Reduced CD38 expression on CD34+ cells as a diagnostic test in myelodysplastic syndromes

Multiparameter flow cytometry in the evaluation of myelodysplasia: Analytical issues: Recommendations from the European LeukemiaNet/International Myelodysplastic Syndrome Flow Cytometry Working Group

Multiparameter flow cytometry (MFC) is one of the essential ancillary methods in bone marrow (BM) investigation of patients with cytopenia and suspected myelodysplastic syndrome (MDS). MFC can also be applied in the follow-up of MDS patients undergoing treatment. This document summarizes recommendations from the International/European Leukemia Net Working Group for Flow Cytometry in Myelodysplastic Syndromes (ELN iMDS Flow) on the analytical issues in MFC for the diagnostic work-up of MDS. Recommendations for the analysis of several BM cell subsets such as myeloid precursors, maturing granulocytic and monocytic components and erythropoiesis are given. A core set of 17 markers identified as independently related to a cytomorphologic diagnosis of myelodysplasia is suggested as mandatory for MFC evaluation of BM in a patient with cytopenia. A myeloid precursor cell (CD34⁺ CD19^- ) count >3% should be considered immunophenotypically indicative of myelodysplasia. However, MFC results should always be evaluated as part of an integrated hematopathology work-up. Looking forward, several machine-learning-based analytical tools of interest should be applied in parallel to conventional analytical methods to investigate their usefulness in integrated diagnostics, risk stratification, and potentially even in the evaluation of response to therapy, based on MFC data. In addition, compiling large uniform datasets is desirable, as most of the machine-learning-based methods tend to perform better with larger numbers of investigated samples, especially in such a heterogeneous disease as MDS.

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

Background

Flow cytometry immunophenotyping (FCIP) can improve diagnosis of myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN), although its application is challenging due to difficulties in standardization, complexity of antibody panels and subjective interpretation of data. Since blasts are invariably affected in these disorders, we developed a FCIP approach for detailed and objective analysis of the blast population.

Methods

FCIP using a one‐tube 10‐color (13‐marker) antibody panel was performed on bone marrow samples from 23 MDS and 8 MDS/MPN patients, 21 cytopenic patients non‐diagnostic for MDS (Non‐MDS), and 16 Control samples.

Results

MDS and MDS/MPN cases demonstrated one to several immunophenotypic abnormalities including: increased myeloblasts, decreased stage‐1 hematogones, aberrant stem cells, abnormal myeloblast heterogeneity/divergence from normal, increased or decreased CD45 intensity, increased CD117 or CD123 intensity, decreased CD38 intensity, and aberrant expression of lineage markers (CD5, CD19, CD56). A Blast score was developed that showed sensitivity of 80.6% and specificity of 90.5% for immunophenotypic diagnosis of MDS and MDS/MPN. Expression levels of CD45RA and CD371 were used to evaluate abnormal myeloblast heterogeneity and stem cell aberrancy. Both these features were, for the first time, incorporated into a scoring system and resulted in 19% increase in the sensitivity of the assay for lower‐risk MDS.

Conclusion

Deep immunophenotypic analysis of the blast population is valuable for diagnosis of MDS and MDS/MPN and can potentially provide sensitivity and specificity figures comparable to those previously described using more comprehensive panels that assess maturing myelomonocytic and erythroid elements in addition to progenitor cells.

Retracted: EBF1 gene promotes the proliferation and inhibits the apoptosis of bone marrow CD34+ cells in patients with myelodysplastic syndrome through negative regulation of mitogen-activated protein kinase axis

