Application of immunophenotypic analysis in distinguishing chronic myelomonocytic leukemia from reactive monocytosis

Abstract

Objectives The purpose of this study was to determine whether immunophenotypic profiles detected by flow cytometry are useful in differentiating chronic myelomonocytic leukemia (CMML) from reactive monocytosis, and between CMML subtypes. Methods Eight‐color flow cytometry was used to immunophenotype blasts, monocytes, and granulocytes in the bone marrow of 34 patients with CMML and 12 patients with reactive monocytosis. Results Bone marrow myeloblast, promonocyte, and monocyte counts by flow cytometry were significantly higher in the CMML group than in the reactive monocytosis group. Myeloblast aberrancies were present in all CMML patients as compared with 2 of 12 (16.7%) reactive monocytosis patients (P < 0.001). The number of blast aberrancies ranged from one to nine (median, four) in CMML patients and 94.1% of CMML cases exhibited ≥ two aberrancies. In contrast, two reactive monocytosis cases showed only one phenotypic abnormality of blasts. Monocyte and granulocyte aberrancies were present in 26 of 34 (76.5%) and in 31 of 34 (91.2%) CMML patients, respectively. Decreased side scatter (SSC) and abnormal CD11b/CD13/CD16 maturation pattern in granulocytes were more frequent in CMML than in reactive monocytosis. No significant differences in antigen expression were detected between the CMML subtypes except that altered CD45/SSC pattern on the blasts was more commonly observed in CMML‐0/1 than in CMML‐2. Conclusions CMML has phenotypic aberrancies in monocytes, granulocytes, and more frequently in myeloblasts. Aberrant expression of two or more antigens in myeloblasts by flow cytometry has a high sensitivity (94.1%) and a high specificity (100%) to differentiate CMML from reactive monocytosis. © 2018 International Clinical Cytometry Society

Exploring blast composition in myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms: CD45RA and CD371 improve diagnostic value of flow cytometry through assessment of myeloblast heterogeneity and stem cell aberrancy

“…MDS and MDS/MPN cases showed higher intensity CD117 expression and lower intensity CD38, as compared to Non‐MDS cases. Bright CD117 expression on myeloblasts appeared highly specific for myelodysplasia, with positivity in 12/23 MDS, and 7/8 MDS/MPN and none of the 21 Non‐MDS cases, in line with a number of previous publications (De Smet et al, 2012 ; Feng et al, 2018 ; Matarraz et al, 2008 ; Ogata et al, 2006 ; Stachurski et al, 2008 ). Comparison of lower‐risk MDS (very low/low IPSS‐R scores) to higher‐risk MDS (intermediate/high/very high IPSS‐R scores) showed no statistically significant difference in the intensity of CD117 expression (MFI of 504 ± 225 in lower‐risk versus 589 ± 358 in higher‐risk, p = 0.7074), suggesting that this marker is useful irrespective of the risk score.…”

“…These abnormalities include myeloblast percentage, frequency of stage‐1 hematogones, myeloblast heterogeneity, and stem cell and myeloblast immunophenotypic aberrancies. Changes in frequency of myeloblasts and hematogones and immunophenotypic aberrancies of myeloblasts have been extensively studied in previous publications (Chen et al, 2020 ; De Smet et al, 2012 ; Della Porta et al, 2012 ; Feng et al, 2018 ; Goardon et al, 2009 ; Kern et al, 2010 ; Kussick et al, 2005 ; Maftoun‐Banankhah et al, 2008 ; Matarraz et al, 2008 ; Ogata et al, 2006 ; Porwit et al, 2014 ; Schenkel et al, 2019 ; Stachurski et al, 2008 ; van de Loosdrecht et al, 2008 ), whereas limited information is available on abnormal blast heterogeneity, changes in relative composition of myeloid progenitors, and frequency of stem cell abnormalities in MDS (Jevremovic et al, 2014 ; Ostendorf et al, 2018 ; Schenkel et al, 2019 ; Toft‐Petersen et al, 2016 ; Will et al, 2012 ). All parameters measured by this approach are quantitative, eliminating the need for extensive expertise in interpretation.…”

“…FCIP analysis of blasts is an ideal target for diagnosis of myelodysplasia for a number of reasons: (1) MDS and MDS/MPN are clonal stem cell disorders and blasts are expected to be affected in almost all cases; (2) Both frequency and immunophenotypic aberrancies of blasts can be evaluated by flow cytometry; (3) Blasts immunophenotype is likely more stable than maturing myelomonocytic elements (of which immunophenotype and granularity index can be affected by storage time, fixation, marrow regeneration, granulocyte colony stimulating factor [G‐CSF] therapy or hemodilution [Alhan et al, 2016 ; Chen et al, 2019a ; Shi et al, 2017 ; Stachurski et al, 2008 ]); (4) Blast and stem cell aberrancies, as compared to aberrancies of maturing myelomonocytic elements, are expected to have higher specificity for diagnosis of myelodysplasia (Behbehani et al, 2020 ; Feng et al, 2018 ; Kern et al, 2010 ; Stachurski et al, 2008 ). Aberrancies of the blast fraction include increased frequency of myeloblasts (CD34 ++ CD117 + precursors), decreased frequency of stage‐1 hematogones (CD34 + CD19 + CD10 + precursors), abnormal intensity of markers normally expressed on myeloblasts (CD45, CD117, CD13, CD33, CD38, and HLA‐DR), asynchronous expression of markers associated with maturity (CD11b and CD15), and expression of lineage infidelity markers (CD5, CD7, CD19 and CD56) (Chen et al, 2019a , 2020 ; De Smet et al, 2012 ; Della Porta et al, 2012 ; Feng et al, 2018 ; Goardon et al, 2009 ; Kern et al, 2010 ; Kussick et al, 2005 ; Maftoun‐Banankhah et al, 2008 ; Matarraz et al, 2008 ; Ogata et al, 2006 ; Porwit et al, 2014 ; Schenkel et al, 2019 ; Shi et al, 2017 ; Stachurski et al, 2008 ; van de Loosdrecht et al, 2008 ).…”

Reproducible measurable residual disease detection by multiparametric flow cytometry in acute myeloid leukemia

“…For other entities like MDS, the evaluation of monocytes using e.g., CD56 is part of various diagnostic scores [ 52 , 53 ]. In addition, CD56 expression has been described to distinguish clonal monocytes within CMML from reactive monocytosis [ 54 – 56 ]. These observations have led us to also analyze aberrations outside of the CD34 + CD117 + compartment.…”

Issue Highlights – November 2018

“…Unlike in most of the acute leukemia cases and in several subgroups of MDS, chronic myelomonocytic leukemia (CMML) remains a disease that may be quite difficult to diagnose since cytogenetic evidence of clonality is found in only 20% to 40% of CMML cases. In the manuscript of Feng et al the authors describe that CMML patients display phenotypic aberrancies not just in monocytes but also in granulocytes, and more frequently in myeloblasts. They found that aberrant expression of two or more antigens in myeloblasts by flow cytometry has a high sensitivity (94.1%) and a high specificity (100%) to differentiate CMML from reactive monocytosis.…”