60
ICCS 2011
P24
Detection Of Rare Paroxysomal Nocturnal
Hemoglobinuria (PNH) Clones In Normal Human
Blood By Flow Cytometry
Michael A Liew
1
, Marjorie Farley
1
, John Andreasen
1
,
Carl T Wittwer
1, 2
1
ARUP Laboratories, Salt Lake City, UT, USA,
2
University of Utah, Salt Lake City, UT, USA
Introduction:
Paroxysomal nocturnal hemoglobinuria
(PNH) is a rare acquired disorder that affects
approximately 1.3 in 1000000 individuals. It is
characterized by increased complement-mediated
lysis of RBC secondary to absent GPI anchors of
several cell surface proteins. The aim of this study
was to determine how many PNH+ RBC are present
in normal human blood.
Methods:
RBC were assayed
by washing 30 microliters of blood with PBS, followed
by staining with Glycophorin A FITC and CD59 PE.
Routine testing involves counting 250,000 events, but
in an attempt to more accurately establish the range
of PNH+ RBC in normal samples, 1 million RBC were
counted in 102 asymptomatic individuals, and 10
million RBC were counted in 12 individuals. Results
were acquired on a FACS Canto II fow cytometer.
Results:
Analysis of the normal individuals by the
RBC assay did demonstrate the presence of PNH
cells. Each sample contained a range of type III PNH
cells (0-8 PNH cells per 1 million RBC). Results for
the 10 million cells were similar. Two PNH samples
measured by the RBC assay had coeffcients of
variation less than 5%, while 2 normal samples were
around 100%.
Conclusions:
Type III PNH RBC
can be visualized and quantifed with this RBC PNH
assay. These results help to defne what the cutoffs
should be to defne subclinical PNH so that therapy
can be implemented in the appropriate patients with
myelodisplastic syndromes.
POSTER ABSTRACTS