Search

The role of eosinophils in airway inflammation and asthma pathogenesis is well established, with raised eosinophil counts in blood and sputum associated with increased disease severity and risk of asthma exacerbation. Conversely, there is also preliminary evidence suggesting antiviral properties of eosinophils in the airways. These dual roles for eosinophils are particularly pertinent as respiratory virus infections contribute to asthma exacerbations. Biologic therapies targeting key molecules implicated in eosinophil-associated pathologies have been approved in patients with severe asthma and, therefore, the effects of depleting eosinophils in a clinical setting are of considerable interest. This review discusses the pathological and antiviral roles of eosinophils in asthma and exacerbations. We also highlight the significant reduction in asthma exacerbations seen with biologic therapies, even at the height of the respiratory virus season. Furthermore, we discuss the implications of these findings in relation to the role of eosinophils in inflammation and antiviral responses to respiratory virus infection in asthma., (© 2024 The Author(s). Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: Type 2 low-severe asthma phenotype is often a result of corticosteroid-overtreated type 2 disease owing to persistent symptoms, often unrelated to asthma and unlikely to respond to high-dose corticosteroid treatment., Objective: This study aimed to characterize patients with severe asthma with low eosinophil counts (<300 cells/μL) and describe their disease burden and treatment across health care settings in the United Kingdom., Methods: A retrospective cohort study of patients with severe asthma using linked Clinical Practice Research Datalink (CPRD) Aurum-Hospital Episode Statistics (HES) and UK Severe Asthma Registry (UKSAR) data indexed patients according to the latest blood eosinophil count (BEC). Clinical characteristics, treatment patterns, outcomes, and health care resource use were described by baseline BEC (≤150 and >150 to <300 cells/μL)., Results: Analysis included 701 (CPRD-HES) and 1,546 (UKSAR) patients; 60.5% and 59.4% had BECs 150 cells/μL or less at baseline, respectively. Across BEC groups, the proportion with uncontrolled asthma (two or more exacerbations) at follow-up (12 months after the index) was 5.4% in CPRD-HES and 45.2% in UKSAR. Maintenance oral corticosteroid use remained high across BEC groups (CPRD-HES: 29.4%; UKSAR: 51.7%), symptom control remained poor (>200 μg short-acting β 2 agonist or >500 μg terbutaline/d in CPRD-HES: 48.8%; median Asthma Control Questionnaire-6 score in UKSAR: 2.0 [range, 1.0-3.3]). Health care resource use was similar across BEC groups., Conclusions: Most patients managed in primary care experienced infrequent exacerbations, whereas UKSAR patients had frequent exacerbations. Large proportions of both patient groups had poor symptom control and continued to receive high levels of maintenance oral corticosteroids, increasing the risk of corticosteroid-induced morbidity. These data highlight the need for rigorous assessment of underlying disease pathology to guide appropriate treatment., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Benralizumab has been reported to lead to clinical remission of severe eosinophilic asthma (SEA) at 1 year in some patients. However, whether this is maintained over a longer term remains unclear. Additionally, the impact of pulmonary and extrapulmonary comorbidities on the ability to meet remission is poorly understood., Methods: Clinical outcomes including remission of SEA with benralizumab at 1 and 2 years were assessed retrospectively in a real-world UK multi-centre severe asthma cohort. The presence of clinically relevant pulmonary and extrapulmonary comorbidities associated with respiratory symptoms was recorded. Analyses to identify factors associated with the ability to meet remission were performed., Results: In total, 276 patients with SEA treated with benralizumab including 113 patients who had switched from a previous biologic to benralizumab were included. Overall, clinical remission was met in 17% (n = 31/186) and 32% (n = 43/133) of patients at 1 and 2 years, respectively. This increased to 28% at 1 year and 49% at 2 years once patients with pulmonary and/or extrapulmonary comorbidities were excluded. Body mass index (BMI) and maintenance OCS (mOCS) use demonstrated a negative association with clinical remission at 1 (BMI: OR: 0.89, 95% CI: 0.82-0.96, p < 0.01; mOCS: OR: 0.94, 95% CI: 0.89-0.99, p < 0.05) and 2 years (BMI: OR: 0.93, 95% CI: 0.87-0.99, p < 0.05; mOCS: OR: 0.95, 95% CI: 0.89-0.99, p < 0.05)., Conclusions: In this long-term, real-world study, patients with SEA demonstrated the ability to meet and sustain clinical remission when treated with benralizumab. The presence of comorbidities including obesity, which are known to be independently associated with respiratory symptoms, reduced the likelihood of meeting clinical remission., (© 2024 The Author(s). Clinical & Experimental Allergy published by John Wiley & Sons Ltd.)

