Detection of dysplasia in peripheral blood: Proposal of an algorithm to detect myelodysplastic syndromes and chronic myelomonocytic leukemias on a high-speed technical platform using the Sysmex XN™ analyser

INTRODUCTION

Chronic Myelomonocytic Leukemia (CMML) and Myelodysplastic Syndromes (MDS) are increasingly represented in the general population. We propose a screening strategy based on algorithms calculated from quantitative and analytical data from the XN analyser.

MATERIALS AND METHODS

We tested the performance of previously published MDS and CMML scores on an evaluation cohort of 749 individual eligible patients over 50 years of age. These patients were classified into 3 groups as follows: 713 patients without MDS or CMML, 18 patients with MDS, and finally 18 patients with CMML. In a second step, a routine cohort of 37 828 samples was studied to evaluate the impact of this approach.

RESULTS

The concordance rate between cytology and the two scores is 92.1%. The sensitivity and specificity of the CMML score are 100% and 96.2%, respectively. For the MDS score, they are 83.3% and 89.6% respectively. The ratio of platelets measured by fluorescence on board (PLT-F) as reflex tests generated is 1.5% after 6 months. The additional smear ratio for suspected MDS is calculated at 0.6%.

CONCLUSION

We propose a flowchart using embedded artificial intelligence to help the cytologist in an optimized smear review and thus improve guidance to the clinician and the patients in the diagnosis process. This strategy permits a more comprehensive approach to MDS and CMML detection fitting with the new definition of CMML according to the recommendations of the World Health Organization (WHO) published in 2022.

Validation of the Artificial Intelligence Prognostic Scoring System for Myelodysplastic Syndromes in chronic myelomonocytic leukaemia: A novel approach for improved risk stratification

Chronic myelomonocytic leukaemia (CMML) is a rare haematological disorder characterized by monocytosis and dysplastic changes in myeloid cell lineages. Accurate risk stratification is essential for guiding treatment decisions and assessing prognosis. This study aimed to validate the Artificial Intelligence Prognostic Scoring System for Myelodysplastic Syndromes (AIPSS-MDS) in CMML and to assess its performance compared with traditional scores using data from a Spanish registry (n = 1343) and a Taiwanese hospital (n = 75). In the Spanish cohort, the AIPSS-MDS accurately predicted overall survival (OS) and leukaemia-free survival (LFS), outperforming the Revised-IPSS score. Similarly, in the Taiwanese cohort, the AIPSS-MDS demonstrated accurate predictions for OS and LFS, showing superiority over the IPSS score and performing better than the CPSS and molecular CPSS scores in differentiating patient outcomes. The consistent performance of the AIPSS-MDS across both cohorts highlights its generalizability. Its adoption as a valuable tool for personalized treatment decision-making in CMML enables clinicians to identify high-risk patients who may benefit from different therapeutic interventions. Future studies should explore the integration of genetic information into the AIPSS-MDS to further refine risk stratification in CMML and improve patient outcomes.

Comparing malignant monocytosis across the updated WHO and ICC classifications of 2022

ABSTRACT

The World Health Organization (WHO) classification of hematolymphoid tumors and the International Consensus Classification (ICC) of 2022 introduced major changes to the definition of chronic myelomonocytic leukemia (CMML). To assess its qualitative and quantitative implications for patient care, we started with 3311 established CMML cases (according to WHO 2017 criteria) and included 2130 oligomonocytosis cases fulfilling the new CMML diagnostic criteria. Applying both 2022 classification systems, 356 and 241 of oligomonocytosis cases were newly classified as myelodysplastic (MD)-CMML (WHO and ICC 2022, respectively), most of which were diagnosed as myelodysplastic syndrome (MDS) according to the WHO 2017 classification. Importantly, 1.5 times more oligomonocytosis cases were classified as CMML according to WHO 2022 than based on ICC, because of different diagnostic criteria. Genetic analyses of the newly classified CMML cases showed a distinct mutational profile with strong enrichment of MDS-typical alterations, resulting in a transcriptional subgroup separated from established MD and myeloproliferative CMML. Despite a different cytogenetic, molecular, immunophenotypic, and transcriptional landscape, no differences in overall survival were found between newly classified and established MD-CMML cases. To the best of our knowledge, this study represents the most comprehensive analysis of routine CMML cases to date, both in terms of clinical characterization and transcriptomic analysis, placing newly classified CMML cases on a disease continuum between MDS and previously established CMML.

MDS/CMML from resource-limited region: Characteristics and comparison to tertiary reference European center

INTRODUCTION

Myelodysplastic Syndromes (MDS) and Chronic Myelomonocytic Leukemia (CMML) are clonal myeloid malignancies, characterized by bone marrow failure leading to cytopenias (and possible myeloproliferation for CMML) and a high propensity to evolve to Acute Myeloid Leukemia (AML).

OBJECTIVE AND METHODS

The aim of our retrospective study was to evaluate the clinical and hematological features; the prevalence of MDS subtypes, R-IPSS, and the outcome of 106 Armenian MDS/CMML patients diagnosed over the 2008-2020 period in a single Armenian Hematology center and compare them to French MDS patients included in the GFM registry.

RESULTS

Median age in the Armenian cohort was 64 years (range 19-84) and 55% were males. The main MDS subtypes were MDS-MLD (29.2%) and MDS-SLD (27.3%), the least frequent was del 5q (0.9%). By comparison, a higher prevalence of MDS-MLD, MDS-EB2, and MDS-RS was found in the French cohort. Armenian patients' cohort generally had poor access to standard MDS treatment and 42.3% of the patients were transfusion dependent. Overall survival, however, did not significantly differ between Armenian and French cohorts.

CONCLUSION

Our study stresses issues regarding epidemiology, access to diagnosis, difficulties of risk stratification, and access to treatment.

[MDS & CMML: Diagnostic and classification]

In 2023, a diagnosis process of myelodysplastic syndrome (MDS) or chronic myelomonocytic leukemia (CMML) is mainly based on morphological results obtained on bone marrow and blood smears which could be completed by cytogenetical analyses. Due to recent finding, flow cytometry data are recognized as useful for the diagnosis of CMML especially. Actual classifications and prognostic scoring systems have changed and nowadays include results of high-throughput sequencing approaches in addition to cytogenetical results. All together, these data allow the medical world to correctly evaluate the prognosis of these patients and to provide some information for targeted therapies. This chapter will provide the most important modifications recently published in the field of diagnosis and prognosis of MDS and CMML.

