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52
ICCS 2012
Previous studies suggest that the level of cell surface
antigen expression may affect response to monoclonal
antibody-based therapy. In this study, we determine
the antigen densities of these therapeutically targeted
antigens in CLL cells.
Methods:
Using the flow cytometric
“Quantibrite” method (BD) to determine antibody binding
capacity per cell (ABC), we quantified the surface antigen
densities of CD20, CD22, CD25 and CD52 in CLL cells
from 28 untreated CLL patients.
Results:
The CLL cells in
all cases expressed CD20, CD22 and CD52 but 4 cases
(14%) were negative for CD25. The level of antigen density,
in decreasing order, was CD52 > CD20 > CD22 > CD25.
However, the highest CD20, CD22, CD25 and CD52 ABC
values were observed in different cases, indicating that the
level of targeted therapeutic antigen expression cannot be
accurately predicted.
Conclusion:
Response to therapy
with these agents is highly variable among CLL patients;
therefore, quantitation of potential therapeutically targeted
antigens may provide a systematic approach in providing
optimal individualized therapy in CLL. Antigen quantitation
may also be informative in evaluating new antigens as
potential therapeutic targets.
P40
ALVEOLAR RHABDOMYOSARCOMA MIMICKING AN
ACUTE LEUKEMIA: A CASE REPORT.
Lucía Veiga, Adriana Arocena, María Brasesco, Noelia
García, Ana I Landoni, Claudia Sejumil, Rossana Bonomi,
Carina Di Matteo, Hugo Giordano
Specialized Techniques Laboratory, Asociación Española
Rhabdomyosarcoma (RMS) is the most common pediatric
malignant soft tissue tumor. It usually presents as solid mass
and the most common locations are head and neck, trunk,
genitourinary tract and extremities. RMS represents around
5% of all malignancies among children and adolescents.
There are two main types of rhabdomyosarcomas:
embryonal rhabdomyosarcoma (ERMS), the most common,
and alveolar rhabdomyosarcoma (ARMS). It is known that
bone marrow infiltration may occur. We report a case of
a 20 year-old man, with a 3 months history of asthenia,
anemia and low back pain. Peripheral blood count showed
hemoglobin concentration 6.5 g/dL, platelet count 39.000/
mm3 and white blood cell count 8.900/ mm3. Bone marrow
(BM) smears showed an infiltration of small round/oval cells
containing one or two nucleus and scant cytoplasm which
led to the suspicion of acute leukemia. Flow cytometric
analysis of BM and peripheral blood (PB) showed abnormal
cells CD56+ CD45-, 38.6% in BM and 3.2% in PB, without
other hematopoietic markers. These results excluded the
diagnosis of leukemia and suggested an extra hematologic
neoplasm. The morphology and immunostaining patterns
of BM biopsy revealed the diagnosis of ARMS metastasis.
Cytogenetic analysis in BM showed t(2;13) (q35q14), that is
present in around 60% of ARMS cases. It is important to do
the differential diagnostic between acute leukemias and solid
tumors with BM infiltration. Flow cytometry (FCM) had a key
role in excluding important diagnostics, quantifying the grade
of infiltration and orienting therapeutic steps.
P41
DETECTION OF EXTRAMEDULLARY (EXCEPT CSF)
INVOLVEMENT OF HEMATOPOIETIC NEOPLASMS
USING FLOW CYTOMETRY
Hui Wang
1
, Chunrong Tong
1
, Ping Wu
1
, Rui Kang
2
, Junyi
Zhen
1
1
Ludaopei Hematology & Oncology Center,
2
Beijing Daopei
Hospital
Objective To study the value of flow cytometry in identifying
POSTER ABSTRACTS