Introduction: After puberty, females are more likely to develop asthma and in a more severe form than males. The associations between asthma and sex are complex with multiple intrinsic and external factors., Aim: To evaluate the sex differences in the characteristics and treatment of patients with severe asthma (SA) in a real-world setting., Methods: Demographic, clinical and treatment characteristics for patients with SA in the UK Severe Asthma Registry (UKSAR) and Optimum Patient Care Research Database (OPCRD) were retrospectively analysed by sex using univariable and multivariable logistic regression analyses adjusted for year, age and hospital/practice., Results: 3679 (60.9% female) patients from UKSAR and 18 369 patients (67.9% female) from OPCRD with SA were included. Females were more likely to be symptomatic with increased Asthma Control Questionnaire-6 (UKSAR adjusted OR (aOR) 1.14, 95% CI 1.09 to 1.18) and Royal College of Physicians-3 Question scores (OPCRD aOR 1.29, 95% CI 1.13 to 1.47). However, they had a higher forced expiratory volume in 1 second per cent (FEV 1 %) predicted (UKSAR 68.7% vs 64.8%, p<0.001) with no significant difference in peak expiratory flow. Type 2 biomarkers IgE (UKSAR 129 IU/mL vs 208 IU/mL, p<0.001) and FeNO (UKSAR 36ppb vs 46ppb, p<0.001) were lower in females with no significant difference in blood eosinophils or biological therapy. Females were less likely to be on maintenance oral corticosteroids (UKSAR aOR 0.86, 95% CI 0.75 to 0.99) but more likely to be obese (UKSAR aOR 1.67, 95% CI 145 to 1.93; OPCRD SA aOR 1.46, 95% CI 1.34 to 1.58)., Conclusions: Females had increased symptoms and were more likely to be obese despite higher FEV 1 % predicted and lower type 2 biomarkers with consistent and clinically important differences across both datasets., Competing Interests: Competing interests: LL has no conflicts of interest. JB has attended advisory boards for NuvoAir, outside the submitted work. RM has no conflicts of interest. TB has received speaker fees from Astra Zeneca, Glaxo Smith Kline, Sanofi, Teva, Novartis and Chiesi; honoraria for advisory board attendance from Astra Zeneca, Sanofi and Teva; sponsorship to attend international scientific meetings from Sanofi, GSK, Teva, Chiesi and Napp Pharmaceuticals. HB has attended advisory board for AstraZeneca, GlaxoSmithKline and Sanofi; has given lectures at meetings with/without lecture honoraria supported by AstraZeneca, GlaxoSmithKline and Chiesi; has attended international conferences with AstraZeneca and Chiesi; has taken part in clinical trials sponsored by AstraZeneca, Chiesi, GlaxoSmithKline, Teva and Sanofi. RC has received lecture fees from GSK, AZ, Teva, Chiesi, Sanofi and Novartis; honoraria for Advisory Board Meetings from GSK, AZ, Teva, Chiesi, Novartis; sponsorship to attend international scientific meetings from Chiesi, Napp, Sanofi and GSK and a research grant to her Institute from AZ for a UK multicentre study. PD has received honoraria/consultancy fees/sponsorship from Teva, AZ, GSK, Novartis and Omron. JWD declares he has received honoraria for participating in advisory boards and given lectures at meetings supported by GSK, Boerhinger Ingelheim, Chiesi, AstraZeneca, Fisher & Paykel, Aerogen; he has received sponsorship for attending international scientific meetings from Chiesi; he has also taken part in asthma clinical trials sponsored by Sanofi, AstraZeneca, Chiesi for which his institution received remuneration. SD has received lecture fees from GSK, AZ, and Sanofi; honoraria for Advisory Board Meetings from GSK, AZ and Novartis; sponsorship to attend international scientific meetings from AZ, Chiesi, Sanofi and GSK. SF has received speaker fees/sponsorship to attend specialty meetings from AstraZeneca, GlaxoSmithKline, Chiesi, Novartis and Sanofi. RG has received speaking/lecture fees from GSK, AstraZeneca, Sanofi and Novartis. EI has no conflicts of interest. DJJ has received lecture fees from GSK, AZ, Teva, Chiesi, and Sanofi; honoraria for Advisory Board Meetings from GSK, AZ, Teva, Chiesi, Sanofi and Novartis; sponsorship to attend international scientific meetings from AZ, Chiesi, Napp, Sanofi and GSK and research grants to his Institute from AZ. MP has no conflicts of interest. TP has received sponsorship for attending international scientific meetings from Chiesi, GlaxoSmithKline and Sanofi