Monitoring treatment with 5-Azacitidine by flow cytometry predicts duration of hematological response in patients with myelodysplastic syndrome

Immunophenotyping myelodysplastic neoplasms: the role of flow cytometry in the molecular classification era

The unique heterogenous landscape of myelodysplastic syndromes/neoplasms (MDS) has resulted in continuous redefinition of disease sub-entities, in view of the novel translational research data that have clarified several areas of the pathogenesis and the progression of the disease. The new international classifications (WHO 2022, ICC 2022) have incorporated genomic data defining phenotypical alterations, that guide clinical management of specific patient subgroups. On the other hand, for over a decade, multiparameter flow cytometry (MFC) has proven its value as a complementary diagnostic tool for these diseases and although it has never been established as a mandatory test for the baseline evaluation of MDS patients in international guidelines, it is almost universally adopted in everyday clinical practice for the assessment of suspected cytopenias through simplified scoring systems or elaborate analytical strategies for the detection of immunophenotypical dysplastic features in every hematopoietic cell lineage in the bone marrow (BM). In this review, we explore the clinically meaningful interplay of MFC data and genetic profiles of MDS patients, to reveal the currently existing and the potential future role of each methodology for routine clinical practice, and the benefit of the patients. We reviewed the existing knowledge and recent advances in the field and discuss how an integrated approach could lead to patient re-stratification and guide personalized management.

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.

Clinical application of flow cytometry in patients with unexplained cytopenia and suspected myelodysplastic syndrome: A report of the European LeukemiaNet International MDS-Flow Cytometry Working Group

This article discusses the rationale for inclusion of flow cytometry (FCM) in the diagnostic investigation and evaluation of cytopenias of uncertain origin and suspected myelodysplastic syndromes (MDS) by the European LeukemiaNet international MDS Flow Working Group (ELN iMDS Flow WG). The WHO 2016 classification recognizes that FCM contributes to the diagnosis of MDS and may be useful for prognostication, prediction, and evaluation of response to therapy and follow-up of MDS patients.

Immunophenotypic changes in juvenile myelomonocytic leukaemia after treatment with hypomethylating agent: Do they help to evaluate dept of response?

5-Azacitidine has been used before stem cell transplantation in juvenile myelomonocytic leukaemia (JMML) patients. Recently, we have described immunophenotypic features in JMML at diagnosis. Here, our aim was to examine the changes in the immunophenotypic features during azacitidine treatment, correlating it with clinical response. Patients treated with 5-azacitidine were evaluated at diagnosis and after three and six cycles of medication. Among 32 patients entering the study, 28 patients were examined after three cycles and 25 patients after six. Patients showed a reduction in CD34/CD117⁺ cells: median 3.35% at diagnosis, 2.8% after three cycles and 1.63% after six. B-cell progenitors were decreased at diagnosis and decreased after treatment. Monocytes decreased: 11.91% to 6.4% and 4.18% respectively. Complete response was associated with increase in classical monocytes. T lymphocytes, reduced at diagnosis, increased in patients responding to 5-azacitidine. Immunophenotypic aberrancies including expression of CD7 in myeloid progenitors remained after treatment. This feature was associated with a worse response to treatment, as well as presence of NF1. Immunophenotyping was feasible in all patients. Clinical response was associated with a decrease of myeloid progenitors and monocytes and a rise in T lymphocytes although phenotypic aberrancies persisted. The largest effect was observed after three cycles.

Lymphocytic Infiltrate and p53 Protein Expression as Predictive Markers of Response and Outcome in Myelodysplastic Syndromes Treated with Azacitidine

High-risk Myelodysplastic syndromes (MDS) represent therapeutical challenges and are usually managed with hypomethylating agents such as azacitidine. Given the lack of data in the literature concerning azacitidine effects on bone marrow, we retrospectively analyzed 57 high-risk MDS cases in order to identify any changes induced by azacitidine therapy or relevant correlations between therapy response and pre- or post-treatment features. Azacitidine treatment had no significant impact on bone marrow cellularity or morphological dysplastic features. On the contrary, although not statistically significant, we observed a slight decrease in CD34+ and CD117+ blasts and p53+ precursors after treatment. Moreover, pre-treatment IPSS-R cytogenetic score (p = 0.004), lymphocytic infiltrate (p = 0.017) and p53+ elements (p = 0.001) correlated with AML progression; pre-treatment lymphocytic infiltrate was also linked to better response to therapy (p = 0.004), suggesting an anti-tumoral role of bone marrow microenvironment. Post-treatment blast count impacted negatively on overall survival (p = 0.035) and risk of leukemic progression (p = 0.04), while both post-treatment lymphocytic infiltrate and p53+ elements showed significant correlation with treatment response (p = 0.004 and p = 0.003 respectively). Higher post-treatment p53+ elements correlated also with risk of leukemic progression (p = 0.013). Our results suggest the possible role of lymphocytic infiltrate and p53+ elements as predictive markers in MDS treated with azacitidine, disclosing new chapters in the understanding of MDS evolution and treatment.