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Korver W, Wong A, Gebremeskel S, Negri GL, Schanin J, Chang K, Leung J, Benet Z, Luu T, Brock EC, Luehrsen K, Xu A, Youngblood BA. The Inhibitory Receptor Siglec-8 Interacts With FcεRI and Globally Inhibits Intracellular Signaling in Primary Mast Cells Upon Activation. Front Immunol 2022; 13:833728. [PMID: 35154156 PMCID: PMC8837033 DOI: 10.3389/fimmu.2022.833728] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/11/2022] [Indexed: 12/13/2022] Open
Abstract
Immunomodulation of mast cell (MC) activity is warranted in allergic and inflammatory diseases where MCs have a central role in pathogenesis. Targeting Siglec-8, an inhibitory receptor on MCs and eosinophils, has shown promising activity in preclinical and clinical studies. While the intracellular pathways that regulate Siglec-8 activity in eosinophils have been well studied, the signaling mechanisms that lead to MC inhibition have not been fully elucidated. Here, we evaluate the intracellular signaling pathways of Siglec-8-mediated inhibition in primary MCs using an anti-Siglec-8 monoclonal antibody (mAb). Phospho-proteomic profiling of FcεRI-activated MCs revealed Siglec-8 mAb-treatment globally inhibited proximal and downstream kinases, leading to attenuated MC activation and degranulation. In fact, Siglec-8 was found to directly interact with FcεRI signaling molecules. Siglec-8 inhibition was dependent on both cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that interact with the SH2 containing protein phosphatase Shp-2 upon Siglec-8 phosphorylation. Taken together, these data support a model in which Siglec-8 regulates proximal FcεRI-induced phosphorylation events through phosphatase recruitment and interaction with FcεRIγ, resulting in global inhibition of MCs upon Siglec-8 mAb engagement.
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Affiliation(s)
| | - Alan Wong
- Allakos Inc., Redwood City, CA, United States
| | | | | | | | | | - John Leung
- Allakos Inc., Redwood City, CA, United States
| | | | - Thuy Luu
- Allakos Inc., Redwood City, CA, United States
| | | | | | - Alan Xu
- Allakos Inc., Redwood City, CA, United States
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2
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Gebremeskel S, Schanin J, Coyle KM, Butuci M, Luu T, Brock EC, Xu A, Wong A, Leung J, Korver W, Morin RD, Schleimer RP, Bochner BS, Youngblood BA. Mast Cell and Eosinophil Activation Are Associated With COVID-19 and TLR-Mediated Viral Inflammation: Implications for an Anti-Siglec-8 Antibody. Front Immunol 2021; 12:650331. [PMID: 33777047 PMCID: PMC7988091 DOI: 10.3389/fimmu.2021.650331] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/18/2021] [Indexed: 12/11/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection represents a global health crisis. Immune cell activation via pattern recognition receptors has been implicated as a driver of the hyperinflammatory response seen in COVID-19. However, our understanding of the specific immune responses to SARS-CoV-2 remains limited. Mast cells (MCs) and eosinophils are innate immune cells that play pathogenic roles in many inflammatory responses. Here we report MC-derived proteases and eosinophil-associated mediators are elevated in COVID-19 patient sera and lung tissues. Stimulation of viral-sensing toll-like receptors in vitro and administration of synthetic viral RNA in vivo induced features of hyperinflammation, including cytokine elevation, immune cell airway infiltration, and MC-protease production—effects suppressed by an anti-Siglec-8 monoclonal antibody which selectively inhibits MCs and depletes eosinophils. Similarly, anti-Siglec-8 treatment reduced disease severity and airway inflammation in a respiratory viral infection model. These results suggest that MC and eosinophil activation are associated with COVID-19 inflammation and anti-Siglec-8 antibodies are a potential therapeutic approach for attenuating excessive inflammation during viral infections.
