Showing papers in "The Journal of Allergy and Clinical Immunology in 2018"

Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management.

Abstract: This review provides general information to serve as a primer for those embarking on understanding food allergy and also details advances and updates in epidemiology, pathogenesis, diagnosis, and treatment that have occurred over the 4 years since our last comprehensive review. Although firm prevalence data are lacking, there is a strong impression that food allergy has increased, and rates as high as approximately 10% have been documented. Genetic, epigenetic, and environmental risk factors are being elucidated increasingly, creating potential for improved prevention and treatment strategies targeted to those at risk. Insights on pathophysiology reveal a complex interplay of the epithelial barrier, mucosal and systemic immune response, route of exposure, and microbiome among other influences resulting in allergy or tolerance. The diagnosis of food allergy is largely reliant on medical history, tests for sensitization, and oral food challenges, but emerging use of component-resolved diagnostics is improving diagnostic accuracy. Additional novel diagnostics, such as basophil activation tests, determination of epitope binding, DNA methylation signatures, and bioinformatics approaches, will further change the landscape. A number of prevention strategies are under investigation, but early introduction of peanut has been advised as a public health measure based on existing data. Management remains largely based on allergen avoidance, but a panoply of promising treatment strategies are in phase 2 and 3 studies, providing immense hope that better treatment will be imminently and widely available, whereas numerous additional promising treatments are in the preclinical and clinical pipeline.

Obesity and asthma

Abstract: Obesity is a vast public health problem and both a major risk factor and disease modifier for asthma in children and adults. Obese subjects have increased asthma risk, and obese asthmatic patients have more symptoms, more frequent and severe exacerbations, reduced response to several asthma medications, and decreased quality of life. Obese asthma is a complex syndrome, including different phenotypes of disease that are just beginning to be understood. We examine the epidemiology and characteristics of this syndrome in children and adults, as well as the changes in lung function seen in each age group. We then discuss the better recognized factors and mechanisms involved in disease pathogenesis, focusing particularly on diet and nutrients, the microbiome, inflammatory and metabolic dysregulation, and the genetics/genomics of obese asthma. Finally, we describe current evidence on the effect of weight loss and mention some important future directions for research in the field.

Phenotype, penetrance, and treatment of 133 cytotoxic T-lymphocyte antigen 4–insufficient subjects

Abstract: Background: Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a negative immune regulator. Heterozygous CTLA4 germline mutations can cause a complex immune dysregulation syndrome in human subjects. Objective: We sought to characterize the penetrance, clinical features, and best treatment options in 133 CTLA4 mutation carriers. Methods: Genetics, clinical features, laboratory values, and outcomes of treatment options were assessed in a worldwide cohort of CTLA4 mutation carriers. Results: We identified 133 subjects from 54 unrelated families carrying 45 different heterozygous CTLA4 mutations, including 28 previously undescribed mutations. Ninety mutation carriers were considered affected, suggesting a clinical penetrance of at least 67%; median age of onset was 11 years, and the mortality rate within affected mutation carriers was 16%(n = 15). Main clinical manifestations included hypogammaglobulinemia (84%), lymphoproliferation (73%), autoimmune cytopenia (62%), and respiratory (68%), gastrointestinal (59%), or neurological features (29%). Eight affectedmutation carriers had lymphoma, and 3 had gastric cancer. An EBV association was found in 6 patients with malignancies. CTLA4 mutations were associated with lymphopenia and decreased T-, B-, and natural killer (NK) cell counts. Successful targeted therapies included application of CTLA-4 fusion proteins, mechanistic target of rapamycin inhibitors, and hematopoietic stem cell transplantation. EBV reactivation occurred in 2 affected mutation carriers after immunosuppression. Conclusions: Affected mutation carriers with CTLA-4 insufficiency can present in any medical specialty. Family members should be counseled because disease manifestation can occur as late as 50 years of age. EBV- and cytomegalovirus-associated complications must be closely monitored. Treatment interventions should be coordinated in clinical trials.

Results from the 5-year SQ grass sublingual immunotherapy tablet asthma prevention (GAP) trial in children with grass pollen allergy.

Abstract: Background Allergy immunotherapy targets the immunological cause of allergic rhinoconjunctivitis and allergic asthma and has the potential to alter the natural course of allergic disease. Objective The primary objective was to investigate the effect of the SQ grass sublingual immunotherapy tablet compared with placebo on the risk of developing asthma. Methods A total of 812 children (5-12 years), with a clinically relevant history of grass pollen allergic rhinoconjunctivitis and no medical history or signs of asthma, were included in the randomized, double-blind, placebo-controlled trial, comprising 3 years of treatment and 2 years of follow-up. Results There was no difference in time to onset of asthma, defined by prespecified asthma criteria relying on documented reversible impairment of lung function (primary endpoint). Treatment with the SQ grass sublingual immunotherapy tablet significantly reduced the risk of experiencing asthma symptoms or using asthma medication at the end of trial (odds ratio = 0.66, P P P Conclusions Treatment with the SQ grass sublingual immunotherapy tablet reduced the risk of experiencing asthma symptoms and using asthma medication, and had a positive, long-term clinical effect on rhinoconjunctivitis symptoms and medication use but did not show an effect on the time to onset of asthma.

Mechanisms of food allergy.

Abstract: Although oral tolerance is the normal physiologic response to ingested antigens, a breakdown in this process appears to have occurred in the past 2 decades, leading to an increasing prevalence of sensitization to food allergens. Over the past decade, basic research has intensified in an attempt to better understand the mechanisms leading to sensitization and disease versus desensitization and short- and long-term tolerance. In this review we assess various factors that can influence tissue and immune responses to food antigens, the current understanding of immune tolerance development, the role of the gastrointestinal microbiota, and current knowledge regarding immunologic mechanisms involved in desensitization and sustained unresponsiveness, although perhaps the latter is more appropriately termed remission.

