Circulating biomarkers of airflow limitation across the life span.

BACKGROUND: Airflow limitation is a hallmark of chronic obstructive pulmonary disease, which can develop through different lung function trajectories across the life span. There is a need for longitudinal studies aimed at identifying circulating biomarkers of airflow limitation across different stages of life. OBJECTIVES: This study sought to identify a signature of serum proteins associated with airflow limitation and evaluate their relation to lung function longitudinally in adults and children. METHODS: This study used data from 3 adult cohorts (TESAOD [Tucson Epidemiological Study of Airway Obstructive Disease], SAPALDIA [Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults], LSC [Lovelace Smoker Cohort]) and 1 birth cohort (TCRS [Tucson Children's Respiratory Study]) (N = 1940). In TESAOD, among 46 circulating proteins, we identified those associated with FEV1/forced vital capacity (FVC) percent (%) predicted levels and generated a score based on the sum of their z-scores. Cross-sectional analyses were used to test the score for association with concomitant lung function. Longitudinal analyses were used to test the score for association with subsequent lung function growth in childhood and decline in adult life. RESULTS: After false discovery rate adjustment, serum levels of 5 proteins (HP, carcinoembryonic antigen, ICAM1, CRP, TIMP1) were associated with percent predicted levels of FEV1/FVC and FEV1 in TESAOD. In cross-sectional multivariate analyses the 5-biomarker score was associated with FEV1 % predicted in all adult cohorts (meta-analyzed FEV1 decrease for 1-SD score increase: -2.9%; 95% CI: -3.9%, -1.9%; P = 2.4 × 10-16). In multivariate longitudinal analyses, the biomarker score at 6 years of age was inversely associated with FEV1 and FEV1/FVC levels attained by young adult life (P = .02 and .005, respectively). In adults, persistently high levels of the biomarker score were associated with subsequent accelerated decline of FEV1 and FEV1/FVC (P = .01 and .001). CONCLUSIONS: A signature of 5 circulating biomarkers of airflow limitation was associated with both impaired lung function growth in childhood and accelerated lung function decline in adult life, indicating that these proteins may be involved in multiple lung function trajectories leading to chronic obstructive pulmonary disease.

Transcriptomic changes associated with oral immunotherapy for food allergy.

This review summarizes recent advances in characterizing the transcriptional pathways associated with outcomes following Oral Immunotherapy. Recent technological advances including single-cell sequencing are transforming the ways in which the transcriptional landscape is understood. The application of these technologies is still in its infancy in food allergy but here we summarize current understanding of gene expression changes following oral immunotherapy for food allergy and specific signatures underpinning the different clinical outcomes of desensitization and remission (sustained unresponsiveness). T helper 2A cells have been identified as a cell type which correlates with disease activity and is modified by treatment. Molecular features at study entry may differentiate individuals who achieve more positive outcomes during OIT. Recent findings point to T cell anergy and Type 1 interferon pathways as potential mechanisms supporting redirection of the allergen-specific immune response away from allergy towards remission. Despite these developments in our understanding of immune mechanisms following OIT, there are still significant gaps. Additional studies examining immune signatures associated with long term and well-defined clinical outcomes are required to gain a more complete understanding of the pathways leading to remission of allergy, in order to optimize treatments and gain improved outcomes for patients.

Airway and parenchyma transcriptomics in a house dust mite model of experimental asthma.