Real world implementation of flow cytometric monocyte subset partitioning for distinguishing chronic myelomonocytic leukaemia from other causes of monocytosis

Monocyte subset partitioning by flow cytometry may be a useful tool in distinguishing chronic myelomonocytic leukaemia (CMML) from other causes of monocytosis, however there has been varying success in real world implementation. Additionally, current assays require an individual tube for analysis despite significant overlap in antibodies used in routine T and NK cell analysis. The objective of this study was to validate a flow cytometry assay for the enumeration of monocyte subsets in our community-based laboratory and compare this to a hybrid panel allowing analysis of monocytes, T cells and NK cells in a single tube. Monocyte subset analysis was performed on peripheral blood samples of patients with monocytosis at the time of bone marrow biopsy or transient monocytosis in the setting of bacteraemia. Cut-offs of >94% classical and <1.13% non-classical monocytes for distinguishing CMML were assessed. Classical monocytes were significantly higher, and non-classical monocytes significantly lower in CMML compared to other causes of monocytosis. The sensitivity and specificity of >94% classical monocytes were 73% [95% confidence interval (CI) 43-90%] and 89% (95% CI 75-96%) regardless of which panel was used. Non-classical monocytes of <1.13% had a sensitivity and specificity of 82% (95% CI 52-97%) and 83% (95% CI 68-92%) with the monocyte panel and 55% (95% CI 28-78%) and 89% (95% CI 75-96%) using the hybrid panel. We have found the estimation of the classical monocyte subset to be the most robust and repeatable variation of this assay with sensitivity and specificity that is clinically useful. A hybrid panel may provide an effective approach to implementing monocyte subsets into practice.

Cutaneous involvement in Ph-negative myeloproliferative neoplasms: from extramedullary hematopoiesis to myeloid metastasis with histiocytic differentiation. A systematic review of the literature

Myeloid neoplasms may metastasize to the skin, presenting a wide range of clinical-pathological features that often lead to a reduction in patients' survival. The presentation varies depending on the category of myeloid neoplasm and its prognostic significance. The literature has specifically focused on the features of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), and chronic myelomonocytic leukemia (CMML). In this article, we aimed to uncover the peculiarities of clonal skin proliferations in the course of Ph-negative myeloproliferative neoplasms (MPNs). We conducted a systematic review and statistical analysis of the literature data. MPN patients mainly exhibited cutaneous extramedullary hematopoiesis, while a minority displayed cutaneous histiocytic lesions. Furthermore, these patients showed lower survival rates compared to the median survival of MPN patients, especially when calculating survival from the appearance of cutaneous lesions. Our work highlights, for the first time, the prognostic relevance and histological heterogeneity of cutaneous lesions in MPN. Moreover, it emphasizes the importance of dermatological and histological examinations when cutaneous lesions are present.

CSF3R-mutant chronic myelomonocytic leukemia is a distinct clinically subset with abysmal prognosis: a case report and systematic review of the literature

Chronic myelomonocytic leukemia (CMML) is a myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) chacaterized by persistent peripheral blood monocytosis, hypercellular bone marrow and dysplasia at least in one myeloid lineage. CMML shares much of its molecular landscape with other myeloid neoplasms, while differs from others such as chronic neutrophilic leukemia (CNL), given the high frequency of CSF3R mutations in the latter. In this article, we report a case of CSF3R-mutated CMML and dissect this rare entity by reviewing the medical literature, with the intent to understand how this rare mutation shapes CMML's clinical and morphological phenotype. CSF3R-mutated CMML emerges as a rare entity meeting the ICC/WHO diagnostic criteria for CMML and simultaneously showing clinical-pathological and molecular traits of CNL and atypical chronic myeloid leukemia, rising an important and difficult diagnostic and therapeutical issue.

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

BACKGROUND

The 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.

METHODS

This 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.

RESULTS

Comparing 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.

CONCLUSIONS

The 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.

A three-gene leukaemic stem cell signature score is robustly prognostic in chronic myelomonocytic leukaemia

Leukaemic stem cell (LSC) gene expression has recently been linked to prognosis in patients with acute myeloid leukaemia (17-gene LSC score, LSC-17) and myelodysplastic syndromes. Although chronic myelomonocytic leukaemia (CMML) is regarded as a stem cell disorder, the clinical and biological impact of LSCs on CMML patients remains elusive. Making use of multiple independent validation cohorts, we here describe a concise three-gene expression signature (LSC-3, derived from the LSC-17 score) as an independent and robust prognostic factor for leukaemia-free and overall survival in CMML. We propose that LSC-3 could be used to supplement existing risk stratification systems, to improve prognostic performance and guide management decisions.

Atypical chronic myeloid leukemia and myelodysplastic/myeloproliferative neoplasm, not otherwise specified: 2023 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Atypical chronic myeloid leukemia (aCML) and myelodysplastic/myeloproliferative (MDS/MPN) neoplasms, not otherwise specified (NOS), are MDS/MPN overlap neoplasms characterized by leukocytosis, in the absence of monocytosis and eosinophilia, with <20% blasts in the blood and bone marrow.

DIAGNOSIS

aCML, previously known as aCML, BCR::ABL1 negative, was renamed as aCML by the ICC classification, and as MDS/MPN with neutrophilia by the 5th edition of the WHO classification. This entity is characterized by dysplastic neutrophilia with immature myeloid cells comprising ≥10% of the white blood cell count, with prominent dysgranulopoiesis. MDS/MPN-NOS consists of MDS/MPN overlap neoplasms not meeting criteria for defined categories such as chronic myelomonocytic leukemia (CMML), MDS/MPN-ring sideroblasts-thrombocytosis (MDS/MPN-RS-T), and aCML.

MUTATIONS AND KARYOTYPE

Cytogenetic abnormalities are seen in 40-50% of patients in both categories. In aCML, somatic mutations commonly encountered include ASXL1, SETBP1, ETNK1, and EZH2 whereas MDS/MPN-NOS can be further stratified by mutational profiles into CMML-like, MDS/MPN-RS-T-like, aCML-like, TP35-mutated, and "others", respectively.

RISK STRATIFICATION

The Mayo Clinic aCML model stratifies patients based on age >67 years, hemoglobin <10 g/dl, and the presence of TET2 mutations into low-risk (0-1 points) and high-risk (>2 points) groups, with median survivals of 18 and 7 months, respectively. MDS/MPN-NOS patients have traditionally been risk stratified using MDS risk models such as IPSS and IPSS-R.

TREATMENT

Leukocytosis and anemia are managed like lower risk MPN and MDS. DNMT inhibitors have been used in both entities with suboptimal response rates. Allogeneic stem cell transplant remains the only curative strategy but is associated with high morbidity and mortality.

Erythroid side scatter: A parameter that improves diagnostic accuracy of flow cytometry myelodysplastic syndrome scoring

BACKGROUND

Flow cytometry immunophenotyping (FCM) is a benchmark test for integrated diagnosis of myelodysplastic syndromes (MDS). Our department's FCM-MDS-score follows international guidelines and additionally includes the maturing erythroid (mEry) side scatter (SSC)/lymphocyte SSC ratio (mErySSCr), often increased in MDS patients. A recent exploratory computational flow analysis study highlighted mErySSC as the top feature for separating MDS from non-MDS. Thus, we sought to systematically evaluate the diagnostic accuracy of mErySSCr in conventional diagnostic FCM as used currently in-house.

