The following information is preliminary and subject to change.
Joint Session: Scientific Committee on Blood Disorders in Childhood & Scientific Committee on Immunology and Host Defense
What the Children Can Teach Us: Congenital Immunodeficiencies Shed Light on Immunity, Hematopoiesis, and Cancer
Over the last 20 years there has been an exponential rise in the identification of inborn errors of immunity, now numbering >400 monogenetic defects. While the classical presentation of these diseases is recurrent and persistent infections in a young child, the uncovering of the genetic underpinnings of these fascinating diseases has led to unexpected roles for these genes in immune dysregulation, hematopoiesis, and malignancy. Furthermore, hypomorphic variants in genes traditionally thought to affect only children may manifest as milder or atypical disease in adults. The investigation of patients with inborn errors of immunity thus provide unique insights into biology, immunology, and molecular mechanisms of disease. In this series of talks, these dynamic speakers will shed some light on the complex and tightly regulated interplay between a dysregulated immune system and abnormal hematopoiesis and malignant transformation. Drs. Lucas and Snow will discuss the roles of PI3K subunits and CARMA proteins respectively, both gain and loss-of-function variants, in lymphocyte biology and lymphomagenesis. Drs. Latour and Holland will discuss the roles of IKZF1 and GATA2 respectively in immune cell development, function, malignancy.
Dr. Carrie Lucas will describe Activated PI3K-delta Syndrome (APDS) patients with germline gain-of-function mutations in the genes encoding the leukocyte-restricted PI3Kdelta subunits p110delta and p85alpha and discuss their similarity to oncogenic mutations. These patients have immunodeficiency, autoimmunity, and lymphoproliferative disease, and have recently been successfully treated with targeted therapy specifically inhibiting the PI3Kdelta complex. She will then transition to recent work on a new disorder termed ‘Inactivated PI3K-gamma Syndrome’ (IPGS), caused by loss-of-function mutations in the gene encoding the p110gamma PI3K subunit. This rare disease has features of immunopathology and immunodeficiency, including features not previously expected from knockout mice. The p110gamma kinase is being inhibited in clinical trials to boost myeloid cell responses in cancer, as such, Dr. Lucas will describe how her lab’s findings in rare disease illuminate roles for this kinase directly in humans.
Dr. Andrew Snow will provide an overview of primary immune regulation disorders associated with mutations in CARMA proteins and their associated signaling partners, BCL10 and MALT1. Particular emphasis will be paid to the broad spectrum of immune diseases associated with mutations in CARMA1 (CARD11). He will discuss underlying molecular mechanisms explaining lymphocyte signaling defects and associated clinical phenotypes, including predisposition to lymphoma. Current and novel therapeutic strategies for CARMA-related immune disorders will also be briefly covered.
Dr. Sylvain Latour will first discuss the biology of the transcription factor IKZF1, its role in development of immune cells, normal hematopoiesis, and lymphomagenesis associated with somatic mutations in IKZF1. He will then focus on work from his laboratory delineating the impact of germinal mutations in IKZF1 in humans on lymphocyte development and function, contrasting the effect of loss of function, dominant negative variants and novel recently identified mutations. He will further discuss the underlying molecular and pathophysiological mechanisms of these different mutations and their association with clinical phenotypes.
Sung-Yun Pai, MD
Boston Children's Hospital
Robert F. Sidonio Jr., MD, MSc.
Children's Hospital of Atlanta
Carrie L. Lucas, PhD
New Haven, CT
Human PI3K Mutations: Immunodeficiency and Malignancy
Andrew L. Snow, PhD
Uniformed Services University
The Biology of CARMA Proteins in Immunity and Malignancy
Sylvain Latour, PhD
The Complete Spectrum of IKZF1 Defects: Immunodeficiency, Immune Dysregulation, Abnormal Hematopoiesis and Leukemia
Steven M. Holland, MD
National Institute of Allergy and Infectious Diseases
GATA2: MonoMac and Beyond
Joint Session: Scientific Committee on Hematopathology and Clinical Laboratory Hematology & Scientific Committee on Lymphoid Neoplasia
Getting the Most from Minimal Residual Disease
Minimal residual disease (MRD) detection has become standard of care in some hematologic malignancies such as acute lymphoblastic leukemia. While MRD has been studied in many different lymphoid and plasma cell malignancies, strategies based on techniques such as, flow cytometry, and detection of patient specific immunoglobulin gene sequence by molecular techniques such as allele-specific PCR have not been successful. Recent technical advances hold great promise in detecting residual disease and providing response assessment as well as prognostic information that may allow intervention to improve outcomes. In this joint session, the speakers will explore advances in using various forms of technology such as next generation sequencing in the context of circulating tumor DNA (ctDNA), mass spectrometry, high throughput biophysical measurements and molecular analysis of single cells to detect MRD. These technologies and application toward MRD detection will influence clinical trial design and improve outcomes for patients with lymphoma and plasmacytic neoplasms.
Dr. David Rossi will discuss the role cell-free circulating tumor DNA (ctDNA) in detecting residual disease. ctDNA in blood is an opportunity for comprehensive and minimally invasive lymphoma diagnostics that is not limited by sampling frequency, tumor accessibility, or the existence of clinically overt disease. Qualification of ctDNA is used for the identification of pre-treatment mutations associated with primary resistance to therapy and for the longitudinal non-invasive detection of acquired-resistance mutations under treatment. Quantification of ctDNA is used as a proxy of imaging for the measurement of tumor volume. It allows identifying residual disease after treatment also when the disease is in complete remission. Persistence of ctDNA detection during curative-intent therapy is proposed as dynamic prognostic marker for ultimate clinical outcome. Given the emerging role of the ctDNA, its implementation to detect genomic variants and residual disease is a priority in the roadmap of lymphoma research. Moving ctDNA applications from the bench to the bedside requires filling the uncertainties surrounding their clinical validity and, most importantly, clinical utility in the context of prospective clinical trials.