Lung transcriptomics studies in asthma have provided valuable information in the whole lung context, however, deciphering the individual contributions of the airway and parenchyma in disease pathogenesis may expedite the development of novel targeted treatment strategies. In this study, we performed transcriptomics on the airway and parenchyma using a house dust mite (HDM)-induced model of experimental asthma that replicates key features of the human disease. HDM exposure increased the expression of 3,255 genes, of which 212 were uniquely increased in the airways, 856 uniquely increased in the parenchyma, and 2187 commonly increased in both compartments. Further interrogation of these genes using a combination of network and transcription factor enrichment analyses identified several transcription factors that regulate airway and/or parenchymal gene expression, including transcription factor EC (TFEC), transcription factor PU.1 (SPI1), H2.0-like homeobox (HLX), metal response element binding transcription factor-1 (MTF1) and E74-like factor 4 (ets domain transcription factor, ELF4) involved in controlling innate immune responses. We next assessed the effects of inhibiting lung SPI1 responses using commercially available DB1976 and DB2313 on key disease outcomes. We found that both compounds had no protective effects on airway inflammation, however DB2313 (8 mg/kg) decreased mucus secreting cell number, and both DB2313 (1 mg/kg) and DB1976 (2.5 mg/kg and 1 mg/kg) reduced small airway collagen deposition. Significantly, both compounds decreased airway hyperresponsiveness. This study demonstrates that SPI1 is important in HDM-induced experimental asthma and that its pharmacological inhibition reduces HDM-induced airway collagen deposition and hyperresponsiveness.

LPS binding protein and activation signatures are upregulated during asthma exacerbations in children.

Asthma exacerbations in children are associated with respiratory viral infection and atopy, resulting in systemic immune activation and infiltration of immune cells into the airways. The gene networks driving the immune activation and subsequent migration of immune cells into the airways remains incompletely understood. Cellular and molecular profiling of PBMC was employed on paired samples obtained from atopic asthmatic children (n = 19) during acute virus-associated exacerbations and later during convalescence. Systems level analyses were employed to identify coexpression networks and infer the drivers of these networks, and validation was subsequently obtained via independent samples from asthmatic children. During exacerbations, PBMC exhibited significant changes in immune cell abundance and upregulation of complex interlinked networks of coexpressed genes. These were associated with priming of innate immunity, inflammatory and remodelling functions. We identified activation signatures downstream of bacterial LPS, glucocorticoids and TGFB1. We also confirmed that LPS binding protein was upregulated at the protein-level in plasma. Multiple gene networks known to be involved positively or negatively in asthma pathogenesis, are upregulated in circulating PBMC during acute exacerbations, supporting the hypothesis that systemic pre-programming of potentially pathogenic as well as protective functions of circulating immune cells preceeds migration into the airways. Enhanced sensitivity to LPS is likely to modulate the severity of acute asthma exacerbations through exposure to environmental LPS.

Protection against severe infant lower respiratory tract infections by immune training: Mechanistic studies.

BACKGROUND: Results from recent clinical studies suggest potential efficacy of immune training (IT)-based approaches for protection against severe lower respiratory tract infections in infants, but underlying mechanisms are unclear. OBJECTIVE: We used systems-level analyses to elucidate IT mechanisms in infants in a clinical trial setting. METHODS: Pre- and posttreatment peripheral blood mononuclear cells from a placebo-controlled trial in which winter treatment with the IT agent OM85 reduced infant respiratory infection frequency and/or duration were stimulated for 24 hours with the virus/bacteria mimics polyinosinic:polycytidylic acid/lipopolysaccharide. Transcriptomic profiling via RNA sequencing, pathway and upstream regulator analyses, and systems-level gene coexpression network analyses were used sequentially to elucidate and compare responses in treatment and placebo groups. RESULTS: In contrast to subtle changes in antivirus-associated polyinosinic:polycytidylic acid response profiles, the bacterial lipopolysaccharide-triggered gene coexpression network responses exhibited OM85 treatment-associated upregulation of IFN signaling. This was accompanied by network rewiring resulting in increased coordination of TLR4 expression with IFN pathway-associated genes (especially master regulator IRF7); segregation of TNF and IFN-γ (which potentially synergize to exaggerate inflammatory sequelae) into separate expression modules; and reduced size/complexity of the main proinflammatory network module (containing, eg, IL-1,IL-6, and CCL3). Finally, we observed a reduced capacity for lipopolysaccharide-induced inflammatory cytokine (eg, IL-6 and TNF) production in the OM85 group. CONCLUSION: These changes are consistent with treatment-induced enhancement of bacterial pathogen detection/clearance capabilities concomitant with enhanced capacity to regulate ensuing inflammatory response intensity and duration. We posit that IT agents exemplified by OM85 potentially protect against severe lower respiratory tract infections in infants principally by effects on innate immune responses targeting the bacterial components of the mixed respiratory viral/bacterial infections that are characteristic of this age group.

