Paroxysmal Nocturnal Hemoglobinuria: An Atypical Clinical Case Report and Proof of the Disease in Blood and BONE Marrow with FLOW Cytometry
Authors: Pineau-Vincent Fabienne , Lemaire Pierre , Ghnaya Habib , Direz Guillaume , Kaabar Mohamed , Laribi Kamel 
Published: October 2019

Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a rare acquired disease, associated with hemolytic anemia and bone marrow failure. The cellular abnormality is a mutation in the phosphatidylinositol glycan class (PIG A) resulting in a deficiency of glycosylphosphadityl-inositol (GPI)-anchored complement regulatory proteins, including CD 55 and CD59, on the surface of blood cells.
Case report
We report the case of a French, 81 year-old-man, who was admitted to our institution with an unusual clinical presentation. He had a rheumatologic monitoring in the context of polyarthritis associated with anemia (98g/L).
No hemolytic events were noticed and there was no notion of either transfusion.
Biological results showed hemolytic regenerative anemia (98g/L) with 136G/L of reticulocytes, neutrophil polynuclears (4.2G/L) without degranulation and nevertheless rare degranulation cells, no blasts, normal level of platelets (258G/l), increase of LDH (Nx3), low haptoglobin (0.07g/L), negative direct Coombs test.
The cytology aspect of medullar cells associated dysgranulopoiesis with degranulation of myeloid lineage and abnormal chromatin condensation, dyserythropoiesis, dysmegacaryopoiesis, in favor of a multilineage dysplasia without blasts. The marrow karyotype was normal.
Due to the morphological results observed on the blood smear and their dissociation with the medullary cytology, flow cytometry (FC500) for GPI‘s expression study was performed.
The used antisera were: CD55, CD59, CD14, CD16, CD24, CD66b, CD157, no FLEAR was tested.
Results TableBloodBone marrowMononuclear cells CD14 FL378% intermediar cells70% negative cellsNeutrophil cells CD16 PE56% intermediar cells56% negative cellsNeutrophil cells CD66b FITC57% negative cells70% negative cellsGranular cells CD24 PE49% negative cells62% negative cellsRed cells CD55 FITC10% negative cells11% negative cellsRed cells CD59 FITC12% negative cells12% negative cells
Figure 1 Blood Figure 1. Blood
Figure 2 Bone Marrow Figure 2. Bone Marrow
The confirmation was obtained by using CD157PE antisera on bone marrow with 70% negative mononuclear and granular cells.
The results confirmed the PNH clone’s presence in the blood and also in bone marrow, and the results of flow cytometry could explain the cytological aspect of neutrophil polynuclear cells. It is rare to explore the expression of GPI molecules in bone marrow and there is no publication about the PNH clone whose identification required bone marrow cells for the confirmation of abnormalities in blood. Thus, the apoptosis in the bone marrow of the defective myeloid cells would explain the difference of granularity of polynuclear cells between bone marrow and blood smear.
Conclusion
The significance of this observation is related to the search of a PNH clone when cytological dissociation is observed between the peripheral blood and bone marrow, associated with biological hemolysis arguments (increased LDH and decreased haptoglobin).
It is well known that 6 at 8% of myelodysplasia had PNH clone; the originality of this case report is the initial clinical signs and the laboratory proof of PNH in the blood and the bone marrow.
This observation was submitted at the national reference center of PNH in France (St Louis Hospital - Hematology Department - Professor SOCIE) and the treatment by eculizumab was introduced.

Disclosures
No relevant conflicts of interest to declare.