Severity of Lung Function Impairment Drives Transcriptional Phenotypes of COPD and Relates to Immune and Metabolic Processes.

Purpose: This study sought to characterize transcriptional phenotypes of COPD through unsupervised clustering of sputum gene expression profiles, and further investigate mechanisms underlying the characteristics of these clusters. Patients and methods: Induced sputum samples were collected from patients with stable COPD (n = 72) and healthy controls (n = 15). Induced sputum was collected for inflammatory cell counts, and RNA extracted. Transcriptional profiles were generated (Illumina Humanref-8 V2) and analyzed by GeneSpring GX14.9.1. Unsupervised hierarchical clustering and differential gene expression analysis were performed, and gene alterations validated in the ECLIPSE dataset (GSE22148). Results: We identified 2 main clusters (Cluster 1 [n = 35] and Cluster 2 [n = 37]), which further divided into 4 sub-clusters (Sub-clusters 1.1 [n = 14], 1.2 [n = 21], 2.1 [n = 20] and 2.2 [n = 17]). Compared with Cluster 1, Cluster 2 was associated with significantly lower lung function (p = 0.014), more severe disease (p = 0.009) and breathlessness (p = 0.035), and increased sputum neutrophils (p = 0.031). Sub-cluster 1.1 had significantly higher proportion of people with comorbid cardiovascular disease compared to the other 3 sub-clusters (92.5% vs 57.1%, 50% and 52.9%, p < 0.013). Through supervised analysis we determined that degree of airflow limitation (GOLD stage) was the predominant factor driving gene expression differences in our transcriptional clusters. There were 452 genes (adjusted p < 0.05 and ≥2 fold) altered in GOLD stage 3 and 4 versus 1 and 2, of which 281 (62%) were also found to be significantly expressed between these GOLD stages in the ECLIPSE data set (GSE22148). Differentially expressed genes were largely downregulated in GOLD stages 3 and 4 and connected in 5 networks relating to lipoprotein and cholesterol metabolism; metabolic processes in oxidation/reduction and mitochondrial function; antigen processing and presentation; regulation of complement activation and innate immune responses; and immune and metabolic processes. Conclusion: Severity of lung function drives 2 distinct transcriptional phenotypes of COPD and relates to immune and metabolic processes.

Randomised controlled trial for the titration of oral corticosteroids using markers of inflammation in severe asthma.

INTRODUCTION: Biomarkers are used to select biologic therapies for patients with severe asthma, but not to regularly adjust therapy, especially oral corticosteroids (OCS). OBJECTIVE: Our goal was to test the efficacy of an algorithm to guide the titration of OCS using blood eosinophil count and fraction of exhaled nitric oxide (FeNO) levels. DESIGN, PARTICIPANTS, INTERVENTIONS AND SETTING: This proof-of-concept prospective randomised controlled trial assigned adult participants with severe uncontrolled asthma (n=32) to biomarker-based management (BBM) where OCS dose was adjusted based on a composite biomarker score comprised of blood eosinophil count and FeNO, or a standard best practice (SBP) arm. The study was conducted at the Hunter Medical Research Institute, Newcastle, Australia. Participants were recruited from the local Severe Asthma Clinic and were blinded to their study allocation. MAIN OUTCOME: The coprimary outcomes were number of severe exacerbations and time to first severe exacerbation assessed over 12 months. RESULTS: There was a longer median time to first severe exacerbation with BBM, although not significant (295 vs 123 days, Adj. HR: 0.714; 95% CI: 0.25 to 2.06; p=0.533). The relative risk of a severe exacerbation in BBM (n=17) vs SBP (n=15) was 0.88 (Adj.; 95% CI: 0.47 to 1.62; p=0.675) with a mean exacerbation rate per year of 1.2 and 2.0, respectively. There was a significant reduction in the proportion of patients requiring an emergency department (ED) visit using BBM (OR 0.09, 95% CI: 0.01 to 0.91; p=0.041). There was no difference in the cumulative OCS dose used between the two groups. CONCLUSION: A treatment algorithm to adjust OCS using blood eosinophil count and FeNO is feasible in a clinical setting and resulted in a reduced odds of an ED visit. This warrants further study to optimise the use of OCS in the future. TRIAL REGISTRATION NUMBER: This trial was registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12616001015437).

Early Th2 inflammation in the upper respiratory mucosa as a predictor of severe COVID-19 and modulation by early treatment with inhaled corticosteroids: a mechanistic analysis.

