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40
ICCS 2012
P18
INCREASED TIM3 EXPRESSION ON LEUKEMIC BLASTS
Kelly Garner, Stephen Ten Eyck, Fiona E Craig, Christine G
Roth
University of Pittsburgh Medical Center
Background:
T-cell immunoglobulin mucin-3 (TIM-3) has
recently been reported to be expressed on acute myeloid
leukemia (AML) stem cells but not on normal hematopoietic
stem cells, and has been proposed as a novel tumor marker.
TIM-3 can be expressed on monocytes, natural killer cells,
and a subset of T cells, however, expression on normal
myeloblasts has not been well-characterized or compared
with AML. The aim of this study was to evaluate the
diagnostic utility of TIM-3 expression in separating leukemic
from non-leukemic myeloblasts.
Design:
Peripheral blood
and bone marrow samples from 23 AML and 19 non-
neoplastic cases were evaluated, using the following flow
cytometric 8 color antibody panel: CD14/TIM-3/CD117/
CD13+CD33/CD34/CD3/CD56/CD45. FACSCanto-II and
BD-FACS-DIVA were used for acquisition and analysis,
respectively. TIM-3 expression was quantitated as a
percentage of the CD34+/CD13+33+ myeloblasts.
Results:
TIM-3 positive myeloblasts were identified in all cases,
however the percentage of myeloblasts expressing TIM-3
was significantly higher in AML cases (median 71.5%,
range 11.2-96.3%) as compared to the non-neoplastic
cases (median 53.5%, range 26.1 – 70.7%) (Mann Whitney
U test, p=0.02). Receiver Operator Curve (ROC) analysis
identified a cut-off value of >70.6% as a useful discriminator
between leukemic and non-leukemic myeloblasts (sensitivity
57%, specificity 95%).
Conclusions:
TIM-3 expression is
not restricted to AML, and may be seen on non-leukemic
myeloblasts. Despite this overlap, a higher proportion of
leukemic blasts express TIM-3, and >70.6% TIM-3 positive
myeloblasts distinguishes between leukemic and non-
leukemic myeloblasts with high specificity. Further studies
are required to validate the diagnostic utility of TIM-3 in
clinical practice.
P19
EVALUATION OF PERIPHERAL BLOOD MEMORY
B-CELLS IN A SMALL RUSSIAN COHORT (A
PILOT STUDY).
Margarita Ivanchenko
1
, Konstantin Slobodnyuk
1
, Margarita
Gorchakova
1
, Vera Golubeva
1
, Marina Guseva
2
, Yekaterina
Zueva
1
1
State Pavlov Medical University,
2
State Pediatric Medical
Academy
The assessment of peripheral blood memory B cells is widely
used in diagnostics of inherited immunodeficiencies, namely,
of Common Variable Immune Deficiency and Hyper IgM-
syndrome. According to EuroClass 2009 recommendations,
we used a whole blood staining-lysis method. The panel of
monoclonal antibodies containing the following markers:
CD45 (to identify lymphocytes), CD19 (to segregate B cells),
CD27 (memory B cell marker), superficial IgM and IgD.
Memory B cells are СD27 positive, and, after class switching
are negative for IgD and IgM (with an exception for a small
subpopulation that have chosen IgD/IgM to synthesis).
Age-matched reference values for the analysis were taken
from the literature. However, the immunophenotyping panel
(including anti-IgM or anti-IgD independently), age intervals
and data representing methods differed profoundly between
the researches, and were difficult to compare. Preliminary,
our results match reference values obtained by Piatosa et
al. in 2011. We found that for sparse subpopulations (for
instance, memory B cells in young children), the accuracy of
evaluation was higher if fewer markers were used (anti-IgD
only) to achieve a phenotype of interest. With this approach
POSTER ABSTRACTS