Using Antigen Expression of Leukemic Cells for a Fast Screening of Acute Promyelocytic Leukemia by Flow Cytometry.

Vitória Ceni-Silva,Marina Pellegrini,Bruno Duarte,Irene Lorand-Metze,Konradin Metze,Gislaine Duarte,Kátia Pagnano

doi:10.3390/diagnostics11111988

Vitória Ceni-Silva, Marina Pellegrini + Show 5 more

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https://doi.org/10.3390/diagnostics11111988

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Abstract

(1) Background: Acute promyelocytic leukemia is curable, but bleeding complications still provoke a high early mortality. Therefore, a fast diagnosis is needed for timely starting treatment. We developed a diagnostic algorithm using flow cytometric features for discrimination between acute promyelocytic leukemia (APL) and other types of acute myeloid leukemias (AML). (2) Methods: we analyzed newly diagnosed AMLs where immunophenotyping was performed at diagnosis by an 8-color protocol. The mean fluorescence intensity (MFI) of each antigen used was assessed, and those best separating APL from other types of AML were obtained by a discriminant analysis. Phenotypic characteristics of myeloblasts of normal bone marrow were used as controls. (3) Results: 24 cases of APL and 56 cases of other primary AMLs entered the study. Among non-APL AMLs, 4 had fms-related tyrosine kinase 3 gene internal tandem duplications (FLT3-ITD) mutation, 2 had nucleophosmin (NPM1) and 10 had both mutations. SSC (p < 0.0001), HLA-DR (p < 0.0001), CD13 (p = 0.001), CD64 (p = 0.004) and CD33 (p = 0.002) were differentially expressed, but this was not the case for CD34 (50% of non-APLs had a low expression). In the discriminant analysis, the best differentiation was achieved with SSC and HLA-DR discriminating 91.25% of the patients. (4) Conclusion: MFC could differentiate APL from non-APL AML in the majority of the cases.

Highlights

The diagnostic work-up of acute myeloid leukemia (AML) is an integrated process using cytology, immunophenotyping, cytogenetics as well as the search for specific mutations, as several subtypes are defined by cytogenetic and molecular features in the WHO 2016 classification [1,2,3]. This is especially true for acute promyelocytic leukemia (APL), a subtype of AML defined genetically by the translocation t(15;17) and the promyelocytic leukemia–retinoic acid receptor α (PML-RARA)
APL is highly curable if appropriate therapy based on all-trans retinoic acid (ATRA) is timely started, preventing bleeding due to a consumption coagulopathy, which is responsible for a high early mortality rate [4,5]
Our aim was to develop a diagnostic algorithm based on the expression intensity of several antigens examined by multiparametric flow cytometry (MFC) that depends only on internal standardization and could be performed with several antibody combinations and software of analysis, but could reliably discriminate between APL and other types of AML

Summary

Introduction

The diagnostic work-up of acute myeloid leukemia (AML) is an integrated process using cytology, immunophenotyping, cytogenetics as well as the search for specific mutations, as several subtypes are defined by cytogenetic and molecular features in the WHO 2016 classification [1,2,3]. This is especially true for acute promyelocytic leukemia (APL), a subtype of AML defined genetically by the translocation t(15;17) and the promyelocytic leukemia–retinoic acid receptor α (PML-RARA). Most of the times, the first screening is made by cytology and immunophenotyping in many institutions, since the results of cytogenetics and molecular tests are not immediately available

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