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Background: The most recognizable phenotype of severe asthma comprises people who are blood eosinophil and FeNO-high, driven by type-2 (T2) cytokine biology which responds to targeted biological therapies. However, in many people with severe asthma, these T2 biomarkers are suppressed but poorly controlled asthma persists. The mechanisms driving asthma in the absence of T2 biology are poorly understood. Objectives: To explore airway pathology in T2 biomarker-high and -low severe asthma. Methods: T2 biomarker-high severe asthma (T2-high, n=17) was compared to biomarker-intermediate (T2-intermediate, n=21) and biomarker-low (T2-low, n=20) severe asthma, and healthy controls (n=28). Bronchoscopy samples were processed for immunohistochemistry, and sputum for cytokines, PGD2 and LTE4 measurements. Results: Tissue eosinophil, neutrophil and mast cell counts were similar across severe asthma phenotypes and not increased when compared to healthy controls. In contrast, the remodeling features of airway smooth muscle mass and MUC5AC expression were increased in all asthma groups compared to health, but similar across asthma subgroups. Submucosal glands were increased in T2-intermediate and T2-low asthma. In spite of similar tissue cellular inflammation, sputum IL-4, IL-5, and CCL26 were increased in T2-high versus T2-low asthma, and several further T2-associated cytokines, PGD2 and LTE4, were increased in T2-high and T2-intermediate asthma compared to healthy controls. Conclusions: Eosinophilic tissue inflammation within proximal airways is suppressed in T2 biomarker-high and T2-low severe asthma, but inflammatory and structural cell activation is present, with sputum T2-associated cytokines highest in T2 biomarker-high patients. Airway remodeling persists, and may be important for residual disease expression beyond eosinophilic exacerbations.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is generally associated with eosinophilic tissue infiltration linked to type 2 inflammation and characterized by elevated levels of interleukin (IL)-5 and other type 2 inflammatory mediators. Although distinct and overlapping contributions of eosinophils and IL-5 to CRSwNP pathology are still being explored, they are both known to play an important role in NP inflammation. Eosinophils secrete numerous type 2 inflammatory mediators including granule proteins, enzymes, cytokines, chemokines, growth factors, lipids, and oxidative products. IL-5 is critical for the differentiation, migration, activation, and survival of eosinophils but is also implicated in the biological functions of mast cells, basophils, innate lymphoid cells, B cells, and epithelial cells. Results from clinical trials of therapeutics that target type 2 inflammatory mediators (including but not limited to anti-IL-5, anti-immunoglobulin-E, and anti-IL-4/13) may provide further evidence of how eosinophils and IL-5 contribute to CRSwNP. Finally, the association between eosinophilia/elevated IL-5 and greater rates of NP recurrence after endoscopic sinus surgery (ESS) suggests that these mediators may have utility as biomarkers of NP recurrence in diagnosing and assessing the severity of CRSwNP. This review provides an overview of eosinophil and IL-5 biology and explores the literature regarding the role of these mediators in CRSwNP pathogenesis and NP recurrence following ESS. Based on current published evidence, we suggest that although eosinophils play a key role in CRSwNP pathophysiology, IL-5, a cytokine that activates these cells, also represents a pertinent and effective treatment target in patients with CRSwNP.

Background: Patients with severe chronic rhinosinusitis with nasal polyps (CRSwNP) often require repeat sinus surgery. Mepolizumab reduced the need for sinus surgery in the SYNAPSE trial; this analysis sought to provide a more in-depth assessment of surgery endpoints in SYNAPSE. Methods: SYNAPSE was a double-blind Phase III trial (NCT03085797) in adults with recurrent, refractory, severe, CRSwNP eligible for repeat sinus surgery despite standard of care treatments and previous surgery. Patients were randomized (1:1) to mepolizumab 100 mg subcutaneously or placebo, plus standard of care, every 4 weeks for 52 weeks. Time to first inclusion on a waiting list for sinus surgery and time to first actual sinus surgery (both up to week 52) were assessed; the latter endpoint was also analyzed post hoc according to time since last sinus surgery before study screening and baseline blood eosinophil count. Results: Among 407 patients (mepolizumab: 206; placebo: 201), mepolizumab versus placebo reduced the risk of being included on a waiting list for sinus surgery (week 52 Kaplan–Meier probability estimate [95% confidence interval]: 13.9% [9.8%, 19.5%] vs. 28.5% [22.7%, 35.4%]). Mepolizumab versus placebo reduced the risk of sinus surgery irrespective of time (

International audience; Eosinophils play a homeostatic role in the body's immune responses. These cells are involved in combating some parasitic, bacterial, and viral infections and certain cancers and have pathologic roles in diseases including asthma, chronic rhinosinusitis with nasal polyps, eosinophilic gastrointestinal disorders, and hypereosinophilic syndromes. Treatment of eosinophilic diseases has traditionally been through nonspecific eosinophil attenuation by use of glucocorticoids. However, several novel biologic therapies targeting eosinophil maturation factors, such as interleukin (IL)-5 and the IL-5 receptor or IL-4/IL-13, have recently been approved for clinical use. Despite the success of biologic therapies, some patients with eosinophilic inflammatory disease may not achieve adequate symptom control, underlining the need to further investigate the contribution of patient characteristics, such as comorbidities and other processes, in driving ongoing disease activity. New research has shown that eosinophils are also involved in several homeostatic processes, including metabolism, tissue remodeling and development, neuronal regulation, epithelial and microbiome regulation, and immunoregulation, indicating that these cells may play a crucial role in metabolic regulation and organ function in healthy humans. Consequently, further investigation is needed into the homeostatic roles of eosinophils and eosinophil-mediated processes across different tissues and their varied microenvironments. Such work may provide important insights into the role of eosinophils not only under disease conditions but also in health. This narrative review synthesizes relevant publications retrieved from PubMed informed by author expertise to provide new insights into the diverse roles of eosinophils in health and disease, with particular emphasis on the implications for current and future development of eosinophil-targeted therapies.

