Can threshold for MPO by flow cytometry be reduced in classifying acute leukaemia? A comparison of flow cytometric and cytochemical myeloperoxidase using different flow cytometric cut-offs. Issue 8 (September 2015)

• Record Type: Journal Article
• Authors: Manivannan, Prabhu; Puri, Vandana; Somasundaram, Venkatesan; Purohit, Abhishek; Sharma, Rahul Kumar; Dabas, Mandeep; Saxena, Renu
• Is Part Of: Hematology. Volume 20:Issue 8(2015)
• Page Start: 455
• Page End: 461
• Publication Date: 2015-09
• Subjects: Blood -- Diseases -- Periodicals; Hematology -- Periodicals; Blood -- Transfusion -- Periodicals; 616.15005
• DOI: 10.1179/1607845414Y.0000000223
• Languages: German
• ISSNs: 1024-5332

Abstract

<abstract> <title> <x content-type="archive" xml:space="preserve">Abstract</x> </title> <sec> <title>Objectives</title> <p>Myeloperoxidase (MPO) detection either by enzyme cytochemistry (cMPO) or flow cytometry (fMPO) plays a major role in acute leukaemia (AL) diagnosis as per World Health Organization (WHO) 2008 classification. Although 3% cMPO was recommended as positivity, no specific cut-off had been mentioned by WHO for fMPO. Various authors recommend different cut-offs ranging from 3 to 28% for fMPO. The aim of this study was to analyse fMPO cut-offs ranging from 3 to 10% in classifying AL and to assess whether a new cut-off could be suggested.</p> </sec> <sec> <title>Methods</title> <p>Totally, 216 cases of AL were retrospectively analysed for fMPO ranging from 3 to 10% and compared with gold standard. Presence of cMPO (≥3%) and/or expression of two or more pan-myeloid markers (CD13, CD33, and CD117) in the absence of CD19 and CD3 were kept as gold standard for diagnosis of acute myeloid leukaemia (AML).</p> </sec> <sec> <title>Results</title> <p>Sensitivities for classifying AL as AML/mixed phenotypic acute leukaemia (MPAL) at 3, 5.4, and 10% were 98.3, 98.3, and 96.6%, respectively, whereas specificities at this cut-off were 22.2, 91, and 71%, respectively.</p> </sec> <sec> <title>Discussion</title> <p>Only few studies have been done in this aspect to define a consistent cut-off for fMPO for proper classification of acute leukaemias. This was one of the largest and few studies available till date in this regard.</p> </sec> <sec> <title>Conclusion</title> <p>The newer cut-off for fMPO (5.4%) emerged out from our study with best sensitivity and specificity for accurately classifying AL cases into acute lymphoblastic leukaemia, AML, and MPAL.</p> </sec> </abstract>