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october 7-9, 2012 • NEW ORLEANS, LA
extramedullary [except Cerebro-Spinal Fluid(CSF)]
involvement of acute leukemia. Methods In the patients who
were diagnosed and treated in our hospital from Oct. 2008
to Oct. 2011, 52 cases were found extramedullary lump
or effusion. We took their extramedullary samples to do 4
color flow cytometry detection. They included 8 lymph node
samples, 31 other tissue samples, 13 effusion samples.
There were 7 B cell acute lymphoblastic leukemia(ALL)
cases,12 T cell ALL cases, 33 Acute Myeloid Leukemia(AML)
cases. Results Malignant cells were found in 38 samples,
and 14 samples were negative. The median percentage of
tumor cells were 35.95% (0.38%~97.87%). After median
following up 21 months(3 months to 3 years), all the
cases could be evaluated in negative group. Except one
continuously had leukemic cells in BM, others kept complete
remission.27 cases could be evaluated in positive group, of
which 16 cases were refractory or relapsed of BM. 11 cases
were in event-free survival (EFS). Comparing with negative
group, positive group had a poor prognosis (P<0.01). CD56
positive AML was proned to had extramedullary involvement
(P<0.02), and might had a poor prognosis.Conclusion
Flow cytometry could effectively detect extramedullary
(except CSF) involvement of hematopoietic neoplasms. The
detection result had a significant prognosis value.
P42
STANDARDISING LEUCOCYTE PNH CLONE
DETECTION: AN INTERNATIONAL STUDY
Liam Whitby
1
, Matthew Fletcher
1
, Stephen Richards
2
,
Michael Borowitz
3
, Michael Keeney
4
, Andrea Illingworth
5
,
Erica Acton
6
, Robert Sutherland
6
, David Barnett
1
1
UK NEQAS for Leucocyte Immunophenotyping,
2
HMDS, St
James University Hospital,
3
Department of Pathology and
Oncology, Johns Hopkins Medical Institution,
4
Hematology/
Flow Cytometry, London Health Sciences Centre,
5
Flow
Cytometry Laboratory, Dahl-Chase Diagnostic Services,
6
Dept of Lab Hematology, University Health Network.
International PNH Flow Cytometry Study Group
PNH, a rare acquired stem cell disorder, is characterized
by loss of GPI-linked surface structures and consequent
increased sensitivity of red blood cells to complement-
mediated lysis. A high risk of thrombosis means accurate
diagnosis is essential for appropriate treatment. Flow
cytometry is the method-of-choice to detect/quantify
PNH RBC and WBC clone size. The UK NEQAS Quality
Assessment Programme has identified large variance
in testing protocols and reagent selection used in PNH
leucocyte clone detection. To study the effect of a
standardised protocol and reagent choice compared to
‘in-house’ methods for PNH leucocyte clone detection, 3
stabilised blood samples manufactured to contain zero,
~8% and ~0.1% PNH leucocyte clone populations were
distributed to 19 international centres experienced in
PNH analysis, together with a standardised protocol and
standardised antibody cocktails: FLAER/CD24/CD15/
CD45 for neutrophils; and FLAER/CD14/CD64/CD45 for
monocytes (optimized for both Beckman Coulter and BD
Biosciences platforms). Whilst overall medians between
the two approaches for leucocyte PNH clone detection
were similar, the standardised approach had lower variation
around the median compared to “in-house” protocols (Table
1). Our results highlight the importance of reagent choice
and a standardised approach in performing PNH analysis
even among experienced laboratories; additional studies are
planned in which the standardised method will be compared
to in house methods among labs with less experience to
evaluate further the potential benefits of standardization.
This study was supported by Alexion Pharmaceuticals, BD
Biosciences, Beckman Coulter and eBioscience.
POSTER ABSTRACTS