The presence of monoclonal cytoplasmic immunoglobulins in leukemic B cells
from patients with chronic lymphocytic leukemia
T Han, H Ozer, M Bloom, K Sagawa and J Minowada
It has generally been assumed that CLL B cells do not contain cytoplasmic
immunoglobulin (Cylg), although these cells express surface membrane
immunoglobulin (Smlg). The present study, in which Smlg and Cylg
determinations were performed simultaneously using leukemia B cells from 20
patients with CLL, demonstrates that Cylg staining was detectable in each
CLL cell population examined and that the intensity of cytoplasmic
immunofluorescent staining in each instance was moderate to strong. Both
Smlg and Cylg light chain determinations indicated monoclonality in all 20
cases. The heavy chain class of Smlg and Cylg in each CLL cell population
was not uniformly comparable, however. The majority (15 cases) of CLL B
cells contained mu heavy chain Cylg and mu and delta heavy chain Cylg was
demonstrated in the remaining 6 cases. In contrast, the Smlg phenotypes
appeared heterogeneous with both gamma and alpha chain determinants found
associated with mu or mu and delta chains on the same leukemia cell
populations. This apparent polyclonal Smlg staining pattern was most likely
due to nonspecific adsorption of the patient's own serum Ig by Fc receptors
on CLL B cells. It is concluded that the great majority of CLL B cells
contain detectable Cylg and that Cylg determination is superior to Smlg
phenotyping in documenting the monoclonality of CLL.
Volume 59,
Issue 2,
pp. 435-438,
02/01/1982
Copyright © 1982 by The American Society of Hematology
