Prevalence and clinical association of clonal T-cell expansions in Myelodysplastic Syndrome

The Emerging Role of CD8+ T Cells in Shaping Treatment Outcomes of Patients with MDS and AML

CD8+ T cells are critical players in anti-tumor immunity against solid tumors, targeted by immunotherapies. Emerging evidence suggests that CD8+ T cells also play a crucial role in anti-tumor responses and determining treatment outcomes in hematologic malignancies like myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML). In this review, we focus on the implication of CD8+ T cells in the treatment response of patients with MDS and AML. First, we review reported studies of aberrant functionality and clonality of CD8+ T cells in MDS and AML, often driven by the immunosuppressive bone marrow microenvironment, which can hinder effective antitumor immunity. Additionally, we discuss the potential use of CD8+ T cell subpopulations, including memory and senescent-like subsets, as predictive biomarkers for treatment response to a variety of treatment regimens, such as hypomethylating agents, which is the standard of care for patients with higher-risk MDS, and chemotherapy which is the main treatment of patients with AML. Understanding the multifaceted role of CD8+ T cells and their interaction with malignant cells in MDS and AML will provide useful insights into their potential as prognostic/predictive biomarkers, but also uncover alternative approaches to novel treatment strategies that could reshape the therapeutic landscape, thus improving treatment efficacy, aiding in overcoming treatment resistance and improving patient survival in these challenging myeloid neoplasms.

Clonal hematopoiesis in large granular lymphocytic leukemia

Past studies described occasional patients with myeloid neoplasms (MN) and coexistent large granular lymphocytic leukemia (LGLL) or T-cell clonopathy of unknown significance (TCUS), which may represent expansion of myeloid clonal hematopoiesis (CH) as triggers or targets of clonal cytotoxic T cell reactions. We retrospectively analyzed 349 LGLL/TCUS patients, 672 MN patients, and 1443 CH individuals to establish the incidence, genetic landscape, and clinical phenotypes of CH in LGLL. We identified 8% of cases overlapping with MN, while CH was found in an additional 19% of cases (CH + /LGLL) of which TET2 (23%) and DNMT3A (14%) were the most common. In MN cohort, 3% of cases showed coexistent LGLL. The incidence of CH in LGLL was exceedingly higher than age-matched CH controls (P < 0.0001). By multivariate analysis, the presence of CH in LGLL (P = 0.026) was an independent risk factor for cytopenia in addition to older age (P = 0.003), splenomegaly (P = 0.015) and STAT3/5B mutations (P = 0.001). CH + /LGLL cases also showed a higher progression rate to MN than CH-/LGLL (10% vs. 2% at 5 years; P = 0.02). A close relationship between CH and LGLL suggests that cytopenia in LGLL may be not only related to LGLL but be also secondary to coexisting clonal cytopenia of unclear significance.

Elucidating the Role of the T Cell Receptor Repertoire in Myelodysplastic Neoplasms and Acute Myeloid Leukemia

T cells, as integral components of the adaptive immune system, recognize diverse antigens through unique T cell receptors (TCRs). To achieve this, during T cell maturation, the thymus generates a wide repertoire of TCRs. This is essential for understanding cancer evolution, progression, and the efficacy of immunotherapies. Myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML) are hematological neoplasms that are characterized by immune evasion mechanisms, with immunotherapy giving only modest results thus far. Our review of TCR repertoire dynamics in these diseases reveals distinct patterns: MDS patients show increased TCR clonality with disease progression, while AML exhibits varied TCR signatures depending on disease stage and treatment response. Understanding these patterns has important clinical implications, as TCR repertoire metrics may serve as potential biomarkers for disease progression and treatment response, particularly in the context of immunotherapy and stem cell transplantation. These insights could guide patient stratification and treatment selection, ultimately improving therapeutic outcomes in MDS and AML.

Single-Cell Analysis of Bone Marrow CD8+ T Cells in Myeloid Neoplasms Reveals Pathways Associated with Disease Progression and Response to Treatment with Azacitidine

Immunophenotypic analysis identified a BM CD57+CXCR3+ subset of CD8+ T cells associated with response to AZA in patients with MDS and AML. Single-cell RNA sequencing analysis revealed that IFN signaling is linked to the response to treatment, whereas TGF-β signaling is associated with treatment failure, providing insights into new therapeutic approaches.

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 immunome of mobilized peripheral blood stem cells is predictive of long-term outcomes and therapy-related myeloid neoplasms in patients with multiple myeloma undergoing autologous stem cell transplant

Upfront autologous stem cell transplant (ASCT) is the standard of care for newly diagnosed multiple myeloma (MM) patients. However, relapse is ubiquitous and therapy-related myeloid neoplasms (t-MN) post-ASCT are commonly associated with poor outcomes. We hypothesized that the enrichment of abnormal myeloid progenitors and immune effector cells (IEC) in the peripheral blood stem cells (PBSCs) is associated with a higher risk of relapse and/or development of t-MN. We performed a comprehensive myeloid and lymphoid immunophenotyping on PBSCs from 54 patients with MM who underwent ASCT. Median progression-free (PFS), myeloid neoplasm-free (MNFS), and overall survival (OS) from ASCT were 49.6 months (95% CI: 39.5-Not Reached), 59.7 months (95% CI: 55-74), and 75.6 months (95% CI: 62-105), respectively. Abnormal expression of CD7 and HLA-DR on the myeloid progenitor cells was associated with an inferior PFS, MNFS, and OS. Similarly, enrichment of terminally differentiated (CD27/CD28-, CD57/KLRG1+) and exhausted (TIGIT/PD-1+) T-cells, and inhibitory NK-T like (CD159a+/CD56+) T-cells was associated with inferior PFS, MNFS, and OS post-transplant. Our observation of abnormal myeloid and IEC phenotype being present even before ASCT and maintenance therapy suggests an early predisposition to t-MN and inferior outcomes for MM, and has the potential to guide sequencing of future treatment modalities.