Dr. Katie Thoren will describe the use of mass spectrometry to detect M-proteins in multiple myeloma, identify the challenges of using this biomarker, and describe work that must be done for these techniques to be incorporated into clinical practice for tracking of low disease burden. Over the last several years, efforts have demonstrated that it is technically feasible to detect low levels of monoclonal proteins in peripheral blood using mass spectrometry. These methods are based on the fact that an M-protein has a specific amino acid sequence, and therefore, a particular mass. This mass can be tracked over time and can serve as a surrogate marker of the presence of clonal plasma cells.
Dr. Ash Alizadeh will discuss the spectrum of available technologies for lymphoma MRD detection and quantitation by next-generation sequencing, including the strengths and weaknesses of methods such as IgHTS, CAPP-Seq, PhasED-Seq, and related techniques. He will separately discuss the role of ctDNA in several lymphoma subtypes using blood plasma, including for noninvasive lymphoma genotyping, disease classification, and risk assessment before therapy. Finally, he will discuss the use of ctDNA for early molecular response measurements as informative for adaptive clinical trial designs, for noninvasively detecting the emergence of resistance mechanisms, and for late MRD detection for early detection of progression.
Dr. Scott Manalis will discuss advances made towards monitoring and targeting MRD. Over the past decade, there have been significant advancements in microfluidic approaches for isolating rare cells and characterizing their molecular as well as biophysical properties. These approaches hold great promise for defining personalized vulnerabilities. His talk will focus on their prospects for monitoring as well as targeting MRD.
Eric D. Hsi, MD
Lisa G. Roth, MD
Weill Cornell Medical College
New York, NY
Davide Rossi, MD, PhD
Oncology Institute of Southern Switzerland
Use of Minimal Residual Disease and Advances in Clinical Trials
Katie Thoren, PhD
Memorial Sloan Kettering Cancer Center
New York, NY
Advances in Mass Spectrometry for Myeloma Minimal Residual Disease
Ash A. Alizadeh, MD, PhD
Newest Discoveries Using Next Generation Sequencing Approaches for Minimal Residual Disease
Scott R. Manalis, PhD
Massachusetts Institute of Technology
Bioengineering Strategies to Phenotypically Define Minimal Residual Disease
Single Cell Analysis of Hematopoietic Development and Clonal Complexity of Malignant Hematopoiesis
Sandra S. Zinkel, MD, PhD
Vanderbilt University School of Medicine
Soheil Meshinchi, MD, PhD
Fred Hutchinson Cancer Research Center
Vijay G. Sankaran, MD, PhD
Boston Children's Hospital
Single Cell Understanding of Hematopoiesis and Myeloid Lineage Commitment
Timm Schroeder, PhD
Single Cell Analysis of the Bone Marrow Niche - Quantitative Understanding of Stem/Progenitor Niche Interactions
Margaret Goodell, PhD
Baylor College of Medicine
Subclonal Complexity in Myeloid Malignancies and Mechanism of Selection and Resistance
University Hospital of Ulm
Measuring Disease Burden in Myeloid Malignancies/Residual Disease
Precision Medicine Approaches to Leukemia Predisposition in Bone Marrow Failure
Inherited and acquired bone marrow failure disorders are associated with an increased risk of myeloid malignancies. Treatment of MDS or AML is challenging for these patients due to both malignancy resistance and toxicities from disease co-morbidities. An understanding of the biologic mechanisms driving bone marrow failure and clonal evolution would inform rational surveillance strategies and provide opportunities for leukemia interception. This session will present cutting-edge advances in the understanding of the molecular mechanisms driving marrow failure and clonal evolution in three different germline genetic leukemia predisposition disorders. Clinical implications for surveillance and therapeutics will be discussed.
Dr. Leighton Grimes will discuss severe congenital neutropenia, which is caused by inherited and de novo mutations leading to a profound block in neutrophil granulopoiesis. Dr. Grimes will present insights gleaned using mouse models of severe congenital neutropenia. The successive cell states encountered during normal neutrophil granulopoiesis will be described. Differential single cell gene expression and chromatic patterns in mutant cells assigned to wild type cell states via comparative genomics will be presented. These studies highlight the dominance of cell state in integrating the effects of mutations and therapy, and illustrate cell-state-specific effects of mutations, with direct consequences for attempts to repair defects.
Dr. Coleman Lindsley will discuss insights from Shwachman-Diamond syndrome, a disorder characterized by impaired ribosome assembly. Dr. Lindsley will present novel somatic mutation pathways driven by the germline genetic background. These studies show how germline genetic context together with the cell-specific somatic mutational context determine the functional contribution of a somatic mutation to relative cell fitness, selection, and malignant potential. These studies identify adaptive and maladaptive pathways of clonal expansion in response to a germline genetic selective pressure and provide a mechanistic rationale for clinical surveillance.
Dr. Paula Rio will discuss clonal tracking following gene therapy to treat Fanconi anemia, a disorder of DNA repair. She will provide an update on a phase I/II gene therapy trial that has shown successful engraftment and proliferative advantage of corrected HSCs in FA-A patients in the absence of conditioning. Dr. Rio will discuss the engraftment, clonal tracking and phenotypic correction of HSCs in these initial patients with up to 3 years of follow up.
Akiko Shimamura, MD, PhD
Boston Children's Hospital
H. Leighton Grimes, PhD
Cincinnati Children's Hospital Medical Center
Neutrophil Development and Neutropenia
R. Coleman Lindsley, MD, PhD
Dana-Farber Cancer Institute
Germline and Somatic Genomics in Ribosomopathies
Paula Rio, PhD
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT)
Clonal Tracking Post-Gene Therapy for Fanconi Anemia
RNA in Normal and Malignant Hematopoiesis
Post-transcriptional control of gene expression is emerging as a new frontier in the regulating stemness, differentiation and malignant transformation. Mutations in spliceosomal genes are a common cause of acute myeloid leukemia. In addition, RNA processing, splicing, and feedback loops to transcriptional regulation represent opportunities for drug development, therapeutic targeting, as well as immunotherapy. This session will present cutting-edge developments in how the regulation of splicing, RNA stability, and RNA processing impact fundamental processes in hematopoiesis. In addition, it will address how dysregulation of these processes induces or contribute to leukemia, and how it can be modulated for therapeutic purposes.