The transcription factor, early B cell factor 1 (EBF1), plays a vital role in the lineage specification involving early B cell development and the onset of myelodysplastic syndrome (MDS). Therefore, to investigate whether or not EBF1 affects MDS as well as the transcription factor's underlying mechanism, we used CD34+ hematopoietic stem cells in bone marrow from patients with MDS. The extracted cells were then transfected with a series of EBF1, short hairpin RNA against EBF1 (shEBF1), and SB203580 (a specific mitogen-activated protein kinase [MAPK] axis inhibitor). The effects EBF1 gene and MAPK axis had on cell proliferation, apoptosis, and migration were determined by in vitro cell culturing. We made observations that involved EBF1 inhibiting the messenger RNA (mRNA) level of p38 MAPK, increasing the mRNA levels of extracellular-signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), extracellular-signal-regulated kinase 5 (ERK5), decreasing the protein expression of Bcl-2-associated X protein (Bax), and finally elevating the protein levels of B cell lymphoma/leukemia-2 (Bcl-2), stem cell factor (SCF), erythropoietin receptor (EpoR), p-ERK, p-JNK, p-ERK5, cyclin D, cyclin E, cyclin-dependent kinase 2 (CDK2), and CDK6, implying that EBF1 may very well have an inhibitory role in the MAPK axis. Another discovery found that EBF1 had a positive effect on the promotion of bone marrow CD34+ cell proliferation as well as its migration, but inhibited the apoptosis of cells. The results we obtained from this study indicated that the EBF1 gene suppresses the activation of the MAPK axis, thereby promoting both the proliferation and migration of bone marrow CD34+ cells as well as inhibiting the associating apoptosis. The effects of the EBF1 gene are likely to present a new therapeutic target in preventing the progression of MDS.

Altered follicular helper T cell impaired antibody production in a murine model of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of clonal hematopoietic diseases which have a high risk of progressing to acute myeloid leukemia. MDS patients have immunologic deficiency, including T and B cells dysfunction. Follicular T helper cells (Tfh, CD4⁺CXCR5⁺) are an important subset of helper T cells which help to the formation of germinal centers and B cells differentiation. In this study, we investigated the proportion and function of Tfh using NUP98-HOXD13 transgenic (NHD13) mice model with MDS phenotype. The proportion of Tfh from bone marrow and spleen of NHD13 mice decreased compared with wild type (WT) mice tested by flow cytometry. In NHD13 mice spleens, there were decreased CXCR5⁺ cells and increased PD-1⁺ cells using immunohistochemistry. The active markers (ICOS, CD40L and OX40) expressed on Tfh of NHD13 mice were decreased. In contrast, PD-1 expression on Tfh of NHD13 mice was higher than that of WT mice. After coculture with Tfh from NHD13 mice, IgG and IgM production of B cells were decreased. In conclusion, the proportion and function of Tfh in the MDS mice model were altered. The dysfunction and reduction of Tfh may inhibit B cells differentiation and antibody production. Abnormal Tfh might contribute to the immune tolerance promoting the progression of MDS.

Loss of blast heterogeneity in myelodysplastic syndrome and other chronic myeloid neoplasms

OBJECTIVES

Flow cytometry immunophenotyping has been suggested as an adjunctive technique in the evaluation of myeloid malignancies, especially in the myelodysplastic syndromes. However, its use has been limited due to complexity and cost restraints. The goal of this study is to attempt a simpler approach to flow cytometry immunophenotyping in myeloid neoplasms.

METHODS

We analyzed bone marrow specimens of 45 selected patients and an additional 99 consecutive random patients using a limited antibody panel.

RESULTS

Normal CD34-positive blasts show a characteristic pattern of CD13/HLA-DR expression, with three readily identifiable subpopulations. In contrast, myeloid neoplasms frequently show loss of this heterogeneity.

CONCLUSIONS

Analysis of a limited antibody panel with a focus on CD13/HLA-DR expression provides relatively high specificity and sensitivity for the detection of myeloid neoplasms.