Genzyme; he is also taking part in asthma clinical trials sponsored by AstraZeneca and Sanofi Genzyme for which his institution receives remuneration. IP has received speaker’s honoraria for speaking at sponsored meetings from Astra Zeneca, Boehringer Inglehiem, Aerocrine, Almirall, Novartis, Teva, Chiesi, Sanofi/Regeneron, Menarini and GSK and payments for organising educational events from AZ, GSK, Sanofi/Regeneron and Teva. He has received honoraria for attending advisory panels with Genentech, Sanofi/Regeneron, Astra Zeneca, Boehringer Ingelheim, GSK, Novartis, Teva, Merck, Circassia, Chiesi and Knopp and payments to support FDA approval meetings from GSK. He has received sponsorship to attend international scientific meetings from Boehringer Ingelheim, GSK, Astra Zeneca, Teva and Chiesi. He has received a grant from Chiesi to support a phase 2 clinical trial in Oxford. PEP has attended advisory board for AstraZeneca, GlaxoSmithKline and Sanofi; has given lectures at meetings with/without lecture honoraria supported by AstraZeneca and GlaxoSmithKline; has attended international conferences with AstraZeneca; has taken part in clinical trials sponsored by AstraZeneca, GlaxoSmithKline, Novartis and Sanofi; and is conducting research funded by GlaxoSmithKline for which his institution receives remuneration. DBP has advisory board membership with Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, Circassia, Viatris, Mundipharma, Novartis, Regeneron Pharmaceuticals, Sanofi Genzyme, Teva Pharmaceuticals and Thermofisher; consultancy agreements with Amgen, AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Viatris, Mundipharma, Novartis, Pfizer, Teva Pharmaceuticals and Theravance; grants and unrestricted funding for investigator-initiated studies (conducted through Observational and Pragmatic Research Institute) from AstraZeneca, Boehringer Ingelheim, Chiesi, Circassia, Viatris, Mundipharma, Novartis, Pfizer, Regeneron Pharmaceuticals, Sanofi Genzyme, Teva Pharmaceuticals, Theravance and UK National Health Service; payment for lectures/speaking engagements from AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, GlaxoSmithKline, Viatris, Mundipharma, Novartis, Pfizer, Regeneron Pharmaceuticals, Sanofi Genzyme and Teva Pharmaceuticals; payment for travel/accommodation/meeting expenses from AstraZeneca, Boehringer Ingelheim, Circassia, Mundipharma, Novartis, Teva Pharmaceuticals and Thermofisher; funding for patient enrolment or completion of research from Novartis; stock/stock options from AKL Research and Development Ltd which produces phytopharmaceuticals; owns 74% of the social enterprise Optimum Patient Care Ltd (Australia and UK) and 74% of Observational and Pragmatic Research Institute Pte Ltd (Singapore); 5% shareholding in Timestamp which develops adherence monitoring technology; is peer reviewer for grant committees of the UK Efficacy and Mechanism Evaluation programme, and Health Technology Assessment; and was an expert witness for GlaxoSmithKline. HR has received lecture fees from GSK, AZ, Chiesi, and Sanofi; honoraria for Advisory Board Meetings from GSK, AZ and Teva; sponsorship to attend international scientific meetings from AZ and Sanofi and research grants to her Institute from GSK and AZ. SS has received honoraria for speaking or providing advisory services from AstraZeneca, Boehringer Inglehiem, GSK, CSL Behring, Chiesi, MUDIPHARMA, Owlstone Medical, ERT Medical. LGH declares he has received grant funding, participated in advisory boards and given lectures at meetings supported by Amgen, AstraZeneca, Boehringer Ingelheim, Circassia, Hoffmann la Roche, GlaxoSmithKline, Novartis, Theravance, Evelo Biosciences, Sanofi, and Teva; he has received grants from MedImmune, Novartis UK, Roche/Genentech, and Glaxo Smith Kline, Amgen, Genentech/Hoffman la Roche, Astra Zeneca, MedImmune, Glaxo Smith Kline, Aerocrine and Vitalograph; he has received sponsorship for attending international scientific meetings from AstraZeneca, Boehringer Ingelheim, Chiesi, GSK and Napp Pharmaceuticals; he has also taken part in asthma clinical trials sponsored by Boehringer Ingelheim, Hoffmann la Roche, and GlaxoSmithKline for which his institution received remuneration; he is the Academic Lead for the Medical Research Council Stratified Medicine UK Consortium in Severe Asthma which involves industrial partnerships with a number