Dr. Christopher Burge will focus on mechanism of RNA-processing and their impact on gene expression, including feedback loops to promoter regulation. Almost all human genes undergo alternative processing of their primary transcripts, including alternative splicing and/or alternative cleavage and polyadenylation, with RNA-binding proteins playing key regulatory roles. Pre-mRNA processing can impact the expression levels of genes in a variety of ways, including by producing alternative mRNA isoforms that differ in their stability, nuclear export, or translation. He will discuss recent work showing that splicing of internal exons near the 5' ends of genes can activate transcription from proximal upstream promoters, and exploring the mechanisms underlying this and other connections between RNA processing and gene expression. This work has implications for understanding programs of gene regulation in T cells and other immune cell types, and also opens up new approaches for therapeutic manipulation of gene expression.
Dr. Omar Abdel Wahab will focus on mutations in slicing factors and their contribution to hematologic malignancies. He will describe the role of genomic as well as transcriptomic and proteomic studies in defining critical events altered by mutant splicing factors in myeloid and lymphoid leukemias. Mutations in the spliceosomal genes SRSF2, U2AF1, SF3B1, and ZRSR2 are commonly found in patients with leukemia and are among the most common class of genetic alterations in clonal hematopoiesis, myelodysplastic neoplasms, and chronic lymphocytic leukemia. These mutations that occur at highly restricted amino acid residues, are always heterozygous, and rarely co-occur with one another. These data suggest that splicing mutations confer an alteration of splicing function and/or that cells may only tolerate a certain degree of splicing modulation.
Dr. Kristin Hope will focus on the role of RNA processing in determining cell states. This has broad implications for hematopoietic development, differentiation, and malignant transformation. RNA based mechanisms are contributing to proper enforcement of the stemness state in hematopoiesis. Dysregulation of these processes can underpin the pathogenesis of hematopoietic malignancies and acute myeloid leukemia in particular. RNA binding protein (RBP)-directed control of the post-transcriptional landscape is beginning to be appreciated for its importance in control of cell states. Dr. Hope will describe new strategies to both define key RBP regulators of normal vs leukemic stem cells (LSC) as well as unbiased approaches such as integrative RBP-interactome mapping, transcriptomics and proteomics, to identify their RNA substrates and the nature of their effects on RNA metabolism. She will also discuss the potential for carrying out rational manipulations of these circuitries to advance hematopoietic stem cell regeneration or target LSCs.
Kathrin M. Bernt, MD
Children's Hospital of Philadelphia
Chris B. Burge, MD, PhD
Massachusetts Institute of Technology
Basic Mechanisms and Significance of Altered Splicing in Cancer and Hematology
Omar Abdel-Wahab, MD
Memorial Sloan Kettering Cancer Center
New York, NY
Understanding and Targeting Spliceosomal Gene Mutations in Leukemia
Kristin Hope, PhD
Hamilton, ON, Canada
RNA Processing in Benign and/or Malignant Hematology
Hematopoietic Aging: Mechanisms and Consequences
Advancing age frequently associates with the onset of a variety of hematological conditions characterized by diminished clonal heterogeneity and homeostatic control of blood cell production. Upstream hematopoietic stem and progenitor cells are obligate mediators of homeostatic control of all blood lineages. Hematopoietic stem cell and progenitor clonality is frequently associated with specific epigenetic changes and mutations resulting in inflammation, impaired adaptive immune system and elevated incidence of myeloproliferative diseases. The cell-autonomous and non-autonomous causative of clonal-dependent and clonal-independent hematopoietic aging represent a major area of interest in hematology and vascular biology.
Dr. Danica Chen will highlight a mitochondrial metabolic checkpoint that is critical for the maintenance of hematopoietic stem cells (HSCs) and discuss how dysregulation of that mitochondrial metabolic checkpoint leads to HSC aging. Evidence is provided to support the role of the NLRP3 inflammasome in the mitochondrial metabolic checkpoint of HSC aging and, more broadly, how HSC aging impacts the distance tissues and organismal aging. Therapeutic implications will also be discussed.
Dr. Carolina Florian will discuss the aging of the stem cell niche. With aging, intrinsic HSC activity decreases, resulting in impaired tissue homeostasis, reduced engraftment following transplantation, and increased susceptibility to diseases. However, whether aging also affects the HSC niche impairing its capacity to support HSC function is still largely debated. Recently by using in vivo long-term label retention assays, we demonstrated that aged labeling (LR) HSCs, which are in old mice, reside predominantly in perisinusoidal niches. These cells are also the most quiescent HSC subpopulation with the highest regenerative capacity and cellular polarity. Furthermore, studies in her lab have revealed that sinusoidal niches are uniquely preserved in shape, morphology, and number upon aging, and that myeloablative chemotherapy can selectively disrupt aged sinusoidal niches long term. This is linked to the lack of recovery of endothelial Jag2 at sinusoids and to decreased survival of aged mice to chemotherapy. Overall, Dr. Florian’s research has characterized the functional alterations of the aged HSC niche and unveiled that perisinusoidal niches are uniquely preserved and protect HSCs from aging.
Dr. Hartmut Geiger will describe the implications of hematopoietic aging on HSC activity. Aging of HSCs is linked to age-associated remodeling of the immune system, age-associated leukemia as well as a large number of other age-associated diseases. Besides changes intrinsic to HSCs that are causatively linked to the aging of HSCs (aka cause the changes in the function of HSCs that are found in HSCs from old animals for example), more recent research supports that changes in the local bone marrow niche microenvironment are also very potent influencers of the aging- associated decline in HSCs function. Dr. Geiger’s talk will present novel data and concepts on causes and consequences of aging of hematopoietic stem cells, and implications for the clinic.
