Immunohistochemistry is a more sensitive marker for the detection of myeloperoxidase in acute myeloid leukemia compared with flow cytometry and cytochemistry

Abstract

Myeloperoxidase (MPO) is an unequivocal marker of myeloid differentiation which is routinely detected using cytochemistry (CC), flow cytometry (FC) and immunohistochemistry (IH). Several studies have compared the use of two of these methods, but to our knowledge none has compared all three techniques. We compared the performance of these three modalities in the detection of MPO in 158 cases of acute myeloid leukaemia (AML). Discrepancies were noted in a total of 28 cases. Of 110 cases in which all three modalities were performed, 23 cases showed discrepancies. CC was the least sensitive marker, being negative in 11 of 23 cases in the presence of positive IH and/or FC. IH was the most sensitive marker with only one case being negative in the presence of a positive result by FC and/or CC. The results highlight the necessity of employing more than one method in determining the presence of MPO and confirm the important role of IH in the diagnosis of AML particularly in cases where MPO is not detected by CC and FC.

Flow cytometry thresholds of myeloperoxidase detection to discriminate between acute lymphoblastic or myeloblastic leukaemia

“…The European Group for Immunophenotypic Characterization of Leukaemias (EGIL) has established guidelines for the immunological classification of AL with a threshold of at least 10% of blast cells stained to consider MPO positivity as for other intracellular markers such as CD3, CD79a and TdT (Bene et al , ). Several series have compared the detection of MPO by cytochemistry and FCM, using different methods to assess positivity in FCM (isotype external control or residual lymphocytes as negative internal control) with cut‐offs varying from 3 to 20% in various subtypes of acute myeloid leukaemia (AML) (Nakase et al , ; Nguyen et al , ; Peffault de Latour et al , ; Saravanan & Juneja, ) . In order to improve sensitivity, it has been proposed to lower the FCM threshold down to 3% as per cytochemistry (Peffault de Latour et al , ).…”

Comparison of Immunohistochemistry, Cytochemistry, and Flow Cytometry in AML for Myeloperoxidase Detection

“…The absence of MPO positivity by cytochemistry is a known fact in AML M-0 (\3%) and acute monocytic/monoblastic leukemia (AML-M5) [10,11]. The low sensitivity of the cytochemistry in present and other studies [7,10,11] in contrast to Peffault de Latour et al [4], Kheiri et al [5] and Nguyen et al [12] can be due to technical flaw or alteration of the MPO enzymatic activity in leukemic blasts while maintaining immunological activity [13,14]. The false negativity can be further reduced by repetition and careful analysis of the internal control.…”

“…Because of non-availability of uniform acceptable cutoffs value for IHC and FCM, present study has considered the cutoff of C3% for the IHC and C10% MPO positive blast cells for FCM as was suggested by Saravanan et al [7] and Bene et al [2] respectively. With the use of cutoff of C10% for the IHC as suggested by British task force, 1994 [8], the discrepant cases has reduced to 26 from the 28.…”

Chronic Inflammation in Response to Injury: Retention of Myeloid Cells in Injured Tissue Is Driven by Myeloid Cell Intrinsic Factors

“…However, flow cytometry cannot provide spatial information and is a less sensitive method for detection of some markers (Saravanan and Juneja, 2010), as cell cluster removal from population analyses can skew results, particularly in sclerotic tissues such as wounds (Dunphy, 2004). Therefore, we performed immunofluorescence for Gr-1 and CD31, an endothelial cell marker, to analyze their co-localization at days 2, 3, and 5, as these time points represent the height of the inflammatory phase of healing and the onset of chronic inflammation in the diabetic wound.…”