The measurement of exhaled volatile organic compounds (VOCs) in exhaled breath (breathomics) represents an exciting biomarker matrix for airways disease, with early research indicating a sensitivity to airway inflammation. One of the key aspects to analytical validity for any clinical biomarker is an understanding of the short-term repeatability of measures. We collected exhaled breath samples on 5 consecutive days in 14 subjects with severe asthma who had undergone extensive clinical characterisation. Principal component analysis on VOC abundance across all breath samples revealed no variance due to the day of sampling. Samples from the same patients clustered together and there was some separation according to T2 inflammatory markers. The intra-subject and between-subject variability of each VOC was calculated across the 70 samples and identified 30.35% of VOCs to be erratic: variable between subjects but also variable in the same subject. Exclusion of these erratic VOCs from machine learning approaches revealed no apparent loss of structure to the underlying data or loss of relationship with salient clinical characteristics. Moreover, cluster evaluation by the silhouette coefficient indicates more distinct clustering. We are able to describe the short-term repeatability of breath samples in a severe asthma population and corroborate its sensitivity to airway inflammation. We also describe a novel variance-based feature selection tool that, when applied to larger clinical studies, could improve machine learning model predictions.

Background Sputum cytology is currently the gold standard to evaluate cellular inflammation in the airways and phenotyping patients with airways diseases. Sputum eosinophil proportions have been used to guide treatment for moderate to severe asthma. Furthermore, raised sputum neutrophils are associated with poor disease control and impaired lung function in both asthma and COPD and small airways disease in cystic fibrosis. However, induced-sputum analysis is subjective and resource heavy, requiring dedicated specialist processing and assessment; this limits its utility in most clinical settings. Indirect blood eosinophil measures have been adopted in clinical care. However, there are currently no good peripheral blood biomarkers of airway neutrophils. A resource-light sputum processing approach could thus help integrate induced sputum more readily into routine clinical care. New mechanical disruption (MD) methods can rapidly obtain viable single cell suspensions from sputum samples. Aims The aim of this study was to compare MD sputum processing to traditional methods for cell viability, granulocyte proportions and sputum cytokine analysis. Methods Sputum plugs were split and processed using traditional methods and the MD method, and samples were then compared. Results The MD method produced a homogeneous cell suspension in 62 s; 70 min faster than the standard method used. No significant difference was seen between the cell viability (p = 0.09), or the concentration of eosinophils (p = 0.83), neutrophils (p = 0.99) or interleukin-8 (p = 0.86) using MD. Conclusion This cost-effective method of sputum processing could provide a more pragmatic, sustainable means of directly monitoring the airway milieu. Therefore, we recommend this method be taken forward for further investigation.

Background: IL-13 is considered an archetypal T2 cytokine central to the clinical disease expression of asthma. The IL-13 response genes, which are upregulated in central airway bronchial epithelial of asthma patients, can be normalized by high-dose inhaled steroid therapy in severe asthma. However, this is not the case within the peripheral airways. We have sought to further understand IL-13 in the peripheral airways in severe asthma through bronchoalveolar analysis. Methods: bronchoalveolar lavage samples were collected from 203 asthmatic and healthy volunteers, including 78 with severe asthma. Inflammatory mediators were measured using a multiple cytokine immunoassay platform. This analysis was replicated in a further 59 volunteers, in whom 16S rRNA analysis of BAL samples was undertaken by terminal restriction fragment length polymorphism. Results: severe asthma patients with high BAL IL-13, despite treatment with high-dose inhaled corticosteroids, had more severe lung function and significantly higher BAL neutrophil percentages, but not BAL eosinophils than those with normal BAL-13 concentrations. This finding was replicated in the second cohort, which further associated BAL IL-13 and neutrophilia with a greater abundance of potentially pathogenic bacteria in the peripheral airways. Conclusion: our findings demonstrate a steroid unresponsive source of IL-13 that is associated with BAL neutrophilia and bacterial dysbiosis in severe asthma. Our findings highlight the biological complexity of severe asthma and the importance of a greater understanding of the innate and adaptive immune responses in the peripheral airways in this disease.

Background Patients with severe asthma may have a greater risk of dying from COVID-19 disease. Angiotensin converting enzyme-2 (ACE2) and the enzyme proteases, transmembrane protease serine 2 (TMPRSS2) and FURIN, are needed for viral attachment and invasion into host cells. Methods We examined microarray mRNA expression of ACE2, TMPRSS2 and FURIN in sputum, bronchial brushing and bronchial biopsies of the European U-BIOPRED cohort. Clinical parameters and molecular phenotypes, including asthma severity, sputum inflammatory cells, lung functions, oral corticosteroid (OCS) use, and transcriptomic-associated clusters, were examined in relation to gene expression levels. Results ACE2 levels were significantly increased in sputum of severe asthma compared to mild-moderate asthma. In multivariate analyses, sputum ACE2 levels were positively associated with OCS use and male gender. Sputum FURIN levels were significantly related to neutrophils (%) and the presence of severe asthma. In bronchial brushing samples, TMPRSS2 levels were positively associated with male gender and body mass index, whereas FURIN levels with male gender and blood neutrophils. In bronchial biopsies, TMPRSS2 levels were positively related to blood neutrophils. The neutrophilic molecular phenotype characterised by high inflammasome activation expressed significantly higher FURIN levels in sputum than the eosinophilic Type 2-high or the pauci-granulocytic oxidative phosphorylation phenotypes. Conclusion Levels of ACE2 and FURIN may differ by clinical or molecular phenotypes of asthma. Sputum FURIN expression levels were strongly associated with neutrophilic inflammation and with inflammasome activation. This might indicate the potential for a greater morbidity and mortality outcome from SARS-CoV-2 infection in neutrophilic severe asthma.