Airway and parenchymal transcriptomics in a novel model of asthma and COPD overlap.

BACKGROUND: Asthma and chronic obstructive pulmonary disease (COPD) are common chronic respiratory diseases, and some patients have overlapping disease features, termed asthma-COPD overlap (ACO). Patients characterized with ACO have increased disease severity; however, the mechanisms driving this have not been widely studied. OBJECTIVES: This study sought to characterize the phenotypic and transcriptomic features of experimental ACO in mice induced by chronic house dust mite antigen and cigarette smoke exposure. METHODS: Female BALB/c mice were chronically exposed to house dust mite antigen for 11 weeks to induce experimental asthma, cigarette smoke for 8 weeks to induce experimental COPD, or both concurrently to induce experimental ACO. Lung inflammation, structural changes, and lung function were assessed. RNA-sequencing was performed on separated airway and parenchyma lung tissues to assess transcriptional changes. Validation of a novel upstream driver SPI1 in experimental ACO was assessed using the pharmacological SPI1 inhibitor, DB2313. RESULTS: Experimental ACO recapitulated features of both asthma and COPD, with mixed pulmonary eosinophilic/neutrophilic inflammation, small airway collagen deposition, and increased airway hyperresponsiveness. Transcriptomic analysis identified common and distinct dysregulated gene clusters in airway and parenchyma samples in experimental asthma, COPD, and ACO. Upstream driver analysis revealed increased expression of the transcription factor Spi1. Pharmacological inhibition of SPI1 using DB2313, reduced airway remodeling and airway hyperresponsiveness in experimental ACO. CONCLUSIONS: A new experimental model of ACO featuring chronic dual exposures to house dust mite and cigarette smoke mimics key disease features observed in patients with ACO and revealed novel disease mechanisms, including upregulation of SPI1, that are amenable to therapy.

Remission of peanut allergy is associated with rewiring of allergen-driven T helper 2-related gene networks.

BACKGROUND: The immunological changes underpinning acquisition of remission (also called sustained unresponsiveness) following food immunotherapy remain poorly defined. Limited access to effective therapies and biosamples from treatment responders has prevented progress. Probiotic peanut oral immunotherapy is highly effective at inducing remission, providing an opportunity to investigate immune changes. METHODS: Using a systems biology approach, we examined gene co-expression network patterns in peanut-specific CD4+ T cell responses before and after probiotic and peanut oral immunotherapy in subjects enrolled in the PPOIT-001 randomized trial: Responders who attained remission (n = 16), placebo-treated who remained allergic (n = 16). RESULTS: Acquisition of remission was associated with rewiring of gene network patterns, which was characterized by integration of T helper 2 and interferon signalling modules, markedly reduced T helper 2 gene connectivity, and shutdown in co-expression activity between T helper 2 effectors and cell cycle regulators. CONCLUSION: The immunological changes underlying remission following peanut oral immunotherapy are mediated by reprogramming of T helper 2-associated gene networks in the CD4+ T cell compartment. Findings provide insight into immune mechanisms driving the acquisition of remission following oral immunotherapy, paving the way for the development of improved approaches to induce remission/sustained unresponsiveness in patients with food allergy.

Unlocking immune-mediated disease mechanisms with transcriptomics.