BACKGROUND: Community-based clinical trials of the inhaled corticosteroid budesonide in early COVID-19 have shown improved patient outcomes. We aimed to understand the inflammatory mechanism of budesonide in the treatment of early COVID-19. METHODS: The STOIC trial was a randomised, open label, parallel group, phase 2 clinical intervention trial where patients were randomly assigned (1:1) to receive usual care (as needed antipyretics were only available treatment) or inhaled budesonide at a dose of 800 µg twice a day plus usual care. For this experimental analysis, we investigated the nasal mucosal inflammatory response in patients recruited to the STOIC trial and in a cohort of SARS-CoV-2-negative healthy controls, recruited from a long-term observational data collection study at the University of Oxford. In patients with SARS-CoV-2 who entered the STOIC study, nasal epithelial lining fluid was sampled at day of randomisation (day 0) and at day 14 following randomisation, blood samples were also collected at day 28 after randomisation. Nasal epithelial lining fluid and blood samples were collected from the SARS-CoV-2 negative control cohort. Inflammatory mediators in the nasal epithelial lining fluid and blood were assessed for a range of viral response proteins, and innate and adaptive response markers using Meso Scale Discovery enzyme linked immunoassay panels. These samples were used to investigate the evolution of inflammation in the early COVID-19 disease course and assess the effect of budesonide on inflammation. FINDINGS: 146 participants were recruited in the STOIC trial (n=73 in the usual care group; n=73 in the budesonide group). 140 nasal mucosal samples were available at day 0 (randomisation) and 122 samples at day 14. At day 28, whole blood was collected from 123 participants (62 in the budesonide group and 61 in the usual care group). 20 blood or nasal samples were collected from healthy controls. In early COVID-19 disease, there was an enhanced inflammatory airway response with the induction of an anti-viral and T-helper 1 and 2 (Th1/2) inflammatory response compared with healthy individuals. Individuals with COVID-19 who clinically deteriorated (ie, who met the primary outcome) showed an early blunted respiratory interferon response and pronounced and persistent Th2 inflammation, mediated by CC chemokine ligand (CCL)-24, compared with those with COVID-19 who did not clinically deteriorate. Over time, the natural course of COVID-19 showed persistently high respiratory interferon concentrations and elevated concentrations of the eosinophil chemokine, CCL-11, despite clinical symptom improvement. There was persistent systemic inflammation after 28 days following COVID-19, including elevated concentrations of interleukin (IL)-6, tumour necrosis factor-α, and CCL-11. Budesonide treatment modulated inflammation in the nose and blood and was shown to decrease IL-33 and increase CCL17. The STOIC trial was registered with ClinicalTrials.gov, NCT04416399. INTERPRETATION: An initial blunted interferon response and heightened T-helper 2 inflammatory response in the respiratory tract following SARS-CoV-2 infection could be a biomarker for predicting the development of severe COVID-19 disease. The clinical benefit of inhaled budesonide in early COVID-19 is likely to be as a consequence of its inflammatory modulatory effect, suggesting efficacy by reducing epithelial damage and an improved T-cell response. FUNDING: Oxford National Institute of Health Research Biomedical Research Centre and AstraZeneca.

Patterns of azithromycin use in obstructive airway diseases: a real-world observational study.

BACKGROUND: Low-dose long-term azithromycin is recommended in clinical practice guidelines for obstructive airway diseases (OAD); however, an optimal therapeutic regimen is not yet established. AIM: To understand the patterns of azithromycin use in OAD, characterise the patients who received it and evaluate its safety and efficacy using real-world data. METHODS: We audited 91 patients who had received azithromycin for at least 4 weeks for the management of asthma, chronic obstructive pulmonary disease (COPD) or non-cystic fibrosis bronchiectasis. RESULTS: The mean age was 65 ± 18 years, 60% were female and 48% were ex-smokers. The majority had asthma (75%), either alone (50%) or in combination with COPD (12%) or bronchiectasis (13%). Most (64%) reported cough or sputum at baseline. The most common treatment regimen was azithromycin 250 mg daily (73%) for more than 1 year (57%), with only seven adverse events. There was a significant reduction in the proportions of patients requiring emergency department visits (48% vs 32%; P < 0.001) and hospital admissions (35% vs 31%; P < 0.001) after starting azithromycin. In 88% of cases, physicians favoured the use of azithromycin. CONCLUSION: Physicians are currently using low-dose azithromycin for a long duration of more than 1 year for the management of OAD. The typical case definition is an older non-smoking adult with persistent asthma, often in combination with another OAD and presenting with bothersome cough or sputum. Azithromycin was well tolerated and led to reduced healthcare utilisation. Further research is required to establish an optimal dosage regimen of azithromycin in OAD.