of pharmaceutical companies including Amgen, AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Hoffmann la Roche and Janssen. AM-G is an employee of Astra Zeneca., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: The Modern Innovative Solutions to Improve Outcomes in Asthma, Breathlessness and Chronic Obstructive Pulmonary Disease (COPD) (MABC) service aimed to enhance disease management for chronic respiratory conditions through specialist multidisciplinary clinics, predominantly in the community. This study assesses the outcomes of these clinics., Design: This study used a prospective, longitudinal, participatory action research approach., Setting: The study was conducted in primary care practices across Hampshire, UK., Participants: Adults aged 16 years and above with poorly controlled asthma or COPD, as well as those with undifferentiated breathlessness not under specialist care, were included., Interventions: Participants received care through the multidisciplinary, specialist-led MABC clinics., Primary and Secondary Outcome Measures: Primary outcomes included disease activity, quality of life and healthcare utilisation. Secondary outcomes encompassed clinic attendance, diagnostic changes, patient activation, participant and healthcare professional experiences and cost-effectiveness., Results: A total of 441 participants from 11 general practitioner practices were recruited. Ninety-six per cent of participants would recommend MABC clinics. MABC assessments led to diagnosis changes for 64 (17%) participants with asthma and COPD and treatment adjustments for 252 participants (57%). Exacerbations decreased significantly from 236 to 30 after attending the clinics (p<0.005), with a mean reduction of 0.53 exacerbation events per participant. Reductions were also seen in unscheduled and out-of-hours primary care attendance, emergency department visits and hospital admissions (all p<0.005). Cost savings from reduced exacerbations and healthcare utilisation offset increased medication costs and clinic expenses., Conclusions: Specialist-supported multidisciplinary teams in MABC clinics improved diagnosis accuracy and adherence to guidelines. High patient satisfaction, disease control improvements and reduced exacerbations resulted in decreased unscheduled healthcare use and cost savings., Trial Registration Number: NCT03096509., Competing Interests: Competing interests: All authors report no conflicts of interest. EL reports personal fees from Chiesi and Clement Clarke, not associated with this submitted work. TLJ reports non-financial support from Chiesi Farmaceutici outside of the submitted work. HR reports honoraria and lecture fees from Astra Zeneca, Teva, Novartis, GlaxoSmithKline and Chiesi, all of which are outside of the submitted work. TB reports personal fees from Astra Zeneca, grants, personal fees and non-financial support from GlaxoSmithKline, personal fees and non-financial support from Teva, non-financial support from Napp Pharmaceuticals and personal fees and non-financial support from Novartis, outside of the submitted work. AJC reports honoraria and lecture fees from Teva, Astra Zeneca and Sanofi and research grants from Airsonett, Novartis and GlaxoSmithKline, all of which are outside of the submitted work., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

The ability of human tissue to reorganize and restore its existing structure underlies tissue homeostasis in the healthy airways, but in disease can persist without normal resolution, leading to an altered airway structure. Eosinophils play a cardinal role in airway remodeling both in health and disease, driving epithelial homeostasis and extracellular matrix turnover. Physiological consequences associated with eosinophil-driven remodeling include impaired lung function and reduced bronchodilator reversibility in asthma, and obstructed airflow in chronic rhinosinusitis with nasal polyps. Given the contribution of airway remodeling to the development and persistence of symptoms in airways disease, targeting remodeling is an important therapeutic consideration. Indeed, there is early evidence that eosinophil attenuation may reduce remodeling and disease progression in asthma. This review provides an overview of tissue remodeling in both health and airway disease with a particular focus on eosinophilic asthma and chronic rhinosinusitis