Background: Asthma treatment guidelines recommend increasing corticosteroid dose to control symptoms and reduce exacerbations. This approach is potentially flawed because symptomatic asthma can occur without corticosteroid responsive type-2 (T2)-driven eosinophilic inflammation, and inappropriately high-dose corticosteroid treatment might have little therapeutic benefit with increased risk of side-effects. We compared a biomarker strategy to adjust corticosteroid dose using a composite score of T2 biomarkers (fractional exhaled nitric oxide [FENO], blood eosinophils, and serum periostin) with a standardised symptom–risk-based algorithm (control). Methods: We did a single-blind, parallel group, randomised controlled trial in adults (18–80 years of age) with severe asthma (at treatment steps 4 and 5 of the Global Initiative for Asthma) and FENO of less than 45 parts per billion at12 specialist severe asthma centres across England, Scotland, and Northern Ireland. Patients were randomly assigned (4:1) to either the biomarker strategy group or the control group by an online electronic case-report form, in blocks of ten, stratified by asthma control and use of rescue systemic steroids in the previous year. Patients were masked to study group allocation throughout the entirety of the study. Patients attended clinic every 8 weeks, with treatment adjustment following automated treatment-group-specific algorithms: those in the biomarker strategy group received a default advisory to maintain treatment and those in the control group had their treatment adjusted according to the steps indicated by the trial algorithm. The primary outcome was the proportion of patients with corticosteroid dose reduction at week 48, in the intention-to-treat (ITT) population. Secondary outcomes were inhaled corticosteroid (ICS) dose at the end of the study; cumulative dose of ICS during the study; proportion of patients on maintenance oral corticosteroids (OCS) at study end; rate of protocol-defined severe exacerbations per patient year; time to first severe exacerbation; number of hospital admissions for asthma; changes in lung function, Asthma Control Questionnaire-7 score, Asthma Quality of Life Questionnaire score, and T2 biomarkers from baseline to week 48; and whether patients declined to progress to OCS. A secondary aim of our study was to establish the proportion of patients with severe asthma in whom T2 biomarkers remained low when corticosteroid therapy was decreased to a minimum ICS dose. This study is registered with ClinicalTrials.gov, NCT02717689 and has been completed. Findings: Patients were recruited from Jan 8, 2016, to July 12, 2018. Of 549 patients assessed, 301 patients were included in the ITT population and were randomly assigned to the biomarker strategy group (n=240) or to the control group(n=61). 28·4% of patients in the biomarker strategy group were on a lower corticosteroid dose at week 48 compared with 18·5% of patients in the control group (adjusted odds ratio [aOR] 1·71 [95% CI 0·80–3·63]; p=0·17). In the per-protocol (PP) population (n=121), a significantly greater proportion of patients were on a lower corticosteroid dose at week 48 in the biomarker strategy group (30·7% of patients) compared with the control group (5·0% of patients; aOR 11·48 [95% CI 1·35–97·83]; p=0·026). Patient choice to not follow treatment advice was the principle reason for loss to PP analysis. There was no difference in secondary outcomes between study groups and no loss of asthma control among patients in the biomarker strategy group who reduced their corticosteroid dose. Interpretation: Biomarker-based corticosteroid adjustment did not result in a greater proportion of patients reducing corticosteroid dose versus control. Understanding the reasons for patients not following treatment advice in both treatment strategies is an important area for future research. The prevalence of T2 biomarker-low severe asthma was low.

Background: Asthma is a complex disease with multiple phenotypes that may differ in disease pathobiology and treatment response. IL33 single nucleotide polymorphisms (SNPs) have been reproducibly associated with asthma. IL33 levels are elevated in sputum and bronchial biopsies of patients with asthma. The functional consequences of IL33 asthma SNPs remain unknown. Objective: This study sought to determine whether IL33 SNPs associate with asthma-related phenotypes and with IL33 expression in lung or bronchial epithelium. This study investigated the effect of increased IL33 expression on human bronchial epithelial cell (HBEC) function. Methods: Association between IL33 SNPs (Chr9: 5,815,786-6,657,983) and asthma phenotypes (Lifelines/DAG [Dutch Asthma GWAS]/GASP [Genetics of Asthma Severity & Phenotypes] cohorts) and between SNPs and expression (lung tissue, bronchial brushes, HBECs) was done using regression modeling. Lentiviral overexpression was used to study IL33 effects on HBECs. Results: We found that 161 SNPs spanning the IL33 region associated with 1 or more asthma phenotypes after correction for multiple testing. We report a main independent signal tagged by rs992969 associating with blood eosinophil levels, asthma, and eosinophilic asthma. A second, independent signal tagged by rs4008366 presented modest association with eosinophilic asthma. Neither signal associated with FEV 1, FEV 1/forced vital capacity, atopy, and age of asthma onset. The 2 IL33 signals are expression quantitative loci in bronchial brushes and cultured HBECs, but not in lung tissue. IL33 overexpression in vitro resulted in reduced viability and reactive oxygen species–capturing of HBECs, without influencing epithelial cell count, metabolic activity, or barrier function. Conclusions: We identify IL33 as an epithelial susceptibility gene for eosinophilia and asthma, provide mechanistic insight, and implicate targeting of the IL33 pathway specifically in eosinophilic asthma.

Background Mepolizumab (100 mg delivered s.c. every 4 weeks) is indicated for add-on maintenance treatment for patients with severe eosinophilic asthma. Mepolizumab has been shown to reduce exacerbations and the requirement for daily oral corticosteroids, and improve asthma control and symptoms. However, data on the durability of the response to mepolizumab during dosing periods are limited. The aim of this study was to investigate the efficacy profile in patients with severe eosinophilic asthma over the 4-weekly dosing period for various fixed mepolizumab doses. Methods This was a post hoc analysis of data from the phase IIb/III DREAM study. Patients ≥12 years of age with severe eosinophilic asthma were randomised (1:1:1:1) to receive intravenous mepolizumab 75 mg (equivalent to 100 mg s.c.), 250 mg, 750 mg or placebo, plus standard of care, every 4 weeks for 52 weeks. The number of exacerbations and eDiary data (peak expiratory flow, rescue medication use and symptom scores) from two periods in each 4-weekly dosing interval (days 1–14 and 15–28) over the 52-week treatment period were analysed. Findings eDiary data and the proportion of patients experiencing ≥1 exacerbation were similar during the first and second 2 weeks of a dosing period across all mepolizumab doses. Interpretation These results demonstrate that the response to mepolizumab is sustained over the 4-weekly dosing period with no differences across a 10-fold dose range and supports the use of the current mepolizumab dosing regimen in patients with severe eosinophilic asthma., Post hoc analysis of data from DREAM demonstrated a sustained response to mepolizumab across the 4-weekly dosing period, suggesting therapeutic benefit is maintained between each mepolizumab dose following long-term treatment https://bit.ly/3843lH6

