Phenotypic and functional characterization of neutrophils and monocytes from patients with myelodysplastic syndrome by flow cytometry

The immunoregulatory role of monocytes and thrombomodulin in myelodysplastic neoplasms

Myelodysplastic neoplasms (MDS) are clonal disorders of the myeloid lineage leading to peripheral blood cytopenias. Dysregulation of innate immunity is hypothesized to be a potent driver of MDS. A recent study revealed increased thrombomodulin (TM) expression on classical monocytes in MDS, which was associated with prolonged survival. TM is a receptor with immunoregulatory capacities, however, its exact role in MDS development remains to be elucidated. In this review we focus on normal monocyte biology and report on the involvement of monocytes in myeloid disease entities with a special focus on MDS. Furthermore, we delve into the current knowledge on TM and its function in monocytes in health and disease and explore the role of TM-expressing monocytes as driver, supporter or epiphenomenon in the MDS bone marrow environment.

Immune-monitoring of myelodysplastic neoplasms: Recommendations from the i4MDS consortium

Advancements in comprehending myelodysplastic neoplasms (MDS) have unfolded significantly in recent years, elucidating a myriad of cellular and molecular underpinnings integral to disease progression. While molecular inclusions into prognostic models have substantively advanced risk stratification, recent revelations have emphasized the pivotal role of immune dysregulation within the bone marrow milieu during MDS evolution. Nonetheless, immunotherapy for MDS has not experienced breakthroughs seen in other malignancies, partly attributable to the absence of an immune classification that could stratify patients toward optimally targeted immunotherapeutic approaches. A pivotal obstacle to establishing "immune classes" among MDS patients is the absence of validated accepted immune panels suitable for routine application in clinical laboratories. In response, we formed International Integrative Innovative Immunology for MDS (i4MDS), a consortium of multidisciplinary experts, and created the following recommendations for standardized methodologies to monitor immune responses in MDS. A central goal of i4MDS is the development of an immune score that could be incorporated into current clinical risk stratification models. This position paper first consolidates current knowledge on MDS immunology. Subsequently, in collaboration with clinical and laboratory specialists, we introduce flow cytometry panels and cytokine assays, meticulously devised for clinical laboratories, aiming to monitor the immune status of MDS patients, evaluating both immune fitness and identifying potential immune "risk factors." By amalgamating this immunological characterization data and molecular data, we aim to enhance patient stratification, identify predictive markers for treatment responsiveness, and accelerate the development of systems immunology tools and innovative immunotherapies.

The Absolute Monocyte Count at Diagnosis Affects Prognosis in Myelodysplastic Syndromes Independently of the IPSS-R Risk Score

The absolute monocyte count (AMC) is associated with mortality in a variety of medical conditions. Its prognostic impact in myelodysplastic syndromes (MDSs) is less well studied. Therefore, we investigated its potential prognostic value in a cohort from the Düsseldorf MDS registry in relationship to the revised international prognostic scoring system (IPSS-R). An AMC below the population's median (<0.2 × 109/L) was associated with several adverse disease features such as lower haemoglobin levels, lower count of neutrophils and platelets, and a higher percentage of blasts in the bone marrow. MDS patients with an AMC < 0.2 × 109/L had a significantly higher risk of progression into acute myeloid leukemia (AML). In a univariate, proportional hazards model the effect of the AMC as a continuous variable was modelled via p-splines. We found a U-shaped effect with the lowest hazard around 0.3 × 109/L. Accordingly, an AMC within the last quartile of the population (0.4 × 109/L) was associated with a reduced overall survival independently of IPSS-R, but not with the risk of secondary AML. Considering monocytopenia as a risk factor for AML progression in MDS may provide an additional argument for allogeneic transplantation or the use of hypomethylating agents in patients who are not clear candidates for those treatments according to current prognostic scoring systems and/or recommendations. Further studies are needed to assess the prognostic impact of the AMC in the context of prognostic scoring systems, considering the molecular risk profile, and to identify the mechanisms responsible for the higher mortality in MDS patients with a subtle monocytosis.