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Affiliation(s)
| | | | - Krysta M Coyle
- Department of Molecular Biology and Biochemistry, Research Centre, Simon Fraser University, Vancouver, BC, Canada
| | | | - Thuy Luu
- Allakos Inc., Redwood City, CA, United States
| | | | - Alan Xu
- Allakos Inc., Redwood City, CA, United States
| | - Alan Wong
- Allakos Inc., Redwood City, CA, United States
| | - John Leung
- Allakos Inc., Redwood City, CA, United States
| | | | - Ryan D Morin
- Department of Molecular Biology and Biochemistry, Research Centre, Simon Fraser University, Vancouver, BC, Canada
| | - Robert P Schleimer
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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3
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Kerr SC, Gonzalez JR, Schanin J, Peters MC, Lambrecht BN, Brock EC, Charbit A, Ansel KM, Youngblood BA, Fahy JV. An anti-siglec-8 antibody depletes sputum eosinophils from asthmatic subjects and inhibits lung mast cells. Clin Exp Allergy 2020; 50:904-914. [PMID: 32542913 DOI: 10.1111/cea.13681] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/24/2020] [Accepted: 05/29/2020] [Indexed: 01/09/2023]
Abstract
BACKGROUND Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is expressed on mast cells and eosinophils, but information about Siglec-8 expression and function in the lung is limited. A humanized antibody, AK002, targeting Siglec-8 is undergoing development for treatment of diseases associated with mast cell and eosinophil-driven inflammation. OBJECTIVE To characterize Siglec-8 expression in the airway in asthma and determine whether antibodies that target Siglec-8 (S8mAbs) can decrease airway eosinophils in asthma or inhibit lung mast cell activation. METHODS Gene expression profiling and flow cytometry were used to characterize Siglec-8 expression in sputum cells from stable asthma. An antibody-dependent cellular cytotoxicity (ADCC) assay was used to determine whether an S8mAb can decrease eosinophils in sputum from asthma patients ex vivo. A mast cell activation assay was used to determine whether an S8mAb can inhibit mast cell activation in human lung tissue ex vivo. RESULTS Gene expression for Siglec-8 is increased in sputum cells in asthma and correlates with gene expression for eosinophils and mast cells. Gene expression for Siglec-8 is inversely and significantly correlated with measures of airflow obstruction in asthma patients. Siglec-8 is prominently expressed on the surface of eosinophils and mast cells in sputum. S8mAbs decrease eosinophils in sputum from patients with asthma and inhibit FcεR1-activated mast cells in lung tissues. CONCLUSIONS AND CLINICAL RELEVANCE Siglec-8 is highly expressed on eosinophils and mast cells in asthmatic sputum and targeting Siglec-8 with an antibody is a plausible strategy to decrease sputum eosinophils and inhibit lung mast cells in asthma.
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Affiliation(s)
- Sheena C Kerr
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, CA, USA
| | - Jeanmarie R Gonzalez
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA.,Sandler Asthma Basic Research Center, University of California, San Francisco, CA, USA
| | | | - Michael C Peters
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, CA, USA
| | - Bart N Lambrecht
- VIB Center for Inflammation Research, Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | | | - Annabelle Charbit
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, CA, USA
| | - K M Ansel
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA.,Sandler Asthma Basic Research Center, University of California, San Francisco, CA, USA
| | | | - John V Fahy
- Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, CA, USA.,Sandler Asthma Basic Research Center, University of California, San Francisco, CA, USA
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Walsh CM, Hill RZ, Schwendinger-Schreck J, Deguine J, Brock EC, Kucirek N, Rifi Z, Wei J, Gronert K, Brem RB, Barton GM, Bautista DM. Neutrophils promote CXCR3-dependent itch in the development of atopic dermatitis. eLife 2019; 8:48448. [PMID: 31631836 PMCID: PMC6884397 DOI: 10.7554/elife.48448] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 10/17/2019] [Indexed: 12/12/2022] Open
Abstract
Chronic itch remains a highly prevalent disorder with limited treatment options. Most chronic itch diseases are thought to be driven by both the nervous and immune systems, but the fundamental molecular and cellular interactions that trigger the development of itch and the acute-to-chronic itch transition remain unknown. Here, we show that skin-infiltrating neutrophils are key initiators of itch in atopic dermatitis, the most prevalent chronic itch disorder. Neutrophil depletion significantly attenuated itch-evoked scratching in a mouse model of atopic dermatitis. Neutrophils were also required for several key hallmarks of chronic itch, including skin hyperinnervation, enhanced expression of itch signaling molecules, and upregulation of inflammatory cytokines, activity-induced