68
ICCS 2011
P32
Use of CD157 in FLAER-based assays for high-
sensitivity PNH granulocyte and PNH monocyte
detection
D. Robert Sutherland
1
, Michael Keeney
2
, Erica Acton
1
,
Bruce H. Davis
3
, Andrea Illingworth
4
1
University Health Network, Toronto, ON, Canada,
2
London Health Sciences, London, ON, Canada,
3
Trillium Diagnostics LLC, Bangor, ME, USA,
4
Dahl-
Chase Diagnostics, Bangor, ME, USA
PNH is a rare acquired disease of hematopoietic
cells characterized by loss of glyco-phosphatidyl-
inositol (GPI) linked structures. The ability to rapidly
diagnose PNH by fow cytometry has led to improved
diagnosis, patient management and prognosis. The
International Clinical Cytometry Society Guidelines
for the Diagnosis and Monitoring of PNH and related
disorders recommended cocktails based on FLAER
and GPI-linked protein expression for leukocyte
analysis. We developed a 4-colour combination
for high-resolution detection of PNH neutrophils
using FLAER, CD24, CD15 and CD45 that is
highly sensitive and usable on a variety of clinical
cytometers. Similarly, a 4-colour combination of
FLAER, CD14, CD64 and CD45 was developed for
high-resolution detection of PNH monocytes. Both
WBC assays are capable of detecting PNH cells at
<0.05% with very low background rates on normal
samples (<2-4/100,000 granulocytes). CD157 is
another GPI-linked structure expressed on both
granulocytes and monocytes raising the possibility
that this single reagent might replace the GPI-linked
structures CD24 (in the granulocyte assay) and CD14
(monocyte assay). We have found in preliminary
studies that CD157 generates the same results for
PNH clone size when substituted for CD24 and CD14
in the granulocyte and monocyte assays respectively
and has similar background staining levels in normal
blood samples as the current predicate assays. We
conclude CD157 may be a more advantageous GPI-
linked protein target for use in PNH diagnostic assays,
with the potential to reduce both reagent use and
technical time required to detect PNH clones. Studies
of a wider variety of samples is ongoing.
POSTER ABSTRACTS