Immunophenotype of myeloid granulocytes: a pilot study for distinguishing myelodysplastic syndrome and aplastic anemia by flow cytometry

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.

Immunophenotypic changes of monocytes in myelodysplastic syndrome and clinical significance

Background

Myelodysplastic syndrome (MDS) is a type of heterogeneous myeloid clonal disorder usually diagnosed based on a combination of multiple laboratory examinations, including analysis of peripheral blood cells, bone marrow cell morphology and cytogenetics. However, there is a certain difficulty in cases with no distinct changes in hematology and marrow cell morphology.

Methods

We adopt flow cytometry to quantitatively analyze the immunophenotypic changes of marrow monocytes according to the surface antigens and their combinations at different differentiation stages, so as to study the changes of monocytes during differentiation in patients with bone marrow failure. In the meantime, the relationship between the immunophenotypic changes of marrow monocytes and IPSS-R score and prognosis of MDS patients was analyzed.

Results

Our results demonstrated disorders of maturation and differentiation of monocytes in patients with MDS and clonal cytopenias of undetermined significance as compared to those with aplastic anemia and healthy individuals. In addition, the differentiation abnormality gradually increased with the disease progression. Furthermore, CD300e expression was found to show significant associations with the clinical stage and disease progression of MDS, and the progression-free survival and AML-free survival were much longer in MDS patients highly expressing CD300e on monocytes.

Conclusions

CCUS and MDS patients have disorders of differentiation and maturation of monocytes, which tends to be more critical with MDS progression or transforms to AML. Moreover, high CD300e expression has the potential to be a favorable prognostic marker for MDS. This study provides important insights to the role of monocyte immunotyping in the diagnosis, differentiation and prognosis of MDS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10238-022-00856-7.

Circulating tumor-associated neutrophils (cTAN) contribute to circulating tumor cell survival by suppressing peripheral leukocyte activation

During malignant progression, primary tumors rebuild leukocyte profile and suppress the host anti-tumor immune response. Tumor-associated neutrophils (TAN) increased in the cancer patients and emerged as an important participant and regulator of immune responses. The aim of this study is to investigate the role of circulating TAN (cTAN) in the metastatic process of advanced malignancy. We tested circulating neutrophils from patients (n = 180) with various types of cancer using flow cytometry analyses. We also used B16F10 cell-implanted C57BL/6 tumor-bearing mice model to simulate the advanced malignancy. Peripheral neutrophils were isolated by ficoll density gradient centrifugation, and in vitro tumor-leukocyte co-culture model was used to test tumor cell survival under leukocyte challenge condition. Here, we showed that neutrophils increased in the peripheral blood under the pathological condition of advanced malignancy both in cancer patients and in tumor-bearing mice. In mouse model, the malignantly increased neutrophils were identified as TAN according to the gene transcriptional analyses. We also showed that cTAN enhance tumor metastasis and cTAN could inhibit the activation of the peripheral leukocytes and rescue tumor cells from leukocyte challenge. In conclusion, our finding suggests that the abundance of cTAN in advanced cancer patients contributes to the circulating tumor cell survival by suppressing peripheral leukocyte activation.