METHODS

Historical MDS (n = 93), chronic myelomonocytic leukemia (CMML; n = 27) and non-neoplastic cytopenia (n = 57) cohorts were created. Differences between these cohorts and LG-MDS entities were mapped and the mErySSCr cut-off was refined. Prospective bone marrows (n = 213) received for marrow failure work-up were used to determine the sensitivity and specificity of mErySSCr, both as a sole parameter and as a component of the MDS-score.

RESULTS

Low-grade (LG)-MDS mErySSCr differed more prominently from controls (p = <0.0001) than high-grade (HG)-MDS (p = 0.024). CMML and controls had a similar mErySSCr. As sole parameter, mErySSCr specificity was 91.1% (n = 112 non-MDS diagnoses) and sensitivity was 36% for LG-MDS (n = 36) and 25% for new HG-MDS diagnoses (n = 16). The specificity of the MDS-score was similar if mErySSCr was omitted (81.3% with and 82.1% without). The MDS-score sensitivity for new HG-MDS diagnoses and CMML (n = 17) was 100%, and was not affected by mErySSCr. The score sensitivity for LG-MDS however, dropped from 86.1% to 72.2% when mErySSCr was excluded.

CONCLUSION

mErySSCr increases the diagnostic accuracy of flow-based MDS scoring in our setting, particularly for LG-MDS.

ELN iMDS flow working group validation of the monocyte assay for chronic myelomonocytic leukemia diagnosis by flow cytometry

BACKGROUND

It was proposed that peripheral blood (PB) monocyte profiles evaluated by flow cytometry, called "monocyte assay," could rapidly and efficiently distinguish chronic myelomonocytic leukemia (CMML) from other causes of monocytosis by highlighting an increase in the classical monocyte (cMo) fraction above 94%. However, the robustness of this assay requires a large multicenter validation and the assessment of its feasibility on bone marrow (BM) samples, as some centers may not have access to PB.

METHODS

PB and/or BM samples from patients displaying monocytosis were assessed with the "monocyte assay" by 10 ELN iMDS Flow working group centers with harmonized protocols. The corresponding files were reanalyzed in a blind fashion and the cMo percentages obtained by both analyses were compared. Confirmed diagnoses were collected when available.

RESULTS

The comparison between cMo percentages from 267 PB files showed a good global significant correlation (r = 0.88) with no bias. Confirmed diagnoses, available for 212 patients, achieved a 94% sensitivity and an 84% specificity. Hence, 95/101 CMML patients displayed cMo ≥94% while cMo <94% was observed in 83/99 patients with reactive monocytosis and in 10/12 patients with myeloproliferative neoplasms (MPN) with monocytosis. The established Receiver Operator Curve again provided a 94% cut-off value of cMo. The 117 BM files reanalysis led to an 87% sensitivity and an 80% specificity, with excellent correlation between the 43 paired samples to PB.

CONCLUSIONS

This ELN multicenter study demonstrates the robustness of the monocyte assay with only limited variability of cMo percentages, validates the 94% cutoff value, confirms its high sensitivity and specificity in PB and finally, also confirms the possibility of its use in BM samples.

Multicenter prospective evaluation of diagnostic potential of flow cytometric aberrancies in myelodysplastic syndromes by the ELN iMDS flow working group

BACKGROUND

Myelodysplastic syndromes (MDS) represent a diagnostic challenge. This prospective multicenter study was conducted to evaluate pre-defined flow cytometric markers in the diagnostic work-up of MDS and chronic myelomonocytic leukemia (CMML).

METHODS

Thousand six hundred and eighty-two patients with suspected MDS/CMML were analyzed by both cytomorphology according to WHO 2016 criteria and flow cytometry according to ELN recommendations. Flow cytometric readout was categorized 'non-MDS' (i.e. no signs of MDS/CMML and limited signs of MDS/CMML) and 'in agreement with MDS' (i.e., in agreement with MDS/CMML).

RESULTS

Flow cytometric readout categorized 60% of patients in agreement with MDS, 28% showed limited signs of MDS and 12% had no signs of MDS. In 81% of cases flow cytometric readouts and cytomorphologic diagnosis correlated. For high-risk MDS, the level of concordance was 92%. A total of 17 immunophenotypic aberrancies were found independently related to MDS/CMML in ≥1 of the subgroups of low-risk MDS, high-risk MDS, CMML. A cut-off of ≥3 of these aberrancies resulted in 80% agreement with cytomorphology (20% cases concordantly negative, 60% positive). Moreover, >3% myeloid progenitor cells were significantly associated with MDS (286/293 such cases, 98%).

CONCLUSION

Data from this prospective multicenter study led to recognition of 17 immunophenotypic markers allowing to identify cases 'in agreement with MDS'. Moreover, data emphasizes the clinical utility of immunophenotyping in MDS diagnostics, given the high concordance between cytomorphology and the flow cytometric readout. Results from the current study challenge the application of the cytomorphologically defined cut-off of 5% blasts for flow cytometry and rather suggest a 3% cut-off for the latter.

Role of allogeneic transplantation in chronic myelomonocytic leukemia: an international collaborative analysis

To determine the survival benefit of allogeneic hematopoietic cell transplantation (allo-HCT) in chronic myelomonocytic leukemias (CMML), we assembled a retrospective cohort of CMML patients 18-70 years old diagnosed between 2000 and 2014 from an international CMML dataset (n = 730) and the EBMT registry (n = 384). The prognostic impact of allo-HCT was analyzed through univariable and multivariable time-dependent models and with a multistate model, accounting for age, sex, CMML prognostic scoring system (low or intermediate-1 grouped as lower-risk, intermediate-2 or high as higher-risk) at diagnosis, and AML transformation. In univariable analysis, lower-risk CMMLs had a 5-year overall survival (OS) of 20% with allo-HCT vs 42% without allo-HCT (P < .001). In higher-risk patients, 5-year OS was 27% with allo-HCT vs 15% without allo-HCT (P = .13). With multistate models, performing allo-HCT before AML transformation reduced OS in patients with lower-risk CMML, and a survival benefit was predicted for men with higher-risk CMML. In a multivariable analysis of lower-risk patients, performing allo-HCT before transformation to AML significantly increased the risk of death within 2 years of transplantation (hazard ratio [HR], 3.19; P < .001), with no significant change in long-term survival beyond this time point (HR, 0.98; P = .92). In higher-risk patients, allo-HCT significantly increased the risk of death in the first 2 years after transplant (HR 1.46; P = .01) but not beyond (HR, 0.60; P = .09). Performing allo-HCT before AML transformation decreases life expectancy in lower-risk patients but may be considered in higher-risk patients.

Integrated Human and Murine Clinical Study Establishes Clinical Efficacy of Ruxolitinib in Chronic Myelomonocytic Leukemia

PURPOSE

CMML is a rare leukemia characterized by peripheral monocytosis with no disease-modifying therapies. CMML cells are uniquely hypersensitive to GM-CSF and robustly engraft in immunocompromised mice that secrete human cytokines. To leverage these unique biologic features, we conducted an integrated human and murine study evaluating ruxolitinib, a JAK1/2 inhibitor that potently downregulates intracellular GM-CSF signaling.