Jose A. Cancelas, MD
University of Cincinnati
Danica Chen, PhD
University of California, Berkley
Hematopoietic Stem Cell Aging and its Impact on Lifespan
Maria Carolina Florian, PhD
Bellvitge Institute for Biomedical Research
Aging of the Stem Cell Niche
Hartmut Geiger, PhD
Cincinnati Children's Hospital Medical Center
Hematopoietic Aging on Hematopoietic Stem Cell Activity
Mechanisms and Modifiers of Bleeding
Coagulation is a dynamic process. In its normal setting, it involves a pro-coagulant pathway that results in the development of a fibrin clot that is balanced by mechanisms that limit the extent of the clot to the site of injury. This complex highly regulated system involves interactions between the vessel wall, platelets, and coagulation factors among others. Disruption to this balance may result in either bleeding or thrombosis. Over the last decade great strides have been made in understanding mechanisms and modifiers of this system. This session will present recent developments across diverse fields that continue to push the envelope on our knowledge and understanding of the mechanisms and modifiers of bleeding.
Dr. Mitchell Cohen will discuss the drivers and mechanisms of acute traumatic coagulopathy. Specifically, he will describe the clinical and biologic picture of coagulation and inflammatory perturbations after severe injury and shock. In addition, Dr. Cohen will address translational approaches to the study of these topics and future research.
Dr. Valerie O’Donnell will discuss the interaction of the phospholipid membrane surface of platelets and white blood cells with coagulation factors, specifically the generation and action of enzymatically-oxidized phospholipids formed by lipoxygenases. Her lab has shown that these lipids regulate coagulation during development of abdominal aortic aneurysms (AAA) in mice, and that they are found in human AAA lesions. Extensive in vitro studies have defined the mechanisms of action of these lipids, showing that they enhance the ability of phosphatidylserine to support coagulation.
Dr. Karin Leiderman will discuss a mathematical and computational approach to studying variability in bleeding patterns among individuals with hemophilia A. Uncertainty and sensitivity analysis were recently performed on a mathematical model of flow-mediated coagulation to identify parameters most likely to enhance thrombin generation in the context of FVIII deficiency. Results from those computational studies identified low-normal FV (50%) as the strongest modifier, with additional thrombin enhancement when combined with high-normal prothrombin (150%). Partial FV inhibition (60% activity) augmented thrombin generation in FVIII-inhibited or FVIII-deficient plasma in CAT and boosted fibrin deposition in flow assays performed with whole blood from individuals with mild and moderate FVIII deficiencies; these effects were amplified by high-normal prothrombin levels in both experimental models. Dr. Leiderman will highlight how the mathematical model was used to predict a biochemical mechanism underlying the modified thrombin response.
Shannon L. Meeks, MD
Mitchell J. Cohen, MD
University of Colorado
Understanding the Dynamics of Bleeding in Trauma
Cardiff, United Kingdom
Innate Immune Cell-Derived Phospholipids and Hemostasis
Karin Leiderman, PhD
Colorado School of Mines
A Systems Biology Approach to Identifying Modifiers of Bleeding in Hemophilia
Well-Regulated vs Malfunctioning Mechanisms of Iron Metabolism
As we approach the 20th anniversary of the first description of the central iron-regulatory hormone hepcidin and its molecular target, the cellular iron exporter ferroportin, we will take the opportunity to delve more deeply into the regulation of this axis in normal homeostasis, the cellular mediators of iron metabolism and the contribution of iron status to morbidity/mortality in diseases of ineffective hematopoiesis. Hepcidin expression and subsequent iron flux through intestinal absorption and reticuloendothelial macrophage release is regulated through iron status, erythropoietic drive, and inflammatory mediators. In addition to these systemic regulatory mechanisms, there is an emerging role of intestinal regulation of iron handling by local HIF-2a. Recent work demonstrates that hepatic hepcidin regulates intestinal HIF-2a, and this axis can be targeted in iron-related disorders.
Reticuloendothelial macrophages are the primary source of iron for erythropoiesis given their ability to recycle hemoglobin-derived iron. However, macrophages also have considerable functional and phenotypic plasticity directed by signals from the microenvironment, including iron. The spectrum of macrophage phenotypes derived from exposure to differing iron sources (e.g., hemoglobin, heme, iron) could modulate the inflammatory response, oxidative stress, and natural history of iron-loaded and hemolytic disease states. The primary toxicity of excess iron is mediated through oxidant generation and oxidative stress, which contribute to a variety of human disease states. Although this toxicity is a well-recognized contributor to organ damage/failure and mortality in iron-loading anemias, the association with poor outcomes in hematologic malignancy, and stem cell transplant is becoming established. Well-designed large trials have revealed the deleterious effects of iron overload in myelodysplastic syndrome (MDS) and the beneficial effects of iron chelation.
Dr. Yatrik Shah will describe how cell autonomous oxygen signaling pathways integrate with systemic hepcidin signaling to control intestinal iron absorption. Intestinal HIF-2a is essential for the local absorptive response to systemic iron deficiency and iron overload. Recent work has uncovered a hetero-tissue crosstalk mechanism, whereby hepatic hepcidin regulates intestinal HIF-2a in iron deficiency, anemia, and iron overload. A decrease in systemic hepcidin alters the activity on intestinal PHDs, which subsequently leads to the stabilization of HIF-2a. Pharmacological targeting of HIF-2a using a clinically relevant and highly specific inhibitor successfully treated iron overload in mouse models. These findings demonstrate a molecular link between hepatic hepcidin and intestinal HIF-2a that controls physiological iron uptake and drives iron hyperabsorption during iron overload.
Dr. Francesca Vinchi will demonstrate how the modulation of macrophage plasticity through the application of either iron sources or scavengers/chelators achieves therapeutic effects that improve disease conditions. Along with the regulation of iron homeostasis, macrophages play a crucial role in the orchestration of inflammatory and tissue remodeling processes through the acquisition of distinct functional phenotypes in response to the surrounding microenvironment. The iron-related and immune functions of macrophages are tightly interconnected: on the one hand, macrophage polarization dictates the expression of iron-regulated genes and determines cell iron handling; on the other, iron availability affects macrophage immune effector functions. Recent observations support a role for free heme and iron in shaping macrophage plasticity towards a pro-inflammatory phenotype. These findings have implications for the pathophysiology of diseases hallmarked by elevated circulating heme and iron, including hemolytic diseases and transfusion- or iv iron-dependent anemias, as well as conditions associated with increased local heme and iron accumulation, including trauma, atherosclerosis, and tumors.