genes, and markers of neuropathic itch. Finally, we demonstrate that neutrophils are required for induction of CXCL10, a ligand of the CXCR3 receptor that promotes itch via activation of sensory neurons, and we find that that CXCR3 antagonism attenuates chronic itch. Chronic itch is a debilitating disorder that can last for months or years. Eczema, or atopic dermatitis, is the most common cause for chronic itch, affecting one in ten people worldwide. Many treatments for the condition are ineffective, and the exact cause of the disease is unknown, but many different types of cells are likely involved. These include skin cells and inflammation-promoting immune cells, as well as nerve cells that detect inflammation, relay itch and pain information to the brain, and regulate the immune system. Learning more about how these cells interact in eczema may help scientists find better treatments for the condition. So far, a lot of research has focused on static ‘snapshots’ of mature eczema lesions from human skin or animal models. These studies have identified abnormalities in genes or cells, but have not revealed how these genes and cells interact over time to cause chronic itch and inflammation. Now, Walsh et al. reveal that immune cells called neutrophils trigger chronic itch in eczema. The experiments involved mice with a condition that mimics eczema, and showed that removing the neutrophils in these mice alleviated their itching. They also showed that dramatic and rapid changes occur in the nervous system of mice suffering from the eczema-like condition. For example, excess nerves grow in the animals’ damaged skin, genes in the nerves that detect sensations become hyperactive, and changes occur in the spinal cord that have been linked to nerve pain. When neutrophils are absent, these changes do not take place. These findings show that neutrophils play a key role in chronic itch and inflammation in eczema. Drugs that target neutrophils, which are already used to treat other diseases, might help with chronic itch, but they would need to be tested before they can be used on people with eczema.
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Affiliation(s)
- Carolyn M Walsh
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Rose Z Hill
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | | | - Jacques Deguine
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Emily C Brock
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Natalie Kucirek
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Ziad Rifi
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Jessica Wei
- Vision Science Program, School of Optometry, University of California, Berkeley, Berkeley, United States
| | - Karsten Gronert
- Vision Science Program, School of Optometry, University of California, Berkeley, Berkeley, United States
| | - Rachel B Brem
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, United States.,Buck Institute for Research on Aging, Novato, United States
| | - Gregory M Barton
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Diana M Bautista
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States
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Youngblood BA, Brock EC, Leung J, Falahati R, Bochner BS, Rasmussen HS, Peterson K, Bebbington C, Tomasevic N. Siglec-8 antibody reduces eosinophils and mast cells in a transgenic mouse model of eosinophilic gastroenteritis. JCI Insight 2019; 4:126219. [PMID: 31465299 DOI: 10.1172/jci.insight.126219] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 08/23/2019] [Indexed: 01/18/2023] Open
Abstract
Aberrant accumulation and activation of eosinophils and potentially mast cells (MCs) contribute to the pathogenesis of eosinophilic gastrointestinal diseases (EGIDs), including eosinophilic esophagitis (EoE), gastritis (EG), and gastroenteritis (EGE). Current treatment options, such as diet restriction and corticosteroids, have limited efficacy and are often inappropriate for chronic use. One promising new approach is to deplete eosinophils and inhibit MCs with a monoclonal antibody (mAb) against sialic acid-binding immunoglobulin-like lectin 8 (Siglec-8), an inhibitory receptor selectively expressed on MCs and eosinophils. Here, we characterize MCs and eosinophils from human EG and EoE biopsies using flow cytometry and evaluate the effects of an anti-Siglec-8 mAb using a potentially novel Siglec-8-transgenic mouse model in which EG/EGE was induced by ovalbumin sensitization and intragastric challenge. MCs and eosinophils were significantly increased and activated in human EG and EoE biopsies compared with healthy controls. Similar observations were made in EG/EGE mice. In Siglec-8-transgenic mice, anti-Siglec-8 mAb administration significantly reduced eosinophils and MCs in the stomach, small intestine, and mesenteric lymph nodes and decreased levels of inflammatory mediators. In summary, these findings suggest a role for both MCs and eosinophils in EGID pathogenesis and support the evaluation of anti-Siglec-8 as a therapeutic approach that targets both eosinophils and MCs.