PATIENTS AND METHODS

A total of 50 patients with WHO-defined CMML were enrolled in this open-label, multi-institution phase 1/2 clinical study, with a ruxolitinib dose of 20mg twice daily studied in phase 2. In parallel, 49 patient-derived xenografts (PDX) derived from 13 study participants were generated and randomized to receive ruxolitinib or vehicle control.

RESULTS

The most common grade 3/4 treatment-related toxicities observed were anemia (10%) and thrombocytopenia (6%). The clinical overall response rate was 38% by MDS/MPN IWG criteria and 43% of patients with baseline splenomegaly achieved a spleen response. Profiling of cytokine levels and somatic mutations at baseline failed to identify predictive biomarkers. PDX models derived from screening samples of study participants recapitulated responses seen in humans, particularly spleen responses, and corroborated ruxolitinib's clinical efficacy in a randomized murine study not feasible in human trials.

CONCLUSIONS

Ruxolitinib demonstrated clinical efficacy and an acceptable adverse event profile in patients with CMML, identifying a potential novel therapeutic in this rare malignancy. Furthermore, this study demonstrates proof of concept that PDX modeling can recapitulate responses of patients treated on clinical trial and represents a novel correlative study that corroborates clinical efficacy seen in humans.

Diagnosis and management of neutrophilic myeloid neoplasms

Chronic neutrophilia is commonly seen with persistent infections, inflammatory disorders, smoking, solid tumors, and specific medications. However, after reactive causes have been excluded, a workup for primary (clonal) neutrophilic disorders, such as myeloproliferative neoplasms (MPNs) and myelodysplastic/myeloproliferative overlap syndromes, should be pursued. Except for chronic myeloid leukemia, which is defined by the presence of the Philadelphia (Ph) chromosome, and the classic Ph chromosome-negative MPNs (polycythemia vera, essential thrombocythemia, and primary myelofibrosis), clonal neutrophilic neoplasms historically have been challenging to diagnose and classify. The 2016 revised World Health Organization classification of these disorders has been based mainly on clinicopathologic features. However, recent discoveries of the molecular alterations underlying these disorders have served to supplement our knowledge of their morphologic and clinical features, opening new therapeutic avenues. In this review, we discuss the diagnostic approach, prognostic features, and treatments of neutrophilic myeloid neoplasms, with a focus on chronic neutrophilic leukemia, atypical chronic myeloid leukemia, and chronic myelomonocytic leukemia.

Contemporary Risk Stratification and Treatment of Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy characterized by absolute monocytosis, one or more lineage dysplasia, and proliferative features including myeloid hyperplasia, splenomegaly, and constitutional symptoms. Because of vast clinical heterogeneity in presentation and course, risk stratification is used for a risk-adapted treatment strategy. Numerous prognostic scoring systems exist, some of which incorporate mutational information. Treatment ranges from observation to allogeneic hematopoietic stem cell transplantation. Therapies include hydroxyurea for cytoreduction, hypomethylating agents, and the JAK1/2 inhibitor ruxolitinib to address splenomegaly and constitutional symptoms. Recently, oral decitabine with cedazuridine was approved and represents a convenient treatment option for CMML patients. Although novel therapeutics are in development for CMML, further work is needed to elucidate possible targets unique to the CMML clone. In this review, we will detail the pathophysiology, risk stratification, available treatment modalities, and novel therapies for CMML, and propose a modern treatment algorithm. IMPLICATIONS FOR PRACTICE: Chronic myelomonocytic leukemia (CMML) is a clinically heterogenous disease, which poses significant management challenges. The diagnosis of CMML requires bone marrow biopsy and aspirate with thorough evaluation. Risk stratification and symptom assessment are essential to designing an effective treatment plan, which may include hypomethylating agents (HMAs) in intermediate or high-risk patients. The recently approved oral decitabine/cedazuridine provides a convenient alternative to parenteral HMAs. Ruxolitinib may be effective in ameliorating proliferative symptoms and splenomegaly. Allogeneic stem cell transplantation remains the only treatment with curative potential; however, novel therapies are in clinical development which may significantly alter the therapeutic landscape of CMML.

Prognostic assessment for chronic myelomonocytic leukemia in the context of the World Health Organization 2016 proposal: a multicenter study of 280 patients

Knowledge on chronic myelomonocytic leukemia (CMML) patients from Argentina and Brazil is limited. Our series of 280 patients depicted an older age at diagnosis (median 72 years old), 26% of aberrant karyotypes, and a prevalence of myelodysplastic (60%) and CMML-0 subtypes (56%). The median overall survival (OS) was 48.2 months for patients in CMML-0 (Ref.), 24.7 months for those in CMML-1 (HR = 2.0, p = 0.001), and 8.8 months for patients in CMML-2 (HR = 4.6, p < 0.001). In the CMML-0 category, median OS were different between myelodysplastic and myeloproliferative subtypes (63.7 vs 21.2 months, p < 0.001); however, no differences were observed within CMML-1 and CMML-2 subtypes (24.7 vs 23.7 months, p = 0.540, and 9.1 vs 8.2 months, p = 0.160). The prognostic impact of 24 variables and 7 prognostic systems was adjusted to the WHO 2016 after validating their usefulness. Multivariate analysis were performed, and the final model revealed Hb ≥ 8 -< 10g/dL (HR 1.7), Hb < 8g/dL (HR 2.8), poor karyotypes (HR 2.1), WHO 2016-CMML-1 (HR 2.1), and CMML-2 (HR 3.5) as independent adverse clinical parameters in our cohort with a borderline influence of platelets count < 50 × 10⁹/L (HR 1.4). We could validate several scoring systems, the WHO 2016 proposal and its prognostic capability, along with accessible covariates, on predicting the outcome in our series of CMML patients from Latin America.

Clinical spectrum, outcome and management of immune thrombocytopenia associated with myelodysplastic syndromes and chronic myelomonocytic leukemia

Myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) are associated with systemic inflammatory or autoimmune diseases in 10-20 % of cases. Among them, immune thrombocytopenia (ITP) has been reported but large studies assessing this association are missing. Whether such patients have a particular phenotype and require particular management is unclear. This study analyzes the clinical spectrum, outcome and therapeutic management of patients with ITP associated with MDS or CMML, in comparison (i) to patients with primary ITP without MDS/CMML and (ii) to patients with MDS/CMML without ITP. Forty-one MDS/CMML-associated ITP patients were included, with chronic ITP in 26 (63%) patients, low-risk myelodysplasia in 30 (73%) patients and CMML in 24 (59%) patients. An associated autoimmune disease was noted in 10 (24%) patients. In comparison to primary ITP patients, MDS/CMML-associated ITP patients had a higher occurrence of severe bleeding despite similar platelet counts at diagnosis. First-line treatment consisted of glucocorticoids (98%) and intravenous immunoglobulin (IVIg) (56%). Response achievement with IVIg was more frequent in primary ITP than in MDS/CMML-associated ITP patients. Response rates to second-line therapies were not statistically different between primary ITP and MDS/CMMLassociated ITP patients. Ten percent (n=4) of patients with MDS/CMML-associated ITP had multirefractory ITP versus none in primary ITP controls. After a median follow-up of 60 months, there was no difference in overall survival between MDS/CMML-associated ITP and primary ITP patients. Leukemia-free-survival was significantly better in MDS/CMMLassociated ITP patients than in MDS/CMML without ITP MDS/CMML-associated ITP have a particular outcome with more severe bleeding and multirefractory profile than primary ITP, similar response profile to primary ITP therapy except for IVIg, and less progression toward acute myeloid leukemia than MDS/CMML without ITP.