Inappropriate Expression of PD-1 and CTLA-4 Checkpoints in Myeloma Patients Is More Pronounced at Diagnosis: Implications for Time to Progression and Response to Therapeutic Checkpoint Inhibitors

Multiple myeloma (MM) is a hematologic malignancy characterized by severely profound immune dysfunction. Therefore, the efficacy of drugs targeting the immune environments, such as immune checkpoint inhibitors (ICIs), is of high clinical importance. However, several clinical trials evaluating ICIs in MM in different therapeutic combinations revealed underwhelming results showing a lack of clinical efficacy and excessive side effects. The underlying mechanisms of resistance to ICIs observed in the majority of MM patients are still under investigation. Recently, we demonstrated that inappropriate expression of PD-1 and CTLA-4 on CD4 T cells in active MM is associated with adverse clinical outcomes and treatment status. The aim of the current study was to determine the usefulness of immune checkpoint expression assessment as a predictive biomarker of the response to therapeutic inhibitors. For this purpose, along with checkpoint expression estimated by flow cytometry, we evaluated the time to progression (TTP) of MM patients at different clinical stages (disease diagnosis and relapse) depending on the checkpoint expression level; the cut-off point (dividing patients into low and high expressors) was selected based on the median value. Herein, we confirmed the defective levels of regulatory PD-1, CTLA-4 receptors, and the CD69 marker activation in newly diagnosed (ND) patients, whereas relapsed/refractory patients (RR) exhibited their recovered values and reactivity. Additionally, substantially higher populations of senescent CD4+CD28− T cells were found in MM, primarily in NDMM subjects. These observations suggest the existence of two dysfunctional states in MM CD4 T cells with the predominance of immunosenescence at disease diagnosis and exhaustion at relapse, thus implying different responsiveness to the external receptor blockade depending on the disease stage. Furthermore, we found that lower CTLA-4 levels in NDMM patients or higher PD-1 expression in RRMM patients may predict early relapse. In conclusion, our study clearly showed that the checkpoint level in CD4 T cells may significantly affect the time to MM progression concerning the treatment status. Therefore, when considering novel therapies and potent combinations, it should be taken into account that blocking PD-1 rather than CTLA-4 might be a beneficial form of immunotherapy for only a proportion of RRMM patients.

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.

Cutaneous T-cell lymphomas: 2023 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multidisciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or the blood involvement are generally approached with systemic therapies, including biologic-response modifiers, histone deacetylase inhibitors, or antibody-based strategies, in an escalating fashion. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Bone Marrow Immune Microenvironment in Myelodysplastic Syndromes

The BM, the major hematopoietic organ in humans, consists of a pleiomorphic environment of cellular, extracellular, and bioactive compounds with continuous and complex interactions between them, leading to the formation of mature blood cells found in the peripheral circulation. Systemic and local inflammation in the BM elicit stress hematopoiesis and drive hematopoietic stem cells (HSCs) out of their quiescent state, as part of a protective pathophysiologic process. However, sustained chronic inflammation impairs HSC function, favors mutagenesis, and predisposes the development of hematologic malignancies, such as myelodysplastic syndromes (MDS). Apart from intrinsic cellular mechanisms, various extrinsic factors of the BM immune microenvironment (IME) emerge as potential determinants of disease initiation and evolution. In MDS, the IME is reprogrammed, initially to prevent the development, but ultimately to support and provide a survival advantage to the dysplastic clone. Specific cellular elements, such as myeloid-derived suppressor cells (MDSCs) are recruited to support and enhance clonal expansion. The immune-mediated inhibition of normal hematopoiesis contributes to peripheral cytopenias of MDS patients, while immunosuppression in late-stage MDS enables immune evasion and disease progression towards acute myeloid leukemia (AML). In this review, we aim to elucidate the role of the mediators of immune response in the initial pathogenesis of MDS and the evolution of the disease.

Bone Marrow CD3+ CD56+ Regulatory T lymphocytes (TR3-56 cells) are inversely associated with activation and expansion of Bone Marrow cytotoxic T cells in IPSS-R very-low/low risk MDS patients

Background

Emergence of dysplastic haematopoietic precursor/s, cytopenia and variable leukaemia risk characterise myelodysplastic syndromes (MDS). Impaired immune‐regulation, preferentially affecting cytotoxic T cells (CTL), has been largely observed in MDS. Recently, we described the T_R3−56 T cell subset, characterised by the co‐expression of CD3 and CD56, as a novel immune‐regulatory population, able to modulate cytotoxic functions. Here, we address the involvement of T_R3−56 cells in MDS pathogenesis/progression.

Objectives

To analyse the relationship between T_R3−56 and CTL activation/expansion in bone marrow (BM) of very‐low/low‐risk MDS subjects.

Methods

Peripheral blood and BM specimens, obtained at disease onset in a cohort of 58 subjects, were analysed by immune‐fluorescence and flow cytometry, to preserve the complexity of the biological sample.

Results

We observed that a trend‐increase of BM T_R3−56 in high/very‐high MDS stage, as compared with very‐low/low group, associates with a decreased activation of BM resident CTL; significant correlation of T_R3−56 with BM blasts has been also revealed. In addition, in very‐low/low‐risk subjects the T_R3−56 amount in BM inversely correlates with the presence of activated BM CTL showing a skewed Vβ T‐cell repertoire.

Conclusions

These data add T_R3−56 to the immune‐regulatory network involved in MDS pathogenesis/progression. Better knowledge of the immune‐mediated processes associated with the disease might improve MDS clinical management.

Dysregulation of immune cell and cytokine signaling correlates with clinical outcomes in myelodysplastic syndrome (MDS)

OBJECTIVES

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis. Although hypomethylating agents (HMA) have improved survival in higher-risk MDS, most patients eventually succumb to progressive disease. Utilizing samples collected prospectively from three MDS clinical trials, we analyzed genetic and immunological biomarkers and correlated them with clinical outcomes.

METHODS

154 samples were analyzed from 133 de novo MDS patients for T-cell and myeloid cell immunophenotyping and gene expression analysis. Treatments were with HMA or immunomodulatory drug (IMiD) alone or in combination.

RESULTS

We observed differences in immune cell subsets between lower and higher risk IPSS groups with NKT cells, MDSCs, intermediate-proinflammatory and non-classical monocytes being higher in the latter group while naïve CD4+ T-cells were reduced. Intermediate-proinflammatory monocytes were increased in non-responders and those failing to achieve at least a hematological improvement. Pro-inflammatory NKT cells were increased at diagnosis for patients failing to derive clinical benefit after 12 months of treatment. Gene expression analysis of paired bone marrow (BM) colony-forming units (CFUs) from diagnosis and 4 cycles post-treatment confirmed that genes involved in cytokine signaling were downregulated in C4 normal colonies.