Inflammatory phenotypes in patients with severe asthma are associated with distinct airway microbiology

Abstract: Background Asthma pathophysiology and treatment responsiveness are predicted by inflammatory phenotype. However, the relationship between airway microbiology and asthma phenotype is poorly understood. Objective We aimed to characterize the airway microbiota in patients with symptomatic stable asthma and relate composition to airway inflammatory phenotype and other phenotypic characteristics. Methods The microbial composition of induced sputum specimens collected from adult patients screened for a multicenter randomized controlled trial was determined by using 16S rRNA gene sequencing. Inflammatory phenotypes were defined by sputum neutrophil and eosinophil cell proportions. Microbiota were defined by using α- and β-diversity measures, and interphenotype differences were identified by using similarity of percentages, network analysis, and taxon fold change. Phenotypic predictors of airway microbiology were identified by using multivariate linear regression. Results Microbiota composition was determined in 167 participants and classified as eosinophilic (n = 84), neutrophilic (n = 14), paucigranulocytic (n = 60), or mixed neutrophilic-eosinophilic (n = 9) asthma phenotypes. Airway microbiology was significantly less diverse ( P = .022) and more dissimilar ( P = .005) in neutrophilic compared with eosinophilic participants. Sputum neutrophil proportions, but not eosinophil proportions, correlated significantly with these diversity measures (α-diversity: Spearman r = −0.374, P r = 0.238, P = .002). Interphenotype differences were characterized by a greater frequency of pathogenic taxa at high relative abundance and reduced Streptococcus , Gemella , and Porphyromonas taxa relative abundance in patients with neutrophilic asthma. Multivariate regression confirmed that sputum neutrophil proportion was the strongest predictor of microbiota composition. Conclusions Neutrophilic asthma is associated with airway microbiology that is significantly different from that seen in patients with other inflammatory phenotypes, particularly eosinophilic asthma. Differences in microbiota composition might influence the response to antimicrobial and steroid therapies and the risk of lung infection.

Steroid resistance of airway type 2 innate lymphoid cells from patients with severe asthma: The role of thymic stromal lymphopoietin.

Abstract: Background Type 2 innate lymphoid cells (ILC2s) represent an important type 2 immune cell. Glucocorticoid regulation of human ILC2s is largely unknown. Objective We sought to assess steroid resistance of human blood and airway ILC2s from asthmatic patients and to examine its mechanism of induction. Methods We studied human blood and lung ILC2s from asthmatic patients and control subjects using flow cytometry and ELISA. Results Dexamethasone inhibited ( P = .04) chemoattractant receptor–homologous molecule expressed on T H 2 lymphocytes and type 2 cytokine expression by blood ILC2s stimulated with IL-25 and IL-33. However, it did not do so when ILC2s were stimulated with IL-7 and thymic stromal lymphopoietin (TSLP), 2 ligands of IL-7 receptor α. Unlike blood ILC2s, bronchoalveolar lavage (BAL) fluid ILC2s from asthmatic patients were resistant to dexamethasone. BAL fluid from asthmatic patients had increased TSLP but not IL-7 levels. BAL fluid TSLP levels correlated ( r = 0.74) with steroid resistance of ILC2s. TSLP was synergistically induced in epithelial cells by IL-13 and human rhinovirus. Mechanistically, dexamethasone upregulated ILC2 expression of IL-7 receptor α, which augmented and sustained signal transducer and activator of transcription (STAT) 5 signaling by TSLP. TSLP induced mitogen-activated protein kinase kinase (MEK), c-Fos, inhibitor of DNA binding 3, phosphorylated signal transducer and activator of transcription (pSTAT) 3, and pSTAT5, molecules linked to steroid resistance. Dexamethasone inhibited c-Fos, inhibitor of DNA binding 3, and pSTAT3 but not pSTAT5 and MEK. The MEK inhibitor trametinib, the Janus kinase–STAT inhibitor tofacitinib, and the STAT5 inhibitor pimozide reversed steroid resistance of BAL ILC2s. Conclusions Dexamethasone inhibited type 2 cytokine production by blood ILC2s. IL-7 and TSLP abrogated this inhibition and induced steroid resistance of ILC2s in a MEK- and STAT5-dependent manner. BAL fluid ILC2s from asthmatic patients with increased TSLP levels were steroid resistant, which was reversed by clinically available inhibitors of MEK and STAT5.

Itch: From mechanism to (novel) therapeutic approaches.

Abstract: Itch is a common sensory experience that is prevalent in patients with inflammatory skin diseases, as well as in those with systemic and neuropathic conditions. In patients with these conditions, itch is often severe and significantly affects quality of life. Itch is encoded by 2 major neuronal pathways: histaminergic (in acute itch) and nonhistaminergic (in chronic itch). In the majority of cases, crosstalk existing between keratinocytes, the immune system, and nonhistaminergic sensory nerves is responsible for the pathophysiology of chronic itch. This review provides an overview of the current understanding of the molecular, neural, and immune mechanisms of itch: beginning in the skin, proceeding to the spinal cord, and eventually ascending to the brain, where itch is processed. A growing understanding of the mechanisms of chronic itch is expanding, as is our pipeline of more targeted topical and systemic therapies. Our therapeutic armamentarium for treating chronic itch has expanded in the last 5 years, with developments of topical and systemic treatments targeting the neural and immune systems.

Oral corticosteroid exposure and adverse effects in asthmatic patients.