A prognostic score including mutation profile and clinical features for patients with CMML undergoing stem cell transplantation

The inclusion of mutation status improved risk stratification for newly diagnosed patients with chronic myelomonocytic leukemia (CMML). Stem cell transplantation is a potentially curative treatment option, and patient selection is critical because of relevant transplant-related morbidity and mortality. We aimed to evaluate the impact of mutation status together with clinical presentations on posttransplant outcome. Our study included 240 patients with a median follow-up of 5.5 years. A significant association with worse survival was identified for the presence of mutations in ASXL1 and/or NRAS. In multivariable analysis, ASXL1- and/or NRAS-mutated genotype (hazard ratio [HR], 1.63), marrow blasts >2% (HR, 1.70), and increasing comorbidity index (continuous HR, 1.16) were independently associated with worse survival. A prognostic score (CMML transplant score) was developed, and the following points were assigned: 4 points for an ASXL1- and/or NRAS-mutated genotype or blasts >2% and 1 point each for an increase of 1 in the comorbidity index. The CMML transplant score (range, 0-20) was predictive of survival and nonrelapse mortality (P < .001 for both). Up to 5 risk groups were identified, showing 5-year survival of 81% for a score of 0 to 1, 49% for a score of 2 to 4, 43% for a score of 5 to 7, 31% for a score of 8 to 10, and 19% for a score >10. The score retained performance after validation (concordance index, 0.68) and good accuracy after calibration. Predictions were superior compared with existing scores designed for the nontransplant setting, which resulted in significant risk reclassification. This CMML transplant score, which incorporated mutation and clinical information, was prognostic in patients specifically undergoing transplantation and may facilitate personalized counseling.

Clinical Applications of Chromosomal Microarray Testing in Myeloid Malignancies

PURPOSE OF REVIEW

Knowledge of both somatic mutations and copy number aberrations are important for the understanding of cancer pathogenesis and management of myeloid neoplasms. The currently available standard of care technologies for copy number assessment such as conventional karyotype and FISH are either limited by low resolution or restriction to targeted assessment.

RECENT FINDINGS

Chromosomal microarray (CMA) is effective in characterization of chromosomal and gene aberrations of diagnostic, prognostic, and therapeutic significance at a higher resolution than conventional karyotyping. These results are complementary to NGS mutation studies. Copy-neutral loss of heterozygosity (CN-LOH), which is prognostic in AML, is currently only identified by CMA. Yet, despite the widespread availability, CMA testing is not routinely performed in diagnostic laboratories due to lack of knowledge on best-testing practices for clinical work-up of myeloid neoplasms. In this review, we provide an overview of the clinical significance of CMA in acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). We will also elaborate the specific clinical scenarios where CMA can provide additional information essential for management and could potentially alter treatment. Chromosomal microarray (CMA) is an effective technology for characterizing chromosomal copy number changes and copy-neutral loss of heterozygosity of diagnostic, prognostic, and therapeutic significance at a high resolution in myeloid malignancies.

Chronic myelomonocytic leukemia (CMML)-0 with pleural effusion as first manifestation: A case report

RATIONALE

Extramedullary invasion of chronic myelomonocytic leukemia (CMML) usually occurs in the liver, spleen, and lymph nodes, while the pleural infiltration of CMML is rare. The presence of pleural effusion is usually associated with uncontrolled leukocytosis and increased monocytes.

PATIENT CONCERNS

Here we reported a rare case of CMML-0 with pleural effusion as the first manifestation in a 44-year-old woman. The pleural effusion was caused by blasts infiltration confirmed by the flow cytometer and the pleural biopsy.

DIAGNOSES

CMML with pleural invasion.

INTERVENTIONS

The patient was treated with azacitidine 75 mg/m d for 2 cycles, followed by daily oral intake of hydroxyurea (500 mg/d).

OUTCOMES

Pleural effusion was resolved and chest pain was relieved.

LESSONS

The current case indicated that leukemic infiltration into pleura could occur despite mild leukocytes, while demethylation may be an effective therapy.

Flow Cytometric Analysis of Monocytes and Granulocytes May Be Useful in the Distinction of Myeloid Neoplasms from Reactive Conditions: A Single Institution Experience and Literature Review

OBJECTIVE

To determine if the immunophenotype of monocytes and granulocytes could help differentiate between reactive conditions and myeloid neoplasms.

MATERIALS

We analyzed 94 patients including acute myeloid leukemia (n=53), myelodysplastic syndrome (n=19), chronic myelomonocytic leukemia (n=13), and chronic myelogenous leukemia (n=9). Twenty-five cases of reactive condition were included as controls.

RESULTS

Myeloid neoplasm cases showed significantly altered expression patterns including overexpression of CD56, altered expression of HLA-DR, underexpression of CD14, CD64, and altered expression of CD33 when compared to controls.

CONCLUSIONS

There are significant and consistent differences in immunophenotype of monocytes and granulocytes in neoplastic groups versus controls. Immunophenotypic evaluation of monocytes and granulocytes in addition to blasts may be useful in flow cytometric assessment of minimal residual disease in myeloid neoplasms.

Transcriptomic analysis implicates necroptosis in disease progression and prognosis in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis and cytopenias due to uncontrolled programmed cell death. The presence of pro-inflammatory cytokines and constitutive activation of innate immunity signals in MDS cells suggest inflammatory cell death, such as necroptosis, may be responsible for disease phenotype. We evaluated 64 bone marrow samples from 55 patients with MDS or chronic myelomonocytic leukemia (CMML) obtained prior to (n = 46) or after (n = 18) therapy with hypomethylating agents (HMAs). RNA from sorted bone marrow CD34+ cells was isolated and subject to amplification and RNA-Seq. Compared with healthy controls, expression levels of MLKL (CMML: 2.09 log2FC, p = 0.0013; MDS: 1.89 log2FC, p = 0.003), but not RIPK1 or RIPK3, were significantly upregulated. Higher expression levels of MLKL were associated with lower hemoglobin levels at diagnosis (-0.19 log2FC per 1 g/dL increase of Hgb, p = 0.03). Significant reduction in MLKL levels was observed after HMA therapy (-1.06 log2FC, p = 0.05) particularly among nonresponders (-2.89 log2FC, p = 0.06). Higher RIPK1 expression was associated with shorter survival (HR 1.92, 95% CI 1.00-3.67, p = 0.049 by Cox proportional hazards). This data provides further support for a role of necroptosis in MDS, and potentially response to HMAs and prognosis. This data also indicate that RIPK1/RIPK3/MLKL are potential therapeutic targets in MDS.

