Normal patterns of expression of glycosylphosphatidylinositol‐anchored proteins on different subsets of peripheral blood cells: A frame of reference for the diagnosis of paroxysmal nocturnal hemoglobinuria

Background: Evaluation of the expression of glycosylphosphatidylinositol‐anchored membrane proteins (GPI‐AP) is currently used for the diagnosis of paroxysmal nocturnal hemoglobinuria (PNH). In this study, we analyzed the amount of expression of a wide variety of GPI‐AP in different subsets of hematopoietic cells present in normal peripheral blood (PB), to establish their normal patterns of expression and provide a frame of reference for the definition of the best combination of GPI‐AP and PB cell subsets to be applied in the diagnosis and monitoring of PNH. Results: Our results show variable patterns of expression of different GPI‐AP in distinct subsets of normal PB cells. Combined use of CD55 and CD59 represented the most useful dual‐marker combination; however, its utility remained suboptimal for several subsets of leukocytes and for platelets. Conclusions: For some cell subsets such as the neutrophils additional useful markers could be selected from a relatively broad panel (CD16/CD24/CD55/CD59/CD66b/CD157), whereas for other cell subsets the number of useful antigens was either restricted (monocytes: CD14/CD55/CD157; B cells: CD24/CD48/CD52/CD55; CD4 + T cells: CD48/CD52/CD55; eosinophils: CD55/CD59; CD8 + T cells: CD48/CD55) or limited to a single marker (CD48 on CD56 low NK cells, CD55 on BDCA3 − dendritic cells and CD56 high NK cells, and CD59 for red cells), from all antigens analyzed. © 2006 International Society for Analytical Cytology