Abstract: Background Significant adverse effects (AEs) have been associated with continuous exposure to oral corticosteroids (OCSs). The potential association with intermittent exposure is unknown. Objective We sought to assess the association between OCSs and AEs based on the number of OCS prescriptions. Methods This was a retrospective cohort study of asthmatic patients 18 years and older in the 2000-2014 MarketScan data set. Propensity score matching was used at baseline (12 months before the index date: first OCS use). Logistic regression was used to examine the association between OCSs and new incident AEs (either combined or individual) controlling for covariates. Follow-up continued for 24 months minimum and 10 years maximum after the index date. Results There were 72,063 and 156,373 subjects in the OCS and no OCS cohorts, respectively. Subjects taking 4 or more OCS (1-3) prescriptions within the year had 1.29 (1.04) times the odds of experiencing a new AE within the year. Each year of exposure to 4 or more OCS prescriptions (current and past) resulted in 1.20 times the odds of having an AE in the current year. Exposure to 4 or more prescriptions was associated with significantly greater odds of AEs for osteoporosis, hypertension, obesity, type 2 diabetes, gastrointestinal ulcers/bleeds, fractures, and cataracts (odds, 1.21-1.44 depending on the AE). Conclusion Although previous research has documented the deleterious effect of continuous OCS exposure in patients with severe asthma, our results suggest that each OCS prescription might result in a cumulative burden on current and future health regardless of dose and duration. OCS-sparing strategies are extremely important to improve patient outcomes.

Neutrophil extracellular traps are associated with disease severity and microbiota diversity in patients with chronic obstructive pulmonary disease

Abstract: Background Neutrophil extracellular traps (NETs) have been observed in the airway in patients with chronic obstructive pulmonary disease (COPD), but their clinical and pathophysiologic implications have not been defined. Objective We sought to determine whether NETs are associated with disease severity in patients with COPD and how they are associated with microbiota composition and airway neutrophil function. Methods NET protein complexes (DNA-elastase and histone-elastase complexes), cell-free DNA, and neutrophil biomarkers were quantified in soluble sputum and serum from patients with COPD during periods of disease stability and during exacerbations and compared with clinical measures of disease severity and the sputum microbiome. Peripheral blood and airway neutrophil function were evaluated by means of flow cytometry ex vivo and experimentally after stimulation of NET formation. Results Sputum NET complexes were associated with the severity of COPD evaluated by using the composite Global Initiative for Obstructive Lung Disease scale ( P 1 , symptoms evaluated by using the COPD assessment test, and higher levels of NET complexes in patients with frequent exacerbations ( P = .002). Microbiota composition was heterogeneous, but there was a correlation between NET complexes and both microbiota diversity ( P = .009) and dominance of Haemophilus species operational taxonomic units ( P = .01). Ex vivo airway neutrophil phagocytosis of bacteria was reduced in patients with increased sputum NET complexes. Consistent results were observed regardless of the method of quantifying sputum NETs. Failure of phagocytosis could be induced experimentally by incubating healthy control neutrophils with soluble sputum from patients with COPD. Conclusion NET formation is increased in patients with severe COPD and associated with more frequent exacerbations and a loss of microbiota diversity.

Nemolizumab in patients with moderate-to-severe atopic dermatitis: Randomized, phase II, long-term extension study

Abstract: Background Nemolizumab, an anti–IL-31 receptor A mAb, improved pruritus, dermatitis, and sleep in adults with moderate-to-severe atopic dermatitis that was inadequately controlled by topical treatments in a phase II, 12-week, randomized, double-blind, placebo-controlled study (part A; NCT01986933 ). Objective We sought to assess the long-term efficacy and safety of nemolizumab injected subcutaneously every 4 weeks (Q4W) or every 8 weeks (Q8W) in a 52-week, double-blind extension (part B). Methods During part B, patients continued the previous nemolizumab dose (0.1, 0.5, or 2.0 mg/kg Q4W or 2.0 mg/kg Q8W). Part B end points included percentage improvement from baseline in pruritus visual analog scale and dermatitis scores (including the Eczema Area and Severity Index). Results Overall, 216 of 264 patients completed part A, and 191 entered part B; 131 completed part B. In 153 patients randomized to nemolizumab in part A, improvement from baseline in pruritus visual analog scale score was maintained/increased from weeks 12 to 64, with greatest improvement in the 0.5-mg/kg Q4W group (percentage change from baseline at week 64: −73.0, −89.6, −74.7, and −79.1 in the 0.1-, 0.5-, and 2.0-mg/kg Q4W and 2.0-mg/kg Q8W groups, respectively). Improvement from baseline in dermatitis scores was also maintained/increased to week 64 (percentage change in Eczema Area and Severity Index score: −68.5, −75.8, −78.9, and −69.3 in the 0.1-, 0.5-, and 2.0-mg/kg Q4W and 2.0-mg/kg Q8W groups, respectively). Over 64 weeks, 83% to 89% had 1 or more adverse events, with no new safety concerns identified. Conclusion Nemolizumab for up to 64 weeks was efficacious and overall well tolerated in patients with moderate-to-severe atopic dermatitis inadequately controlled by topical therapy.

Vaccine-associated hypersensitivity

Abstract: Vaccine-associated hypersensitivity reactions are not infrequent; however, serious acute-onset, presumably IgE-mediated or IgG and complement-mediated anaphylactic or serious delayed-onset T cell-mediated systemic reactions are considered extremely rare Hypersensitivity can occur because of either the active vaccine component (antigen) or one of the other components Postvaccination acute-onset hypersensitivity reactions include self-limited localized adverse events and, rarely, systemic reactions ranging from urticaria/angioedema to full-blown anaphylaxis with multisystem involvement Risk of anaphylaxis after all vaccines is estimated to be 131 (95% CI, 090-184) per million vaccine doses, respectively Serious hypersensitivity reactions after influenza vaccines are particularly important because of the large number of persons vaccinated annually Influenza vaccines are unique in requiring annual changes in the vaccines' antigenic composition to match the predicted circulating influenza strains Recently, novel influenza vaccine types were introduced in the United States (recombinant vaccines, some with higher antigen content and a new adjuvanted vaccine) Providers should be aware of changing recommendations on the basis of recent published evidence for persons with a history of egg allergy to receive annual influenza vaccination Further research is needed to elucidate the pathophysiology and risk factors for reported vaccine-associated adverse events Further research is also needed to determine whether repeated annual inactivated influenza vaccination, the number of vaccine antigens administered at the same time, and the current timing of routine infant vaccinations are optimal for overall population well-being

Jakinibs for the treatment of immune dysregulation in patients with gain-of-function signal transducer and activator of transcription 1 (STAT1) or STAT3 mutations.