The transcriptome represents the entire set of RNA transcripts expressed in a cell, reflecting both the underlying genetic and epigenetic landscape and environmental influences, providing a comprehensive view of functional cellular states at any given time. Recent technological advances now enable the study of the transcriptome at the resolution of individual cells, providing exciting opportunities to characterise cellular and molecular events that underpin immune-medicated diseases. Here, we draw on recent examples from the literature to highlight the application of advanced bioinformatics tools to extract mechanistic insight and disease biology from bulk and single-cell transcriptomic profiles. Key considerations for the use of available analysis techniques are presented throughout.

Small nucleolar RNA networks are up-regulated during human anaphylaxis.

BACKGROUND: Anaphylaxis is a severe, potentially life-threatening allergic reaction driven primarily by the activation of mast cells. We still fail to understand factors underlying reaction severity. Furthermore, there is currently no reliable diagnostic test to confirm anaphylaxis in the emergency department (ED). OBJECTIVE: This study sought to explore gene expression changes associated with anaphylaxis severity in peripheral blood leucocytes and evaluate biomarker potential. METHODS: Microarray analysis (total RNA) was performed using peripheral blood samples from ED patients with moderate (n = 6) or severe (n = 12) anaphylaxis and sepsis (n = 20) at presentation (T0) and one hour later (T1). Results were compared between groups and healthy controls (n = 10 and n = 11 matched to anaphylaxis and sepsis patients, respectively). Changes in gene expression were determined using R programming language, and pathway analysis applied to explore biological processes and pathways associated with genes. Differentially expressed genes were validated in an independent cohort of anaphylaxis (n = 30) and sepsis (n = 20) patients, and healthy controls (n = 10), using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). RESULTS: Significant up-regulation of small nucleolar RNAs (snoRNAs) was demonstrated in anaphylaxis compared to sepsis patients in the microarray cohort, at T0 and T1. qRT-PCR analysis of the validation cohort showed five genes: SNORD61, SNORD8, SNORD69, SNORD119 and HIST1H1D to be significantly up-regulated (adjusted p < 0.05) in severe anaphylaxis compared to sepsis. Seven genes (SNORD61, SNORD8, SCARNA21, SNORD69, SNORD110, SNORD119 and SNORD59A) were significantly up-regulated (adjusted p < 0.05) in severe anaphylaxis compared to healthy controls. CONCLUSION: This study demonstrates for the first time the unique involvement of snoRNAs in the pathogenesis of anaphylaxis and suggests they are not a general feature of systemic inflammation. Further investigation of snoRNA expression in anaphylaxis could provide insights into disease pathogenesis. CLINICAL RELEVANCE: SnoRNAs are up-regulated during acute anaphylaxis in humans and could potentially be used as biomarkers of severe anaphylaxis.

Upper Airway Cell Transcriptomics Identify a Major New Immunological Phenotype with Strong Clinical Correlates in Young Children with Acute Wheezing.

Asthma exacerbations are triggered by rhinovirus infections. We employed a systems biology approach to delineate upper-airway gene network patterns underlying asthma exacerbation phenotypes in children. Cluster analysis unveiled distinct IRF7hi versus IRF7lo molecular phenotypes, the former exhibiting robust upregulation of Th1/type I IFN responses and the latter an alternative signature marked by upregulation of cytokine and growth factor signaling and downregulation of IFN-γ. The two phenotypes also produced distinct clinical phenotypes. For IRF7lo children, symptom duration prior to hospital presentation was more than twice as long from initial symptoms (p = 0.011) and nearly three times as long for cough (p < 0.001), the odds ratio of admission to hospital was increased more than 4-fold (p = 0.018), and time to recurrence was shorter (p = 0.015). In summary, our findings demonstrate that asthma exacerbations in children can be divided into IRF7hi versus IRF7lo phenotypes with associated differences in clinical phenotypes.

Differential Gene Expression of Lymphocytes Stimulated with Rhinovirus A and C in Children with Asthma.

