Identification of Unsuspected PNH-Type Cells in Flow Cytometric Immunophenotypic Analysis of Peripheral Blood and Bone Marrow

Abstract

In this report, the flow cytometric expression patterns for CD14 on monocytic cells and CD16 on granulocytic cells in peripheral blood or bone marrow specimens are illustratedfor 15 patients proven to have a paroxysmal nocturnal hemoglobinuria (PNH) phenotype by flow cytometric analysis for CD55 and CD59. The varied clinical manifestations of PNH and its rarity may make it difficult to recognize clinically. As a result, blood or bone marrow samples may be submitted for flow cytometric analysis to exclude bone marrow neoplasia or dysplasia in patients with cytopenias rather than to exclude PNH. This was true in 5 of 15 study cases. Unlike CD55 and CD59, CD14 and/or CD16 are assessed routinely in the flow cytometric analysis of blood and bone marrow samples. Recognition of abnormal patterns of CD14 and CD16 expression might permit the identification of clinically unsuspected PNH by routine flow cytometric analysis.

Detailed immunophenotypic characterization of different major and minor subsets of peripheral blood cells in patients with paroxysmal nocturnal hemoglobinuria

“…Nevertheless, independently of the unimodal versus bimodal pattern of expression, all GPI‐APs analyzed were systematically decreased in the different subsets of PNH cells compared to normal PB cells from healthy donors, except for CD16 expression on CD16 + DCs. Interestingly, on some patients, this marker was diminished rather than completely absent in PNH neutrophils, which is consistent with previous reports indicating that CD16 expression could be partially maintained among PNH cells 13,14,22,29 . A similar behavior was also found for CD66b and CD157 on neutrophils, for CD157 and CD48 on monocytes, and for CD48 and CD52 on CD4 ‐ /CD8 + and CD4 + /CD8 + T cells.…”

“…In this regard, both CD55 and CD59 have been considered as the most informative markers 10,14,17,21‐24 . This is due to the fact that both proteins are ubiquitously distributed throughout the different subsets of PB cells 10,11,22 and because their deficient expression on RBCs leads to complement‐mediated intravascular hemolysis, the most frequent clinical manifestation of the disease 10,16 . As previously done by others, 1,9,13 in this study we analyzed the pattern of expression of these and other GPI‐AP in RBCs, PLTs, neutrophils, and monocytes from PNH patients; in addition, we also determined the patterns of expression of a high number of GPI‐APs on other minor subsets of circulating lymphocytes and DCs, which have not been systematically explored, so far.…”

“…At present, flow cytometric analysis of the expression of GPI‐AP on PB cells is the preferred method for the diagnostic screening of PNH 1,13,17,21,22 . In this regard, both CD55 and CD59 have been considered as the most informative markers 10,14,17,21‐24 .…”

“…At present, flow cytometric analysis of the expression of GPI‐AP on PB cells is the preferred method for the diagnostic screening of PNH 1,13,17,21,22 . In this regard, both CD55 and CD59 have been considered as the most informative markers 10,14,17,21‐24 . This is due to the fact that both proteins are ubiquitously distributed throughout the different subsets of PB cells 10,11,22 and because their deficient expression on RBCs leads to complement‐mediated intravascular hemolysis, the most frequent clinical manifestation of the disease 10,16 .…”