Abstract: Treatment of the autoimmune and immune-dysregulatory features of patients with STAT1 GOF or STAT3 GOF disease remains challenging. Jakinibs have been used to treat the severe immune-dysregulation in patients with either STAT1 GOF or STAT3 GOF mutations.

Type 2 innate lymphoid cells disrupt bronchial epithelial barrier integrity by targeting tight junctions through IL-13 in asthmatic patients.

Abstract: Background Bronchial epithelial barrier leakiness and type 2 innate lymphoid cells (ILC2s) have been separately linked to asthma pathogenesis; however, the influence of ILC2s on the bronchial epithelial barrier has not been investigated previously. Objective We investigated the role of ILC2s in the regulation of bronchial epithelial tight junctions (TJs) and barrier function both in bronchial epithelial cells of asthmatic patients and healthy subjects and general innate lymphoid cell– and ILC2-deficient mice. Methods Cocultures of human ILC2s and bronchial epithelial cells were used to determine transepithelial electrical resistance, paracellular flux, and TJ mRNA and protein expressions. The effect of ILC2s on TJs was examined by using a murine model of IL-33–induced airway inflammation in wild-type, recombination-activating gene 2 (Rag2)−/−, Rag2−/−Il2rg−/−, and Rorasg/sg mice undergoing bone marrow transplantation to analyze the in vivo relevance of barrier disruption by ILC2s. Results ILC2s significantly impaired the epithelial barrier, as demonstrated by reduced transepithelial electrical resistance and increased fluorescein isothiocyanate–dextran permeability in air-liquid interface cultures of human bronchial epithelial cells. This was in parallel to decreased mRNAs and disrupted protein expression of TJ proteins and was restored by neutralization of IL-13. Intranasal administration of recombinant IL-33 to wild-type and Rag2−/− mice lacking T and B cells triggered TJ disruption, whereas Rag2−/−Il2rg−/− and Rorasg/sg mice undergoing bone marrow transplantation that lack ILC2s did not show any barrier leakiness. Direct nasal administration of IL-13 was sufficient to induce deficiency in the TJ barrier in the bronchial epithelium of mice in vivo. Conclusion These data highlight an essential mechanism in asthma pathogenesis by demonstrating that ILC2s are responsible for bronchial epithelial TJ barrier leakiness through IL-13.

Early-onset pediatric atopic dermatitis is characterized by TH2/TH17/TH22-centered inflammation and lipid alterations

Abstract: Background Although atopic dermatitis (AD) often starts in early childhood, detailed tissue profiling of early-onset AD in children is lacking, hindering therapeutic development for this patient population with a particularly high unmet need for better treatments. Objective We sought to globally profile the skin of infants with AD compared with that of adults with AD and healthy control subjects. Methods We performed microarray, RT-PCR, and fluorescence microscopy studies in infants and young children ( Results Transcriptomic analyses revealed profound differences between pediatric patients with early-onset versus adult patients with longstanding AD in not only lesional but also nonlesional tissues. Although both patient populations harbored TH2-centered inflammation, pediatric AD also showed significant TH17/TH22 skewing but lacked the TH1 upregulation that characterizes adult AD. Pediatric AD exhibited relatively normal expression of epidermal differentiation and cornification products, which is downregulated in adults with AD. Defects in the lipid barrier (eg, ELOVL fatty acid elongase 3 [ELOVL3] and diacylglycerol o-acyltransferase 2 [DGAT2]) and tight junction regulation (eg, claudins 8 and 23) were evident in both groups. However, some lipid-associated mediators (eg, fatty acyl-CoA reductase 2 and fatty acid 2-hydroxylase) showed preferential downregulation in pediatric AD, and lipid barrier genes (FA2H and DGAT2) showed inverse correlations with transepidermal water loss, a functional measure of the epidermal barrier. Conclusions Skin samples from children and adult patients with AD share lipid metabolism and tight junction alterations, but epidermal differentiation complex defects are only present in adult AD, potentially resulting from chronic immune aberration that is not yet present in early-onset disease.

Age-associated distribution of normal B-cell and plasma cell subsets in peripheral blood

Abstract: Background: Humoral immunocompetence develops stepwise throughout life and contributes to individual susceptibility to infection, immunodeficiency, autoimmunity, and neoplasia. Immunoglobulin heavy chain (IgH) isotype serum levels can partly explain such age-related differences, but their relationship with the IgH isotype distribution within memory B-cell (MBC) and plasma cell (PCs) compartments remains to be investigated. Objective: We studied the age-related distribution of MBCs and PCs expressing different IgH isotypes in addition to the immature/transitional and naive B-cell compartments. Methods: B-cell and PC subsets and plasma IgH isotype levels were studied in cord blood (n = 19) and peripheral blood (n = 215) from healthy donors aged 0 to 90 years by using flow cytometry and nephelometry, respectively. Results: IgH-switched MBCs expressing IgG1, IgG2, IgG3, IgA1, and IgA2 were already detected in cord blood and newborns at very low counts, whereas CD27+IgM++IgD+ MBCs only became detectable at 1 to 5 months and remained stable until 2 to 4 years, and IgD MBCs peaked at 2 to 4 years, with both populations decreasing thereafter. MBCs expressing IgH isotypes of the second immunoglobulin heavy chain constant region (IGHC) gene block (IgG1, IgG3, and IgA1) peaked later during childhood (2-4 years), whereas MBCs expressing third IGHC gene block immunoglobulin isotypes (IgG2, IgG4, and IgA2) reached maximum values during adulthood. PCs were already detected in newborns, increasing in number until 6 to 11 months for IgM, IgG1, IgG2, IgG3, IgA1, and IgA2; until 2 to 4 years for IgD; and until 5 to 9 years for IgG4 and decreasing thereafter. For most IgH isotypes (except IgD and IgG4), maximum plasma levels were reached after PC and MBC counts peaked. Conclusions: PC counts reach maximum values early in life, followed by MBC counts and plasma IgH isotypes. Importantly, IgH isotypes from different IGHC gene blocks show different patterns, probably reflecting consecutive cycles of IgH isotype switch recombination through life.