CONCLUSIONS

These findings support the central roles of dysregulation in innate immunity and inflammatory signaling in the pathogenesis of MDS which correlated with clinical outcomes post-treatment.

Looking beyond VEXAS: Coexistence of undifferentiated systemic autoinflammatory disease and myelodysplastic syndrome

It has been established that individuals with myelodysplastic syndromes (MDS) have a higher frequency of systemic inflammatory disorders. On the other hand, patients with autoimmune diseases are at increased risk of MDS development. Both diseases can be associated with various genetic lesions and share diverse pathogenetic mechanisms. Recently identified VEXAS (Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic) syndrome, associated with somatic mutations in UBA1, encompasses a range of inflammatory conditions involving multiple organs along with hematological pathologies, including MDS, as well as characteristic bone marrow vacuolization of myeloid and erythroid precursors. This novel syndrome drove further attention to complex associations between MDS and adult-onset inflammatory conditions. The present narrative literature review discusses the clinical presentation, pathophysiology, management of concurrent MDS and systemic inflammatory diseases in parallel to the clinical picture of VEXAS syndrome.

From Immune Dysregulations to Therapeutic Perspectives in Myelodysplastic Syndromes: A Review

The pathophysiology of myelodysplastic syndromes (MDSs) is complex and often includes immune dysregulation of both the innate and adaptive immune systems. Whereas clonal selection mainly involves smoldering inflammation, a cellular immunity dysfunction leads to increased apoptosis and blast proliferation. Addressing immune dysregulations in MDS is a recent concept that has allowed the identification of new therapeutic targets. Several approaches targeting the different actors of the immune system have therefore been developed. However, the results are very heterogeneous, indicating the need to improve our understanding of the disease and interactions between chronic inflammation, adaptive dysfunction, and somatic mutations. This review highlights current knowledge of the role of immune dysregulation in MDS pathophysiology and the field of new drugs.

Cutaneous T-cell lymphomas: 2021 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multi-disciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or blood involvement are generally approached with systemic therapies, including biologic-response modifiers, histone deacetylase inhibitors, or antibody-based strategies, in an escalating fashion. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Cutaneous T cell lymphoma

Primary cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of lymphomas that present in the skin with no evidence of extracutaneous disease at the time of diagnosis. CTCL subtypes demonstrate a variety of clinical, histological, and molecular features, and can follow an indolent or a very aggressive course. The underlying pathogenetic mechanisms are not yet entirely understood. The pathophysiology of CTCL is complex and a single initiating factor has not yet been identified. Diagnosis is based on clinicopathological correlation and requires an interdisciplinary team. Treatment decision is made based on short-term and long-term goals. Therapy options comprise skin-directed therapies, such as topical steroids or phototherapy, and systemic therapies, such as monoclonal antibodies or chemotherapy. So far, the only curative treatment approach is allogeneic haematopoietic stem cell transplantation. Novel therapies, such as chimeric antigen receptor T cells, monoclonal antibodies or small molecules, are being investigated in clinical trials. Patients with CTCL have reduced quality of life and a lack of effective treatment options. Further research is needed to better identify the underlying mechanisms of CTCL development and course as well as to better tailor treatment strategies to individual patients.

Immunologic effects on the haematopoietic stem cell in marrow failure

Acquired bone marrow failure (BMF) syndromes comprise a diverse group of diseases with variable clinical manifestations but overlapping features of immune activation, resulting in haematopoietic stem and progenitor cells (HSPC) damage and destruction. This review focuses on clinical presentation, pathophysiology, and treatment of four BMF: acquired aplastic anaemia, large granular lymphocytic leukaemia, paroxysmal nocturnal haemoglobinuria, and hypoplastic myelodysplastic syndrome. Autoantigens are speculated to be the inciting event that result in immune activation in all of these diseases, but specific pathogenic antigens have not been identified. Oligoclonal cytotoxic T cell expansion and an active role of proinflammatory cytokines, primarily interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α), are two main contributors to HSPC growth inhibition and apoptosis in BMF. Emerging evidence also suggests involvement of the innate immune system.

Myelodysplastic Syndromes: A New Decade

Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal hematopoietic stem cell disorders. The 2020 Surveillance, Epidemiology, and End Results data demonstrates the incidence rate of MDS increases with age especially in those greater than 70 years of age. Risk stratification that impact prognosis, survival, and rate of acute myeloid leukemia (AML) transformation in MDS is largely dependent on revised International Prognostic Scoring System along with molecular genetic testing as a supplement. Low risk MDS typically have a more indolent disease course in which treatment is only initiated to ameliorate symptoms of cytopenias. In many, anemia is the most common cytopenia requiring treatment and erythroid stimulating agents, are considered first line. In contrast, high risk MDS tend to behave more aggressively for which treatment should be initiated rapidly with Hypomethylating Agents (HMA) being in the frontline. In those with high risk MDS and eligible, evaluation for allogeneic stem cell transplant should be considered as this is the only potential curative option for MDS. With the use of molecular genetic testing, a personalized approach to therapy in MDS has ensued. As the treatment landscape in MDS continues to flourish with novel targeted agents, we ambitiously seek to improve survival rates especially among the relapsed/refractory and transplant ineligible.

Inflammatory and Immune Disorders Associated with Myelodysplastic Syndromes

Systemic auto-inflammatory or autoimmune diseases (SIADs) develop in up to a quarter of patients with myelodysplastic syndromes (MDS) or chronic myelomonocytic leukemia (CMML). With or without the occurrence of SIADs, the distribution of MDS subtypes and the international or CMML-specific prognostic scoring systems have been similar between MDS/CMML patients. Moreover, various SIADs have been described in association with MDS, ranging from limited clinical manifestations to systemic diseases affecting multiple organs. Defined clinical entities including systemic vasculitis, connective tissue diseases, inflammatory arthritis and neutrophilic diseases are frequently reported; however, unclassified or isolated organ impairment can also be seen. Although the presence of SIADs does not impact the overall survival nor disease progression to acute myeloid leukemia, they can help with avoiding steroid dependence and make associated adverse events of immunosuppressive drugs challenging. While therapies using steroids and immunosuppressive treatment remain the backbone of first-line treatment, increasing evidence suggests that MDS specific therapy (hypomethylating agents) and sparing steroids may be effective in treating such complications based on their immunomodulatory effect. The aim of this review was to analyze the epidemiological, pathophysiological, clinical and therapeutic factors of systemic inflammatory and immune disorders associated with MDS.

