Myeloperoxidase Detection by Three-Color Flow Cytometry and by Enzyme Cytochemistry in the Classification of Acute Leukemia

Abstract

A b s t r a c t In the classification of acute leukemia, the presence of myeloperoxidase (MPO) within the leukemic blasts indicates myeloid leukemia. Previous studies compared enzyme cytochemistry (EC) or flow cytometry (FC) with immunocytochemistry in detecting MPO

Comparison of flow cytometry and enzyme cytochemistry for the detection of myeloperoxydase in acute myeloid leukaemia: interests of a new positivity threshold

“…FC has, therefore, gained an important position in the classification of AML (Foon & Todd, 1986; Bene et al , 1998; Borowitz et al , 1993), although the methods for this analysis have not been completely standardized, and data directly comparing EC and FC are surprisingly rare. Indeed, previous studies suggest that FC may be more sensitive than routine EC in detecting MPO in AML, but these results were obtained on very small groups of AML patients [26 patients in Nguyen et al (1998) and 47 patients in Kheiri et al (1998), including 38 AML and nine biphenotypic leukaemias]. These two studies compared the performances of FC and EC based on the analysis of only a few patients of each AML subtype, type 6 and 7 being totally absent.…”

“…This means that, surprisingly enough, using the current recommendations, FC was less sensitive than EC in detecting the myeloid lineage of adult acute leukaemias. Unfortunately, Nguyen et al (1998) and Kheiri et al (1998) who had reported a better sensitivity of FC over EC did not provide the MPO‐positive thresholds they used in their techniques. In the light of these results, we think that a cut‐off point set to a minimum of 10% of blast cells in the detection of MPO in FC (following the EGIL) yields an unacceptable number of false‐negative patients, which is worrying for a technique that is claimed to be the method of choice.…”

“…A few years ago, the European Group for Immunological Characterization of Leukaemia (EGIL) established guidelines for the classification of leukaemias using flow cytometry (FC), which required a minimum of 10% of the blast cells to be MPO reactive in order to establish their myeloid origin (Bene et al , 1995). To our knowledge, there are limited data in the recent literature comparing the detection of MPO by EC and FC (Kheiri et al , 1998; Nguyen et al , 1998) and the clinical relevance of these two suggested thresholds has not been assessed. We initially had two goals: to confirm FC superiority in the detection of MPO, and to assess what sensibly could be gained by lowering the FC positivity threshold from 10% to 3%.…”

Flow cytometric analysis of cell‐surface and intracellular antigens in the diagnosis of acute leukemia

“…When combined with immunophenotype, this also provides valuable insights about the cellular origin of AL, as was the case in a patient with ALL with a CD2/CD19 immunophenotype in whom double positive cytoplasmic Ag expression strongly suggested a probable common lymphoid precursor as the origin of these cells [41,42]. Recent reports have demonstrated better sensitivity using immunologic than cytochemical methods and similar or better sensitivity using FC methods, than with immunoenzymatic or cytochemistry methods (antialkaline phosphatase linked to alkaline phosphatase), to detect MPO and proforms of MPO in the cytoplasm of CD34+ hematopoietic progenitors [43][44][45][46][47][48]. In congruence with a previous report that demonstrated cyMPO in virtually all cases of AML [13], in the present study we also found cyMPO expression in all our cases of AML.…”

Flowcytometric comparative analysis in acute leukemias between Indian and proposed minimal screening panel

“…5,[22][23][24] In our study, we found cMPO expression in 91.11% of the cases without any aberrance. However, cMPO was found negative in two AML M0 cases, one case of AML M6 and one case of acute Note: U* -unclassified.…”