Inflammatory health effects of indoor and outdoor particulate matter

Abstract: Credit can now be obtained, free for a limited time, by reading the review articles in this issue. Please note the following instructions.Method of Physician Participation in Learning Process: The core material for these activities can be read in this issue of the Journal or online at the JACI Web site: www.jacionline.org. The accompanying tests may only be submitted online at www.jacionline.org. Fax or other copies will not be accepted.Date of Original Release: March 2018. Credit may be obtained for these courses until February 28, 2019.Copyright Statement: Copyright © 2018-2019. All rights reserved.Overall Purpose/Goal: To provide excellent reviews on key aspects of allergic disease to those who research, treat, or manage allergic disease.Target Audience: Physicians and researchers within the field of allergic disease.Accreditation/Provider Statements and Credit Designation: The American Academy of Allergy, Asthma & Immunology (AAAAI) is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians. The AAAAI designates this journal-based CME activity for a maximum of 1.00 AMA PRA Category 1 Credit™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.List of Design Committee Members: Weidong Wu, PhD, Yuefei Jin, MD, and Chris Carlsten, MD, MPH (authors); Zuhair K. Ballas, MD (editor)Disclosure of Significant Relationships with Relevant CommercialCompanies/Organizations: The authors declare that they have no relevant conflicts of interest. Z. K. Ballas (editor) disclosed no relevant financial relationships.Activity Objectives: 1.To recognize that particulate matter (PM) can have significant pulmonary and cardiovascular effects. 2.To identify some of the inflammatory changes and potential health consequences that can occur with exposure to PM. Recognition of Commercial Support: This CME activity has not received external commercial support.List of CME Exam Authors: Evelyn Angulo, MD, Anna Lang, MD, PhD, David Peloza, MD, Cheryl Steiman, MD, and Sameer K. Mathur, MD, PhD.Disclosure of Significant Relationships with Relevant CommercialCompanies/Organizations: The exam authors disclosed no relevant financial relationships.Inflammation is a common and essential event in the pathogenesis of diverse diseases. Decades of research has converged on an understanding that all combustion-derived particulate matter (PM) is inflammatory to some extent in the lungs and also systemically, substantially explaining a significant portion of the massive cardiopulmonary disease burden associated with these exposures. In general, this means that efforts to do the following can all be beneficial: reduce particulates at the source, decrease the inflammatory potential of PM output, and, where PM inhalation is unavoidable, administer anti-inflammatory treatment. A range of research, including basic illumination of inflammatory pathways, assessment of disease burden in large cohorts, tailored treatment trials, and epidemiologic, animal, and in vitro studies, is highlighted in this review. However, meaningful translation of this research to decrease the burden of disease and deliver a clear and cohesive message to guide daily clinical practice remains rudimentary. Ongoing efforts to better understand substantial differences in the concentration and type of PM to which the global community is exposed and then distill how that influences inflammation promises to have real-world benefit. This review addresses this complex topic in 3 sections, including ambient PM (typically associated with ground-level transportation), wildfire-induced PM, and PM from indoor biomass burning. Recognizing the overlap between these domains, we also describe differences and suggest future directions to better inform clinical practice and public health.

Hypersensitivity reactions to therapeutic monoclonal antibodies: Phenotypes and endotypes

Abstract: Background The increasing use of mAbs has led to a rise in hypersensitivity reactions (HSRs), which prevent their use as first-line therapy. HSRs' symptoms, diagnostic tools, and directed management approaches have not been standardized. Objective We propose a novel evidence-based classification of HSRs to mAbs, based on the clinical phenotypes, underlying endotypes and biomarkers, as well as their management with desensitization. Methods Phenotypes, endotypes, and biomarkers of HSRs to 16 mAbs for 104 patients were described and compared with the outcomes of 526 subcutaneous and intravenous desensitizations. Results Initial reactions presented with 4 patterns: type I–like reactions (63%), cytokine-release reactions (13%), mixed reactions (21%), and delayed type IV reactions (3%). In contrast, of the 23% breakthrough HSRs during desensitization, 52% were cytokine-release reactions, 32% were type 1, 12% were mixed, and 4% were type I with delayed type IV. Skin testing to 10 mAbs in 58 patients was positive in 41% of patients. Serum tryptase was elevated in 1 patient and IL-6 was elevated in 8 patients during desensitization and was associated with a cytokine-release phenotype. Conclusions HSRs to mAbs can be defined as type I, cytokine-release, mixed (type I/cytokine-release), and type IV reactions, which are identified by biomarkers such as skin test, tryptase, and IL-6. These phenotypes can be used to improve personalized and precision medicine when diagnosing HSRs to mAbs and providing management recommendations with desensitization. Desensitization provides a safe and effective retreatment option to remain on culprit mAbs as first-line therapy.