[Prognostic factors of cyclosporine A combined with danazol with or without thalidomide in myelodysplastic syndrome treatment with low-percentage bone marrow blasts]

Objective: To explore the outcome of cyclosporine A (CsA) combined with danazol with or without thalidomide regimen for myelodysplastic syndrome (MDS) with low-percentage bone marrow blasts and predictive factors for treatment response. Methods: Data of 115 subjects who were newly diagnosed with primary MDS with low-percentage bone marrow blasts and were treated with CsA combined with danazol with or without thalidomide from December 2011 to December 2019 in our center were collected. Their clinical features, efficacy, and predictive factors of efficacy were retrospectively analyzed. A model for predicting this response was developed. Results: A total of 55 subjects responded (47.8%) , including 11 complete responses and 44 hematologic improvements. Fifty-two patients (52/105, 49.5%) achieved erythrocyte response; 35 (35/86, 40.7%) , platelet response; and 14 (14/40, 35%) , neutrophil response. Of 29 subjects (24.1%) , 7 who were red blood cell (RBC) transfusion-dependent became independent of transfusion. The median response duration was 20 months (range, 3-84 months) . In the univariate analysis, patients <0 years had a higher response rate than those ≥60 years (52.5% vs 22.2%, P=0.018) . Contrarily, the response rate was substantially decreased in patients with RBC transfusion dependence compared with those without RBC transfusion dependence (24.1% vs 55.8%, P=0.003) , as well as in patients with the mutated U2AF1 compared with those with the wild-type U2AF1 (26.1% vs 53.2%, P=0.020) . In multivariable analyses, age <0 years (OR=4.302, 95% CI 1.245-14.820, P=0.021) , RBC transfusion dependence (OR=3.774, 95% CI 1.400-10.177, P=0.009) , and U2AF1 mutation (OR=3.414, 95% CI 1.168-9.978, P=0.025) were significantly correlated with response. Variables that independently predicted the response were combined to generate the predictive model. According to the model, the overall response rates of patients with 0, 1, 2, and 3 risk factors were 65%, 30%-35%, 10%-15%, and 3%, respectively. Conclusion: CsA combined with danazol with or without thalidomide regimen could improve cytopenia symptoms in patients with MDS with low-percentage bone marrow blasts. At age <60 years, no transfusion dependence of RBC and wild-type U2AF1 mutation is a favorable prognostic factor.

Prognostic value of indoleamine 2,3 dioxygenase in patients with higher-risk myelodysplastic syndromes treated with azacytidine

Hypomethylating agents (HMAs) are widely used in patients with higher-risk myelodysplastic syndromes (MDS) not eligible for stem cell transplantation; however, the response rate is <50%. Reliable predictors of response are still missing, and it is a major challenge to develop new treatment strategies. One current approach is the combination of azacytidine (AZA) with checkpoint inhibitors; however, the potential benefit of targeting the immunomodulator indoleamine-2,3-dioxygenase (IDO-1) has not yet been evaluated. We observed moderate to strong IDO-1 expression in 37% of patients with high-risk MDS. IDO-1 positivity was predictive of treatment failure and shorter overall survival. Moreover, IDO-1 positivity correlated inversely with the number of infiltrating CD8⁺ T cells, and IDO-1+ patients failed to show an increase in CD8⁺ T cells under AZA treatment. In vitro experiments confirmed tryptophan catabolism and depletion of CD8⁺ T cells in IDO-1+ MDS, suggesting that IDO-1 expression induces an immunosuppressive microenvironment in MDS, thereby leading to treatment failure under AZA treatment. In conclusion, IDO-1 is expressed in more than one-third of patients with higher-risk MDS, and is predictive of treatment failure and shorter overall survival. Therefore, IDO-1 is emerging as a promising predictor and therapeutic target, especially for combination therapies with HMAs or checkpoint inhibitors.

Src Tyrosine Kinase Inhibitors: New Perspectives on Their Immune, Antiviral, and Senotherapeutic Potential

Deregulated activity of the Src tyrosine kinases leads to malignant transformation. Since the FDA approval of the tyrosine kinase inhibitor, imatinib, in 2001 for the treatment of chronic myeloid leukemia (CML), the number of these inhibitors together with Src tyrosine kinase inhibitors (STKIs) has increased notably due to their beneficial effects. Dasatinib, a second-generation STKI inhibitor widely studied, proved high efficiency in CML patients resistant to imatinib. In the last decade STKIs have also been implicated and showed therapeutic potential for the treatment of diverse pathologies other than cancer. In this regard, we review the properties of STKIs, dasatinib in particular, including its immunomodulatory role. Similarly, the potential benefits, adverse effects, and safety concerns of these inhibitors regarding viral infections are considered. Moreover, since life expectancy has increased in the last decades accompanied by age-related morbidity, the reduction of undesirable effects associated to aging has become a powerful therapeutic target. Here, we comment on the ability of STKIs to alleviate age-associated physical dysfunction and their potential impact in the clinic.