Rationale: Individuals with asthma have heightened antibody responses to rhinoviruses (RVs), although those specific for RV-C are lower than responses specific for RV-A, suggesting poor immunity to this species.Objectives: To ascertain and compare T-cell memory responses induced by RV-A and RV-C in children with and without asthma.Methods: Peripheral blood mononuclear cells from 17 children with asthma and 19 control subjects without asthma were stimulated in vitro with peptide formulations to induce representative species-specific responses to RV-A and RV-C. Molecular profiling (RNA sequencing) was used to identify enriched pathways and upstream regulators.Measurements and Main Results: Responses to RV-A showed higher expression of IFNG and STAT1 compared with RV-C, and significant expression of CXCL9, 10, and 11 was not found for RV-C. There was no reciprocal increase of T-helper cell type 2 (Th2) cytokine genes or the Th2 chemokine genes CCL11, CCL17, and CCL22. RV-C induced higher expression of CCL24 (eotaxin-2) than RV-A in the responses of children with and without asthma. Upstream regulator analysis showed both RV-A and, although to a lesser extent, RV-C induced predominant Th1 and inflammatory cytokine expression. The responses of children with asthma compared with those without asthma were lower for both RV-A and RV-C while retaining the pattern of gene expression and upstream regulators characteristic of each species. All groups showed activation of the IL-17A pathway.Conclusions: RV-C induced memory cells with a lower IFN-γ-type response than RV-A without T-helper cell type 2 (Th2) upregulation. Children with asthma had lower recall responses than those without asthma while largely retaining the same gene activation profile for each species. RV-A and RV-C, therefore, induce qualitatively different T-cell responses.

Assessing the unified airway hypothesis in children via transcriptional profiling of the airway epithelium.

BACKGROUND: Emerging evidence suggests that disease vulnerability is expressed throughout the airways, the so-called unified airway hypothesis, but the evidence to support this is predominantly indirect. OBJECTIVES: We sought to establish the transcriptomic profiles of the upper and lower airways and determine their level of similarity irrespective of airway symptoms (wheeze) and allergy. METHODS: We performed RNA sequencing on upper and lower airway epithelial cells from 63 children with or without wheeze and accompanying atopy, using differential gene expression and gene coexpression analyses to determine transcriptional similarity. RESULTS: We observed approximately 91% homology in the expressed genes between the 2 sites. When coexpressed genes were grouped into modules relating to biological functions, all were found to be conserved between the 2 regions, resulting in a consensus network containing 16 modules associated with ribosomal function, metabolism, gene expression, mitochondrial activity, and antiviral responses through IFN activity. Although symptom-associated gene expression changes were more prominent in the lower airway, they were reflected in nasal epithelium and included IL-1 receptor like 1, prostaglandin-endoperoxide synthase 1, CCL26, and periostin. Through network analysis we identified a cluster of coexpressed genes associated with atopic wheeze in the lower airway, which could equally distinguish atopic and nonatopic phenotypes in upper airway samples. CONCLUSIONS: We show that the upper and lower airways are significantly conserved in their transcriptional composition, and that variations associated with disease are present in both nasal and tracheal epithelium. Findings from this study supporting a unified airway imply that clinical insight regarding the lower airway in health and disease can be gained from studying the nasal epithelium.

Rewiring of gene networks underlying mite allergen-induced CD4 + Th-cell responses during immunotherapy.