with nasal polyps, as well as the role of eosinophils in these processes and the implications for therapeutic interventions. Areas for future research are also noted, to help improve our understanding of the homeostatic and pathological roles of eosinophils in tissue remodeling, which should aid the development of targeted and effective treatments for eosinophilic diseases of the airways., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Asthma is conventionally stratified as type 2 inflammation (T2)-high or T2-low disease. Identifying T2 status has therapeutic implications for patient management, but a real-world understanding of this T2 paradigm in difficult-to-treat and severe asthma remains limited., Objectives: To identify the prevalence of T2-high status in difficult-to-treat asthma patients using a multicomponent definition and compare clinical and pathophysiologic characteristics between patients classified as T2-high and T2-low., Methods: We evaluated 388 biologic-naive patients from the Wessex Asthma Cohort of difficult asthma (WATCH) study in the United Kingdom. Type 2-high asthma was defined as 20 parts per billion or greater FeNO , 150 cells/μL or greater peripheral blood eosinophils, the need for maintenance oral corticosteroids, and/or clinically allergy-driven asthma., Results: This multicomponent assessment identified T2-high asthma in 93% of patients (360 of 388). Body mass index, inhaled corticosteroid dose, asthma exacerbations, and common comorbidities did not differ by T2 status. Significantly worse airflow limitation was found in T2-high compared with T2-low patients (FEV 1 /FVC 65.9% vs 74.6%). Moreover, 75% of patients defined as having T2-low asthma had raised peripheral blood eosinophils within the preceding 10 years, which left only seven patients (1.8%) who had never had T2 signals. Incorporation of sputum eosinophilia 2% or greater into the multicomponent definition in a subset of 117 patients with induced sputum data similarly found that 96% (112 of 117) met criteria for T2-high asthma, 50% of whom (56 of 112) had sputum eosinophils 2% or greater., Conclusions: Almost all patients with difficult-to-treat asthma have T2-high disease; less than 2% of patients never display T2-defining criteria. This highlights a need to assess T2 status comprehensively in clinical practice before labeling a patient with difficult-to-treat asthma as T2-low., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Supporting self-management is key in improving disease control, with technology increasingly utilised. We hypothesised the addition of telehealth support following assessment in an integrated respiratory clinic could reduce unscheduled healthcare visits in patients with asthma and COPD. Following treatment optimisation, exacerbation-prone participants or those with difficulty in self-management were offered telehealth support. This comprised automated twice-weekly telephone calls, with a specialist nurse triaging alerts. We performed a matched cohort study assessing additional benefits of the telehealth service, matching by: confirmed diagnosis, age, sex, FEV 1 percent predicted, smoking status and ≥1 exacerbation in the last year. Thirty-four telehealth participants were matched to twenty-nine control participants. The telehealth cohort generated 165 alerts, with 29 participants raising at least one alert; 88 (53.5%) alerts received a call discussing self-management, of which 35 (21%) received definitive advice that may otherwise have required an unscheduled healthcare visit. There was a greater reduction in median exacerbation rate across both telehealth groups at 6 months post-intervention (1 to 0, p < 0.001) but not in control groups (0.5 to 0.0, p = 0.121). Similarly, there was a significant reduction in unscheduled GP visits across the telehealth groups (1.5 to 0.0, p < 0.001), but not the control groups (0.5 to 0.0, p = 0.115). These reductions led to cost-savings across all groups, but greater in the telehealth cohorts. The addition of telehealth support to exacerbation-prone patients with asthma or COPD, following comprehensive assessment and treatment optimisation, proved beneficial in reducing exacerbation frequency and unscheduled healthcare visits and thus leads to significant cost-savings for the NHS.Clinical Trial Registration: ClinicalTrials.gov: NCT03096509., (© 2022. The Author(s).)