Increased Circulating of CD54highCD181low Neutrophils in Myelodysplastic Syndrome

Myelodysplastic syndromes (MDSs) are a group of heterogeneous hematopoietic stem/progenitor cells clonal diseases, characteristic features with myeloid dysplasia, leading to abnormality of neutrophils. Recent studied have showed that neutrophils act not only as professional killers, but also as regulators of innate and adaptive immune in infection and inflammatory condition. The CD54^highCD181^low neutrophils are a kind of reverse-transmigrated neutrophils characterized proinflammatory phenotype. We investigated the frequency and functional properties of circulating CD54^highCD181^low neutrophils in patients with untreated MDS. Frequency of CD54^highCD181^low neutrophils was significantly increased in MDS patients and related to the severity of the disease. Furthermore, CD54^highCD181^low neutrophils suppressed CD8+ T cells functions in vitro. CD54^highCD181^low neutrophils lead to upregulation of PD1 on CD8+ T cells. Higher CD54^highCD181^low neutrophils were related to poor prognosis and more infections. The frequency of CD54^highCD181^low neutrophils decreased in high risk MDS patients who had response after treatment with decitabine. Overall, we identified CD54^highCD181^low neutrophils expanded in MDS. The exact mechanisms of increased CD54^highCD181^low neutrophils and its effect on immune function remain to be elucidated.

Integrating the "Immunome" in the Stratification of Myelodysplastic Syndromes and Future Clinical Trial Design

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis and often include a dysregulation and dysfunction of the immune system. In the context of population aging, MDS incidence is set to increase substantially, with exponential increases in health care costs, given the limited and expensive treatment options for these patients. Treatment selection is mainly based on calculated risk categories according to a Revised International Prognostic Scoring System (IPSS-R). However, although IPSS-R is an excellent predictor of disease progression, it is an ineffective predictor of response to disease-modifying therapies. Redressing these unmet needs, the "immunome" is a key, multifaceted component in the initiation and overall response against malignant cells in MDS, and the current omission of immune status monitoring may in part explain the insufficiencies of current prognostic stratification methods. Nevertheless, integrating these and other recent molecular advances into clinical practice proves difficult. This review highlights the complexity of immune dysregulation in MDS pathophysiology and the fine balance between smoldering inflammation, adaptive immunity, and somatic mutations in promoting or suppressing malignant clones. We review the existing knowledge and discuss how state-of-the-art immune monitoring strategies could potentially permit novel patient substratification, thereby empowering practical predictions of response to treatment in MDS. We propose novel multicenter studies, which are needed to achieve this goal.

The investigation of immunomodulatory effects of adipose tissue mesenchymal stem cell educated macrophages on the CD4 T cells

Mesenchymal stem cells (MSCs) are strong immunomodulatory cells investigated in numerous clinical studies on fatal pathologies, such as graft versus host disease and autoimmune diseases; e.g., systemic lupus erythematosus, Crohn's disease, and ulcerative colitis. Macrophages are one of the critical cells linking the innate and adaptive immune system, and it has been shown that MSCs can differentiate between pro-inflammatory M1 phenotype and anti-inflammatory M2 phenotype of macrophages. However, it has not yet been fully clarified whether these differentiated macrophages are functional. In this study, we compared the immunomodulatory effects on the CD4 T cells of M1, M2a and M2c macrophages with the macrophages that directly and indirectly cultured with MSCs. We analyzed the changes in CD14, CD64, CD80, CD163 and CD200R expression to evaluate macrophage phenotypes, and the changes in CD4, IFN-g, IL-4, IL-17a and FoxP3 expression to evaluate T helper subsets using the FACS method. The changes in IL-1b, IL-4, IL-10, IL-12p70, IL-17a and IFN-g in the media supernatants were analyzed using the Luminex method. We also performed WST-1 and Caspase-3 ELISA analyses to observe the proliferation and apoptosis status of the T cells. MSCs were found to differentiate macrophages into a distinctive phenotype, which was close to the M2c phenotype, but was not considered as an M2c cell due to the low expression of CD163, a characteristic marker for M2c. While MEM-D, MEM-ID and MSCs showed similar inhibitory effects on the Th2 and Th17 cells, the most significant increase in Treg cell frequencies was seen in MEM-D cells. Macrophages can alter their phenotypes and functions according to the stimuli from the environment. The fact that macrophages educated with MSCs suppressed the production of all the cytokines we evaluated even after the removal of MSCs suggests that these cells may be differentiated by MSCs into a suppressive macrophage subgroup. However, the Treg cell activation caused by direct interactions between MSCs and macrophage cells may be the most prominent observation of this study compared to previous work. As a result, according to our data, the interactions between MSCs and macrophages may lead to differentiation of macrophage cells into an immunosuppressive phenotype, and these macrophages may suppress the T lymphocyte subgroups at least as effectively as MSCs. However, our data obtained from in vitro experiments should be supported by future in vivo studies.