BACKGROUND: Multiple regulatory mechanisms have been identified employing conventional hypothesis-driven approaches as contributing to allergen-specific immunotherapy outcomes, but understanding of how these integrate to maintain immunological homeostasis is incomplete. OBJECTIVE: To explore the potential for unbiased systems-level gene co-expression network analysis to advance understanding of immunotherapy mechanisms. METHODS: We profiled genome-wide allergen-induced Th-cell responses prospectively during 24 months subcutaneous immunotherapy (SCIT) in 25 rhinitis, documenting changes in immunoinflammatory pathways and associated co-expression networks and their relationships to symptom scores out to 36 months. RESULTS: Prior to immunotherapy, mite-induced Th-cell response networks involved multiple discrete co-expression modules including those related to Th2-, type1 IFN-, inflammation- and FOXP3/IL2-associated signalling. A signature comprising 109 genes correlated with symptom scores, and these mapped to cytokine signalling/T-cell activation-associated pathways, with upstream drivers including hallmark Th1/Th2- and inflammation-associated genes. Reanalysis after 3.5 months SCIT updosing detected minimal changes to pathway/upstream regulator profiles despite 32.5% symptom reduction; however, network analysis revealed underlying merging of FOXP3/IL2-with inflammation-and Th2-associated modules. By 12 months SCIT, symptoms had reduced by 41% without further significant changes to pathway/upstream regulator or network profiles. Continuing SCIT to 24 months stabilized symptoms at 47% of baseline, accompanied by upregulation of the type1 IFN-associated network module and its merging into the Th2/FOXP3/IL2/inflammation module. CONCLUSIONS: Subcutaneous immunotherapy stimulates progressive integration of mite-induced Th cell-associated Th2-, FOXP3/IL2-, inflammation- and finally type1 IFN-signalling subnetworks, forming a single highly integrated co-expression network module, maximizing potential for stable homeostatic control of allergen-induced Th2 responses via cross-regulation. Th2-antagonistic type1 IFN signalling may play a key role in stabilizing clinical effects of SCIT.

Personalized Transcriptomics Reveals Heterogeneous Immunophenotypes in Children with Viral Bronchiolitis.

Rationale: A subset of infants are hypersusceptible to severe/acute viral bronchiolitis (AVB), for reasons incompletely understood. Objectives: To characterize the cellular/molecular mechanisms underlying infant AVB in circulating cells/local airway tissues. Methods: Peripheral blood mononuclear cells and nasal scrapings were obtained from infants (<18 mo) and children (≥18 mo to 5 yr) during AVB and after convalescence. Immune response patterns were profiled by multiplex analysis of plasma cytokines, flow cytometry, and transcriptomics (RNA-Seq). Molecular profiling of group-level data used a combination of upstream regulator and coexpression network analysis, followed by individual subject-level data analysis using personalized N-of-1-pathways methodology. Measurements and Main Results: Group-level analyses demonstrated that infant peripheral blood mononuclear cell responses were dominated by monocyte-associated hyperupregulated type 1 IFN signaling/proinflammatory pathways (drivers: TNF [tumor necrosis factor], IL-6, TREM1 [triggering receptor expressed on myeloid cells 1], and IL-1B), versus a combination of inflammation (PTGER2 [prostaglandin E receptor 2] and IL-6) plus growth/repair/remodeling pathways (ERBB2 [erbb-b2 receptor tyrosine kinase 2], TGFB1 [transforming growth factor-ß1], AREG [amphiregulin], and HGF [hepatocyte growth factor]) coupled with T-helper cell type 2 and natural killer cell signaling in children. Age-related differences were not attributable to differential steroid usage or variations in underlying viral pathogens. Nasal mucosal responses were comparable qualitatively in infants/children, dominated by IFN types 1-3, but the magnitude of upregulation was higher in infants (range, 6- to 48-fold) than children (5- to 17-fold). N-of-1-pathways analysis confirmed differential upregulation of innate immunity in infants and natural killer cell networks in children, and additionally demonstrated covert AVB response subphenotypes that were independent of chronologic age. Conclusions: Dysregulated expression of IFN-dependent pathways after respiratory viral infections is a defining immunophenotypic feature of AVB-susceptible infants and a subset of children. Susceptible subjects seem to represent a discrete subgroup who cluster based on (slow) kinetics of postnatal maturation of innate immune competence.

Decoding Susceptibility to Respiratory Viral Infections and Asthma Inception in Children.