Asthma is a common and heterogeneous disease characterized by lower airway inflammation and airflow limitation. Critical factors in asthma management include establishing an accurate diagnosis and ensuring appropriate selection and dosage of antiinflammatory therapies. Most patients with asthma exhibit type 2 inflammation, with increased IL-4, IL-5, and IL-13 signalling, often with associated eosinophilia. Identifying lower airway eosinophilia with sputum induction improves asthma outcomes, but is time-consuming and costly. Increased type 2 inflammation leads to upregulation of nitric oxide (NO) release into the airway, with increasing fractional exhaled NO (Feno) reflecting greater type 2 inflammation. Feno can be measured easily and quickly in the clinic, offering a point-of-care surrogate measurement of the degree of lower airway inflammation. Feno testing can be used to help confirm an asthma diagnosis, to guide inhaled corticosteroid therapy, to assess adherence to treatment, and to aid selection of appropriate biologic therapy. However, Feno levels also may be influenced by a variety of intrinsic and extrinsic factors other than asthma, including nasal polyposis and cigarette smoking, and must be interpreted in the broader clinical context, rather than viewed in isolation. This review discusses the clinical application of Feno measurement in asthma care, from diagnosis to treatment selection, and describes its place in current international expert guidelines., (Copyright © 2021 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

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., (© 2021 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Asthma is the commonest chronic lung disease. Airway inflammation is a central component of asthma but clinical symptoms of asthma and standard spirometry are insensitive in reflecting the underlying inflammatory processes. Measurement of the fractional nitric oxide concentration in exhaled breath (FeNO) is a quantitative, non-invasive and safe method of measuring airway inflammation. Advances in technology and standardization have made FeNO measurements simple, enabling their use as a biomarker alongside traditional clinical tools in the assessment and management of asthma. Specifically, it can predict responsiveness to steroids and also newer biological therapy, predict future risk of exacerbation and help highlight treatment non-adherence, making it a useful asset to personalized medicine.

MicroRNAs are small noncoding RNAs that inhibit gene expression posttranscriptionally, implicated in virtually all biological processes. Although the effect of individual microRNAs is generally studied, the genome-wide role of multiple microRNAs is less investigated. We assessed paired genome-wide expression of microRNAs with total (cytoplasmic) and translational (polyribosome-bound) mRNA levels employing subcellular fractionation and RNA sequencing (Frac-seq) in human primary bronchoepithelium from healthy controls and severe asthmatics. Severe asthma is a chronic inflammatory disease of the airways characterized by poor response to therapy. We found genes (i.e., isoforms of a gene) and mRNA isoforms differentially expressed in asthma, with novel inflammatory and structural pathophysiological mechanisms related to bronchoepithelium disclosed solely by polyribosome-bound mRNAs (e.g., IL1A and LTB genes or ITGA6 and ITGA2 alternatively spliced isoforms). Gene expression (i.e., isoforms of a gene) and mRNA expression analysis revealed different molecular candidates and biological pathways, with differentially expressed polyribosome-bound and total mRNAs also showing little overlap. We reveal a hub of six dysregulated microRNAs accounting for ∼90% of all microRNA targeting, displaying preference for polyribosome-bound mRNAs. Transfection of this hub in bronchial epithelial cells from healthy donors mimicked asthma characteristics. Our work demonstrates extensive posttranscriptional gene dysregulation in human asthma, in which microRNAs play a central role, illustrating the feasibility and importance of assessing posttranscriptional gene expression when investigating human disease., (Copyright © 2018 by The American Association of Immunologists, Inc.)

Management of severe asthma remains a challenge despite treatment with glucocorticosteroid therapy. The majority of studies investigating disease mechanisms in treatment-resistant severe asthma have previously focused on the large central airways, with very few utilizing transcriptomic approaches. The small peripheral airways, which comprise the majority of the airway surface area, remain an unexplored area in severe asthma and were targeted for global epithelial gene expression profiling in this study. Differences between central and peripheral airways were evaluated using transcriptomic analysis (Affymetrix HG U133 plus 2.0 GeneChips) of epithelial brushings obtained from severe asthma patients (N = 17) and healthy volunteers (N = 23). Results were validated in an independent cohort (N = 10) by real-time quantitative PCR. The IL-13 disease signature that is associated with an asthmatic phenotype was upregulated in severe asthmatics compared to healthy controls but was predominantly evident within the peripheral airways, as were genes related to mast cell presence. The gene expression response associated with glucocorticosteroid therapy (i.e. FKBP5) was also upregulated in severe asthmatics compared to healthy controls but, in contrast, was more pronounced in central airways. Moreover, an altered epithelial repair response (e.g. FGFBP1) was evident across both airway sites reflecting a significant aspect of disease in severe asthma unadressed by current therapies. A transcriptomic approach to understand epithelial activation in severe asthma has thus highlighted the need for better-targeted therapy to the peripheral airways in severe asthma, where the IL-13 disease signature persists despite treatment with currently available therapy., Competing Interests: Gene array analysis was funded by UCB Celtech as part of an academic collaboration with The University of Southampton. This commercial affiliation does not alter our adherence to PLOS ONE policies on sharing data and materials.

