Standardized High-Sensitivity Flow Cytometry Testing for Paroxysmal Nocturnal Hemoglobinuria in Children with Acquired Bone Marrow Failure Disorders: A Single Center U.S. Study | Aplastic Anemia and MDS International Foundation

Standardized High-Sensitivity Flow Cytometry Testing for Paroxysmal Nocturnal Hemoglobinuria in Children with Acquired Bone Marrow Failure Disorders: A Single Center U.S. Study

Journal Title: 
Cytometry B Clin Cytom
Primary Author: 
Donohue RE
Author(s): 
Donohue RE, Marcogliese AN, Sasa GS, Elghetany MT, Redkar AA, Bertuch AA, Curry CV
Original Publication Date: 
Friday, June 2, 2017

BACKGROUND:
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematopoietic stem cell disorder that has not been well documented in children, particularly those with acquired bone marrow failure disorders (ABMFD) - acquired aplastic anemia (AAA) and myelodysplastic syndrome (MDS). Therefore, we sought to determine the prevalence of PNH populations in children with ABMFD.
METHODS:
PNH testing was performed in children with an ABMFD diagnosis using high sensitivity (≥0.01%) fluorescent aerolysin (FLAER)-based assay according to 2010 International Clinical Cytometry Society (ICCS) PNH Consensus Guidelines and 2012 Practical PNH Guidelines. FLAER/CD64/CD15/CD24/CD14/CD45 and CD235a/CD59 panels were used for white blood cell and red blood cell testing, respectively.
RESULTS:
Thirty seven patients with ABMFD (34 AAA, 3 MDS) were included (17 M/20 F, age 2 to 18 years, median 9 years). PNH populations were identified in 17 of 37 (46%) patients. Of the 17 patients with PNH populations identified, 7 were PNH clones (> 1% PNH population) and 10 had minor PNH population or rare cells with PNH phenotype (≤ 1% PNH population).
CONCLUSIONS:
This is the first study to use a standardized high-sensitivity FLAER-based flow cytometry assay and the recommended cutoff of 0.01% to identify cells with PNH phenotype in pediatric patients with ABMFD in the United States. The identification of a PNH population in 46% of ABMFD supports the recommendation for high sensitivity PNH testing in children with these disorders, as a routine assay. Using a cutoff of ≥ 1% PNH population would have missed 10 (27%) patients with minor PNH population or rare cells with PNH phenotype.