Background: Myelodysplastic syndrome (
MDS) is characterized by peripheral blood cytopenias, with most patients developing significant anemia and dependence on red blood cell (
RBC) transfusion. In paroxysmal nocturnal hemoglobinuria (
PNH), mutations in the PIGA gene lead to lack
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Background: Myelodysplastic syndrome (
MDS) is characterized by peripheral blood cytopenias, with most patients developing significant anemia and dependence on red blood cell (
RBC) transfusion. In paroxysmal nocturnal hemoglobinuria (
PNH), mutations in the PIGA gene lead to lack of cell-surface glycosylphosphatidylinositol, allowing complement-mediated lysis to occur. Paroxysmal nocturnal hemoglobinuria results in direct antiglobulin test–negative hemolysis and cytopenias, and up to 50% of patients with
MDS test positive for
PNH cells. We wanted to determine whether
PNH is considered to be a contributor to anemia in
MDS.
Methods: Patients with a diagnosis of
MDS confirmed by bone-marrow biopsy since 2009 were reviewed. Highresolution
PNH testing by flow cytometry examined
FLAER (fluorescein-labeled proaerolysin) binding and expression of CD14, CD15, CD24, CD45, CD59, CD64, and CD235 on neutrophils, monocytes, and
RBCS.
Results: In 152 patients with
MDS diagnosed in 2009 or later, the
MDS diagnosis included subtypes associated with
PNH positivity (refractory anemia,
n = 7, and hypoplastic
MDS,
n = 4). Of 11 patients who underwent
PNH testing, 1 was positive (9.0%). Reasons for
PNH testing were anemia (
n = 3), new
MDS diagnosis (
n = 2), hypoplastic
MDS (
n = 2), decreased haptoglobin (
n = 1), increased
RBC transfusion requirement (
n = 1), and unexplained iron deficiency (
n = 1).
Conclusions: Testing for
PNH was infrequent in
MDS patients, and the criteria for testing were heterogeneous. Clinical indicators prompted
PNH testing in 6 of 11 patients. Given that effective treatment is now available for
PNH and that patients with
PNH-positive
MDS can respond to immunosuppressive therapy,
PNH testing in
MDS should be considered. Prospective analyses to clarify the clinical significance of
PNH positivity in
MDS are warranted.
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