PNH clone assessment by flow cytometry and its clinical correlation in PNH and aplastic anemia

Abstract

Flow cytometry is the most sensitive and specific diagnostic modality for paroxysmal nocturnal hemoglobinuria (PNH) clone assessment in PNH and other bone marrow failure states. A total of 101 samples included 23 PNH, 46 aplastic anemia (AA), seven myelodysplastic syndrome (MDS) cases, and 25 normal controls. Flow cytometry was performed using CD55, CD59, and stain-lyse-wash method, and the PNH clone size was correlated with the severity of disease. The PNH clone size on granulocytes in PNH patients varied from 7% to 97% detected with a sensitivity of 0.2% and correlated with the clone on monocytes (r = 0.563; p & 0.01). In PNH patients, a significant correlation was seen between PNH clone and the hemoglobin of patient (r = -0.523; p & 0.05), however, not with the transfusion frequency, cytopenias, and hemolytic parameters (p > 0.05). PNH clone (0.4-38.7%) was detected in 23 (50%) AA patients. Three (42.9%) of the seven MDS patients showed PNH clone (&1%). CD55 and CD59 have the advantage of simultaneously analyzing granulocytes and monocytes for PNH clone which correlated with degree of anemia in PNH. A larger patient data is required to assess the clinical impact of PNH clone of variable size in AA and MDS patients. © 2010 Springer-Verlag.