Background: Disease heterogeneity in patients with severe asthma and its relationship to inflammatory mechanisms remain poorly understood., Objective: We aimed to identify and replicate clinicopathologic endotypes based on analysis of blood and sputum parameters in asthmatic patients., Methods: One hundred ninety-four asthmatic patients and 21 control subjects recruited from 2 separate centers underwent detailed clinical assessment, sputum induction, and phlebotomy. One hundred three clinical, physiologic, and inflammatory parameters were analyzed by using topological data analysis and Bayesian network analysis., Results: Severe asthma was associated with anxiety and depression, obesity, sinonasal symptoms, decreased quality of life, and inflammatory changes, including increased sputum chitinase 3-like protein 1 (YKL-40) and matrix metalloproteinase (MMP) 1, 3, 8, and 12 levels. Topological data analysis identified 6 clinicopathobiologic clusters replicated in both geographic cohorts: young, mild paucigranulocytic; older, sinonasal disease; obese, high MMP levels; steroid resistant TH2 mediated, eosinophilic; mixed granulocytic with severe obstruction; and neutrophilic, low periostin levels, severe obstruction. Sputum IL-5 levels were increased in patients with severe particularly eosinophilic forms, whereas IL-13 was suppressed and IL-17 levels did not differ between clusters. Bayesian network analysis separated clinical features from intricately connected inflammatory pathways. YKL-40 levels strongly correlated with neutrophilic asthma and levels of myeloperoxidase, IL-8, IL-6, and IL-6 soluble receptor. MMP1, MMP3, MMP8, and MMP12 levels were associated with severe asthma and were correlated positively with sputum IL-5 levels but negatively with IL-13 levels., Conclusion: In 2 distinct cohorts we have identified and replicated 6 clinicopathobiologic clusters based on blood and induced sputum measures. Our data underline a disconnect between clinical features and underlying inflammation, suggest IL-5 production is relatively steroid insensitive, and highlight the expression of YKL-40 in patients with neutrophilic inflammation and the expression of MMPs in patients with severe asthma., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Rationale: Asthma is one of the most common chronic diseases worldwide, and individuals with severe asthma experience recurrent exacerbations. Exacerbations are predominantly viral associated and have been linked to defective airway IFN responses. Ascertaining the molecular mechanisms underlying this deficiency is a major research goal to identify new therapeutic targets., Objectives: We investigated the hypothesis that reduced Toll-like receptor 7 (TLR7)-derived signaling drove the impaired IFN responses to rhinovirus by asthmatic alveolar macrophages (AMs); the molecular mechanisms underlying this deficiency were explored., Methods: AMs were recovered from bronchoalveolar lavage from healthy subjects and patients with severe asthma. Expression of pattern-recognition receptors and microRNAs was evaluated by quantitative polymerase chain reaction and Western blotting. A TLR7-luciferase reporter construct was created to evaluate binding of microRNAs to the 3' untranslated region of TLR7. IFN production was measured by quantitative polymerase chain reaction and ELISA., Measurements and Main Results: The expression of TLR7 was significantly reduced in severe asthma AMs and was associated with reduced rhinovirus and imiquimod-induced IFN responses by these cells compared with healthy AMs. Severe asthma AMs also expressed increased levels of three microRNAs, which we showed were able to directly reduce TLR7 expression. Ex vivo knockdown of these microRNAs restored TLR7 expression with concomitant augmentation of virus-induced IFN production., Conclusions: In severe asthma, TLR7 deficiency drives impaired innate immune responses to virus by AMs. Blocking a group of microRNAs that are up-regulated in these cells can restore antiviral innate responses, providing a novel approach for therapy in asthma.