Mast cells signal their importance in health and disease

Abstract: FceRI is the primary receptor in mast cells that mediates allergic reactions by inducing rapid release of mediators, an adaptive immune response that might have evolved as a host defense against parasites and venoms. Yet it is apparent that mast cells are also activated through non-IgE receptors, the significance of which is just beginning to be understood. This includes the Mas-related G protein–coupled receptor X2, which might contribute to reactions to diverse antimicrobials and polybasic compounds, and the adhesion G protein–coupled receptor E2, variants of which are associated with familial vibratory urticaria and are activated by mechanical vibration. Similarly, mast cells have long been recognized as the main repository for histamine, heparin, and proteases. Recent evidence also points to new functions, modes of delivery, and mechanisms of action of mast cell proteases that add new dimensions to the roles of mast cells in human biology. In addition, exposure of mast cells to environmental cues can quantitatively and qualitatively modulate their responses and thus their effect on allergic inflammation. Illustrating this paradigm, we summarize a number of recent studies implicating the injury/tissue damage cytokine IL-33 as a modulator of allergen-induced mast cell responses. We also discuss the discovery of markers associated with transformed mast cells and new potential directions in suppressing mast cell activity.

Cancer in primary immunodeficiency diseases: Cancer incidence in the United States Immune Deficiency Network Registry

Abstract: Background We evaluated the overall and site-specific incidence of cancer in subjects with primary immunodeficiency diseases (PIDD) enrolled in the United States Immune Deficiency Network (USIDNET) registry compared with age-adjusted cancer incidence in the Surveillance, Epidemiology and End Results Program (SEER) database. Objective We hypothesized that subjects with PIDD would have an increased incidence of cancer due to impaired immune function. Methods Overall and site-specific cancer incidence rates were evaluated in subjects with PIDD ( n = 3658) enrolled in the USIDNET registry from 2003 to 2015 and compared with age-adjusted incidence rates in the SEER database. Results We observed a 1.42-fold excess relative risk of cancer in subjects with PIDD compared with the age-adjusted SEER population ( P P P P Conclusions Excess incidence of cancer occurred in subjects with PIDD. An excess of lymphoma in specific PIDD populations principally drove this increased incidence, while no increased risk of the most common solid tumor malignancies was observed. These data point to a restricted role of the immune system in protecting from specific cancers.

Loss-of-function nuclear factor κB subunit 1 (NFKB1) variants are the most common monogenic cause of common variable immunodeficiency in Europeans

Abstract: Background The genetic cause of primary immunodeficiency disease (PID) carries prognostic information. Objective We conducted a whole-genome sequencing study assessing a large proportion of the NIHR BioResource–Rare Diseases cohort. Methods In the predominantly European study population of principally sporadic unrelated PID cases (n = 846), a novel Bayesian method identified nuclear factor κB subunit 1 (NFKB1) as one of the genes most strongly associated with PID, and the association was explained by 16 novel heterozygous truncating, missense, and gene deletion variants. This accounted for 4% of common variable immunodeficiency (CVID) cases (n = 390) in the cohort. Amino acid substitutions predicted to be pathogenic were assessed by means of analysis of structural protein data. Immunophenotyping, immunoblotting, and ex vivo stimulation of lymphocytes determined the functional effects of these variants. Detailed clinical and pedigree information was collected for genotype-phenotype cosegregation analyses. Results Both sporadic and familial cases demonstrated evidence of the noninfective complications of CVID, including massive lymphadenopathy (24%), unexplained splenomegaly (48%), and autoimmune disease (48%), features prior studies correlated with worse clinical prognosis. Although partial penetrance of clinical symptoms was noted in certain pedigrees, all carriers have a deficiency in B-lymphocyte differentiation. Detailed assessment of B-lymphocyte numbers, phenotype, and function identifies the presence of an increased CD21 low B-cell population. Combined with identification of the disease-causing variant, this distinguishes between healthy subjects, asymptomatic carriers, and clinically affected cases. Conclusion We show that heterozygous loss-of-function variants in NFKB1 are the most common known monogenic cause of CVID, which results in a temporally progressive defect in the formation of immunoglobulin-producing B cells.

Endotype-driven care pathways in patients with chronic rhinosinusitis

Abstract: Chronic rhinosinusitis (CRS) has been differentiated clinically into CRS without nasal polyps and CRS with nasal polyps, with both forms subjected to glucocorticosteroid and antibiotic treatments and, if not successful, to nasal and sinus surgery tailored to endoscopic and computed tomographic scan findings. The elaboration of endotypes based on pathomechanisms involving different immune responses offers new possibilities in terms of prediction of prognosis and risks and sophisticated guidance in personalized pharmacotherapy, surgical approaches, and innovative treatment approaches in the CRS field with various biologics. Surgical approaches can vary from classical functional endoscopic sinus surgery to extended and "reboot" approaches, with the idea to completely remove the dysfunctional and inflamed mucosa and replace it with a newly grown healthy mucosa. Biologics in this field are targeting the type 2 cytokines IL-4, IL-5, and IL-13, as well as IgE. Phase I and II study results are promising, and phase III studies are currently being performed. The development of endotype-driven integrated care pathways appreciating these innovations are now needed for the management of CRS.

Treatment for food allergy

Abstract: The prevalence of IgE-mediated food allergy is an increasing public health concern effecting millions of persons worldwide. The current standard of treatment is strict avoidance of the offending food or foods, and to date, there are no regulatory approved treatments for food allergy. A significant amount of research has been directed at various forms of food immunotherapy, including oral, sublingual, and epicutaneous delivery routes. Although oral immunotherapy has shown the greatest promise for efficacy in terms of the amount of protein that can be ingested, it has also demonstrated less tolerability and a less favorable safety profile compared with sublingual immunotherapy and epicutaneous immunotherapy, which offers the least protection but has the best safety and tolerability profile. Studies have been conducted with adding adjuvants and anti-IgE to enhance either the efficacy or safety of food immunotherapy. Multiple concepts of food immunotherapy beyond these first-generation treatments are in either animal or early phase 1 studies.