Mycosis fungoides and Sézary syndrome: 2019 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas (CTCL) are a heterogenous group of T-cell neoplasms involving the skin, the majority of which may be classified as Mycosis fungoides (MF) or Sézary syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multi-disciplinary approach to treatment. For patients with disease limited to the skin, skin-directed therapies are preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or blood involvement are generally approached with systemic therapies. These include biologic-response modifiers, histone deacetylase (HDAC) inhibitors, or antibody-based strategies, in an escalating fashion. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Treatment of Lymphoid and Myeloid Malignancies by Immunomodulatory Drugs

Thalidomide and its derivatives (lenalidomide, pomalidomide, avadomide, iberdomide hydrochoride, CC-885 and CC-90009) form the family of immunomodulatory drugs (IMiDs). Lenalidomide (CC5013, Revlimid®) was approved by the US FDA and the EMA for the treatment of multiple myeloma (MM) patients, low or intermediate-1 risk transfusion-dependent myelodysplastic syndrome (MDS) with chromosome 5q deletion [del(5q)] and relapsed and/or refractory mantle cell lymphoma following bortezomib. Lenalidomide has also been studied in clinical trials and has shown promising activity in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). Lenalidomide has anti-inflammatory effects and inhibits angiogenesis. Pomalidomide (CC4047, Imnovid® [EU], Pomalyst® [USA]) was approved for advanced MM insensitive to bortezomib and lenalidomide. Other IMiDs are in phases 1 and 2 of clinical trials. Cereblon (CRBN) seems to have an important role in IMiDs action in both lymphoid and myeloid hematological malignancies. Cereblon acts as the substrate receptor of a cullin-4 really interesting new gene (RING) E3 ubiquitin ligase CRL4CRBN. This E3 ubiquitin ligase in the absence of lenalidomide ubiquitinates CRBN itself and the other components of CRL4CRBN complex. Presence of lenalidomide changes specificity of CRL4CRBN which ubiquitinates two transcription factors, IKZF1 (Ikaros) and IKZF3 (Aiolos), and casein kinase 1α (CK1α) and marks them for degradation in proteasomes. Both these transcription factors (IKZF1 and IKZF3) stimulate proliferation of MM cells and inhibit T cells. Low CRBN level was connected with insensitivity of MM cells to lenalidomide. Lenalidomide decreases expression of protein argonaute-2, which binds to cereblon. Argonaute-2 seems to be an important drug target against IMiDs resistance in MM cells. Lenalidomide decreases also basigin and monocarboxylate transporter 1 in MM cells. MM cells with low expression of Ikaros, Aiolos and basigin are more sensitive to lenalidomide treatment. The CK1α gene (CSNK1A1) is located on 5q32 in commonly deleted region (CDR) in del(5q) MDS. Inhibition of CK1α sensitizes del(5q) MDS cells to lenalidomide. CK1α mediates also survival of malignant plasma cells in MM. Though, inhibition of CK1α is a potential novel therapy not only in del(5q) MDS but also in MM. High level of full length CRBN mRNA in mononuclear cells of bone marrow and of peripheral blood seems to be necessary for successful therapy of del(5q) MDS with lenalidomide. While transfusion independence (TI) after lenalidomide treatment is more than 60% in MDS patients with del(5q), only 25% TI and substantially shorter duration of response with occurrence of neutropenia and thrombocytopenia were achieved in lower risk MDS patients with normal karyotype treated with lenalidomide. Shortage of the biomarkers for lenalidomide response in these MDS patients is the main problem up to now.

The Emerging Role of CD244 Signaling in Immune Cells of the Tumor Microenvironment

In cancer, immune exhaustion contributes to the immunosuppressive tumor microenvironment. Exhausted immune cells demonstrate poor effector function and sustained expression of certain immunomodulatory receptors, which can be therapeutically targeted. CD244 is a Signaling Lymphocyte Activation Molecule (SLAM) family immunoregulatory receptor found on many immune cell types—including NK cells, a subset of T cells, DCs, and MDSCs—that represents a potential therapeutic target. Here, we discuss the role of CD244 in tumor-mediated immune cell regulation.

DNA Methyltransferase Inhibition Promotes Th1 Polarization in Human CD4+CD25high FOXP3+ Regulatory T Cells but Does Not Affect Their Suppressive Capacity

Regulatory T cells (Treg) can show plasticity whereby FOXP3 expression, the master transcription factor for Treg suppressor function, is lost and proinflammatory cytokines are produced. Optimal FOXP3 expression strongly depends on hypomethylation of the FOXP3 gene. 5-Azacytidine (Aza) and its derivative 5-aza-2'-deoxycytidine (DAC) are DNA methyltransferase inhibitors (DNMTi) that are therapeutically used in hematological malignancies, which might be an attractive strategy to promote Treg stability. Previous in vitro research primarily focused on Treg induction by DAC from naïve conventional CD4⁺ T cells (Tconv). Here, we examined the in vitro effect of DAC on the stability and function of FACS-sorted human naturally occurring CD4⁺CD25^high FOXP3⁺ Treg. We found that in vitro activation of Treg in the presence of DAC led to a significant inhibition of Treg proliferation, but not of Tconv. Although Treg activation in the presence of DAC led to increased IFNγ expression and induction of a Thelper-1 phenotype, the Treg maintained their suppressive capacity. DAC also induced a trend towards increased IL-10 expression. In vivo studies in patients with hematological malignancies that were treated with 5-azacytidine (Vidaza) supported the in vitro findings. In conclusion, despite its potential to increase IFNγ expression, DAC does preserve the suppressor phenotype of naturally occurring Treg.

The bone-marrow niche in MDS and MGUS: implications for AML and MM

Several haematological malignancies, including multiple myeloma (MM) and acute myeloid leukaemia (AML), have well-defined precursor states that precede the development of overt cancer. MM is almost always preceded by monoclonal gammopathy of undetermined significance (MGUS), and at least a quarter of all patients with myelodysplastic syndromes (MDS) have disease that evolves into AML. In turn, MDS are frequently anteceded by clonal haematopoiesis of indeterminate potential (CHIP). The acquisition of additional genetic and epigenetic alterations over time clearly influences the increasingly unstable and aggressive behaviour of neoplastic haematopoietic clones; however, perturbations in the bone-marrow microenvironment are increasingly recognized to have key roles in initiating and supporting oncogenesis. In this Review, we focus on the concept that the haematopoietic neoplasia-microenvironment relationship is an intimate rapport between two partners, provide an overview of the evidence supporting a role for the bone-marrow niche in promoting neoplasia, and discuss the potential for niche-specific therapeutic targets.

