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october 7-9, 2012 • NEW ORLEANS, LA
P1
NORMAL SPLENIC LYMPHOID SUBSETS MIMIC
ABERRANT ANTIGEN EXPRESSION.
Nidhi Aggarwal, Jason Fischer, Fiona E. Craig
University of Pittsburgh School of Medicine, Department of
Pathology
Background:
Flow cytometry (FC) assists in the diagnosis
of lymphoma through identification of aberrant antigen
expression. However, normal lymphoid subsets with less
well-recognized phenotypes can mimic lymphoma. This
study characterizes lymphoid subsets in normal spleen
using 8-color FC.
Design:
20 spleens removed for traumatic
rupture, with cell viability >50%, were analyzed within 24 hrs
with the following FC combinations: CD16&57/CD7/CD4/
CD2/CD56/CD3/CD5/CD8; K//CD5/CD19/CD10/CD38/CD20/
CD45; TCRab/TCRgd/CD3/CD25 and CD14/CD13&33/
CD45/CD34.
Results:
This study reveals the normal
variation in splenic lymphoid subsets and demonstrates
some subsets with phenotypes that have been associated
with lymphoid neoplasms. Well recognized lymphoma-
associated phenotypes identified in this study include CD5+
B-cells (20 of 20 specimens), CD7- T-cells (20 of 20), and
CD3 bright gamma-delta T-cells (16 of 20). In addition,
less well-recognized lymphoid subsets were identified that
resemble those described- in lymphoma: CD5- T-cells (20
of 20) (Figure 1a), CD2- NK-cells (20 of 20) and CD7dim+
NK-cells (20 of 20) (Figure 1b). The latter two NK-cell
phenotypes were seen more often in the mature subtype
(p<0.01).
Conclusion:
8-color FC analysis of normal spleen
demonstrates lymphoid phenotypes that may resemble
those described in subtypes of lymphoma, such as LGL
leukemia, hepatosplenic lymphoma, and chronic NK-cell
lymphoproliferative disorders. Familiarity with these normal
phenotypes can help prevent misinterpretation. Furthermore,
these findings support that these neoplastic phenotypes
reflect expanded normal subsets rather than aberrant antigen
expression.
P2
A METHOD FOR STABILIZING CD69 ANTIGENIC
EPITOPES ON ACTIVATED LYMPHOCYTES
Jodi R. Alt, Wayne L. Ryan Streck
CD69, also known as activator inducer molecule (AIM), early
activation antigen 1 (EA-1), Leu-23, and MLR3 is a type II
integral membrane protein. Although not normally expressed
on peripheral blood lymphocytes, surface expression is
upregulated in response to a wide variety of stimuli and
is identified as an early stage T-cell activation event. In
addition to its involvement in T-cell mediated responses, it
plays a pivotal role in the differentiation of the Th17 immune
response via direct binding and inhibition of the Jak3/Stat5
transcription factor pathway. Because of CD69’s role in
immune responses, immune cell development, and potential
antitumor effects, it is being evaluated as an important
marker for the analysis of clinical patients in a variety of
applications. Thus, the ability to measure CD69 expression
for clinical or research flow cytometry is of significant value.
We demonstrate the in vitro stimulation of peripheral blood
mononuclear cells (PBMCs) followed by stabilization of CD69
expression for 7 days in Cyto-Chex® BCT. This is in contrast
to stimulated cells maintained in K2EDTA alone as cells were
unstable and CD69 percent recoveries were overtly elevated.
This discovery allows more flexibility in testing protocols
which can benefit clinical sample analysis by contract
research organizations and hospitals.
POSTER ABSTRACTS
POSTER ABSTRACTS