Surveillance of Myelodysplastic Syndrome via Migration Analyses of Blood Neutrophils: A Potential Prognostic Tool

Autonomous migration is a central characteristic of immune cells, and changes in this function have been correlated to the progression and severity of diseases. Hence, the identification of pathologically altered leukocyte migration patterns might be a promising approach for disease surveillance and prognostic scoring. However, because of the lack of standardized and robust assays, migration patterns have not been clinically exploited so far. In this study, we introduce an easy-to-use and cross-laboratory, standardized two-dimensional migration assay for neutrophil granulocytes from peripheral blood. By combining time-lapse video microscopy and automated cell tracking, we calculated the average migration of neutrophils from 111 individual participants of the German Heinz Nixdorf Recall MultiGeneration study under steady-state, formyl-methionyl-leucyl-phenylalanine-, CXCL1-, and CXCL8-stimulated conditions. Comparable values were obtained in an independent laboratory from a cohort in Belgium, demonstrating the robustness and transferability of the assay. In a double-blinded retrospective clinical analysis, we found that neutrophil migration strongly correlated with the Revised International Prognostic Scoring System scoring and risk category of myelodysplastic syndrome (MDS) patients. In fact, patients suffering from high-risk subtypes MDS with excess blasts I or II displayed highly significantly reduced neutrophil migration. Hence, the determination of neutrophil migration patterns might represent a useful tool in the surveillance of MDS. Taken together, we suggest that standardized migration assays of neutrophils and other leukocyte subtypes might be broadly applicable as prognostic and surveillance tools for MDS and potentially for other diseases.

Monocyte function in patients with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a malignant hematopoietic stem cell disorder that frequently evolves into acute myeloid leukemia (AML). Patients with MDS are prone to infectious complications, in part due to the presence of severe neutropenia and/or neutrophil dysfunction. However, not all patients with neutropenia become infected, suggesting that other immune cells may compensate in these patients. Monocytes are also integral to immunologic defense; however, much less is known about monocyte function in patients with MDS. In the current study, we monitor the composition of peripheral blood monocytes and several aspects of monocyte function in MDS patients, including HLA-DR expression, LPS-induced inflammatory cytokine production, and phagocytosis. We find that monocytes from MDS patients exhibit relatively normal innate immune functions compared to monocytes from healthy control subjects. We also find that HLA-DR expression is moderately increased in monocytes from MDS patients. These results suggest that monocytes could compensate for other immune deficits in MDS patients to help fight infection. We also find that the range of immune functions in monocytes from MDS patients correlates with several key clinical parameters, including blast cell count, monocyte count, and revised International Prognostic Scoring System score, suggesting that disease severity impacts monocyte function in MDS patients.

Advances in Proteomic Techniques for Cytokine Analysis: Focus on Melanoma Research

Melanoma is a skin cancer with permanently increasing incidence and resistance to therapies in advanced stages. Reports of spontaneous regression and tumour infiltration with T-lymphocytes makes melanoma candidate for immunotherapies. Cytokines are key factors regulating immune response and intercellular communication in tumour microenvironment. Cytokines may be used in therapy of melanoma to modulate immune response. Cytokines also possess diagnostic and prognostic potential and cytokine production may reflect effects of immunotherapies. The purpose of this review is to give an overview of recent advances in proteomic techniques for the detection and quantification of cytokines in melanoma research. Approaches covered span from mass spectrometry to immunoassays for single molecule detection (ELISA, western blot), multiplex assays (chemiluminescent, bead-based (Luminex) and planar antibody arrays), ultrasensitive techniques (Singulex, Simoa, immuno-PCR, proximity ligation/extension assay, immunomagnetic reduction assay), to analyses of single cells producing cytokines (ELISpot, flow cytometry, mass cytometry and emerging techniques for single cell secretomics). Although this review is focused mainly on cancer and particularly melanoma, the discussed techniques are in general applicable to broad research field of biology and medicine, including stem cells, development, aging, immunology and intercellular communication.

Infectious complications in patients with myelodysplastic syndromes: A review of the literature with emphasis on patients treated with 5-azacitidine

Myelodysplastic Syndromes are oligo-clonal stem cell disorders that are associated with cytopenias in the peripheral blood. Major causes for morbidity and mortality in myelodysplastic syndromes (MDS) patients are infections mostly due to bacteria or fungi. Beside leucopenia per se in affected patients, function of white blood cells particularly that of neutrophils seems to be impaired. Here we summarize the available data on infections in MDS patients in general and particularly those treated with 5-azacitidine.