Background: Transcriptomic changes in patients who respond clinically to biological therapies may identify responses in other tissues or diseases. Objective: We sought to determine whether a disease signature identified in atopic dermatitis (AD) is seen in adults with severe asthma and whether a transcriptomic signature for patients with AD who respond clinically to anti–IL-22 (fezakinumab [FZ]) is enriched in severe asthma. Methods: An AD disease signature was obtained from analysis of differentially expressed genes between AD lesional and nonlesional skin biopsies. Differentially expressed genes from lesional skin from therapeutic superresponders before and after 12 weeks of FZ treatment defined the FZ-response signature. Gene set variation analysis was used to produce enrichment scores of AD and FZ-response signatures in the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes asthma cohort. Results: The AD disease signature (112 upregulated genes) encompassing inflammatory, T-cell, T H2, and T H17/T H22 pathways was enriched in the blood and sputum of patients with asthma with increasing severity. Patients with asthma with sputum neutrophilia and mixed granulocyte phenotypes were the most enriched (P H22/IL-22 pathways. Conclusions: The FZ-response signature in AD identifies severe neutrophilic asthmatic patients as potential responders to FZ therapy. This approach will help identify patients for future asthma clinical trials of drugs used successfully in other chronic diseases.

Objective The efficacy and safety of mepolizumab in patients with severe eosinophilic asthma in randomized controlled trials is well established. Following approval of mepolizumab as add-on therapy for severe eosinophilic asthma in multiple regions worldwide, it is now important to determine its impact in real-world settings in which patients are not subject to stringent eligibility criteria. This systematic literature review assessed published evidence of clinical outcomes, safety, and healthcare resource use among patients with severe asthma receiving mepolizumab in real-world settings. Data sources Searches were conducted in Embase, MEDLINE, and MEDLINE In-Process via Ovid. Study selections Eligible studies were observational, and enrolled >= 10 patients with asthma who received mepolizumab 100 mg subcutaneously. Data extracted included annualized exacerbation rate, mean daily oral corticosteroid (OCS) dose, proportion of patients using OCS, several measures of lung function, patient-reported asthma control and health-related quality of life (HRQoL), safety, and economic burden. Results Twenty-three articles (22 unique studies; 2,040 patients with severe asthma on mepolizumab) were identified. Mepolizumab use was associated with a reduction in annualized exacerbation rates (requiring OCS) of 54-97% (p < 0.05 in all studies), reduced mean/median daily OCS doses, and OCS discontinuation during follow-up (27-84% of patients). Improvements in lung function, asthma control, and HRQoL were also observed. The most commonly reported adverse events included headache and arthralgia; discontinuation of mepolizumab due to adverse events occurred in 0-10.6% of patients. Conclusion Findings show that patients with severe asthma consistently demonstrate clinically relevant benefits with mepolizumab treatment in a real-world setting. Supplemental data for this article is available online at at www.tandfonline.com/ijas .

IntroductionAsthma is a heterogeneous disease with poorly defined phenotypes. Patients with severe asthma often receive multiple treatments including oral corticosteroids (OCS). Treatment may modify the observed metabotype, rendering it challenging to investigate underlying disease mechanisms. Here, we aimed to identify dysregulated metabolic processes in relation to asthma severity and medication.MethodsBaseline urine was collected prospectively from healthy participants (n=100), patients with mild-to-moderate asthma (n=87) and patients with severe asthma (n=418) in the cross-sectional U-BIOPRED cohort; 12–18-month longitudinal samples were collected from patients with severe asthma (n=305). Metabolomics data were acquired using high-resolution mass spectrometry and analysed using univariate and multivariate methods.ResultsA total of 90 metabolites were identified, with 40 significantly altered (p−20), OCS-treated asthmatic patients differed significantly from non-treated patients (p=9.5×10−4), and longitudinal metabotypes demonstrated temporal stability. Carnitine levels evidenced the strongest OCS-independent decrease in severe asthma. Reduced carnitine levels were associated with mitochondrial dysfunction via decreases in pathway enrichment scores of fatty acid metabolism and reduced expression of the carnitine transporter SLC22A5 in sputum and bronchial brushings.ConclusionsThis is the first large-scale study to delineate disease- and OCS-associated metabolic differences in asthma. The widespread associations with different therapies upon the observed metabotypes demonstrate the need to evaluate potential modulating effects on a treatment- and metabolite-specific basis. Altered carnitine metabolism is a potentially actionable therapeutic target that is independent of OCS treatment, highlighting the role of mitochondrial dysfunction in severe asthma.