Chronic Myelomonocytic Leukemia Presenting With Polyserositis and Seropositivity for Rheumatoid Arthritis

Chronic myelomonocytic leukemia (CMML) is a rare clonal stem cell disorder associated with clinical and pathologic of myelodysplasia and myeloproliferation. Systemic autoimmune/inflammatory disorders (SAID) and polyserositis have been associated with CMML. These manifestations can be observed concomitantly, shortly before diagnosis or anytime along the course of illness. We report a case of myeloproliferative CMML who presented with polyserositis and positive serology for rheumatoid arthritis. Retrospective studies of myelodysplasia/CMML have reported 15% to 25% incidence of SAID. The most commonly observed disorders include systemic vasculitis, connective tissue diseases, polychondritis, seronegative arthritis, and immune thrombocytopenia. SAID does not confer adverse prognosis in retrospective studies. Polyserositis is less common; this may result from leukemic infiltrate or result from autoimmunity. Treatment of serositis includes steroids and cytoreductive agents. Serositis may confer poor prognosis and hypomethylating therapy may improve the outcome.

Oligo-monocytic CMML and other pre-CMML states: Clinical impact, prognostication and management

Chronic myelomonocytic leukemia (CMML) is defined by myelodysplasia, pathologic accumulation of monocytes and a substantial risk to transform to secondary acute myeloid leukemia (sAML). In recent years, minimal diagnostic criteria for classical CMML and CMML-variants were proposed. Moreover, potential pre-stages of CMML and interface conditions have been postulated. Oligomonocytic CMML is a condition where the absolute peripheral blood monocyte count does not reach a diagnostic level but all other criteria for CMML are fulfilled. Among potential pre-stages of CMML, clonal and non-clonal conditions have been described, including idiopathic monocytosis (IMUS) and clonal monocytosis of unknown significance (CMUS). Patients with myelodysplastic syndromes (MDS), clonal cytopenia of unknown significance (CCUS), clonal hematopoiesis of indeterminate potential (CHIP) and idiopathic cytopenia of undetermined significance (ICUS) may also progress to CMML. The current article provides an overview of pre-CMML conditions and oligomonocytic CMML, with special reference to diagnostic criteria, differential diagnoses, clinical outcomes and management.

Incorporating flow cytometry and next-generation sequencing in the diagnosis of CMML. Are we ready for prime?

In the last version of the WHO classification of myeloid malignancies, flow cytometry and molecular investigation are listed as potentially useful, yet non-essential diagnostic tools in hard-to-recognize chronic myelomonocytic leukemias (CMML). Flow recognition of CMML was initially based on an increase in the fraction of peripheral blood, CD14⁺,CD16^- classical monocytes ≥94% of total monocytes. An associated inflammatory disease can preclude the detection of classical monocyte fraction increase by inducing accumulation of CD14⁺,CD16⁺ intermediate monocytes. In such a situation, decrease in the Slan⁺,CD14^low,CD16⁺ non-classical monocyte fraction below 1.7% still supports CMML diagnosis. This robust, two-step flow cytometry assay identifies CMML with a very high sensitivity. Otherwise, detection of one or several acquired gene mutations with high variant allele frequency supports the diagnosis of CMML, oligomonocytic CMML or clonal monocytosis of clinical significance. Together, recent investigations support integration of flow cytometry analysis of peripheral blood monocyte subsets and new generation sequencing of a panel of 20-30 recurrently mutated genes in the diagnostic work-up of CMML.

Targeted sequencing aids in identifying clonality in chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia (CMML) typically shows monocytosis in the peripheral blood (PB), which must be differentiated from reactive monocytosis. To determine the clonality of CMML, we performed molecular and cytogenetic analysis in Korean patients. To investigate whether monocytes in the PB harbored clonal mutational changes, we performed single-cell sequencing after selecting monocytes, neutrophils, and lymphocytes by morphology-aided laser microdissection. Targeted sequencing was performed in 35 patients with CMML with 41 bone marrow samples. Single-cell analysis was performed in two cases. Most (94.3%) patients harbored at least one variant, in genes considered as potential therapeutic targets, while cytogenetic aberrations occurred in only 28.6% of cases. ASXL1 (54.3%), SRSF2 (37.1%), NRAS (31.4%), and TET2 (25.7%) were frequently mutated, with lower frequencies of TET2 mutation and higher frequencies of NRAS, DNMT3A (17.1%), and NPM1 (11.4%) mutations compared to in previous studies of Caucasians. Patients with SETBP1 mutation and those with more than two variants showed poorer survival than those without mutation (P < 0.001 and P = 0.007, respectively). Most (70.8%) variants were detected at diagnosis and follow-up with no significant differences in variant allele frequency, warranting sequencing during follow-up if diagnostic samples were unavailable. Single-cell analysis revealed clonal monocytes with mutations, and the same mutations were also identified in lymphocytes and neutrophils. Targeted sequencing aided in clonality detection in most patients with CMML and single-cell sequencing facilitated identification of clonal monocytes and the co-existence of mutations in non-myeloid cells, suggesting that certain mutations are acquired by pluripotent stem cells.

Successful eltrombopag treatment of severe refractory thrombocytopenia in chronic myelomonocytic leukemia: Two cases reports: A CARE-compliant article

RATIONALE

Thrombocytopenia in chronic myelomonocytic leukemia (CMML) is usually attributed to impaired marrow production resulting from cytotoxic drug use or CMML itself ("CMML-induced thrombocytopenia"). In very rare cases, immune thrombocytopenia (ITP) can be a complication of CMML ("CMML-associated ITP"). However, treatment of severe thrombocytopenia in patients with CMML is still a challenge.

PATIENT CONCERNS

Case 1 was a 61-year-old female patient admitted to our hospital because of skin petechiae and purpura for 6 days. She had increased monocyte cell count (1.82 × 10/L), markedly decreased platelet count (2 × 10/L), hypercellularity of the megakaryocyte lineage with many immature megakaryocytes, and ZRSR2(zinc finger CCCH-type, RNA binding motif and serine/arginine rich 2) mutation. She failed to the treatment of corticosteroids, intravenous immunoglobulin (IVIg), TPO (thrombopoietin), and cyclosporin A (CsA). Case 2 was a 72-year-old female patient with thrombocytosis and monocytosis for 4 years, and thrombocytopenia for 6 months. After 10 courses of decitabine therapy, she had a persistent severe thrombocytopenia and decreased number of megakaryocytes, TET2 (tet methylcytosine dioxygenase 2) and SRSF2 (serine and arginine rich splicing factor 2) mutations were detected. She was dependent on platelet transfusion.

DIAGNOSES

Case 1 was diagnosed as CMML-associated ITP, and case 2 as CMML with decitabine therapy-induced thrombocytopenia.