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Affiliation(s)
| | | | - John Leung
- Allakos, Inc., Redwood City, California, USA
| | | | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Kathryn Peterson
- Division of Gastroenterology, Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
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Youngblood BA, Brock EC, Leung J, Falahati R, Bryce PJ, Bright J, Williams J, Shultz LD, Greiner DL, Brehm MA, Bebbington C, Tomasevic N. AK002, a Humanized Sialic Acid-Binding Immunoglobulin-Like Lectin-8 Antibody that Induces Antibody-Dependent Cell-Mediated Cytotoxicity against Human Eosinophils and Inhibits Mast Cell-Mediated Anaphylaxis in Mice. Int Arch Allergy Immunol 2019; 180:91-102. [PMID: 31401630 DOI: 10.1159/000501637] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 06/19/2019] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Pathologic accumulation and activation of mast cells and eosinophils are implicated in allergic and inflammatory diseases. Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is an inhibitory receptor selectively expressed on mast cells, eosinophils and, at a lower extent, basophils. When engaged with an antibody, Siglec-8 can induce apoptosis of activated eosinophils and inhibit mast cell activation. AK002 is a humanized, non-fucosylated IgG1 anti-Siglec-8 antibody undergoing clinical investigation for treatment of allergic, inflammatory, and proliferative diseases. Here we examine the human tissue selectivity of AK002 and evaluate the in vitro, ex vivo, and in vivo activity of AK002 on eosinophils and mast cells. METHODS The affinity of AK002 for Siglec-8 and CD16 was determined by biolayer interferometry. Ex vivo activity of AK002 on human eosinophils from blood and dissociated human tissue was tested in apoptosis and antibody-dependent cell-mediated cytotoxicity (ADCC) assays. The in vivo activity of a murine precursor of AK002 (mAK002) was tested in a passive systemic anaphylaxis (PSA) humanized mouse model. RESULTS AK002 bound selectively to mast cells, eosinophils and, at a lower level, to basophils in human blood and tissue and not to other cell types examined. AK002 induced apoptosis of interleukin-5-activated blood eosinophils and demonstrated potent ADCC activity against blood eosinophils in the presence of natural killer cells. AK002 also significantly reduced eosinophils in dissociated human lung tissue. Furthermore, mAK002 prevented PSA in humanized mice through mast cell inhibition. CONCLUSION AK002 selectively evokes potent apoptotic and ADCC activity against eosinophils and prevents systemic anaphylaxis through mast cell inhibition.
