Late Breaking Abstract - Comparison of the blood transcriptomic profiles of adults and children from the U-BIOPRED asthma study

Background: We have previously reported altered gene expression in adults with asthma compared to healthy controls from the U-BIOPRED study (Bigler, 2016). Altered transcripts may define dysregulated biological pathways and identify novel therapeutic targets. We hypothesised that similar dysregulation would be seen in children with asthma. Aim: To compare blood transcriptomic profiles of children and adults with asthma. Methods: Affymetrix blood transcriptomic profiles of severe asthmatic adult non-smokers, n=152, were compared to mild moderate asthmatics, n=50 (Shaw, 2015; Fleming, 2015). Profiles of school-aged children with severe asthma, n=75, were compared to mild moderate asthmatics, n=37, and in the preschool age group severe wheeze, n=62, was compared to mild moderate wheeze, n=42. Differentially expressed genes (DEG) were identified as probe sets with maximum median group intensity >log2 5, with a significant (raw P≤0.01) change ≥ 20%. Overlapping genes were determined and pathway analysis performed. Results: We found 1887 DEG comparing severe and mild moderate asthmatic adults. Only 28 DEG were found between the severe wheeze and mild pre-school age children, with a larger signature (569 DEG) in the school aged children. 480 genes were specific to school-aged children and 1801 specific to adults, with 89 DEG in common between the adults and school-aged children. Conclusions: Preschool age children were poorly defined in terms of blood transcriptomics by the clinical definitions used. While the school-aged children showed some DEG overlap with the adults, they were distinct in many DEG and pathways indicating that childhood and adult asthma may be mechanistically different

Late Breaking Abstract - Longitudinal analysis of variation in clinical features from the U-BIOPRED severe asthma cohort

Introduction: The U-BIOPRED cohort presents an exceptional opportunity to longitudinally monitor disease variation in severe asthma.Aims: To determine the variability of severe asthma over 12-24 months in the U-BIOPRED cohort by initially focusing on clinical parameters; lung function, exacerbations and asthma symptom control.Methods: Lung function, exacerbation history and asthma control questionnaire (ACQ-5) were determined at baseline (Shaw et al.) and longitudinally.Results: 321 severe asthma patients were present in the longitudinal cohort with a mean of 454 days in the study. The longitudinal set of participants (321) were a good representation of the whole of severe asthma cohort at baseline (421). Most clinical and biomarker measurements including the FEV1 actual, exacerbation and ACQ means were not significantly different between the baseline and longitudinal visits- Table 1. There was no difference between the smoking and non-smoking cohorts. However at an individual level there was variation and some participants deteriorated, and some improved.Summary: Longitudinal U-BIOPRED data quality is valid. Further methods of analysis will move away from characterisation of group means towards understanding individual factors relating to disease progression in the U-BIOPRED cohort

IL-17–high asthma with features of a psoriasis immunophenotype

Background: The role of IL-17 immunity is well established in patients with inflammatory diseases, such as psoriasis and inflammatory bowel disease, but not in asthmatic patients, in whom further study is required. Objective: We sought to undertake a deep phenotyping study of asthmatic patients with upregulated IL-17 immunity. Methods: Whole-genome transcriptomic analysis was performed by using epithelial brushings, bronchial biopsy specimens (91 asthmatic patients and 46 healthy control subjects), and whole blood samples (n = 498)from the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED)cohort. Gene signatures induced in vitro by IL-17 and IL-13 in bronchial epithelial cells were used to identify patients with IL-17–high and IL-13–high asthma phenotypes. Results: Twenty-two of 91 patients were identified with IL-17, and 9 patients were identified with IL-13 gene signatures. The patients with IL-17–high asthma were characterized by risk of frequent exacerbations, airway (sputum and mucosal)neutrophilia, decreased lung microbiota diversity, and urinary biomarker evidence of activation of the thromboxane B2 pathway. In pathway analysis the differentially expressed genes in patients with IL-17-high asthma were shared with those reported as altered in psoriasis lesions and included genes regulating epithelial barrier function and defense mechanisms, such as IL1B, IL6, IL8, and β-defensin. Conclusion: The IL-17–high asthma phenotype, characterized by bronchial epithelial dysfunction and upregulated antimicrobial and inflammatory response, resembles the immunophenotype of psoriasis, including activation of the thromboxane B2 pathway, which should be considered a biomarker for this phenotype in further studies, including clinical trials targeting IL-17

