Flow cytometric monocyte repartition demonstrates overlap between chronic myelomonocytic leukaemia and myeloid neoplasms with monocytosis

Allen, Sharon; Ng, Eugene; Hahn, Uwe; Banovic, Tatjana; Ross, David M.

doi:10.1016/j.pathol.2021.12.294

Cited by 2 publications

(8 citation statements)

References 7 publications

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“…We included CD56 for its well‐known upregulation in myeloid malignancies and recognized diagnostic value. Despite being recommended to exclude NK cells (Ziegler‐Heitbrock et al, 2010), CD56 was not used for this purpose precisely because monocytes can be CD56‐positive (Allen et al, 2022). Although expression of CD56 in monocytes occurs in MO1 and therefore could be used to exclude NK cells out of the MO3 gate, this process seems more cumbersome and error‐prone than using CD2 to exclude most NK cells and then use specific monocyte markers for positive gating.…”

Section: Resultsmentioning

confidence: 99%

“…This is in line with previous evidence (Zawada et al, 2015). The apparent substantial overlap in MO2 and MO3 when using the CD14‐vs‐CD16 dot plot (Thomas et al, 2017) and the notion that this test involves splitting a biological continuum (Mair & Liechti, 2021; Ziegler‐Heitbrock et al, 2010) may explain the controversial diagnostic value of %MO3 (Allen et al, 2022; Calvo et al, 2020; Hudson et al, 2018; Pophali et al, 2019; Tarfi et al, 2020). This latter idea is further supported by the large variation coefficient between strategies in the first part of the study.…”

Section: Discussionmentioning

confidence: 99%

“…This landmark publication established that the accumulation of classical monocytes (MO1, CD14++/CD16-, >94%) in peripheral blood (PB) had a sensitivity of 0.9-0.92 and specificity of 0.94-0.95 for CMML. Subsequent publications have largely but not uniformly supported these results (Allen et al, 2022;Calvo et al, 2020;Hudson et al, 2018;Murali et al, 2021;Pophali et al, 2019). A possible cause of these discrepancies is the strategy used to gate monocytes, which varies widely.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of monocyte gating to quantify monocyte subsets for the diagnosis of chronic myelomonocytic leukemia

Jurado

Huguet

Xicoy

et al. 2022

Cytometry Part B Clinical

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BackgroundThe presence of >94% classical monocytes (MO1, CD14++/CD16‐) in peripheral blood (PB) has an excellent performance for the diagnosis of chronic myelomonocytic leukemia (CMML). However, the monocyte gating strategy is not well defined. The objective of the study was to compare monocyte gating strategies and propose an optimal one.MethodsThis is a prospective, single center study assessing monocyte subsets in PB. First, we compared monocyte subsets using 13 monocyte gating strategies in 10 samples. Then we developed our own 10 color tube and tested it on 124 patients (normal white blood cell counts, reactive monocytosis, CMML and a spectrum of other myeloid malignancies). Both conventional and computational (FlowSOM) analyses were used.ResultsComparing different monocyte gating strategies, small but significant differences in %MO1 and percentually large differences in %MO3 (nonclassical monocytes) were found, suggesting that the monocyte gating strategy can impact monocyte subset quantification. Then, we designed a 10‐color tube for this purpose (CD45/CD33/CD14/CD16/CD64/CD86/CD300/CD2/CD66c/CD56) and applied it to 124 patients. This tube allowed proper monocyte gating even in highly abnormal PB. Computational analysis found a higher %MO1 and lower %MO3 compared to conventional analysis. However, differences between conventional and computational analysis in both MO1 and MO3 were globally consistent and only minimal differences were observed when comparing the ranking of patients according to %MO1 or %MO3 obtained with the conventional versus the computational approach.ConclusionsThe choice of monocyte gating strategy appears relevant for the monocyte subset distribution test. Our 10‐color proposal allowed satisfactory monocyte gating even in highly abnormal PB. Computational analysis seems promising to increase reproducibility in monocyte subset quantification.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optimization of monocyte gating to quantify monocyte subsets for the diagnosis of chronic myelomonocytic leukemia

Jurado

Huguet

Xicoy

et al. 2022

Cytometry Part B Clinical

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“…As monocyte subset maturation primarily occurs in the peripheral circulation (Patel et al, 2017), the partitioning of monocyte populations was developed for blood analysis purposes. However, a limited number of studies have explored its application on bone marrow samples (Allen et al, 2022;Hudson et al, 2018;Wagner-Ballon et al, 2023).…”

Section: Feasibility On Bone Marrow Samplesmentioning

confidence: 99%

“…The primary challenge in the analysis of marrow samples lies in the precise gating of cMo, as monocyte progenitors, which appear as CD14 low cells on the CD14/CD16 histogram, should be encompassed within the overall monocyte population. Failure to do so, as observed in the participating centers during ELN multicenter study (Wagner-Ballon et al, 2023), may result in a slight underestimation of the cMo percentage, potentially accounting for the lower threshold values established by other teams (Allen et al, 2022;Hudson et al, 2018). However, a specific entity called "oligomonocytic CMML" (OM-CMML), defined by an absolute monocyte count of 0.5-1 Â 10 9 L À1 and ≥10% peripheral blood monocytes, has been described over the past years and considered as an early phase of a "dysplastic type" CMML (Geyer et al, 2017).…”

Section: Feasibility On Bone Marrow Samplesmentioning

confidence: 99%

Technical, gating and interpretation recommendations for the partitioning of circulating monocyte subsets assessed by flow cytometry

Tarfi,

Kern,

Goulas

et al. 2024

Cytometry Part B Clinical

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The monocyte subset partitioning by flow cytometry, known as “monocyte assay,” is now integrated into the new classifications as a supporting criterion for CMML diagnosis, if a relative accumulation of classical monocytes above 94% of total circulating monocytes is observed. Here we provide clinical flow cytometry laboratories with technical support adapted for the most commonly used cytometers. Step‐by‐step explanations of the gating strategy developed on whole peripheral blood are presented while underlining the most common difficulties. In a second part, interpretation recommendations of circulating monocyte partitioning from the dedicated French working group “CytHem‐LMMC” are shared as well as the main pitfalls, including false positive and false negative cases. The particular flow‐defined inflammatory profile is described and the usefulness of the nonclassical monocyte specific marker, namely slan, highlighted. Examples of reporting to the physician with frequent situations encountered when using the monocyte assay are also presented.

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Flow cytometric monocyte repartition demonstrates overlap between chronic myelomonocytic leukaemia and myeloid neoplasms with monocytosis

Cited by 2 publications

References 7 publications

Optimization of monocyte gating to quantify monocyte subsets for the diagnosis of chronic myelomonocytic leukemia

Optimization of monocyte gating to quantify monocyte subsets for the diagnosis of chronic myelomonocytic leukemia

Technical, gating and interpretation recommendations for the partitioning of circulating monocyte subsets assessed by flow cytometry

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