Cutaneous T-cell lymphoma: 2017 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell lymphoproliferative disorders involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multi-disciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral or blood involvement are generally approached with biologic-response modifiers or histone deacetylase inhibitors prior to escalating therapy to include systemic, single-agent chemotherapy. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

A 4-lncRNA scoring system for prognostication of adult myelodysplastic syndromes

Long noncoding RNAs (lncRNAs) not only participate in normal hematopoiesis but also contribute to the pathogenesis of acute leukemia. However, their clinical and prognostic relevance in myelodysplastic syndromes (MDSs) remains unclear to date. In this study, we profiled lncRNA expressions in 176 adult patients with primary MDS, and identified 4 lncRNAs whose expression levels were significantly associated with overall survival (OS). We then constructed a risk-scoring system with the weighted sum of these 4 lncRNAs. Higher lncRNA scores were associated with higher marrow blast percentages, higher-risk subtypes of MDSs (based on both the Revised International Prognostic Scoring System [IPSS-R] and World Health Organization classification), complex cytogenetic changes, and mutations in RUNX1, ASXL1, TP53, SRSF2, and ZRSR2, whereas they were inversely correlated with SF3B1 mutation. Patients with higher lncRNA scores had a significantly shorter OS and a higher 5-year leukemic transformation rate compared with those with lower scores. The prognostic significance of our 4-lncRNA risk score could be validated in an independent MDS cohort. In multivariate analysis, higher lncRNA scores remained an independent unfavorable risk factor for OS (relative risk, 4.783; P < .001) irrespective of age, cytogenetics, IPSS-R, and gene mutations. To our knowledge, this is the first report to provide a lncRNA platform for risk stratification of MDS patients. In conclusion, our integrated 4-lncRNA risk-scoring system is correlated with distinctive clinical and biological features in MDS patients, and serves as an independent prognostic factor for survival and leukemic transformation. This concise yet powerful lncRNA-based scoring system holds the potential to improve the current risk stratification of MDS patients.

The immune landscape of myelodysplastic syndromes

Even though the pathogenesis of myelodysplastic syndromes (MDS) is dominated by specific molecular defects involving hematopoietic precursors, also immune mechanisms seem to play a fundamental functional role. In this review we will first describe the clinical and laboratory autoimmune manifestations often detectable in MDS patients. We will then focus on studies addressing the possible influence of different immune cell subpopulations on the disease onset and evolution. We will finally consider therapeutic approaches based on immunomodulation, ranging from immunosuppressants to vaccination and transplantation strategies.

Reduced potency of cytotoxic T lymphocytes from patients with high-risk myelodysplastic syndromes

INTRODUCTION

Myelodysplastic syndromes (MDS) are a group of clonal bone marrow disorders, with dysplasia, cytopenias and increased risk of progression to acute myeloid leukemia. A dysregulated immune system precipitates MDS, and to gain insights into the relevance of cytotoxic T lymphocyte (CTL) in this process, we examined the frequency and function of CX3CR1- and CD57-positive T lymphocytes from MDS patients.

MATERIALS AND METHODS

Peripheral blood and/or bone marrow samples from 31 MDS patients and 12 healthy controls were examined by flow cytometry. Expression of cytotoxic granule constituents, immunological co-receptors, adhesion molecules and markers of activation were quantified on unstimulated lymphocytes. Degranulation, cytotoxicity and conjugate formation with target cells following co-culture of CTL with target cell lines or autologous bone marrow-derived CD34(+) cells were quantified by flow cytometry.

RESULTS

CX3CR1 expression was increased in bone marrow from high-risk MDS patients compared to healthy controls. Expression of CD57 and CX3CR1 was closely correlated, identifying a CTL subset with high cytotoxic capacity. In vitro, TCR-induced redirected cytotoxicity was markedly decreased for high-risk MDS patients compared to controls. CTL from MDS patients with the lowest target cell cytotoxicity had reduced expression of adhesion molecules and formed fewer conjugates with target cells.

DISCUSSION

Although phenotypically defined CTL numbers were increased in the bone marrow of MDS patients, we found that CTL from high-risk MDS patients exhibited a lower TCR-induced redirected cytotoxic capacity. Thus, decreased T cell cytotoxicity seems related to reduced adhesion to target cells and may contribute to impaired anti-leukemic immune surveillance in MDS.

Autoimmunity and Inflammation in Myelodysplastic Syndromes

Autoimmune and inflammatory conditions (AICs) are encountered in up to 25% of patients with myelodysplastic syndromes (MDS). A wide range of AICs have been reported in association with MDS and can range from limited clinical manifestations to systemic diseases affecting multiple organs. Vasculitides, connective tissue diseases, and inflammatory arthritis are frequently reported in different studies; noninfectious fever and constitutional symptoms at presentation are common. Associations between AICs and specific MDS characteristics vary by study, but the available data suggest that AICs cluster more often in younger patients with higher-risk MDS. In general, AICs do not seem to confer worse survival, although certain AICs may be associated with adverse outcome (e.g. vasculitis) or progression of MDS (Sweet's syndrome). Nonetheless, these complications may have a significant impact on quality of life and affect the timing and type of MDS-directed therapy. The mainstay of management of these complications in the short term relies on immunosuppressive drugs. Increasing evidence suggests that hypomethylating agents may be effective in treating these complications and reduce steroid dependence. While the pathogenesis of AICs is incompletely understood, growing appreciation of cellular immune deregulation, cytokine hypersecretion, and the genetic heterogeneity underlying MDS may improve our understanding of common pathways linking MDS, inflammation, and autoimmunity.

Autoimmune diseases and myelodysplastic syndromes

Immune dysregulation and altered T-cell hemostasis play important roles in the pathogenesis of myelodysplastic syndromes (MDS). Recent studies suggest an increased risk of MDS among patients with autoimmune diseases. Here, we investigated the prevalence of autoimmune diseases among MDS patients, comparing characteristics and outcomes in those with and without autoimmune diseases. From our study group of 1408 MDS patients, 391 (28%) had autoimmune disease, with hypothyroidism being the most common type, accounting for 44% (n = 171) of patients (12% among all MDS patients analyzed). Other autoimmune diseases with ≥5% prevalence included idiopathic thrombocytopenic purpura in 12% (n = 46), rheumatoid arthritis in 10% (n = 41), and psoriasis in 7% (n = 28) of patients. Autoimmune diseases were more common in female MDS patients, those with RA or RCMD WHO subtype, and those who were less dependent on red blood cell transfusion. Median overall survival (OS) was 60 months (95% CI, 50-70) for patients with autoimmune diseases versus 45 months (95% CI, 40-49) for those without (log-rank test, P = 0.006). By multivariate analysis adjusting for revised IPSS and age >60 years, autoimmune diseases were a statistically significant independent factor for OS (HR 0.78; 95% CI, 0.66-0.92; P = 0.004). The rate of acute myeloid leukemia (AML) transformation was 23% (n = 89) in MDS patients with autoimmune disease versus 30% (n = 301) in those without (P = 0.011). Patient groups did not differ in response to azacitidine or lenalidomide treatment. Autoimmune diseases are prevalent among MDS patients. MDS patients with autoimmune diseases have better OS and less AML transformation.