IL-17–high asthma with features of a psoriasis immunophenotype

© 2019 American Academy of Allergy, Asthma & Immunology Background: The role of IL-17 immunity is well established in patients with inflammatory diseases, such as psoriasis and inflammatory bowel disease, but not in asthmatic patients, in whom further study is required. Objective: We sought to undertake a deep phenotyping study of asthmatic patients with upregulated IL-17 immunity. Methods: Whole-genome transcriptomic analysis was performed by using epithelial brushings, bronchial biopsy specimens (91 asthmatic patients and 46 healthy control subjects), and whole blood samples (n = 498) from the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) cohort. Gene signatures induced in vitro by IL-17 and IL-13 in bronchial epithelial cells were used to identify patients with IL-17–high and IL-13–high asthma phenotypes. Results: Twenty-two of 91 patients were identified with IL-17, and 9 patients were identified with IL-13 gene signatures. The patients with IL-17–high asthma were characterized by risk of frequent exacerbations, airway (sputum and mucosal) neutrophilia, decreased lung microbiota diversity, and urinary biomarker evidence of activation of the thromboxane B2 pathway. In pathway analysis the differentially expressed genes in patients with IL-17-high asthma were shared with those reported as altered in psoriasis lesions and included genes regulating epithelial barrier function and defense mechanisms, such as IL1B, IL6, IL8, and β-defensin. Conclusion: The IL-17–high asthma phenotype, characterized by bronchial epithelial dysfunction and upregulated antimicrobial and inflammatory response, resembles the immunophenotype of psoriasis, including activation of the thromboxane B2 pathway, which should be considered a biomarker for this phenotype in further studies, including clinical trials targeting IL-17

U-BIOPRED clinical adult asthma clusters linked to a subset of sputum omics

Background: Asthma is a heterogeneous disease in which there is a differential response to asthma treatments. This heterogeneity needs to be evaluated so that a personalized management approach can be provided. Objectives: We stratified patients with moderate-to-severe asthma based on clinicophysiologic parameters and performed an omics analysis of sputum. Methods: Partition-around-medoids clustering was applied to a training set of 266 asthmatic participants from the European Unbiased Biomarkers for the Prediction of Respiratory Diseases Outcomes (U-BIOPRED) adult cohort using 8 prespecified clinic-physiologic variables. This was repeated in a separate validation set of 152 asthmatic patients. The clusters were compared based on sputum proteomics and transcriptomics data. Results: Four reproducible and stable clusters of asthmatic patients were identified. The training set cluster T1 consists of patients with well-controlled moderate-to-severe asthma, whereas cluster T2 is a group of patients with late-onset severe asthma with a history of smoking and chronic airflow obstruction. Cluster T3 is similar to cluster T2 in terms of chronic airflow obstruction but is composed of nonsmokers. Cluster T4 is predominantly composed of obese female patients with uncontrolled severe asthma with increased exacerbations but with normal lung function. The validation set exhibited similar clusters, demonstrating reproducibility of the classification. There were significant differences in sputum proteomics and transcriptomics between the clusters. The severe asthma clusters (T2, T3, and T4) had higher sputum eosinophilia than cluster T1, with no differences in sputum neutrophil counts and exhaled nitric oxide and serum IgE levels. Conclusion: Clustering based on clinicophysiologic parameters yielded 4 stable and reproducible clusters that associate with different pathobiological pathways