Background: fungal sensitivity has been associated with severe asthma outcomes. However, the clinical implication of Aspergillus fumigatus sensitization in difficult-to-treat (or difficult) asthma is unclear.Objectives: to characterize the clinical implications of A fumigatus sensitization in a large difficult asthma cohort.Methods: participants who underwent both skin prick and specific IgE testing to A fumigatus (n = 318) from the longitudinal real-life Wessex AsThma CoHort of difficult asthma, United Kingdom, were characterized by A fumigatus sensitization (either positive skin prick test result or specific IgE) and allergic bronchopulmonary aspergillosis status using clinical/pathophysiological disease measures.Results: a fumigatus sensitization was found in 23.9% (76 of 318) of patients with difficult asthma. Compared with A fumigatus nonsensitized subjects, those with sensitization were significantly more often male (50% vs 31%), older (58 years) with longer asthma duration (33 years), higher maintenance oral corticosteroid (39.7%) and asthma biologic use (27.6%), raised current/maximum log10 total IgE+1 (2.43/2.72 IU/L), worse prebronchodilator airflow obstruction (FEV1 62.2% predicted, FEV1/forced vital capacity 61.2%, forced expiratory flow between 25% and 75% exhalation 30.9% predicted), and frequent radiological bronchiectasis (40%), but had less psychophysiologic comorbidities. Allergic bronchopulmonary aspergillosis diagnosis was associated with higher treatment needs and stronger eosinophilic signals. Factors independently associated with A fumigatus sensitization in difficult asthma included maintenance oral corticosteroid use (odds ratio [OR], 3.34) and maximum log10 total IgE+1 (OR, 4.30), whereas for allergic bronchopulmonary aspergillosis included maintenance oral corticosteroid use (OR, 6.98), maximum log10 total IgE+1 (OR, 4.65), and radiological bronchiectasis (OR, 4.08).Conclusions: a fumigatus sensitization in difficult asthma identifies a more severe form of airways disease associated with greater morbidity, treatment need, and airways dysfunction/damage, but fewer psychophysiologic comorbidities. Screening of A fumigatus status should be an early element in the comprehensive assessment of patients with difficult asthma.

Patients with severe asthma may have a greater risk of dying from COVID-19 disease. Angiotensin converting enzyme-2 (ACE2) and the enzyme proteases, transmembrane protease serine 2 (TMPRSS2) and FURIN, are needed for viral attachment and invasion into host cells.We examined microarray mRNA expression of ACE2, TMPRSS2 and FURIN in sputum, bronchial brushing and bronchial biopsies of the European U-BIOPRED cohort. Clinical parameters and molecular phenotypes, including asthma severity, sputum inflammatory cells, lung functions, oral corticosteroid (OCS) use, and transcriptomic-associated clusters, were examined in relation to gene expression levels.ACE2 levels were significantly increased in sputum of severe asthma compared to mild-moderate asthma. In multivariate analyses, sputum ACE2 levels were positively associated with OCS use and male gender. Sputum FURIN levels were significantly related to neutrophils (%) and the presence of severe asthma. In bronchial brushing samples, TMPRSS2 levels were positively associated with male gender and body mass index, whereas FURIN levels with male gender and blood neutrophils. In bronchial biopsies, TMPRSS2 levels were positively related to blood neutrophils. The neutrophilic molecular phenotype characterised by high inflammasome activation expressed significantly higher FURIN levels in sputum than the eosinophilic Type 2-high or the pauci-granulocytic oxidative phosphorylation phenotypes.Levels of ACE2 and FURIN may differ by clinical or molecular phenotypes of asthma. Sputum FURIN expression levels were strongly associated with neutrophilic inflammation and with inflammasome activation. This might indicate the potential for a greater morbidity and mortality outcome from SARS-CoV-2 infection in neutrophilic severe asthma.

Background: understanding why patients with severe asthma do not follow healthcare provider (HCP) advice to adjust treatment is critical to achieving personalised disease management.Methods: we reviewed patient choice to follow HCP advice to adjust asthma treatment in a randomised, controlled, single-blind (study participant), multi-centre, parallel group 48-week clinical study comparing biomarker directed treatment adjustment to standard care in severe asthma.Results: of 1572 treatment advisories (301 participants), instructions were followed in 1377 cases (87.6%). Patients were more likely to follow advice to remain on treatment (96.7%) than to either reduce (70.3%) or increase (67.1%) their treatment, with 64% of patients following all treatment advice. Multivariate analysis associated belonging to an ethnic minority group (OR: 3.10; 95% CI: 1.68, 5.73) and prior study medication changes (≥2 OR: 2.77, 95% CI: 1.51, 5.10) with failure to follow treatment advice. In contrast, emergency room attendance in the prior year (OR: 0.54, 95% CI: 0.32, 0.92) was associated with following treatment advice. The largest effect was seen with transition onto or off oral corticosteroids (OR: 29.28; 95% CI: 16.07, 53.36) when compared to those requested to maintain treatment. Centre was also an important determinant regarding the likelihood of patients to follow treatment advice.Conclusions: belonging to an ethnic minority group and multiple prior treatment adjustments were associated with not following HCP treatment advice. Patients also responded differently to HCP advice across UK specialist centres. These findings have implications for generalisability for models of care in severe asthma and require further focussed studies.

Asthma is a heterogeneous disease with multiple clinical presentations (phenotypes). Neutrophilic asthma is characterised by increased sputum neutrophils and generally has a poor response to corticosteroids and limited other therapeutic options. Neutrophilia originates from different factors, including the defective resolution of inflammation or bacterial infections. An association between airway bacterial imbalance (disturbance) and the neutrophilic phenotype has been reported, suggesting that airway microbiota composition is involved in neutrophilic asthma. Rather than being a separate entity, neutrophilic asthma may be in part, an alliance between innate immunity and microbiota composition that prompts protective mechanisms against invading pathogens.

Background: blood eosinophil measurement is essential for the phenotypic characterization of patients with difficult asthma and in determining eligibility for anti-IL-5/IL-5Rα biological therapies. However, assessing such measures over limited time spans may not reveal the true underlying eosinophilic phenotype, as treatment, including daily oral corticosteroid therapy, suppresses eosinophilic inflammation and asthma is intrinsically variable.Methods: we interrogated the electronic healthcare records of patients in the Wessex AsThma CoHort of difficult asthma (WATCH) study (UK). In 501 patients being evaluated in this tertiary care centre for difficult to control asthma, all requested full blood count test results in a 10-year retrospective period from the index WATCH assessment were investigated (n = 11,176).Results: in 235 biological therapy-naïve participants who had 10 or more measures in this time period, 40.3% were eosinophilic (blood eosinophils ≥300 cells/µl) at WATCH enrolment whilst an additional 43.1%, though not eosinophilic at enrolment, demonstrated eosinophilia at least once in the preceding decade. Persistent eosinophilia was associated with worse post-bronchodilator airway obstruction and higher Fractional exhaled Nitric Oxide (FeNO). In contrast, the 16.6% of patients who never demonstrated eosinophilia at this blood eosinophil threshold showed preserved lung function and lower markers of Type 2 inflammation.Conclusions: this highlights the central role that type 2 inflammation, as indicated by blood eosinophilia, has in difficult asthma and suggests that longitudinal electronic healthcare record analysis can be an important tool in clinical asthma phenotyping, providing insight that may help understand disease progression and better guide more specific treatment approaches.