R othia mucilaginosa is an anti-inflammatory bacterium in the respiratory tract of patients with chronic lung disease.

BACKGROUND: Chronic airway inflammation is the main driver of pathogenesis in respiratory diseases such as severe asthma, chronic obstructive pulmonary disease, cystic fibrosis (CF) and bronchiectasis. While the role of common pathogens in airway inflammation is widely recognised, the influence of other microbiota members is still poorly understood. METHODS: We hypothesised that the lung microbiota contains bacteria with immunomodulatory activity which modulate net levels of immune activation by key respiratory pathogens. Therefore, we assessed the immunomodulatory effect of several members of the lung microbiota frequently reported as present in CF lower respiratory tract samples. RESULTS: We show that Rothia mucilaginosa, a common resident of the oral cavity that is also often detectable in the lower airways in chronic disease, has an inhibitory effect on pathogen- or lipopolysaccharide-induced pro-inflammatory responses, in vitro (three-dimensional cell culture model) and in vivo (mouse model). Furthermore, in a cohort of adults with bronchiectasis, the abundance of Rothia species was negatively correlated with pro-inflammatory markers (interleukin (IL)-8 and IL-1ß) and matrix metalloproteinase (MMP)-1, MMP-8 and MMP-9 in sputum. Mechanistic studies revealed that R. mucilaginosa inhibits NF-κB pathway activation by reducing the phosphorylation of IκBα and consequently the expression of NF-κB target genes. CONCLUSIONS: These findings indicate that the presence of R. mucilaginosa in the lower airways potentially mitigates inflammation, which could in turn influence the severity and progression of chronic respiratory disorders.

Endoplasmic reticulum-unfolded protein response signalling is altered in severe eosinophilic and neutrophilic asthma.

INTRODUCTION: The significance of endoplasmic reticulum (ER) stress in asthma is unclear. Here, we demonstrate that ER stress and the unfolded protein response (UPR) are related to disease severity and inflammatory phenotype. METHODS: Induced sputum (n=47), bronchial lavage (n=23) and endobronchial biopsies (n=40) were collected from participants with asthma with varying disease severity, inflammatory phenotypes and from healthy controls. Markers for ER stress and UPR were assessed. These markers were also assessed in established eosinophilic and neutrophilic murine models of asthma. RESULTS: Our results demonstrate increased ER stress and UPR pathways in asthma and these are related to clinical severity and inflammatory phenotypes. Genes associated with ER protein chaperone (BiP, CANX, CALR), ER-associated protein degradation (EDEM1, DERL1) and ER stress-induced apoptosis (DDIT3, PPP1R15A) were dysregulated in participants with asthma and are associated with impaired lung function (forced expiratory volume in 1 s) and active eosinophilic and neutrophilic inflammation. ER stress genes also displayed a significant correlation with classic Th2 (interleukin-4, IL-4/13) genes, Th17 (IL-17F/CXCL1) genes, proinflammatory (IL-1b, tumour necrosis factor α, IL-8) genes and inflammasome activation (NLRP3) in sputum from asthmatic participants. Mice with allergic airway disease (AAD) and severe steroid insensitive AAD also showed increased ER stress signalling in their lungs. CONCLUSION: Heightened ER stress is associated with severe eosinophilic and neutrophilic inflammation in asthma and may play a crucial role in the pathogenesis of asthma.

An altered sputum macrophage transcriptome contributes to the neutrophilic asthma endotype.