Multiple myeloma causes clonal T-cell immunosenescence: identification of potential novel targets for promoting tumour immunity and implications for checkpoint blockade

Tumour-induced dysfunction of cytotoxic T cells in patients with multiple myeloma (MM) may contribute to immune escape and be responsible for the lack of therapeutic efficacy of immune checkpoint blockade. We therefore investigated dysfunctional clonal T cells in MM and demonstrated immunosenescence but not exhaustion as a predominant feature. T-cell clones were detected in 75% of MM patients and their prognostic significance was revalidated in a new post-immunomodulatory drug cohort. The cells exhibited a senescent secretory effector phenotype: KLRG-1+/CD57+/CD160+/CD28-. Normal-for-age telomere lengths indicate that senescence is telomere independent and potentially reversible. p38-mitogen-activated protein kinase, p16 and p21 signalling pathways known to induce senescence were not elevated. Telomerase activity was found to be elevated and this may explain how normal telomere lengths are maintained in senescent cells. T-cell receptor signalling checkpoints were normal but elevated SMAD levels associated with T-cell inactivation were detected and may provide a potential target for the reversal of clonal T-cell dysfunction in MM. Low programmed death 1 and cytotoxic T-lymphocyte-associated antigen 4 expression detected on T-cell clones infers that these cells are not exhausted but suggests that there would be a suboptimal response to immune checkpoint blockade in MM. Our data suggest that other immunostimulatory strategies are required in MM.

T-cell large granular lymphocyte proliferation in myelodysplastic syndromes: Clinicopathological features and prognostic significance

Inflammatory and immune dysregulation are crucial in the initiation and development of myelodysplastic syndromes (MDS). It is noted that clonal T-cell large granular lymphocyte (T-LGL) proliferation associated with MDS is not uncommon. However, clinicopathological features, and prognostic and predictive value of presence of T-LGL proliferation in MDS patients is not very clear. This study compared 35 MDS patients with T-LGL proliferation with 36 MDS patients without T-LGL proliferation and summarized clinicopathologic features, including peripheral blood LGL cell counts, immunophenotype, T cell receptor gene rearrangement, bone marrow hematopoietic status, and adjuvant immunosuppressive therapy. The peripheral blood CD3+/CD57+ cell counts were significantly different (p<0.01) between the two groups. Notably, on examination of the bone marrow, MDS patients with T-LGL proliferation showed more frequent hypocellularity and/or lineage hypoplasia, particularly erythroid hypoplasia. On survival analysis, no overall difference was noted between MDS patients with T-LGL proliferation and those without T-LGL proliferation, and between the patients who received therapy for LGL and those who did not receive adjuvant therapy for LGL in the same risk group. In conclusion, T-LGL proliferation present in MDS patients can be associated with bone marrow hypocellularity and lineage hypoplasia. Although immunosuppressive therapy to eliminate T-LGL cells is potentially beneficial to the MDS patients with associated T-LGL proliferation, there is no overall survival benefit to the patients who received such treatment.

Cutaneous T-cell lymphoma: 2016 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Cutaneous T-cell lymphomas are a heterogenous group of T-cell lymphoproliferative disorders involving the skin, the majority of which may be classified as Mycosis Fungoides (MF) or Sézary Syndrome (SS).

DIAGNOSIS

The diagnosis of MF or SS requires the integration of clinical and histopathologic data.

RISK-ADAPTED THERAPY

TNMB (tumor, node, metastasis, blood) staging remains the most important prognostic factor in MF/SS and forms the basis for a "risk-adapted," multidisciplinary approach to treatment. For patients with disease limited to the skin, expectant management or skin-directed therapies is preferred, as both disease-specific and overall survival for these patients is favorable. In contrast, patients with advanced-stage disease with significant nodal, visceral, or blood involvement are generally approached with biologic-response modifiers or histone deacetylase inhibitors before escalating therapy to include systemic, single-agent chemotherapy. In highly-selected patients, allogeneic stem-cell transplantation may be considered, as this may be curative in some patients.

Comparison of immune manifestations between refractory cytopenia of childhood and aplastic anemia in children: A single-center retrospective study

This retrospective single-center study assessed the incidence and clinical features of immune manifestations of refractory cytopenia of childhood (RCC) and childhood aplastic anemia (AA). We evaluated 72 children with RCC and 123 with AA between February 2008 and March 2013. RCC was associated with autoimmune disease in 4 children, including 1 case each with autoimmune hemolytic anemia, rheumatoid arthritis, systemic lupus erythematosus, and anaphylactoid purpura. No children with AA were diagnosed with autoimmune diseases. Immune abnormalities were common in both RCC and AA; the most significant reductions were in the relative numbers of CD3-CD56+ subsets found in RCC. Despite the many similar immunologic abnormalities in AA and RCC, the rate of autoimmune disease was significantly lower in childhood AA than RCC (p=0.008, χ2=6.976). The relative numbers of natural killer cells were significantly lower in RCC patients than AA patients. By month 6, there was no significant difference in autoimmune manifestations between RCC and AA in relation to the response to immunosuppressive therapy (p=0.907, χ2=0.014). The large overlap of analogous immunologic abnormalities indicates that RCC and childhood AA may share the same pathogenesis.

[Management of myelodysplastic syndromes]

Myelodysplastic syndromes are heterogeneous diseases whose molecular characteristics have only been identified in recent years. Better identification of prognostic factors, larger access to allogeneic stem cell transplantation and the advent of new drugs notably hypomethylating agents (azacitidine, decitabine) and lenalidomide have improved patient outcome.

