73
OCTOBER 16-18, 2011 • PORTLAND, OR
P37
Changes in antigen expression in a follow-up of
chronic lymphocytic leukemia/small lymphocytic
lymphoma
Jiehao Zhou, Anupama Tewari, Magdalena Czader
Indiana University, Indianapolis, IN, USA
Diagnosis of chronic lymphocytic leukemia/small
lymphocytic lymphoma (CLL/SLL) depends on the
clinical and laboratory features including a specifc
immunophenotype. Specifc antigens not only
distinguish CLL/SLL from other B-cell lymphomas,
but are also increasingly used as therapeutic
targets. Patients with CLL/SLL undergo repeat
fow cytometric testing throughout the course of
the disease, however the reports detailing how the
expression of specifc antigens changes over time
are sparse. We have evaluated the variability of CLL/
SLL immunophenotype in paired follow-up samples
from the 32 patients. Our results show a signifcant
variability in the expression levels of CD20, CD5,
CD23, surface immunoglobulin light chain, and
HLA-DR in the initial diagnostic samples. During the
disease course, a systematic statistically signifcant
decrease in the density and percentage of cells
positive for CD23 and a signifcant increase in the
intensity of HLA-DR were observed. The changes
in CD5 were variable with a proportion of samples
showing decrease in CD5 intensity over time.
Howerver, no statistic signifcance is observed. The
number of positive cells and fuorescence intensity
did not change signifcantly for CD19, FMC7 and
CD22 antigen. Flow cytometric immunophenotypes
of CLL/SLL vary in the course of the disease with a
systematic decrease in the expression of CD23 and
increase in HLA-DR. These alterations can potentially
infuence the responsiveness of the disease to the
monoclonal antibody therapy and should be evaluated
systematically. Despite the changes in antigen
expression, in the majority of cases, the diagnosis of
CLL/SLL could be rendered based on the follow-up
immunophenotype.
POSTER ABSTRACTS