Establishment and validation of an updated diagnostic FCM scoring system based on pooled immunophenotyping in CD34+ blasts and its clinical significance for myelodysplastic syndromes

Abnormal immunophenotypes of hematopoietic cells can be detected by flow cytometry (FCM) to assist the diagnosis of myelodysplastic syndromes (MDS). We previously established a FCM scoring system for the diagnosis of low-grade MDS. In this study, additional valuable antigens were involved in an updated FCM scoring system (u-FCMSS) for all MDS subtypes. The u-FCMSS showed better sensitivity and specificity (89.4% and 96.5%) in distinguishing MDS from non-clonal cytopenia diseases. Validation analysis of u-FCMSS exhibited comparable sensitivity and specificity (86.7% and 93.3%) and high agreement rate (88.9%) of FCM diagnosis with morphological diagnosis at optimal cut-off (score 3). The distribution of FCM scores in different disease stages was also analyzed. The results suggested that early scoring from abnormal expression of mature myeloid/lymphoid antigens and advanced scoring from abnormal expression of stem/progenitor antigens expression constituted the majority of FCM scores of low-grade and high-grade MDS, respectively. High early scoring was generally accompanied by low IPSS-R score and superior survival, whereas high advanced scoring was accompanied by high IPSS-R score and inferior survival. In addition, the low-risk MDS patients with high early scoring and low advanced scoring were revealed as candidates for immunosuppressive therapy, whereas those with high advanced scoring and low early scoring may be more suitable for decitabine treatment. In conclusion, the u-FCMSS is a useful tool for diagnosis, prognosis and treatment selection in MDS. Differences in classes of antigens expressed and in distribution of FCM scores may reflect distinctive stage characteristics of MDS during disease progression.

CD47 is expressed abnormally on hematopoietic cells in myelodysplastic syndrome

The increased LSC in MDS has correlation with the progression to AML, which the mechanism of immune evasion is unclear. Our study showed the expression of CD47 on LSC of the patients in high-risk MDS based on IPSS/WPSS score was higher than that of in low-risk MDS and controls. The level of CD47 on erythroblast of MDS patients had a significant positive correlation with their peripheral RBC count. It suggested that the proportion of CD34(+)CD38(-)CD47(+) cells increased in high-risk MDS which might protect LSC from avoiding phagocytosis, and low-expression of CD47 on erythroblast in MDS might be correlated to anemia.

Diagnostic application and clinical significance of FCM progress scoring system based on immunophenotyping in CD34+ blasts in myelodysplastic syndromes

BACKGROUND

Abnormal proliferation and differentiation of hematopoietic stem/progenitor cells, which reflect the malignant nature of clonal cells in myelodysplastic syndromes (MDS), can be detected by flow cytometry (FCM) and potentially applied to assist diagnosis and evaluate prognosis in MDS.

METHODS

In this study, a series of immunophenotypes such as CD34, CD19, CD38, CD117, and CD7, which are related to proliferation and differentiation of HSCs, were determined by FCM in the patients with nonclonal cytopenias diseases and MDS. Based on the expression pattern of these immunophenotypes, a FCM progress scoring (FPS) system was constructed and evaluated.

RESULTS

The FPS system showed good sensitivity and specificity (63.6% and 100.0%) in distinguishing MDS from nonclonal cytopenias diseases. Validation analysis of FPS system indicated comparable sensitivity and specificity (73.7% and 97.1%) and high agreement rate (82.6%) of FCM diagnosis with morphological diagnosis. The high-grade MDS had higher FPS score compared to low-grade MDS (P < 0.001). Noticeably, hypocellular MDS had lower FPS score (P < 0.001), most of which could not be diagnosed by FPS system. Besides, FPS score showed obvious positive correlation with WHO classification, IPSS score, percentage of marrow blasts, and cytogenetic prognosis scoring. Elevated FPS score predicted higher disease progression and shorter survival in MDS.

CONCLUSION

The FPS system based on immunophenotyping in CD34+ blasts is a useful and simple tool for diagnosis and prognosis evaluation in MDS.