Myelodysplastic Syndromes: Diagnosis and Treatment

In the past few years, new biological insights into the myelodysplastic syndromes (MDS) resulting from molecular genetic analysis have improved pathologic understanding, but treatment advances have not kept pace. More than 40 genes are now known to be recurrently mutated in MDS. However, because most of these genes encode spliceosome components, chromatic remodeling factors, epigenetic pattern modulators, or transcription factors rather than more easily inhibited activated tyrosine kinases, there are as of yet few narrowly targeted therapies available for MDS. Three drugs--azacitidine, decitabine, and lenalidomide--were approved by the US Food and Drug Administration for MDS indications a decade ago, and these agents can improve hematopoiesis, delay disease progression, and improve survival and quality of life for a subset of patients. However, only a few patients with MDS respond to these agents, and their benefit is temporary. The only potentially curative therapy for MDS is allogeneic hematopoietic stem cell transplant, but owing to the advanced age of many patients with MDS and the frequency of serious comorbid conditions, less than 10% of patients currently undergo stem cell transplant. This narrative review summarizes the current understanding of MDS and treatment options for these challenging disorders.

The inflammatory microenvironment in MDS

Myelodysplastic syndromes (MDS) are a collection of pre-malignancies characterized by impaired proliferation and differentiation of hematopoietic stem cells and a tendency to evolve into leukemia. Among MDS's pathogenic mechanisms are genetic, epigenetic, apoptotic, differentiation, and cytokine milieu abnormalities. Inflammatory changes are a prominent morphologic feature in some cases, with increased populations of plasma cells, mast cells, and lymphocytes in bone marrow aspirates. Accumulating evidence suggests that the bone marrow microenvironment contributes to MDS disease pathology, with microenvironment alterations and abnormality preceding, and facilitating clonal evolution in MDS patients. In this review, we focus on the inflammatory changes involved in the pathology of MDS, with an emphasis on immune dysfunction, stromal microenvironment, and cytokine imbalance in the microenvironment as well as activation of innate immune signaling in MDS patients. A better understanding of the mechanism of MDS pathophysiology will be beneficial to the development of molecular-targeted therapies in the future.

Missing Cells: Pathophysiology, Diagnosis, and Management of (Pan)Cytopenia in Childhood

Peripheral blood cytopenia in children can be due to a variety of acquired or inherited diseases. Genetic disorders affecting a single hematopoietic lineage are frequently characterized by typical bone marrow findings, such as lack of progenitors or maturation arrest in congenital neutropenia or a lack of megakaryocytes in congenital amegakaryocytic thrombocytopenia, whereas antibody-mediated diseases such as autoimmune neutropenia are associated with a rather unremarkable bone marrow morphology. By contrast, pancytopenia is frequently associated with a hypocellular bone marrow, and the differential diagnosis includes acquired aplastic anemia, myelodysplastic syndrome, inherited bone marrow failure syndromes such as Fanconi anemia and dyskeratosis congenita, and a variety of immunological disorders including hemophagocytic lymphohistiocytosis. Thorough bone marrow analysis is of special importance for the diagnostic work-up of most patients. Cellularity, cellular composition, and dysplastic signs are the cornerstones of the differential diagnosis. Pancytopenia in the presence of a normo- or hypercellular marrow with dysplastic changes may indicate myelodysplastic syndrome. More challenging for the hematologist is the evaluation of the hypocellular bone marrow. Although aplastic anemia and hypocellular refractory cytopenia of childhood (RCC) can reliably be differentiated on a morphological level, the overlapping pathophysiology remains a significant challenge for the choice of the therapeutic strategy. Furthermore, inherited bone marrow failure syndromes are usually associated with the morphological picture of RCC, and the recognition of these entities is essential as they often present a multisystem disease requiring different diagnostic and therapeutic approaches. This paper gives an overview over the different disease entities presenting with (pan)cytopenia, their pathophysiology, characteristic bone marrow findings, and therapeutic approaches.

Advances in diagnosis and treatment of large granular lymphocyte syndrome

PURPOSE OF REVIEW

Large granular lymphocyte (LGL) syndrome comprises a clonal spectrum of T-cell and natural killer (NK)-cell LGL lymphoproliferative disorders associated with neutropenia. This review presents advances in diagnosis and therapy of LGL syndrome.

RECENT FINDINGS

Due to the lack of a single unique genetic or phenotypic feature and clinicopathological overlap between reactive and neoplastic entities, accurate LGL syndrome diagnosis should be based on the combination of morphologic, immunophenotypic, and molecular studies as well as clinical features. For diagnosis and monitoring of LGL proliferations, it is essential to perform flow cytometric blood and/or bone marrow analysis using a panel of monoclonal antibodies to conventional and novel T-cell and NK-cell antigens such as NK-cell receptors and T-cell receptor β-chain variable region families together with TCR gene rearrangement studies. Treatment of symptomatic cytopenias in patients with indolent LGL leukemia is still based on immunosuppressive therapy. Treatment with purine analogs and alemtuzumab may be considered as an alternative option.

SUMMARY

Progress in understanding the pathogenetic mechanisms of these entities, especially resistance of clonal LGLs to apoptosis, due to constitutive activation of survival signaling pathways, has its impact on identification of potential molecular therapeutic targets.

Expression patterns of chemokine receptors on circulating T cells from myelodysplastic syndrome patients

Chemokines and their receptors are involved in the recruitment of leukocytes to sites of inflammation. Recently, chemokine expression signatures have been reported to convey a prognostic value in myelodysplastic syndrome (MDS) patients. In the present study, we investigated the chemokine receptor repertoire on fresh peripheral blood lymphocytes from 31 (22 low-risk and 9 high-risk) patients affected by MDS. Chemokine receptor expression was studied in defined T-cell subsets using eight-color flow cytometry. MDS patients exhibited quantitative differences in peripheral lymphocyte subpopulations. In addition, T cells obtained from MDS patients expressed a chemokine receptor pattern suggesting a dominance of mature and activated T cells. This is illustrated by increased levels of CCR3, CCR5, CX3CR1 and/or by a decreased abundance of CCR7 in defined T-cell subsets. The T-cell subset distribution appears to differ between the peripheral blood and the bone marrow of MDS patients, suggesting a preferential recruitment of specific T-cell subsets to the latter compartment. Alteration in chemokine receptor expression can develop over time even in patients that are considered clinically stable. Elevated expression levels of CXCR4 by CD8⁺ cells were associated with prolonged patient survival and reduced numbers of bone marrow blasts. We conclude that immunological abnormalities in MDS also involve chemokine receptors on different subsets of T cells, and that these changes may have a prognostic value.