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** marked products are registered as Analyte-Specific Reagent (ASR)

* marked products are registered as Medical Device for In Vitro Diagnostic Use (IVD/CE)

Detection of GPI-anchored proteins on red blood cells

Detection of GPI-anchored proteins on white blood cells

^*(N), neutrophils ^#(M), monocytes

Background information

Paroxysmal Nocturnal Hemoglobinuria (PNH) is a clonal hematopoietic stem cell (HSC) disease characterized by the continuous destruction of red blood cells ^[1]. PNH is caused by somatic mutations in the phosphatidylinositol N-acetylglucosaminyl-transferase subunit A (PIGA) gene, which is essential in the biosynthesis of glycosylphosphatidylinositol (GPI) anchors ^[2]. PIGA mutations lead to a deficiency in GPI-anchored proteins including the complement inhibitory proteins CD55 and CD59 that result in chronic complement-mediated hemolysis of GPI-deficient erythrocytes, as well as activation of platelets, monocytes and granulocytes ^[3]. Consequently, when left untreated this may lead to life-threatening thrombosis ^[4].

PNH is a very rare disease with an estimated incidence of 1.3 per million inhabitants ^[5]. The clinical manifestation of PNH includes hemolytic anemia, thrombosis, and smooth muscle dystonias, as well as bone marrow failure in some cases ^[6]. However, these symptoms are not solely related to PNH. Therefore, PNH testing is not only recommended for patients that develop PNH, but also for patients with PNH-like symptoms in disorders such as Aplastic Anemia (AA) and Myelodysplastic syndrome (MDS). Both AA and MDS are characterized by diminished production of red- and white blood cells and thrombocytes in the bone marrow.

PNH is a clinical diagnosis that should be confirmed with flow cytometry to detect the absence or severe deficiency of GPI-anchored proteins on ≥ 2 lineages (e.g. monocytes and granulocytes) ^[7]. The loss of GPI-anchored proteins can be detected using a combination of monoclonal antibodies directed against monocyte and granulocyte lineages and FLAER (fluorescent aerolysin) that binds ALL GPI-anchored proteins expressed on the surface of leukocytes ^[8].

References

1. Oni, S. B., Osunkoya, B. O. & Luzzatto, L. Paroxysmal nocturnal hemoglobinuria: evidence for monoclonal origin of abnormal red cells. Blood36, 145–152 (1970).
2. Takeda, J. et al. Deficiency of the GPI anchor caused by a somatic mutation of the PIG-A gene in paroxysmal nocturnal hemoglobinuria. Cell73, 703–711 (1993).
3. Brodsky, R. A. Paroxysmal nocturnal hemoglobinuria. Blood124, 2804–2811 (2014).3.
4. Hill A, Kelly RJ, Hillmen P. Thrombosis in paroxysmal nocturnal hemoglobinuria. Blood. 2013;121(25):4985-4996.
5. Hill A, Platts PJ, Smith A, Richards SJ, Cullen MJ, Hill QA, Roman E, Hillmen P. The incidence and prevalence of paroxysmal nocturnal hemoglobinuria (PNH) and survival of patients in Yorkshire. Blood. 2006;108:985.
6. Parker C, Omine M, Richards S, et al; International PNH Interest Group. Diagnosis and management of paroxysmal nocturnal hemoglobinuria. Blood. 2005;106(12):3699-3709.
7. Sutherland, DR, Illingworth, A, Marinov, I, Ortiz, F, Andreasen, J, Payne,D Wallace, PK, Keeney, M. ICCS/ESCCA Consensus Guidelines to detect GPI‐deficient cells in Paroxysmal Nocturnal Hemoglobinuria (PNH) and Related Disorders: Part 2; Reagent Selection and Assay Optimization for High Sensitivity Testing. Cytometry B Clin Cytom 2018;94B:23–48.
8. Brodsky, R. A. et al. Improved detection and characterization of paroxysmal nocturnal hemoglobinuria using fluorescent aerolysin. Am. J. Clin. Pathol.114, 459–466 (2000).This is the first description of FLAER reagent for the diagnosis of PNH.

* marked products are registered as Medical Device for In Vitro Diagnostic Use (IVD/CE)

* marked products are registered as Medical Device for In Vitro Diagnostic Use (IVD/CE)

* marked products are registered as Medical Device for In Vitro Diagnostic Use (IVD/CE)
(1) Product available in the Netherlands only

* marked products are registered as Medical Device for In Vitro Diagnostic Use (IVD/CE)

* marked products are registered as Medical Device for In Vitro Diagnostic Use (IVD/CE)