Diagnostic potential of CD34+ cell antigen expression in myelodysplastic syndromes

The World Health Organization introduced flow cytometry as an additional criterion for diagnosis of myelodysplastic syndromes (MDS). Aberrant antigen expression on bone marrow (BM) blasts may identify "low-grade MDS." This study aimed to examine differences in antigen expression on CD34+ BM cells between patients with MDS and those with secondary cytopenia. BM aspirates of 175 patients with cytopenia were classified as MDS or secondary cytopenia. Expression of stem cell antigens (CD34, CD133), myeloid antigens (CD13, CD33), B-cell antigens (CD19, CD10), growth factor receptors (CD117, CD123), and chemokine receptor (CD184) was examined. Thirty-two normal adults and 49 patients with CD34+ acute myeloid leukemia (AML) were also examined. High percentage of CD34+ cells, CD117 and CD123 overexpression, and abnormal CD45 expression on these cells are the best markers for MDS. These phenotypic aberrancies correlate with number of blasts and degree of dysplasia, and were similar to those in CD34+ AML, thus reflecting the relationship between these disorders.

Flow cytometry in myelodysplastic syndrome: analysis of diagnostic utility using maturation pattern-based and quantitative approaches

Flow cytometry (FCM) is being increasingly evaluated for the diagnosis of myelodysplastic syndrome (MDS). We employed multiple FCM approaches to assess MDS. Five-color FCM, morphology blind, was done on bone marrow aspirates of 57 suspected MDS and 31 normal controls. Maturation pattern, quantitative FCM for low-grade MDS that awards FCM score, and expression of selected antigens on erythroid cells and CD34(+) blasts were evaluated. FCM results were correlated with clinical and laboratory workup. Patients (n = 57) included proven MDS (n = 14), suspected MDS (n = 13), and non-MDS (n = 30). By pattern-based approach, all proven cases were FCM positive. In suspected MDS, 11 (84.61 %) were positive including morphology-negative cases, and two (15.38 %) were intermediate. In non-MDS cases, 27 of 30 (90 %) were FCM negative, 2 of 30 (6.67 %) intermediate, and 1 of 30 (3.33 %) a hematinic-responsive case, positive. Quantitative parameters that characterized MDS included FCM score of >3, percentage CD34(+) B cells, and expression of CD11b, CD15, and CD56 on myeloblasts. CD71 MFI on CD235a(+) erythroblasts and CD38 MFI on myeloblasts were significantly lower in MDS. The former was present in FCM-intermediate suspected MDS but not FCM-intermediate non-MDS cases. Used in the overall clinical context, both maturation pattern recognition and quantitative approaches, the latter for low-grade MDS, are sensitive methods of diagnosing MDS, including cases negative by morphology and cytogenetics, especially if combined with evaluation of selected antigens, CD71 on CD235a(+) cells and CD38 on CD34(+) cells. The value of FCM in morphology-negative cases needs better definition of specificity through more extensive evaluation of secondary dyspoiesis.

Standardization of flow cytometry in myelodysplastic syndromes: a report from an international consortium and the European LeukemiaNet Working Group

Flow cytometry (FC) is increasingly recognized as an important tool in the diagnosis and prognosis of myelodysplastic syndromes (MDS). However, validation of current assays and agreement upon the techniques are prerequisites for its widespread acceptance and application in clinical practice. Therefore, a working group was initiated (Amsterdam, 2008) to discuss and propose standards for FC in MDS. In 2009 and 2010, representatives from 23, mainly European, institutes participated in the second and third European LeukemiaNet (ELN) MDS workshops. In the present report, minimal requirements to analyze dysplasia are refined. The proposed core markers should enable a categorization of FC results in cytopenic patients as 'normal', 'suggestive of', or 'diagnostic of' MDS. An FC report should include a description of validated FC abnormalities such as aberrant marker expression on myeloid progenitors and, furthermore, dysgranulopoiesis and/or dysmonocytopoiesis, if at least two abnormalities are evidenced. The working group is dedicated to initiate further studies to establish robust diagnostic and prognostic FC panels in MDS. An ultimate goal is to refine and improve diagnosis and prognostic scoring systems. Finally, the working group stresses that FC should be part of an integrated diagnosis rather than a separate technique.