Dr. Nobert Gatterman will address the impact of iron overload and chelation in patients with myelodysplastic syndrome (MDS). There is no reason to believe that transfusional iron overload (IOL) is less toxic in elderly MDS patients than young thalassemia patients. Comorbidities, in particular cardiac problems, may increase vulnerability to the toxic effects of IOL in elderly MDS patients. Nevertheless, the prognostic impact of IOL is more challenging to prove in MDS, due to considerable overlap between iron-related and age-related clinical problems. Registry studies have consistently shown a survival benefit of iron chelation therapy (ICT) in lower-risk MDS. At least two registry studies have reached high quality through extensive matched-pair-analyses, virtually eliminating the bias resulting from uneven distribution of comorbidities and performance scores. The prognostic impact of ICT has recently been corroborated by improved EFS shown in the randomized Telesto trial.
Matthew M. Heeney, MD
Children's Hospital - Boston
Yatrik Shah, PhD
University of Michigan
Ann Arbor, MI
Update on Ferroportin Regulation
Francesca Vinchi, PhD
New York Blood Center
New York, NY
Iron Handling by Macrophages
Norbert Gattermann, MD
Prognostic Impact of Iron Overload and Iron Chelation in Myelodysplastic Syndromes
Molecular Basis of Platelet/Megakaryocyte Dysfunction: Novel Approaches
Last few years have witnessed a tremendous advance in approaches to study the basic biology of megakaryocytes and platelets and their role in disease. This session focuses on three state-of-the-art approaches that have provided remarkable new insights. The first talk focuses on the application of single cell multi-omic approaches to advance understanding of megakaryocyte biology and their application to myelofibrosis, an acquired stem cell disorder. The second talk extends this with a focus on the unique insights provided by studies using induced pluripotent stem cell (iPSC) in the context of a disorder associated with germline mutations in hematopoietic transcription factor RUNX1. These patients are characterized by aberrations in platelet function and number and a predisposition to myeloid malignancies. These studies cover the spectrum from insights into the biology of the disease to potential therapeutic approaches. Last few years have seen an explosion of information on the gene abnormalities in patients with inherited platelet disorders, and much of this has come through the application of new-generation sequencing - the focus of the third talk. These approaches have advanced understanding of the genetic abnormalities in patients and provided novel and unexpected insights into the causative genes and their role in platelets and megakaryocytes.
Dr. Bethan Psaila will discuss the application of single cell multi-omic approaches to studying normal and aberrant pathways of megakaryocyte differentiation. She will discuss changes to megakaryopoiesis over normal human ontogeny and the mechanisms of megakaryocyte-biased hematopoiesis in myelofibrosis. Single cell approaches can identify heterogeneous megakaryocyte subpopulations with distinct metabolic and inflammatory signatures, and implications for novel approaches for therapeutic targeting of malignant megakaryocytes will be discussed.
Dr. Mortimer Poncz will address the role induced pluripotent stem cells (iPSC) have played in highlighting mechanisms in inherited platelet/megakaryocyte disorders. RUNX1 is a transcription factor central to hematopoiesis. Haploinsufficiency of RUNX1 results in a clinical disorder termed Familial Platelet Disorder associated with Myeloid Malignancy or FPDMM that is associated with quantitative and qualitative defects and an increased risk of myeloid leukemia. Studies of iPSCs derived from patients with FPDMM recapitulate the defect in megakaryopoiesis and have led to new insights into the pathogenesis of this disorder, including a deficiency of megakaryocyte-biased progenitor cells and upregulation of proinflammatory pathways during megakaryopoiesis. These pathogenic insights have also led to therapeutics that prevent the defect in megakaryopoiesis in iPSC and primary cell ex vivo studies.
Dr. Kathleen Freson will discuss the value of next generation sequencing (NGS) in providing new insights into platelet and megakaryocyte biology. Patient studies have significantly contributed to our current knowledge of platelet and megakaryocyte biology. NGS-based multi-gene panel tests comprising all platelet disorder genes known today can diagnose about 26 to 48% of patients with platelet function and formation disorders, respectively. This means that many disease-related genes are still unknown and often totally unexpected genes are discovered in exomes and genomes as candidate for a novel platelet disorder. Disease models, platelet transcriptomics and other functional assays are still critical to prove causality and understand their role in platelet and megakaryocyte biology.
Angara Koneti Rao, MBBS
Bethan Psaila, MD, PhD
University of Oxford
Oxford, United Kingdom
Single Cell Approaches to Elucidate Novel and Aberrant Pathways in Megakaryocytes
Mortimer Poncz, MD
Children's Hospital of Philadelphia
Exploiting Induced Pluripotent Stem Cells to Unravel Mechanisms in Inherited Platelet/Megakaryocyte Disorders
Kathleen Freson, PhD
University of Leuven
Insights into Platelet-Megakaryocyte Biology through Next-Generation Sequencing
The Immune System in Multiple Myeloma
The immune repertoire plays an important role in many cancers, and there has been growing recognition of the immune deregulation plays an important and independent role in the progression of malignant plasma cells through the precursor states to active disease. The progression of multiple myeloma is associated with both innate and adaptive immune system dysfunction, notably in the T-cell repertoire Understanding the interplay between the bone marrow microenvironment, immune repertoire and malignant plasma cells will be of utmost important to achieve long-term disease control and potential curability.
Dr. Mark Smyth will discuss the immune system as it related to the progression of the precursor condition MGUS to active myeloma. His lab has been exploring the relative importance of different immune cells and molecules in blood cancers, from their initiation, growth and spread and under therapy. To that end, his research has demonstrated that the pro-inflammatory cytokine IL-18 is critically involved in these hallmarks in multiple myeloma (MM). In addition, blocking TIGIT using monoclonal antibodies (mAbs) increased the effector function of MM patient CD8+ T cells and suppressed MM development. Furthermore, besides examining the role of extracellular adenosine in blood cancers, Dr. Smyth is now also evaluating models of minimal residual disease as a treatment window of opportunity for MM.