A decade of research on the 17q12-21 asthma locus: Piecing together the puzzle

Abstract: Chromosome 17q12-21 remains the most highly replicated and significant asthma locus. Genotypes in the core region defined by the first genome-wide association study correlate with expression of 2 genes, ORM1-like 3 (ORMDL3) and gasdermin B (GSDMB), making these prime candidate asthma genes, although recent studies have implicated gasdermin A (GSDMA) distal to and post-GPI attachment to proteins 3 (PGAP3) proximal to the core region as independent loci. We review 10 years of studies on the 17q12-21 locus and suggest that genotype-specific risks for asthma at the proximal and distal loci are not specific to early-onset asthma and mediated by PGAP3, ORMDL3, and/or GSDMA expression. We propose that the weak and inconsistent associations of 17q single nucleotide polymorphisms with asthma in African Americans is due to the high frequency of some 17q alleles, the breakdown of linkage disequilibrium on African-derived chromosomes, and possibly different early-life asthma endotypes in these children. Finally, the inconsistent association between asthma and gene expression levels in blood or lung cells from older children and adults suggests that genotype effects may mediate asthma risk or protection during critical developmental windows and/or in response to relevant exposures in early life. Thus studies of young children and ethnically diverse populations are required to fully understand the relationship between genotype and asthma phenotype and the gene regulatory architecture at this locus.

External exposome and allergic respiratory and skin diseases

Abstract: Allergies are complex diseases that result from interactions between multiple genetic and environmental factors. However, the increase in allergies observed in the past decades is explained exclusively by environmental changes occurring in the same period. Presently, the exposome, the totality of specific and nonspecific external environmental exposures (external exposome) to which a subject is exposed from preconception onward and their consequences at the organ and cell levels (internal exposome), is being considered to explain the inception, development, and exacerbations of allergic diseases. Among the best-studied environmental factors of the specific external exposome, indoor and outdoor aeroallergens and air pollutants play a key role in the etiopathogenesis of the inflammatory response to allergens and in clinical manifestations of allergic disease. Climate change, urbanization, and loss of biodiversity affect sources, emissions, and concentrations of main aeroallergens and air pollutants and are among the most critical challenges facing the health and quality of life of the still increasing number of allergic patients today and in the coming decades. Thunderstorm-related asthma is a dramatic example of the effects of combined environmental factors and an in vivo model for understanding the mechanisms at work in respiratory allergy. Environment- or lifestyle-driven aberrancies in the gut and skin microbiome composition represent key mediators of allergic diseases. A better knowledge of the effect of the external exposome on allergy development is crucial for urging patients, health professionals, and policymakers to take actions to mitigate the effect of environmental changes and to adapt to them.

A functional splice variant associated with decreased asthma risk abolishes the ability of gasdermin B to induce epithelial cell pyroptosis

Abstract: Background Genetic variants in the chromosomal region 17q21 are consistently associated with asthma. However, mechanistic studies have not yet linked any of the associated variants to a function that could influence asthma, and as a result, the identity of the asthma gene(s) remains elusive. Objectives We sought to identify and characterize functional variants in the 17q21 locus. Methods We used the Exome Aggregation Consortium browser to identify coding (amino acid–changing) variants in the 17q21 locus. We obtained asthma association measures for these variants in both the Genetic Epidemiology Research in Adult Health and Aging (GERA) cohort (16,274 cases and 38,269 matched controls) and the EVE Consortium study (5,303 asthma cases and 12,560 individuals). Gene expression and protein localization were determined by quantitative RT-PCR and fluorescence immunostaining, respectively. Molecular and cellular studies were performed to determine the functional effects of coding variants. Results Two coding variants (rs2305480 and rs11078928) of the gasdermin B ( GSDMB ) gene in the 17q21 locus were associated with lower asthma risk in both GERA (odds ratio, 0.92; P = 1.01 × 10 −6 ) and EVE (odds ratio, 0.85; joint P EVE = 1.31 × 10 −13 ). In GERA, rs11078928 had a minor allele frequency (MAF) of 0.45 in unaffected (nonasthmatic) controls and 0.43 in asthma cases. For European Americans in EVE, the MAF of rs2305480 was 0.45 for controls and 0.39 for cases; for all EVE subjects, the MAF was 0.32 for controls and 0.27 for cases. GSDMB is highly expressed in differentiated airway epithelial cells, including the ciliated cells. We found that, when the GSDMB protein is cleaved by inflammatory caspase-1 to release its N-terminal fragment, potent pyroptotic cell death is induced. The splice variant rs11078928 deletes the entire exon 6, which encodes 13 amino acids in the critical N-terminus, and abolishes the pyroptotic activity of the GSDMB protein. Conclusions Our study identified a functional asthma variant in the GSDMB gene of the 17q21 locus and implicates GSDMB-mediated epithelial cell pyroptosis in pathogenesis.

X-linked carriers of chronic granulomatous disease: Illness, lyonization, and stability.