Role of flow cytometry in diagnostics of myelodysplastic syndromes--beyond the WHO 2008 classification

Multiparameter flow cytometry (FCM) is an excellent method to follow the expression patterns of differentiation antigens using monoclonal antibodies to surface and cytoplasmic proteins. Although several authors described various aberrant immunophenotypic features in the bone marrow of patients with myelodysplastic syndromes (MDS), the World Health Organization 2008 classification recommended that, only if 3 or more phenotypic abnormalities are found involving 1 or more of the myeloid lineages can the aberrant FCM findings be considered suggestive of MDS. In the absence of conclusive morphologic and/or cytogenetic features, FCM abnormalities alone were considered not sufficient to establish MDS diagnosis and further follow-up of the patients was recommended. Review of the literature gives accumulating evidence that FCM has become an important part of the integrated diagnostic work-up of patients with suspected MDS. Several studies have also reported FCM findings significant for prognosis and therapy choice in MDS patients. Technical progress in multicolor FCM and new analysis programs, together with ongoing efforts to standardize the methodology, will make it possible to apply FCM in individual risk assessment and choice of best therapy for MDS patients.

Implementation of flow cytometry in the diagnostic work-up of myelodysplastic syndromes in a multicenter approach: report from the Dutch Working Party on Flow Cytometry in MDS

Flow cytometry (FC) is recognized as an important tool in the diagnosis of myelodysplastic syndromes (MDS) especially when standard criteria fail. A working group within the Dutch Society of Cytometry aimed to implement FC in the diagnostic work-up of MDS. Hereto, guidelines for data acquisition, analysis and interpretation were formulated. Based on discussions on analyses of list mode data files and fresh MDS bone marrow samples and recent literature, the guidelines were modified. Over the years (2005-2011), the concordance between the participating centers increased indicating that the proposed guidelines contributed to a more objective, standardized FC analysis, thereby ratifying the implementation of FC in MDS.

Flow cytometry immunophenotyping for the evaluation of bone marrow dysplasia

The pathological hallmark of myelodysplastic syndromes (MDS) is marrow dysplasia, which represents the basis of the WHO classification of these disorders. This classification provides clinicians with a useful tool for defining the different subtypes of MDS and determining individual prognosis. The WHO proposal has raised some concern regarding minimal diagnostic criteria particularly in patients with normal karyotype without robust morphological markers of dysplasia (such as ring sideroblasts or excess of blasts). Therefore, there is clearly a need to refine the accuracy to detect marrow dysplasia. Flow cytometry (FCM) immunophenotyping has been proposed as a tool to improve the evaluation of marrow dysplasia. Rationale for the application of FCM in the diagnostic work up of MDS is that immunophenotyping is an accurate method for quantitative and qualitative evaluation of hematopoietic cells and that MDS have been found to have abnormal expression of several cellular antigens. To become clinically applicable, FCM analysis should be based on parameters with sufficient specificity and sensitivity, data should be reproducible between different operators and the results should be easily understood by clinicians. In this report, we reviewed the most relevant progresses in detection of marrow dysplasia by FCM in MDS as defined by WHO criteria.

Review of the relevance of aberrant antigen expression by flow cytometry in myeloid neoplasms

This article reviews the use of aberrant antigen expression detected by flow cytometry in the diagnosis and clinical handling of acute myeloid leukaemia (AML) and the myelodysplastic syndromes (MDS). Such aberrancies offer a valuable tool for the proper classification of these myeloid malignancies according the World Health Organization 2008 classification. Aberrant antigen expression by flow cytometry is also important for prognostification. This review supports the view, that minimal residual disease detection methods that make use of such aberrancies should be part of the routine management of AML patients to guide therapy, but also suggests the introduction of flow cytometry in MDS for diagnosis and treatment decisions in the near future.