Human Respiratory Syncytial Virus and Human Rhinovirus are the most frequent cause of respiratory tract infections in infants and children and are major triggers of acute viral bronchiolitis, wheezing and asthma exacerbations. Here, we will discuss the application of the powerful tools of systems biology to decode the molecular mechanisms that determine risk for infection and subsequent asthma. An important conceptual advance is the understanding that the innate immune system is governed by a Bow-tie architecture, where diverse input signals converge onto a few core pathways (e.g., IRF7), which in turn generate diverse outputs that orchestrate effector and regulatory functions. Molecular profiling studies in children with severe exacerbations of asthma/wheeze have identified two major immunological phenotypes. The IRF7hi phenotype is characterised by robust upregulation of antiviral response networks, and the IRF7lo phenotype is characterised by upregulation of markers of TGFß signalling and type 2 inflammation. Similar phenotypes have been identified in infants and children with severe viral bronchiolitis. Notably, genome-wide association studies supported by experimental validation have identified key pathways that increase susceptibility to HRV infection (ORMDL3 and CHDR3) and modulate TGFß signalling (GSDMB, TGFBR1, and SMAD3). Moreover, functional deficiencies in the activation of type I and III interferon responses are already evident at birth in children at risk of developing febrile lower respiratory tract infections and persistent asthma/wheeze, suggesting that the trajectory to asthma begins at birth or in utero. Finally, exposure to microbes and their products reprograms innate immunity and provides protection from the development of allergies and asthma in children, and therefore microbial products are logical candidates for the primary prevention of asthma.

Progressive increase of FcεRI expression across several PBMC subsets is associated with atopy and atopic asthma within school-aged children.

BACKGROUND: Antigen-specific IgE binds the Fcε receptor I (FcεRI) expressed on several types of immune cells, including dendritic cells (DCs). Activation of FcεRI on DCs in atopics has been shown to modulate immune responses that potentially contribute to asthma development. However, the extent to which DC subsets differ in FcεRI expression between atopic children with or without asthma is currently not clear. This study aimed to analyse the expression of FcεRI on peripheral blood mononuclear cells (PBMCs) from atopic children with and without asthma, and non-atopic/non-asthmatic age-matched healthy controls. METHODS: We performed multiparameter flow cytometry on PBMC from 391 children across three community cohorts and one clinical cohort based in Western Australia. RESULTS: We confirmed expression of FcεRI on basophils, monocytes, plasmacytoid and conventional DCs, with higher proportions of all cell populations expressing FcεRI in atopic compared to non-atopic children. Further, we observed that levels of FcεRI expression were elevated across plasmacytoid and conventional DC as well as basophils in atopic asthmatic compared to atopic non-asthmatic children also after adjusting for serum IgE levels. CONCLUSION: Our data suggest that the expression pattern of FcεRI on DC and basophils differentiates asthmatic from non-asthmatic atopic children. Given the significant immune modulatory effects observed as a consequence of FcεRI expression, this altered expression pattern is likely to contribute to asthma pathology in children.

Insights into respiratory disease through bioinformatics.

Respiratory diseases such as asthma, chronic obstructive pulmonary disease and lung cancer represent a critical area for medical research as millions of people are affected globally. The development of new strategies for treatment and/or prevention, and the identification of biomarkers for patient stratification and early detection of disease inception are essential to reducing the impact of lung diseases. The successful translation of research into clinical practice requires a detailed understanding of the underlying biology. In this regard, the advent of next-generation sequencing and mass spectrometry has led to the generation of an unprecedented amount of data spanning multiple layers of biological regulation (genome, epigenome, transcriptome, proteome, metabolome and microbiome). Dealing with this wealth of data requires sophisticated bioinformatics and statistical tools. Here, we review the basic concepts in bioinformatics and genomic data analysis and illustrate the application of these tools to further our understanding of lung diseases. We also highlight the potential for data integration of multi-omic profiles and computational drug repurposing to define disease subphenotypes and match them to targeted therapies, paving the way for personalized medicine.