INTERVENTIONS

Both patients were treated with eltrombopag.

OUTCOMES

In both patients, the platelet counts returned to the normal within 1 week after eltrombopag therapy. The platelet count in case 1 patient remained stable at 141-200 × 10/L for 20 months with stopping therapy for 3 months. In case 2 patient, eltrombopag was stopped 1 month later. Her platelet count decreased to 41 × 10/L, but was stable at ∼30 × 10/L for 3 months with platelet transfusion independency for 12 months. Both patients had no adverse effects with eltrombopag.

LESSONS

CMML-associated ITP is very rare and easily misdiagnosed. To the best of our knowledge, case 1 is the first reported case of the successful treatment of CMML-associated ITP with eltrombopag. Both CMML-associated ITP and decitabine therapy-induced thrombocytopenia in these 2 patients were highly sensitive and safe to eltrombopag therapy.

Recurrent Cytogenetic Abnormalities in Myelodysplastic Syndromes

Cytogenetic analysis has an essential role in diagnosis, classification, and prognosis of myelodysplastic syndromes (MDS). Some cytogenetic abnormalities are sufficiently characteristic of MDS to be considered MDS defining in the appropriate clinical context. MDS with isolated del(5q) is the only molecularly defined MDS subtype. The genes responsible for many aspects of 5q- syndrome, the distinct clinical phenotype associated with this condition, have now been identified. Cytogenetics forms the cornerstone of the most widely adopted prognostic scoring systems in MDS, the international prognostic scoring system (IPSS) and the revised international prognostic scoring system (IPPS-R). Cytogenetic parameters also have utility in chronic myelomonocytic leukemia (CMML) and have been incorporated into specific prognostic scoring systems for this condition. More recently, it has been appreciated that submicroscopic copy number changes and gene mutations play a significant part in MDS pathogenesis. Integration of molecular genetics and cytogenetics holds much promise for improving clinical care and outcomes for patients with MDS.

Targeted Next-Generation Sequencing in Myelodysplastic Syndrome and Chronic Myelomonocytic Leukemia Aids Diagnosis in Challenging Cases and Identifies Frequent Spliceosome Mutations in Transformed Acute Myeloid Leukemia

OBJECTIVES

Optimal integration of next-generation sequencing (NGS) into clinical practice in hematologic malignancies remains unclear. We evaluate the utility of NGS in myeloid malignancies.

METHODS

A 42-gene panel was used to sequence 109 cases of myelodysplastic syndrome (MDS, n = 38), chronic myelomonocytic leukemia (CMML, n = 14), myeloproliferative neoplasm (MPN, n = 24), and MDS and/or MPN transformed to acute myeloid leukemia (AML, n = 33).

RESULTS

At least one pathogenic mutation was identified in 74% of cases of MDS, 100% of CMMLs, and 96% of MPNs. In contrast, only 47% of cases of MDS (18/38) and 7% (1/14) of CMMLs exhibited abnormal cytogenetics. In diagnostically difficult cases of MDS or CMML with normal cytogenetics, NGS identified a pathogenic mutation and was critical in establishing the correct diagnosis. Spliceosomal genes and epigenetic modifiers were frequently mutated. Spliceosome mutations were also frequently detected in AML arising from MDS, CMML, or MPN (39%) compared with the reported rate in de novo AML (7%-14%).

CONCLUSIONS

In difficult cases of MDS or MPN, NGS facilitates diagnosis by detection of gene mutations to confirm clonality, and AMLs evolving from MDS or MPN carry frequent mutations in spliceosomal genes.

Cytogenetic and molecular abnormalities in chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia (CMML) is a clonal stem cell disorder associated with peripheral blood monocytosis and an inherent tendency to transform to acute myeloid leukemia. CMML has overlapping features of myelodysplastic syndromes and myeloproliferative neoplasms. Clonal cytogenetic changes are seen in ~30%, whereas gene mutations are seen in >90% of patients. Common cytogenetic abnormalities include; trisomy 8, -Y, -7/del(7q), trisomy 21 and del(20q), with the Mayo-French risk stratification effectively risk stratifying patients based on cytogenetic abnormalities. Gene mutations frequently involve epigenetic regulators (TET2 ~60%), modulators of chromatin (ASXL1 ~40%), spliceosome components (SRSF2 ~50%), transcription factors (RUNX1 ~15%) and signal pathways (RAS ~30%, CBL ~15%). Of these, thus far, only nonsense and frameshift ASXL1 mutations have been shown to negatively impact overall survival. This has resulted in the development of contemporary, molecularly integrated (inclusive of ASXL1 mutations) CMML prognostic models, including Molecular Mayo Model and the Groupe Français des Myélodysplasies model. Better understanding of the prevalent genetic and epigenetic dysregulation has resulted in emerging targeted treatment options for some patients. The development of an integrated (cytogenetic and molecular) prognostic model along with CMML-specific response assessment criteria are much needed future goals.

Chronic Myelomonocytic Leukemia: Focus on Clinical Practice

Chronic myelomonocytic leukemia (CMML) is a clonal stem cell disorder with features that overlap those of myelodysplastic syndromes (MDSs) and myeloproliferative neoplasms (MPNs). Chronic myelomonocytic leukemia often results in peripheral blood monocytosis and has an inherent tendency to transform to acute myeloid leukemia. Clonal cytogenetic changes are seen in approximately 30% of patients, and molecular abnormalities are seen in more than 90%. Gene mutations involving TET2 (∼60%), SRSF2 (∼50%), ASXL1 (∼40%), and RAS (∼30%) are frequent, with nonsense and frameshift ASXL1 mutations being the only mutations identified thus far to have an independent negative prognostic effect on overall survival. Contemporary molecularly integrated prognostic models (inclusive of ASXL1 mutations) include the Molecular Mayo Model and the Groupe Français des Myélodysplasies model. Given the lack of formal treatment and response criteria, management of CMML is often extrapolated from MDS and MPN, with allogeneic stem cell transplant being the only curative option. Hydroxyurea and other cytoreductive agents have been used to control MPN-like features, while epigenetic modifiers such as hypomethylating agents have been used for MDS-like features. Given the relatively poor response to these agents and the inherent risks associated with hematopoietic stem cell transplant, newer drugs exploiting molecular and epigenetic abnormalities in CMML are being developed. The creation of CMML-specific response criteria is a much needed step in order to improve clinical outcomes.

