sample by a combination of affinity chromatography and
reverse-phase high- performance liquid chromatography (HPLC). this IgE-BF
proved identical to IgE-BF isolated from the culture supernatant of RPMI
8866 cells, a B lymphoblastoid cell line bearing Fc epsilon R and secreting
IgE-BF. Indeed, the two molecules had the same mol wt (25 to 27 kd), the
same isoelectric point, and the same tryptic map. We suggest that
determination of serum IgE-BF might prove useful for clinical monitoring of
CLL.
Volume 71,
Issue 1,
pp. 94-98,
01/01/1988
Copyright © 1988 by The American Society of Hematology