Abstract: Background Chronic granulomatous disease (CGD) is characterized by recurrent life-threatening bacterial and fungal infections and aberrant inflammation. Mutations in CYBB cause X-linked CGD and account for 65% to 70% of cases in Western countries. Objective We sought to understand the clinical manifestations associated with the X-linked CGD carrier state. Methods We undertook a comprehensive retrospective study of 162 affected female subjects. We examined dihydrorhodamine 123 (DHR) oxidation data for percentage of X-chromosome inactivation. We correlated lyonization (%DHR + ) with clinical features. Where possible, we followed %DHR + values over time. Results Clinical data were available for 93 female subjects: %DHR + values were 46% (mean) and 47% (median; SD, 24). Using the %DHR + value as the criterion for X inactivation, 78% of patients had levels of inactivation of 20% to 80%, suggesting random inactivation that was independent of age. In contrast, carriers with CGD-type infections had median %DHR + values of 8% (n = 14; range, 0.06% to 48%), and those with only autoimmune or inflammatory manifestations had median %DHR + values of 39% (n = 31; range, 7.4% to 74%). Those with both infections and autoimmunity had low %DHR + values (n = 6; range, 3% to 14%). A %DHR + value of less than 10% was strongly associated with infections (odds ratio, 99). Strong association persisted when %DHR + values were less than 20% (odds ratio, 12). Autoimmunity was not associated with %DHR + values. In 2 sets of identical twins, the %DHR + populations tracked closely over time. Although the %DHR + populations were very similar between sisters, those between mothers and daughters were unrelated. Conclusions A low %DHR + value strongly predicts infection risk in X-linked CGD carriers, and the carrier state itself is associated with autoimmunity.

Prenatal fine particulate exposure and early childhood asthma: Effect of maternal stress and fetal sex

Abstract: Background The impact of prenatal ambient air pollution on child asthma may be modified by maternal stress, child sex, and exposure dose and timing. Objective We prospectively examined associations between coexposure to prenatal particulate matter with an aerodynamic diameter of less than 2.5 microns (PM 2.5 ) and maternal stress and childhood asthma (n = 736). Methods Daily PM 2.5 exposure during pregnancy was estimated using a validated satellite-based spatiotemporally resolved prediction model. Prenatal maternal negative life events (NLEs) were dichotomized around the median (high: NLE ≥ 3; low: NLE 2.5 exposure on children's asthma by age 6 years, and determine effect modification by maternal stress and child sex. Results Bayesian distributed lag interaction models identified a critical window of exposure (19-23 weeks' gestation, cumulative odds ratio, 1.15; 95% CI, 1.03-1.26; per interquartile range [1.7 μg/m 3 ] increase in prenatal PM 2.5 level) during which children concomitantly exposed to prenatal PM 2.5 and maternal stress had increased risk of asthma. No significant association was seen in children born to women reporting low prenatal stress. When examining modifying effects of prenatal stress and fetal sex, we found that boys born to mothers with higher prenatal stress were most vulnerable (19-21 weeks' gestation; cumulative odds ratio, 1.28; 95% CI, 1.15-1.41; per interquartile range increase in PM 2.5 ). Conclusions Prenatal PM 2.5 exposure during sensitive windows is associated with increased risk of child asthma, especially in boys concurrently exposed to elevated maternal stress.

Blood eosinophil count thresholds and exacerbations in patients with chronic obstructive pulmonary disease

Abstract: Background Eosinophilic airway inflammation in patients with chronic obstructive pulmonary disease (COPD) is associated with exacerbations and responsivity to steroids, suggesting potential shared mechanisms with eosinophilic asthma However, there is no consistent blood eosinophil count that has been used to define the increased exacerbation risk Objective We sought to investigate blood eosinophil counts associated with exacerbation risk in patients with COPD Methods Blood eosinophil counts and exacerbation risk were analyzed in patients with moderate-to-severe COPD by using 2 independent studies of former and current smokers with longitudinal data The Genetic Epidemiology of COPD (COPDGene) study was analyzed for discovery (n = 1,553), and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study was analyzed for validation (n = 1,895) A subset of the ECLIPSE study subjects were used to assess the stability of blood eosinophil counts over time Results COPD exacerbation risk increased with higher eosinophil counts An eosinophil count threshold of 300 cells/μL or greater showed adjusted incidence rate ratios for exacerbations of 132 in the COPDGene study (95% CI, 110-163) The cutoff of 300 cells/μL or greater was validated for prospective risk of exacerbation in the ECLIPSE study, with adjusted incidence rate ratios of 122 (95% CI, 106-141) using 3-year follow-up data Stratified analysis confirmed that the increased exacerbation risk associated with an eosinophil count of 300 cells/μL or greater was driven by subjects with a history of frequent exacerbations in both the COPDGene and ECLIPSE studies Conclusions Patients with moderate-to-severe COPD and blood eosinophil counts of 300 cells/μL or greater had an increased risk exacerbations in the COPDGene study, which was prospectively validated in the ECLIPSE study

Solitary chemosensory cells are a primary epithelial source of IL-25 in patients with chronic rhinosinusitis with nasal polyps.

Abstract: Background IL-25 can function as an early signal for the respiratory type 2 response characteristic of allergic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP). In the mouse gut, tuft cells are the epithelial source of IL-25. However, the source of human airway epithelial IL-25 has remained elusive. Objective In this study we sought to determine whether the solitary chemosensory cell (SCC) is the predominant source of IL-25 in the sinonasal epithelium. Method Flow cytometry and immunofluorescence for SCCs and IL-25 were used to interrogate polyp and turbinate tissue from patients with CRSwNP. Mucus was collected during acute inflammatory exacerbations from patients with CRSwNP or chronic rhinosinusitis without nasal polyps and IL-25 levels determined by using ELISA. Lastly, sinonasal epithelial cultures derived from polyp and turbinate tissue were stimulated with IL-13 and analyzed for SCC proliferation and IL-25 production. Results This study demonstrates that a discrete cell type, likely an SCC, characterized by expression of the taste-associated G protein gustducin and the intestinal tuft cell marker doublecortin-like kinase 1, is the predominant source of IL-25 in the human upper airway. Additionally, we show that patients with CRSwNP have increased numbers of SCCs in nasal polyp tissue and that in vitro IL-13 exposure both increased proliferation and induced apical secretion of IL-25 into the mucosal layer. Conclusions Inflammatory sinus polyps but not adjacent turbinate tissue show expansion of the SCC population, which is the source of epithelial IL-25.