Epigenome-wide analysis links SMAD3 methylation at birth to asthma in children of asthmatic mothers.

BACKGROUND: The timing and mechanisms of asthma inception remain imprecisely defined. Although epigenetic mechanisms likely contribute to asthma pathogenesis, little is known about their role in asthma inception. OBJECTIVE: We sought to assess whether the trajectory to asthma begins already at birth and whether epigenetic mechanisms, specifically DNA methylation, contribute to asthma inception. METHODS: We used the Methylated CpG Island Recovery Assay chip to survey DNA methylation in cord blood mononuclear cells from 36 children (18 nonasthmatic and 18 asthmatic subjects by age 9 years) from the Infant Immune Study (IIS), an unselected birth cohort closely monitored for asthma for a decade. SMAD3 methylation in IIS (n = 60) and in 2 replication cohorts (the Manchester Asthma and Allergy Study [n = 30] and the Childhood Origins of Asthma Study [n = 28]) was analyzed by using bisulfite sequencing or Illumina 450K arrays. Cord blood mononuclear cell-derived IL-1ß levels were measured by means of ELISA. RESULTS: Neonatal immune cells harbored 589 differentially methylated regions that distinguished IIS children who did and did not have asthma by age 9 years. In all 3 cohorts methylation in SMAD3, the most connected node within the network of asthma-associated, differentially methylated regions, was selectively increased in asthmatic children of asthmatic mothers and was associated with childhood asthma risk. Moreover, SMAD3 methylation in IIS neonates with maternal asthma was strongly and positively associated with neonatal production of IL-1ß, an innate inflammatory mediator. CONCLUSIONS: The trajectory to childhood asthma begins at birth and involves epigenetic modifications in immunoregulatory and proinflammatory pathways. Maternal asthma influences epigenetic mechanisms that contribute to the inception of this trajectory.

Distinguishing benign from pathologic TH2 immunity in atopic children.

BACKGROUND: Although most children with asthma and rhinitis are sensitized to aeroallergens, only a minority of sensitized children are symptomatic, implying the underlying operation of efficient anti-inflammatory control mechanisms. OBJECTIVE: We sought to identify endogenous control mechanisms that attenuate expression of IgE-associated responsiveness to aeroallergens in sensitized children. METHODS: In 3 independent population samples we analyzed relationships between aeroallergen-specific IgE and corresponding allergen-specific IgG (sIgG) and associated immunophenotypes in atopic children and susceptibility to asthma and rhinitis, focusing on responses to house dust mite and grass. RESULTS: Among mite-sensitized children across all populations and at different ages, house dust mite-specific IgG/IgE ratios (but not IgG4/IgE ratios) were significantly lower in children with asthma compared with ratios in those without asthma and lowest among the most severely symptomatic. This finding was mirrored by relationships between rhinitis and antibody responses to grass. Depending on age/allergen specificity, 20% to 40% of children with allergen-specific IgE (sIgE) of 0.35 kU/L or greater had negative skin test responses, and these children also expressed the high sIgG/sIgE immunophenotype. sIgG1 from these children inhibited allergen-induced IgE-dependent basophil activation in a dose-dependent fashion. Profiling of aeroallergen-specific CD4(+) TH memory responses revealed positive associations between sIgG/sIgE ratios and IL-10-dependent gene signatures and significantly higher IL-10/TH2 cytokine (protein) ratios among nonsymptomatic children. CONCLUSION: In addition to its role in blocking TH2 effector activation in the late-phase allergic response, IL-10 is a known IgG1 switch factor. We posit that its production during allergen-induced memory responses contributes significantly to attenuation of inflammation through promoting IgG1-mediated damping of the FcεRI-dependent acute-phase reaction. sIgG1/sIgE balance might represent a readily accessible therapeutic target for asthma/rhinitis control.