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Affiliation(s)
| | | | - John Leung
- Allakos, Inc., Redwood City, California, USA
| | | | - Paul J Bryce
- Division of Allergy-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | | | | | - Dale L Greiner
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Michael A Brehm
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Legrand F, Cao Y, Wechsler JB, Zhu X, Zimmermann N, Rampertaap S, Monsale J, Romito K, Youngblood BA, Brock EC, Makiya MA, Tomasevic N, Bebbington C, Maric I, Metcalfe DD, Bochner BS, Klion AD. Sialic acid-binding immunoglobulin-like lectin (Siglec) 8 in patients with eosinophilic disorders: Receptor expression and targeting using chimeric antibodies. J Allergy Clin Immunol 2018; 143:2227-2237.e10. [PMID: 30543818 DOI: 10.1016/j.jaci.2018.10.066] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 09/19/2018] [Accepted: 10/26/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND Sialic acid-binding immunoglobulin-like lectin (Siglec) 8 is selectively expressed on eosinophils, mast cells, and basophils and, when engaged on eosinophils, can cause cell death. OBJECTIVE We sought to characterize surface and soluble Siglec-8 (sSiglec-8) levels in normal donors (NDs) and eosinophilic donors (EOs) and assess the efficacy of anti-Siglec-8 antibodies in inducing eosinophil cell death in vitro. METHODS Eosinophil expression of Siglec-8 was assessed by using flow cytometry and quantitative PCR. Serum sSiglec-8 levels were measured by means of ELISA. Induction of eosinophil death by IgG4 (chimeric 2E2 IgG4) and afucosylated IgG1 (chimeric 2E2 IgG1 [c2E2 IgG1]) anti-Siglec-8 antibodies was evaluated in vitro by using flow cytometry and in vivo in humanized mice. RESULTS Siglec-8 was consistently expressed on eosinophils from NDs and EOs and did not correlate with absolute eosinophil count or disease activity. sSiglec-8 levels were measurable in sera from most donors unrelated to absolute eosinophil counts or Siglec-8 surface expression. c2E2 IgG1 and chimeric 2E2 IgG4 were equally effective at inducing cell death (Annexin-V positivity) of purified eosinophils from NDs and EOs after overnight IL-5 priming. In contrast, killing of purified eosinophils without IL-5 was only seen in EOs, and natural killer cell-mediated eosinophil killing was seen only with c2E2 IgG1. Finally, treatment of humanized mice with anti-Siglec antibody led to robust depletion of IL-5-induced eosinophilia in vivo. CONCLUSIONS Siglec-8 is highly expressed on blood eosinophils from EOs and NDs and represents a potential therapeutic target for eosinophilic disorders. Enhanced killing of eosinophils in the presence of IL-5 might lead to increased efficacy in patients with IL-5-driven eosinophilia.
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MESH Headings
- Animals
- Antibodies, Blocking/genetics
- Antigens, CD/genetics
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/immunology
- Antigens, Differentiation, B-Lymphocyte/metabolism
- Cell Death
- Cells, Cultured
- Cytotoxicity, Immunologic
- Eosinophilia/immunology
- Eosinophilia/therapy
- Eosinophils/immunology
- Humans
- Immunoglobulin G/genetics
- Interleukin-5/metabolism
- Killer Cells, Natural/immunology
- Lectins/genetics
- Lectins/immunology
- Lectins/metabolism
- Leukocyte Count
- Mice
- Mice, SCID
- Molecular Targeted Therapy
- Recombinant Fusion Proteins/genetics
- Transcriptome
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Affiliation(s)
- Fanny Legrand
- Human Eosinophil Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Md.
| | - Yun Cao
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Joshua B Wechsler
- Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, Ill
| | - Xiang Zhu
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Nives Zimmermann
- Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Shakuntala Rampertaap
- Department of Laboratory Medicine, Warren Magnusson Clinical Center, National Institutes of Health, Bethesda
| | - Joseph Monsale
- Department of Laboratory Medicine, Warren Magnusson Clinical Center, National Institutes of Health, Bethesda
| | - Kimberly Romito
- Department of Laboratory Medicine, Warren Magnusson Clinical Center, National Institutes of Health, Bethesda
| | | | | | - Michelle A Makiya
- Human Eosinophil Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Md
| | | | | | - Irina Maric
- Hematology Section, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda
| | - Dean D Metcalfe
- Mast Cell Biology Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Md
| | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Ill
| | - Amy D Klion
- Human Eosinophil Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Md.
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