Manivannan Prabhu, Puri Vandana, Somasundaram Venkatesan, Purohit Abhishek, Sharma Rahul Kumar, Dabas Mandeep, Saxena Renu
a Department of Hematology All India Institute of Medical Sciences , New Delhi , India.
Hematology. 2015 Sep;20(8):455-461. doi: 10.1179/1607845414Y.0000000223. Epub 2014 Dec 23.
Objectives 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. Methods 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). Results 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. Discussion 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. Conclusion 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.
目的 根据世界卫生组织（WHO）2008年分类，通过酶细胞化学法（cMPO）或流式细胞术（fMPO）检测髓过氧化物酶（MPO）在急性白血病（AL）诊断中起主要作用。虽然推荐3%的cMPO为阳性，但WHO未提及fMPO的具体临界值。不同作者推荐的fMPO临界值范围为3%至28%。本研究的目的是分析3%至10%的fMPO临界值在AL分类中的情况，并评估是否可以提出新的临界值。方法 对216例AL病例进行回顾性分析，分析其fMPO范围为3%至10%，并与金标准进行比较。将cMPO（≥3%）的存在和/或在不存在CD19和CD3的情况下两种或更多种泛髓系标志物（CD13、CD33和CD117）的表达作为急性髓系白血病（AML）诊断的金标准。结果 将AL分类为AML/混合表型急性白血病（MPAL）时，3%、5.4%和10%临界值下的敏感性分别为98.3%、98.3%和96.6%，而此临界值下的特异性分别为22.2%、91%和71%。讨论 在这方面，仅有少数研究为准确分类急性白血病确定fMPO的一致临界值。这是迄今为止在这方面最大且为数不多的研究之一。结论 我们的研究得出fMPO的新临界值（5.4%），其对将AL病例准确分类为急性淋巴细胞白血病、AML和MPAL具有最佳的敏感性和特异性。