Background: Asthma is a heterogeneous disease characterized by distinct phenotypes with associated microbial dysbiosis. Objectives: Our aim was to identify severe asthma phenotypes based on sputum microbiome profiles and assess their stability after 12 to 18 months. A further aim was to evaluate clusters’ robustness after inclusion of an independent cohort of patients with mild-to-moderate asthma. Methods: In this longitudinal multicenter cohort study, sputum samples were collected for microbiome profiling from a subset of the Unbiased Biomarkers in Prediction of Respiratory Disease Outcomes adult patient cohort at baseline and after 12 to 18 months of follow-up. Unsupervised hierarchical clustering was performed by using the Bray-Curtis β-diversity measure of microbial profiles. For internal validation, partitioning around medoids, consensus cluster distribution, bootstrapping, and topological data analysis were applied. Follow-up samples were studied to evaluate within-patient clustering stability in patients with severe asthma. Cluster robustness was evaluated by using an independent cohort of patients with mild-to-moderate asthma. Results: Data were available for 100 subjects with severe asthma (median age 55 years; 42% males). Two microbiome-driven clusters were identified; they were characterized by differences in asthma onset, smoking status, residential locations, percentage of blood and/or sputum neutrophils and macrophages, lung spirometry results, and concurrent asthma medications (all P values < .05). The cluster 2 patients displayed a commensal-deficient bacterial profile that was associated with worse asthma outcomes than those of the cluster 1 patients. Longitudinal clusters revealed high relative stability after 12 to 18 months in those with severe asthma. Further inclusion of an independent cohort of 24 patients with mild-to-moderate asthma was consistent with the clustering assignments. Conclusion: Unbiased microbiome-driven clustering revealed 2 distinct robust phenotypes of severe asthma that exhibited relative overtime stability. This suggests that the sputum microbiome may serve as a biomarker for better characterizing asthma phenotypes.

Background: Airway remodelling, which may include goblet cell hyperplasia / hypertrophy, changes in epithelial integrity, accumulation of extracellular matrix components, smooth muscle hypertrophy and thickening of the lamina reticularis, is a feature of severe asthma and contributes to the clinical phenotype. Objective: Within the U-BIOPRED severe asthma study, we have assessed histological elements of airway remodelling and their relationship to computed tomography (CT) measures of proximal airway dimensions. Methods: Bronchial biopsies were collected from two severe asthma groups, one non-smoker (SAns, n=28) and one current/ex-smoker (SAs/ex, n=13), and a mild-moderate asthma group (MMA, n=28) classified and treated according to GINA guidelines, plus a healthy control group (HC, n=33). A Movat’s pentachrome technique was used to identify mucin, elastin and total collagen in these biopsies. The number of goblet cells (mucin+) were counted as a percentage of the total number of epithelial cells and the percentage mucin epithelial area measured. The percentage area of elastic fibres and total collagen within the submucosa were also measured, and the morphology of the elastic fibres classified. Participants in the asthma groups also had a CT scan to assess large airway morphometry.Results: The submucosal tissue elastin percentage was higher in both severe asthma groups (16.1% SAns, 18.9% SAs/ex) compared to the HC (9.7%) but did not differ between asthma groups. There was a positive relationship between elastin and airway wall area measured by CT (n= 18-20, rho=0.544, p=0.024), which also related to an increase in elastic fibres with a thickened lamellar morphological appearance. Mucin epithelial area and total collagen were not different between the four groups. Due to small numbers of suitable CT scans it was not feasible to compare airway morphometry between the asthma groups. Conclusion: These findings identify a link between extent of elastin deposition and airway wall thickening in severe asthma.

Introduction Efficacy of mepolizumab, an anti-interleukin-5 monoclonal antibody, was demonstrated in randomised controlled trials; data on its real-world impact in routine clinical practice are starting to emerge. We assessed the effectiveness and safety of mepolizumab prescribed for patients in the real world. Methods REALITI-A is a global, prospective, observational cohort study, collecting data from routine healthcare visits from patients with asthma. Patients newly prescribed mepolizumab for severe asthma with 12 months of relevant medical history pre-mepolizumab (collected retrospectively) were enrolled. An initial analysis of data from early initiators who had completed 1 year of follow-up (as of February 28, 2019) was conducted. The primary objective was to compare the rate of clinically significant exacerbations (requiring oral corticosteroids (OCS) and/or hospitalisation and/or emergency department visit) before and after mepolizumab; exacerbations requiring hospitalisation and/or emergency department visit and change in maintenance OCS use were secondary objectives. Treatment-related adverse events were reported. Results Overall, 368 mepolizumab-treated patients were included. Rates of clinically significant exacerbations were reduced by 69% from 4.63 per person per year pre-treatment to 1.43 per person per year during follow-up (p, Mepolizumab has demonstrated efficacy in patients with severe eosinophilic asthma in the controlled environment of clinical trials. These initial data from the prospective REALITI-A study show that similar results are obtained in a real-world setting. https://bit.ly/3hINnFO