Dr. Paola Neri will discuss insights into the mechanisms that promote tumor escape, cause inadequate T-cell stimulation and impaired cytotoxicity in MM. In addition, she will highlight current immunotherapies being used to restore adaptive T-cell immune responses in MM and describe strategies created to escape these multiple immune evasion mechanisms. Her lab been examining the complex interaction of BM stromal cells (BMSCs) and malignant cells that using bidirectional connections and cytokines released stimulate disease progression, drug resistance and enable immune escape, showing distinct immunophenotyping features using single cell RNA sequencing and mass spectrometry.
Dr. Madhav Dhodapkar will discuss emerging data from studies to evaluate the immune system in myeloma patients receiving therapy. He will be discussion the potential immune signatures in response to therapy in newly diagnosed and relapsed myeloma patients, as the efficacy of T-cell-dependent immunotherapies for myeloma are going to depend on engaging the endogenous T-cell repertoire. He will discuss the potential applications of different immune monitoring approaches that are providing novel insights for strategies to harness the immune system to treat myeloma.
Saad Z. Usmani, MD,MBBS
Levine Cancer Institute
Mark J. Smyth, PhD, FAA
QIMR Berghofer Medical Research Institute
The Immune System and Progression from Precursor Condition to Active Myeloma
Paola Neri, MD
University of Calgary
Calgary, AB, Canada
Immune Deregulation in Active Multiple Myeloma
Madhav V. Dhodapkar, MBBS
Immune Monitoring in Myeloma
Location, Location, Location
Erythropoiesis is a complex carefully orchestrated process that replenishes billions of erythrocytes lost daily. Producing red blood cells at large scale is a major clinical need. Challenges encountered in producing red blood cells in vitro for clinical use, have highlighted the necessity to better understand processes involved. The molecular mechanisms involved in erythroid differentiation are tightly regulated and compartmentalized in erythroid precursors. In this session, speakers will discuss their work using new technology, including super resolution microscopy to dissect at nanoscale the compartmentalization of proteins or organelles, cytoskeletal rearrangement and erythroid enucleation to better understand red blood cell generation. Another topic addressed will be the overall production of red blood cells from reprogrammed fibroblasts in vitro for clinical use.
Dr. Ke Xu will discuss the importance of using super-resolution fluorescence microscopy to understand the ultrastructure of red cells. Recent advances in super-resolution fluorescence microscopy offers exciting new opportunities to probe intracellular structures at ~20 nm resolution with excellent molecular specificity and minimal sample processing. This presentation will shed new light on related cytoskeletal systems in erythropoiesis. Super-resolution fluorescence microscopy opens a new window into understanding the ultrastructure of red cells, and the impact these methods have on our understating of erythroid differentiation will be discussed.
Dr. Johan Flygare will discuss the background and clinical significance of understanding transcriptional programs regulating the developmental waves of erythropoiesis. He will focus less on what has been learned from loss of function approaches and instead highlight overexpression approaches being used to study key transcription factors in erythropoiesis. Dr. Flygare will include published and unpublished results from his own studies using direct lineage reprogramming from fibroblasts to erythroid progenitor cells and will finish with future perspectives.
Dr. Velia Fowler will discuss how the biogenesis of mammalian red blood cells is a highly orchestrated process of terminal differentiation with a series of cell divisions coupled to dramatic changes in cell and nuclear morphology, culminate in cell cycle exit and nuclear expulsion (enucleation). While enucleation has been assumed to be a type of asymmetric cell division, differences in cell polarity control and nanoscale organization of cytoskeletal structures indicate otherwise. The molecular and structural basis for events of enucleation will be discussed and evaluated critically, with an eye on providing strategies for optimizing red cell production in vitro.
Miguel Abboud, MD
American University of Beirut
Ke Xu, PhD
University of California- Berkeley
Phase Resolution in Erythropoiesis
Johan Flygare, MD, PhD
Molecules Involved in the Generation of Definitive Hematopoiesis
Velia M. Fowler, PhD
University of Delaware
Cytoskeletal Control of Erythroid Properties and Enucleation
Extrinsic Regulation of Hematopoietic Stem Cell Emergence and Homeostasis
Hematopoietic stem cells (HSCs) undergo carefully-orchestrated, dynamic processes of specification, self-renewal and differentiation to yield the most abundant cells in the body. Approximately 1015 cells of diverse structure and function are generated from vastly smaller pools of HSCs over the average human lifespan, in a manner highly responsive to developmental and environmental cues. Cell-autonomous functions define HSCs, from classical experimental systems to clinical hematopoietic cell transplantation. As a consequence, HSC-intrinsic factors, such as epigenetic programs, transcription factors, and growth factor signaling pathways, dominate oft-cited models of hematopoiesis. A fuller understanding of the life of HSCs is revealed through the lens of basic stem cell biology, incorporating determinants such as niche contacts, morphogen gradients, physical forces, and changes in these over time. This session will present the latest developments in our understanding of extrinsic factors that regulate HSC development and function in vertebrate systems, from early specification to homeostasis, regeneration and aging.
Dr. Trista North will discuss the role of the extrinsic factors in governing the location, onset and progression of HSC formation in the vertebrate embryo. Following earlier waves of production of lineage restricted progenitors, HSCs develop de novo from the hemogenic endothelium in the embryonic dorsal aorta, via a process termed endothelial to hematopoietic transition. While key transcriptional regulators of hemogenic endothelial specification and HSC formation are well established in the field, it is only more recently appreciated how these pathways are activated to initiate commitment to HSC production, and repress endothelial fate. In particular, extrinsic regulation from the developing embryo appears to play a key role in biomechanical and metabolic stimuli, inflammatory signals, and morphogen gradients converge to coordinately regulate the timing and location of HSC production. Dr. North will outline emerging data describing the integration of extrinsic developmental cues with intracellular signaling networks to regulate the onset and maintenance of HSC formation across vertebrate species, from zebrafish to human.