Flow Cytometric Immunobead Assay for Detection of BCR-ABL1 Fusion Proteins in Chronic Myleoid Leukemia: Comparison with FISH and PCR Techniques

Chronic Myeloid Leukemia (CML) is characterized by a balanced translocation juxtaposing the Abelson (ABL) and breakpoint cluster region (BCR) genes. The resulting BCR-ABL1 oncogene leads to increased proliferation and survival of leukemic cells. Successful treatment of CML has been accompanied by steady improvements in our capacity to accurately and sensitively monitor therapy response. Currently, measurement of BCR-ABL1 mRNA transcript levels by real-time quantitative PCR (RQ-PCR) defines critical response endpoints. An antibody-based technique for BCR-ABL1 protein recognition could be an attractive alternative to RQ-PCR. To date, there have been no studies evaluating whether flow-cytometry based assays could be of clinical utility in evaluating residual disease in CML patients. Here we describe a flow-cytometry assay that detects the presence of BCR-ABL1 fusion proteins in CML lysates to determine the applicability, reliability, and specificity of this method for both diagnosis and monitoring of CML patients for initial response to therapy. We show that: i) CML can be properly diagnosed at onset, (ii) follow-up assessments show detectable fusion protein (i.e. relative mean fluorescent intensity, rMFI%>1) when BCR-ABL1IS transcripts are between 1-10%, and (iii) rMFI% levels predict CCyR as defined by FISH analysis. Overall, the FCBA assay is a rapid technique, fully translatable to the routine management of CML patients.

Azacitidine access program for Belgian patients with myelodysplastic syndromes, acute myeloid leukemia or chronic myelomonocytic leukemia

OBJECTIVE

Azacitidine (Vidaza *) is approved in Europe for treatment of myelodysplastic syndromes (MDS), acute myeloid leukemia (AML) with 20-30% bone marrow (BM) blasts, and chronic myelomonocytic leukemia (CMML) with 10-29% BM blasts and no myeloproliferative syndrome (i.e. <13.000/μL white blood cells). In Belgium, the azacitidine reimbursement process can take several months, and is often delayed at submission for medical assessment by the Belgian National Institute for Health and Disability Insurance of incomplete patient dossiers, due to disease complexity and classification, and administrative burden. We describe the Vidaza Access Program and its application to an initial 175 patients. Individual medical dossiers were reviewed for completeness to facilitate patient access to treatment in Belgium.

METHODS

A standardized anonymized patient information form is completed by the physician and sent for review to the Belgian Celgene Medical Department. The form is reviewed within three working days and, for complete dossiers, Celgene grants a financial guarantee for treatment with azacitidine. The patient can then be treated without the hospital being subjected to financial risk.

RESULTS

Between January 2013 and June 2014, 63 physicians (53 Belgian hospitals) recruited 175 patients. In total, 163 patient dossiers were approved by Celgene (120 MDS, 36 AML, and 7 CMML), of which 104 dossiers were also approved by the review committee and 49 have been waiting for a final decision for a median of 6 months; no information is currently available for the remaining 10. No dossiers approved by Celgene have been rejected by the review committee.

CONCLUSIONS

The Celgene Vidaza Access Program offers support to healthcare professionals in the appropriate use of azacitidine. By facilitating the assessment of patient dossiers and providing a financial guarantee for prescribers and hospitals, treatment can be initiated more rapidly and patients may better benefit from azacitidine treatment.

Refined diagnostic criteria and classification of mast cell leukemia (MCL) and myelomastocytic leukemia (MML): a consensus proposal

Mast cell leukemia (MCL), the leukemic manifestation of systemic mastocytosis (SM), is characterized by leukemic expansion of immature mast cells (MCs) in the bone marrow (BM) and other internal organs; and a poor prognosis. In a subset of patients, circulating MCs are detectable. A major differential diagnosis to MCL is myelomastocytic leukemia (MML). Although criteria for both MCL and MML have been published, several questions remain concerning terminologies and subvariants. To discuss open issues, the EU/US-consensus group and the European Competence Network on Mastocytosis (ECNM) launched a series of meetings and workshops in 2011-2013. Resulting discussions and outcomes are provided in this article. The group recommends that MML be recognized as a distinct condition defined by mastocytic differentiation in advanced myeloid neoplasms without evidence of SM. The group also proposes that MCL be divided into acute MCL and chronic MCL, based on the presence or absence of C-Findings. In addition, a primary (de novo) form of MCL should be separated from secondary MCL that typically develops in the presence of a known antecedent MC neoplasm, usually aggressive SM (ASM) or MC sarcoma. For MCL, an imminent prephase is also proposed. This prephase represents ASM with rapid progression and 5%-19% MCs in BM smears, which is generally accepted to be of prognostic significance. We recommend that this condition be termed ASM in transformation to MCL (ASM-t). The refined classification of MCL fits within and extends the current WHO classification; and should improve prognostication and patient selection in practice as well as in clinical trials.

Skin Infiltration of Juvenile Myelomonocytic Leukemia

We described a two-year-old boy who developed a skin infiltration from JMML. Several indurated erythematous lesions were seen on his back on his first visit to our department. Edematous erythemas had repeatedly appeared on his auricles and feet for the previous six months. He had had a high fever for a month. Hepatosplenomegaly and superficial lymphadenopathy were recognized. Laboratory investigation showed leukocytosis and anemia. The diagnosis of JMML was confirmed by the findings of myeloid hyperplasia in his bone marrow and the spontaneous colony formation and GM-CSF hypersensitivity in a culture of bone marrow cells. Histopathologically, large atypical mononuclear cells were infiltrated throughout the dermis in a perivascular and interstitial distribution in a skin biopsy specimen. These cells were CD3 (-), CD20 (-), CD45 (+), CD68 (+) and myeloperoxidase (+). Bone marrow transplantation and then cord blood stem cell transplantation were performed but soon rejected. The indurated erythematous lesions appeared again soon after the relapse of JMML. There are other reported cases of JMML with skin infiltration that preceded any other manifestations of the disease. JMML cells in some patients, including our case, seem to have a great affinity for the skin, and skin biopsy aids in early detection of this disease.

Chronic myelomonocytic leukemia can present with diffuse planar xanthoma

There is a documented association between diffuse planar xanthoma and chronic myelomonocytic leukemia. Previous accounts have hypothesized that patients with multiple lesions or extensive cutaneous disease are more likely to have an underlying abnormality of the reticuloendothelial system. However, we document a 62-year-old woman with a large pruritic yellow-orange plaque on the chest and lower anterior neck consistent with planar xanthoma that was discovered to have chronic myelomonocytic leukemia. Solitary large plaques of planar xanthoma should be considered in the same fashion as diffuse planar xanthoma and warrant a prompt hematologic evaluation.

The clinical management of chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia (CMML) is an aggressive malignancy characterized by peripheral monocytosis and ineffective hematopoiesis. It has been historically classified as a subtype of the myelodysplastic syndromes (MDSs) but was recently demonstrated to be a distinct entity with a distinct natural history. Nonetheless, clinical practice guidelines for CMML have been inferred from studies designed for MDSs. It is imperative that clinicians understand which elements of MDS clinical practice are translatable to CMML, including which evidence has been generated from CMML-specific studies and which has not. This allows for an evidence-based approach to the treatment of CMML and identifies knowledge gaps in need of further study in a disease-specific manner. This review discusses the diagnosis, prognosis, and treatment of CMML, with the task of divorcing aspects of MDS practice that have not been demonstrated to be applicable to CMML and merging those that have been shown to be clinically similar.