Background: Allergic sensitization is associated with severe asthma, but assessment of sensitization is not recommended by most guidelines. Objective: We hypothesized that patterns of IgE responses to multiple allergenic proteins differ between sensitized participants with mild/moderate and severe asthma. Methods: IgE to 112 allergenic molecules (components, c-sIgE) was measured using multiplex array among 509 adults and 140 school-age and 131 preschool children with asthma/wheeze from the Unbiased BIOmarkers for the PREDiction of respiratory diseases outcomes cohort, of whom 595 had severe disease. We applied clustering methods to identify co-occurrence patterns of components (component clusters) and patterns of sensitization among participants (sensitization clusters). Network analysis techniques explored the connectivity structure of c-sIgE, and differential network analysis looked for differences in c-sIgE interactions between severe and mild/moderate asthma. Results: Four sensitization clusters were identified, but with no difference between disease severity groups. Similarly, component clusters were not associated with asthma severity. None of the c-sIgE were identified as associates of severe asthma. The key difference between school children and adults with mild/moderate compared with those with severe asthma was in the network of connections between c-sIgE. Participants with severe asthma had higher connectivity among components, but these connections were weaker. The mild/moderate network had fewer connections, but the connections were stronger. Connectivity between components with no structural homology tended to co-occur among participants with severe asthma. Results were independent from the different sample sizes of mild/moderate and severe groups. Conclusions: The patterns of interactions between IgE to multiple allergenic proteins are predictors of asthma severity among school children and adults with allergic asthma.

Background In all chronic airway diseases, the dynamics of airway function are influenced by underlying airway inflammation and bronchial hyperresponsiveness along with limitations in reversibility owing to airway and lung remodeling as well as mucous plugging. The relative contribution of each component translates into specific clinical patterns of symptoms, quality of life, exacerbation risk, and treatment success. Objective We aimed to evaluate whether subgrouping of patients with obstructive airway diseases according to patterns of fluctuation in lung function allows identification of specific phenotypes with distinct clinical characteristics. Methods We applied the novel method of fluctuation-based clustering (FBC) to twice-daily FEV1 measurements recorded over a 1-year period in a mixed group of 134 adults with mild-to-moderate asthma, severe asthma, or chronic obstructive pulmonary disease from the European BIOAIR cohort. Results Independently of clinical diagnosis, FBC divided patients into 4 fluctuation-based clusters with progressively increasing alterations in lung function that corresponded to patterns of increasing clinical severity, risk of exacerbation, and lower quality of life. Clusters of patients with airway disease with significantly elevated levels of biomarkers relating to remodeling (osteonectin) and cellular senescence (plasminogen activator inhibitor-1), accompanied by a loss of airway reversibility, pulmonary hyperinflation, and loss of diffusion capacity, were identified. The 4 clusters generated were stable over time and revealed no differences in levels of markers of type 2 inflammation (blood eosinophils and periostin). Conclusion FBC-based phenotyping provides another level of information that is complementary to clinical diagnosis and unrelated to eosinophilic inflammation, which could identify patients who may benefit from specific treatment strategies or closer monitoring.

SummaryBackgroundPatients with severe asthma may have a greater risk of dying from COVID-19 disease caused by SARS-CoV-2 virus. Angiotensin converting enzyme 2 (ACE2) receptor and enzyme proteases, transmembrane protease, serine 2 (TMPRSS2) and furin are needed for the attachment and invasion of the virus into host cells. We determined whether their expression in the airways of severe asthma patients is increased.MethodWe examined the microarray mRNA expression of ACE2, TMPRSS2 and furin in the sputum, bronchial brush and bronchial biopsies of participants in the European U-BIOPRED cohort.ResultsACE2 and furin sputum gene expression was significantly increased in severe non-smoking asthma compared to mild-moderate asthma and healthy volunteers. By contrast, TMPRSS2 expression in bronchial biopsy and bronchial brushings was increased in severe smoking and ex-smoking asthmatics, and so was furin expression in bronchial brushings. Several clinical parameters including male gender, oral steroid use and nasal polyps were positively associated with ACE2, TMPRSS2 and furin expression levels. There was a higher expression of ACE2 and furin in the sputum neutrophilic molecular phenotype with inflammasome activation compared to the eosinophilic Type2-high or paucigranulocytic phenotypes. The enrichment score of the IL-13-Type2 gene signature was positively correlated with ACE2, TMPRSS2 and furin levels.ConclusionThese key determinants of virus entry into the lungs may contribute to the poorer outcomes from COVID-19 disease in patients with severe asthma.“take home” messageIn severe asthma, gene expression of ACE, TMPRSS2 and furin are elevated compared to mild-moderate asthma and healthy volunteers, particularly in neutrophilic asthma. This might explain the increased risk of death in severe asthma afflicted with COVID19.

To-date, there has not been a clear signal suggesting that asthma or treatment with inhaled steroids are a risk factor for severe COVID-19 disease. We have therefore explored ACE2 receptor mRNA expression, and co-factors for Sars-CoV-2 infectivity (TMPRSS2 and furin) in bronchial brushes and biopsies from people with asthma and healthy controls, and looked for relationships between asthma severity, Th2- and IL-17 dependent gene signatures, and clinical demographics (age, sex). We have looked at a cohort of 356 research participants from previously described studies. The only significant association was a positive correlation between ACE2 and IL-17-dependent gene expression, and an inverse correlation between ACE2 and Th2-cytokine-dependent gene expression. These data suggest that differences in ACE2, TMPRSS2 and furin epithelial and airway gene expression are unlikely to confer enhanced COVID-19 pneumonia risk in patients with asthma across all treatment intensities and severity., Expression of mRNA for ACE2, the Sars-CoV-2 receptor, is similar in the lower airways of healthy controls and people with mild-severe asthma. Altered ACE2 expression is unlikely to confer enhanced COVID-19 pneumonia risk in asthma.