Dr. John Chute will discuss extrinsic factors that regulate adult HSC homeostasis. Bone marrow endothelial cells (BMECs) have an essential role in regulating HSC regeneration following myelotoxicity, but the mechanisms through which BMECs regulate HSC regeneration are not well understood. Dr. Chute will describe the discovery that semaphorin 3A (SEMA3A) - NRP1 signaling negatively regulates BMEC regeneration following chemotherapy or total body irradiation. Systemic administration of a blocking anti-NRP1 antibody or EC-specific deletion of NRP1 or SEMA3A causes the rapid regeneration of the BM vasculature and the hematopoietic system in irradiated mice. Regenerating BMECs in anti-NRP1-treated mice display significantly increased expression and secretion of R-spondin 2, a Wnt pathway amplifying protein, compared to control BMECs. BM HSCs concordantly upregulate expression of LGR5, a receptor for R-spondin 2. Systemic administration of anti-R-spondin 2 antibody blocks both HSC regeneration and hematologic recovery in irradiated mice that otherwise occurred in response to anti-NRP1 treatment. These studies suggest that BMECs drive hematopoietic regeneration through secretion of R-spondin 2 and activation of LGR5+ HSCs.
Dr. Laura Calvi will discuss characteristics of HSC aging in murine models and in humans. These characteristics have been in part ascribed to cell-autonomous processes, but, given the regulatory interactions with HSC with their niche, the aged microenvironment would also be expected to contribute. Recent data from multiple laboratories have outlined mechanisms by which the aged microenvironment influences hematopoietic stem cells, providing evidence the aged components of the microenvironment. Dr. Calvi will review this work and focus particularly on cellular constituents found to impact HSC skewing, as shown by in vivo models. These will include data on aged multipotent stromal cells as well as macrophages.
Suneet Agarwal, MD,PhD
Children's Hosp. Boston
Trista E. North, PhD
Boston Children's Hospital
Extrinsic Factors Governing Hematopoietic Stem Cell Development
John P. Chute, MD
University of California- Los Angeles
Los Angeles, CA
Regenerative Niche-Hematopoietic Stem Cell Interactions
Laura M. Calvi, MD
University of Rochester School of Medicine
Role of the Niche in Hematopoietic Stem Cell Aging
Gut Microbiome and the Endothelium
Commensal microbiota are increasingly recognized participants in cardiometabolic diseases and central modulators of immunity, allergies and autoimmunity. The symbiotic relationship of the microbiome with epithelial interfaces crucially depends on an interplay of microbiota-derived metabolites, host innate immune sensing, and regulation of adaptive immunity. These local interactions particularly in the intestinal milieu have profound effects on the vasculature and contribute to thrombosis through a steadily expanding repertoire of recognized molecular mechanisms. This session will highlight recent cutting-edge research deciphering pathways by which microbiota influence the vascular endothelium and touch in this context on cerebral vascular disease and autoimmunity-evoked thrombosis.
Dr. Martin Kriegel will discuss the role of the microbiota in thrombosis with a focus on the antiphospholipid syndrome. He will provide an overview of the pathogenesis and the importance of ß2-glycoprotein I in thrombosis and of pathobionts within the human gut microbiota that elicit antibodies cross-reactive with epitopes of ß2-glycoprotein I. Dr. Kriegel will link the cross-reactive process with pathogenic autoantibodies leading to thrombosis in an animal model in vivo as well as trophoblast dysfunction in vitro.
Dr. Mark Kahn will present the identification of a gut-brain disease axis for vascular malformation and implications for novel treatment strategies. Loss of function in the genes encoding cerebral cavernous malformation (CCM) adaptor proteins in endothelial cells causes vascular formations that form in the brain and are a significant cause for stroke and seizure in younger individuals. CCM loss of function results in gain of signaling by the MEKK3-KLF2/4 pathway. Unexpectedly, a major input to this pathway in brain endothelial cells is the TLR4 innate immune receptor, the activity of which is strongly influenced by the gut microbiome and gut epithelial barrier function.
Dr. Weifei Zhu has examined the role of gut microbes in modulating stroke susceptibility and functional recovery post stroke onset. Over the past few years, mechanistic links have been developed between nutrients in a western diet, gut microbiota formation of the metabolite trimethylamine N oxide (TMAO), and the development of both platelet hyper-responsiveness and cardiovascular diseases. Dr. Zhu will address the meta-organismal TMAO pathway as a stroke risk factor, depict potential mechanisms contributing to diet enhanced ischemic stroke risks, and explore novel therapeutic approaches targeting gut microbial contributions for prevention and treatment in cerebrovascular disease.
Wolfram Ruf, MD
Johannes Gutenberg University Medical Center
Mainz, CA, Germany
Martin Kriegel, MD, PhD
Yale School of Medicine
New Haven, CT
Microbiota and Thrombosis
Mark Kahn, MD
University of Pennsylvania
Microbiome Regulation of Toll-Like Receptor Signaling and Vascular Malformation
Weifei Zhu, PhD
Cleveland Clinic Foundation
Microbiome-Derived Metabolites Affecting Vascular Function
Novel Blood Therapeutics
While red blood cells (RBCs) play a critical role in the transport and delivery of oxygen to tissue, new research demonstrates that they can be engineered into cargo RBCs that can be used to deliver drugs throughout the body, track red blood cells, visualize blood vessels, or induce immune tolerance to specific antigenic peptides. Additionally, searches for non-cardiotoxic artificial blood substitutes continue to alleviate blood availability concerns and side effects such as alloimmunization. This session will present cutting-edge advancements in the development and potential benefits of RBC-based therapeutics and novel hemoglobin-based oxygen carriers.
Dr. Vladimir Muzykantov will discuss how red blood cells (RBCs) can be used to deliver dugs. RBCs are ideal natural carriers for diverse therapeutic, prophylactic and diagnostic (imaging) agents. Strategies to load these agents into RBCs include encapsulation into isolated RBC via transient pores in cell membrane, genetic modification of RBC precursors, and coupling to RBC surface. Dr. Muzykantov’s talk will focus on the latter approach, whereby a single injection of compounds targeted to RBC surface determinants can uniquely "paint" circulating RBCs in animal studies enabling enhanced pharmacokinetics and unusual distribution of the compound cargoes in the body.