MicroRNAs are short non-coding single stranded RNAs that regulate gene expression. While much is known about the effects of individual microRNAs, there is now growing evidence that they can work in co-operative networks. MicroRNAs are known to be dysregulated in many diseases and affect pathways involved in the pathology. We investigated dysregulation of microRNA networks using asthma as the disease model. Asthma is a chronic inflammatory disease of the airways characterized by bronchial hyperresponsiveness and airway remodelling. The airway epithelium is a major contributor to asthma pathology and has been shown to produce an excess of inflammatory and pro-remodelling cytokines such as TGF-β, IL-6 and IL-8 as well as deficient amounts of anti-viral interferons. After performing microRNA arrays, we found that microRNAs -18a, -27a, -128 and -155 are down-regulated in asthmatic bronchial epithelial cells, compared to cells from healthy donors. Interestingly, these microRNAs are predicted in silico to target several components of the TGF-β, IL-6, IL-8 and interferons pathways. Manipulation of the levels of individual microRNAs in bronchial epithelial cells did not have an effect on any of these pathways. Importantly, knock-down of the network of microRNAs miR-18a, -27a, -128 and -155 led to a significant increase of IL-8 and IL-6 expression. Interestingly, despite strong in silico predictions, down-regulation of the pool of microRNAs did not have an effect on the TGF-β and Interferon pathways. In conclusion, using both bioinformatics and experimental tools we found a highly relevant potential role for microRNA dysregulation in the control of IL-6 and IL-8 expression in asthma. Our results suggest that microRNAs may have different roles depending on the presence of other microRNAs. Thus, interpretation of in silico analysis of microRNA function should be confirmed experimentally in the relevant cellular context taking into account interactions with other microRNAs when studying disease.

Hitasha Rupani,1 Wei Chern Gavin Fong,2,3 Aref Kyyaly,2,3 Ramesh J Kurukulaaratchy1– 4 1Department of Respiratory Medicine, University Hospitals Southampton NHS Foundation Trust, Southampton, UK; 2Clinical and Experimental Sciences, University of Southampton, Southampton, UK; 3David Hide Asthma and Allergy Research Centre, Isle of Wight NHS Trust, Isle of Wight, UK; 4NIHR Biomedical Research Centre, University Hospitals Southampton NHS Foundation Trust, Southampton, UKCorrespondence: Ramesh J KurukulaaratchyClinical Experimental Sciences, University of Southampton, Southampton, UKTel +44 238120 5232Email R.J.Kurukulaaratchy@soton.ac.ukWei Chern Gavin FongClinical and Experimental Sciences, University of Southampton, Southampton, UKTel +44 2381205232Email W.C.Fong@soton.ac.ukAbstract: The present prevailing inflammatory paradigm in asthma is of T2-high inflammation orchestrated by key inflammatory cells like Type 2 helper lymphocytes, innate lymphoid cells group 2 and associated cytokines. Eosinophils are key components of this T2 inflammatory pathway and have become key therapeutic targets. Real-world evidence on the predominant T2-high nature of severe asthma is emerging. Various inflammatory biomarkers have been adopted in clinical practice to aid asthma characterization including airway measures such as bronchoscopic biopsy and lavage, induced sputum analysis, and fractional exhaled nitric oxide. Blood measures like eosinophil counts have also gained widespread usage and multicomponent algorithms combining different parameters are now appearing. There is also growing interest in potential future biomarkers including exhaled volatile organic compounds, micro RNAs and urinary biomarkers. Additionally, there is a growing realisation that asthma is a heterogeneous state with numerous phenotypes and associated treatable traits. These may show particular inflammatory patterns and merit-specific management approaches that could improve asthma patient outcomes. Inhaled corticosteroids (ICS) remain the mainstay of asthma management but their use earlier in the course of disease is being advocated. Recent evidence suggests potential roles for ICS in combination with long-acting beta-agonists (LABA) for as needed use in mild asthma whilst maintenance and reliever therapy regimes have gained widespread acceptance. Other anti-inflammatory strategies including ultra-fine particle ICS, leukotriene receptor antagonists and macrolide antibiotics may show efficacy in particular phenotypes too. Monoclonal antibody biologic therapies have recently entered clinical practice with significant impacts on asthma outcomes. Understanding of the efficacy and use of those agents is becoming clearer with a growing body of real-world evidence as is their potential applicability to other treatable comorbid traits. In conclusion, the evolving understanding of T2 driven inflammation alongside a treatable traits disease model is enhancing therapeutic approaches to address inflammation in asthma.Keywords: asthma, biologics, monitoring, respiratory disease, T2 inflammation, treatable traits