The IL1RL1 (ST2) gene locus is robustly associated with asthma; however, the contribution of single nucleotide polymorphisms (SNPs) in this locus to specific asthma subtypes and the functional mechanisms underlying these associations remain to be defined. We tested for association between IL1RL1 region SNPs and characteristics of asthma as defined by clinical and immunological measures and addressed functional effects of these genetic variants in lung tissue and airway epithelium. Utilizing 4 independent cohorts (Lifelines, Dutch Asthma GWAS [DAG], Genetics of Asthma Severity and Phenotypes [GASP], and Manchester Asthma and Allergy Study [MAAS]) and resequencing data, we identified 3 key signals associated with asthma features. Investigations in lung tissue and primary bronchial epithelial cells identified context-dependent relationships between the signals and IL1RL1 mRNA and soluble protein expression. This was also observed for asthma-associated IL1RL1 nonsynonymous coding TIR domain SNPs. Bronchial epithelial cell cultures from asthma patients, exposed to exacerbation-relevant stimulations, revealed modulatory effects for all 4 signals on IL1RL1 mRNA and/ or protein expression, suggesting SNP-environment interactions. The IL1RL1 TIR signaling domain haplotype affected IL-33-driven NF-κB signaling, while not interfering with TLR signaling. In summary, we identify that IL1RL1 genetic signals potentially contribute to severe and eosinophilic phenotypes in asthma, as well as provide initial mechanistic insight, including genetic regulation of IL1RL1 isoform expression and receptor signaling.

International audience; Background: Asthma is a diverse condition that differs with age and sex. However, it remains unclear how sex, age of asthma-onset, and/or their interaction, influence clinical expression of more problematic adult “difficult” asthma.Objectives: To better understand the clinical features of difficult asthma within a real-world clinical setting using novel phenotypic classification, stratifying subjects by sex and age of asthma-onset.Methods: Participants in a longitudinal difficult asthma clinical cohort study (Wessex AsThma CoHort of difficult asthma; WATCH), United Kingdom, (n=501) were stratified into 4 difficult asthma phenotypes based on sex and age of asthma-onset (early

Asthma arises from the complex interplay of inflammatory pathways in diverse cell types and tissues. We sought to undertake a comprehensive transcriptomic assessment of the epithelium and airway T cells that remain understudied in asthma and investigate interactions between multiple cells and tissues. Epithelial brushings and flow-sorted CD3+ T cells from sputum and BAL were obtained from healthy subjects (n = 19) and patients with asthma (mild, moderate, and severe asthma; n = 46). Gene expression was assessed using Affymetrix HT HG-U133+ PM GeneChips, and results were validated by real-time quantitative PCR. In the epithelium, IL-13 response genes (POSTN, SERPINB2, and CLCA1), mast cell mediators (CPA3 and TPSAB1), inducible nitric oxide synthase, and cystatins (CST1, CST2, and CST4) were upregulated in mild asthma, but, except for cystatins, were suppressed by corticosteroids in moderate asthma. In severe asthma—with predominantly neutrophilic phenotype—several distinct processes were upregulated, including neutrophilia (TCN1 and MMP9), mucins, and oxidative stress responses. The majority of the disease signature was evident in sputum T cells in severe asthma, where 267 genes were differentially regulated compared with health, highlighting compartmentalization of inflammation. This signature included IL-17–inducible chemokines (CXCL1, CXCL2, CXCL3, IL8, and CSF3) and chemoattractants for neutrophils (IL8, CCL3, and LGALS3), T cells, and monocytes. A protein interaction network in severe asthma highlighted signatures of responses to bacterial infections across tissues (CEACAM5, CD14, and TLR2), including Toll-like receptor signaling. In conclusion, the activation of innate immune pathways in the airways suggests that activated T cells may be driving neutrophilic inflammation and steroid-insensitive IL-17 response in severe asthma.

Rationale: Genetic polymorphisms in the asthma susceptibility gene, urokinase plasminogen activator receptor (uPAR/PLAUR) have been associated with lung function decline and uPAR blood levels in asthma subjects. Preliminary studies have identified uPAR elevation in asthma; however, a definitive study regarding which clinical features of asthma uPAR may be driving is currently lacking.Objectives: We aimed to comprehensively determine the uPAR expression profile in asthma and control subjects utilizing bronchial biopsies and serum, and to relate uPAR expression to asthma clinical features.Methods: uPAR levels were determined in control (n = 9) and asthmatic (n = 27) bronchial biopsies using immunohistochemistry, with a semi-quantitative score defining intensity in multiple cell types. Soluble-cleaved (sc) uPAR levels were determined in serum through ELISA in UK (cases n = 129; controls n = 39) and Dutch (cases n = 514; controls n = 96) cohorts.Measurements and main results: In bronchial tissue, uPAR was elevated in inflammatory cells in the lamina propria (P = 0.0019), bronchial epithelial (P = 0.0002) and airway smooth muscle cells (P = 0.0352) of patients with asthma, with uPAR levels correlated between the cell types. No correlation with disease severity or asthma clinical features was identified. scuPAR serum levels were elevated in patients with asthma (1.5-fold; P = 0.0008), and we identified an association between high uPAR serum levels and severe, nonatopic disease.Conclusions: This study provides novel data that elevated airway and blood uPAR is a feature of asthma and that blood uPAR is particularly related to severe, nonatopic asthma. The findings warrant further investigation and may provide a therapeutic opportunity for this refractory population.

MicroRNAs are known to regulate important pathways in asthma pathology including the IL-6 and IFN pathways. MicroRNAs have been found not only within cells but also within extracellular vesicles such as exosomes. In this study, we particularly focused on microRNA cargo of nanovesicles in bronchoalveolar lavage of severe asthmatic patients. We extracted nanovesicle RNA using a serial filtration method. RNA content was analyzed with small RNA sequencing and mapped to pathways affected using WebGestalt 2017 Software. We report that severe asthma patients have deficient loading of microRNAs into their airway luminal nanovesicles and an altered profile of small RNA nanovesicle content (i.e., ribosomal RNA and broken transcripts, etc.). This decrease in microRNA cargo is predicted to increase the expression of genes by promoting inflammation and remodeling. Consistently, a network of microRNAs was associated with decreased FEV1 and increased eosinophilic and neutrophilic inflammation in severe asthma. MicroRNAs in airway nanovesicles may, thus, be valid biomarkers to define abnormal biological disease processes in severe asthma and monitor the impact of interventional therapies.