Dr. Hidde Ploegh will discuss how the immune system can be retrained to ignore the antigens that usually trigger inappropriate immune responses in autoimmune diseases such as multiple sclerosis and type 1 diabetes using mouse models. Autoimmune diseases are characterized by inappropriate immune responses in which the body destroys its own cells. Dr. Ploegh will discuss how cargo red blood cells (RBCs) loaded with antigenic peptides, can be used to redirect the immune system and allow these antigens that usually cause an inappropriate immune response to be tolerated - a method called tolerance induction.
Dr. Leticia Hosta-Rigau will discuss the development of hemoglobin-loaded nanoparticles (Hb-NPs) as a novel type of advanced hemoglobin-based oxygen carriers (HBOCs). She will discuss how Hb-NPs aim at addressing major challenges in the field of blood surrogates such as attaining a high Hb loading and long circulation times. Antioxidant coatings are incorporated into the Hb-NPs in order to minimize the conversion of Hb into nonfunctional methemoglobin. Decoration with PEG results in decreased protein adsorption onto the Hb-NPs surface, suggesting a prolonged retention time within the body. Dr. Hosta-Rigau will also discuss how the Hb-NPs preserve the reversible oxygen-binding and releasing properties of Hb.
Stella P Chou, MD
Children's Hospital of Philadelphia
Simone A. Glynn, MD, MPH
National Heart, Lung and Blood Institute
Vladimir Muzykantov, PhD
Perelman School of Medicine, University of Pennsylvania
Drug Delivery by Red Cells
Hidde L. Ploegh, PhD
Boston Children's Hospital
Immune Tolerance by Red Cells
Leticia Hosta-Rigau, PhD
Technical University of Denmark
Kongens Lyngby, Hovedstaden, Denmark
Synthetic Red Cells
Challenges in Cell Therapy: Relapse and Toxicities
Hematopoietic transplantation and adoptive cellular therapies are expanding fields with increasing established and experimental indications. Even as growing numbers of patients benefit from cell therapy, we are still confronted with addressing two key challenges: that of disease relapse despite these therapies, and that of toxicities that accompany them. This session will present state-of-the-science advances in understanding the basic biology of relapse and toxicity following diverse cell therapies, ranging from allogeneic stem cell transplantation to TCR therapy to chimeric antigen receptor (CAR) T cell therapy. Integrated within the discussions are novel insights gained from the analysis of clinical trials and patient samples, thus providing an opportunity to synthesize biologic features with relevance to confronting these challenges across cellular therapies.
Dr. John F. DiPersio will discuss strategies to enhance efficacy and reduce the toxicity of allogeneic stem cell transplantation (allo-HCT). Allo-HCT remains the best chance of a cure for many patients with newly diagnosed and relapsed hematologic malignancies and marrow failure states. The curative power of allo-HCT rests in the graft vs. tumor/leukemia (GvT/GvL) effect of alloreactive donor T cells. These same donor T cells mediate many of the life-threatening complications of allo-HCT, including graft vs host disease (GvHD), conditioning-associated morbidity, and cytokine release syndrome (in the case of haploidentical stem cell transplantation) limiting success. Furthermore, despite the potential for GvL, a relapse often occurs. The mechanisms of relapse after allo-HCT remain poorly understood, but some patients may be related to defined pathways of immune escape. Dr. Dipersio will discuss pre-clinical mouse models leading to early clinical trials, which explore the use of chemotherapy- and radiation-free conditioning regimens and novel approaches for preventing GvHD. He will also discuss approaches for overcoming immune escape, especially in patients with AML after allo-HCT.
Dr. Aude Chapuis will discuss novel strategies to improve current anti-cancer treatments employing T cells transduced to express T cell receptors (TCRs). State-of-the-art methods are being used to elucidate challenges to the efficacy of such therapies in individual patients. Based on these newly identified mechanisms, she will discuss how we can now improve the next generation of adoptive T cell therapies. For example, her group has performed intensive gene expression profiling to identify immune evasion mechanisms and the shortcomings of transferred T cells. To overcome these limitations, her group is developing strategies such as multiplexing of high-affinity TCRs, engineering both CD4+ and CD8+ T cells, and tethering a co-stimulatory signal to transferred T cells. In collaborative studies, they use mouse models that recapitulate the human immune environment to validate particular strategies. These results will likely have broad applicability across solid tumors and blood malignancies.
Dr. Chiara Bonini will address the challenges of managing the toxicities associated with genetically engineered T lymphocytes. This revolutionary therapeutic approach is yielding, encouraging signs of efficacy, but these innovative cellular therapy products (TCR and CAR redirected T cells) have shown unique toxicity profiles. Such toxicity may be linked to the target antigen and result from on-target/off-tumor reactions, due to antigen recognition on healthy cells and tissues, such as in the case of B-cell aplasia that follows CD19-CART cell infusion. In other contexts, toxicity may result from cross-reactivity due to the recognition of epitopes structurally similar to the cancer antigen, as observed with TCR-redirected T cells specific for MAGE-A3 or MAGE-A12 peptides. Excessive activation of innate immunity can be triggered by the synchronous activation of infused T cells, resulting in cytokine release syndrome (CRS), in some cases followed by neurotoxicity. Also, the presence of an intact TCR repertoire on engineered T-cells might result in graft-versus-host disease. Several approaches have been implemented to reduce and control toxicity associated with adoptive cellular therapy. Anti-inflammatory compounds such as anti-IL6R or anti-IL6 monoclonal antibodies have proven to be successful in taming CRS. The selection of cancer antigen combined with the proper affinity of the CAR/TCR used might offer new therapeutic windows. Modifications in construct design, the inclusion of suicide genes in transfer vectors, and the implementation of genome-editing tools in cell manufacturing protocols provide unique opportunities to increase the safety profile of adoptive T cell therapy.
Catherine J. Wu, MD
Dana-Farber Cancer Institute
John F. DiPersio, MD, PhD
Washington University School of Medicine
St. Louis, MO
Addressing Relapsed Disease Following Hematopoietic Stem Cell Transplantation
Aude G. Chapuis, MD
Fred Hutchinson Cancer Research Center
Addressing Relapsed Disease Following Cellular Therapy
Chiara Bonini, MD
Ospedale San Raffaele
Addressing Toxicities Following Cellular Therapy