BACKGROUND: Neutrophilic asthma (NA) is a clinically important asthma phenotype, the cellular and molecular basis of which is not completely understood. Airway macrophages are long-lived immune cells that exert important homeostatic and inflammatory functions which are dysregulated in asthma. Unique transcriptomic programmes reflect varied macrophage phenotypes in vitro. We aimed to determine whether airway macrophages are transcriptomically altered in NA. METHODS: We performed RNASeq analysis on flow cytometry-isolated sputum macrophages comparing NA (n = 7) and non-neutrophilic asthma (NNA, n = 13). qPCR validation of RNASeq results was performed (NA n = 13, NNA n = 23). Pathway analysis (PANTHER, STRING) of differentially expressed genes (DEGs) was performed. Gene set variation analysis (GSVA) was used to test for enrichment of NA macrophage transcriptomic signatures in whole sputum microarray (cohort 1 - controls n = 16, NA n = 29, NNA n = 37; cohort 2 U-BIOPRED - controls n = 16, NA n = 47, NNA n = 57). RESULTS: Flow cytometry-sorting significantly enriched sputum macrophages (99.4% post-sort, 44.9% pre-sort, p < .05). RNASeq analysis confirmed macrophage purity and identified DEGs in NA macrophages. Selected DEGs (SLAMF7, DYSF, GPR183, CSF3, PI3, CCR7, all p < .05 NA vs. NNA) were confirmed by qPCR. Pathway analysis of NA macrophage DEGs was consistent with responses to bacteria, contribution to neutrophil recruitment and increased expression of phagocytosis and efferocytosis factors. GSVA demonstrated neutrophilic macrophage gene signatures were significantly enriched in whole sputum microarray in NA vs. NNA and controls in both cohorts. CONCLUSIONS: We demonstrate a pathophysiologically relevant sputum macrophage transcriptomic programme in NA. The finding that there is transcriptional activation of inflammatory programmes in cell types other than neutrophils supports the concept of NA as a specific endotype.

Differential cell counts using center-point networks achieves human-level accuracy and efficiency over segmentation.

Differential cell counts is a challenging task when applying computer vision algorithms to pathology. Existing approaches to train cell recognition require high availability of multi-class segmentation and/or bounding box annotations and suffer in performance when objects are tightly clustered. We present differential count network ("DCNet"), an annotation efficient modality that utilises keypoint detection to locate in brightfield images the centre points of cells (not nuclei) and their cell class. The single centre point annotation for DCNet lowered burden for experts to generate ground truth data by 77.1% compared to bounding box labeling. Yet centre point annotation still enabled high accuracy when training DCNet on a multi-class algorithm on whole cell features, matching human experts in all 5 object classes in average precision and outperforming humans in consistency. The efficacy and efficiency of the DCNet end-to-end system represents a significant progress toward an open source, fully computationally approach to differential cell count based diagnosis that can be adapted to any pathology need.

Transcriptomics of biopsies identifies novel genes and pathways linked to neutrophilic inflammation in severe asthma.

BACKGROUND: Severe asthma is a complex disease. Transcriptomic profiling has contributed to understanding the pathogenesis of asthma, especially type-2 inflammation. However, there is still poor understanding of non-type-2 asthma, and consequently, there are limited treatment options. OBJECTIVE: The aim of this study was to identify differentially expressed genes (DEGs) and pathways in endobronchial biopsies associated with inflammatory phenotypes of severe asthma. METHODS: This cross-sectional study examined endobronchial biopsies from 47 adults with severe asthma (neutrophilic asthma (NA) n = 9, eosinophilic asthma (EA) n = 22 and paucigranulocytic asthma (PGA) n = 16) and 13 healthy controls (HC). RNA was extracted and transcriptomic profiles generated (Illumina Humanref-12 V4) and analysed using GeneSpring GX14.9.1. Pathway identification using Ingenuity Pathway Analysis. RESULTS: NA had the most distinct profile, with signature of 60 top-ranked DEGs (FC >±2) including genes associated with innate immunity response, neutrophil degranulation and IL-10 signalling. NA presented enrichment to pathways previously linked to neutrophilic inflammation; dendritic cell maturation, Th1, TREM1, inflammasome, Th17 and p38 MAPK, as well as novel links to neuroinflammation, NFAT and PKCθ signalling. EA presented similar transcriptomic profiles to PGA and HC. Despite the higher proportion of bacterial colonization in NA, no changes were observed in the transcriptomic profiles of severe asthma culture positive compared with severe asthma culture negative. CONCLUSIONS & CLINICAL RELEVANCE: NA features a distinct transcriptomic profile with seven pathways enriched in NA compared to EA, PGA and HC. All those with severe asthma had significant enrichment for SUMOylation, basal cell carcinoma signalling and Wnt/ß-catenin pathways compared to HC, despite high-dose inhaled corticosteroids. These findings contribute to the understanding of mechanistic pathways in endobronchial biopsies associated with NA and identify potential novel treatment targets for severe asthma.

Airway monocyte modulation relates to tumour necrosis factor dysregulation in neutrophilic asthma.

BACKGROUND: Dysregulation of tumour necrosis factor-α (TNF-α) signalling is implicated in neutrophilic asthma. TNF-α signalling involves membrane-bound and soluble ligand (TNF-α) and receptors (TNFRs); however, little is known about how these proteins are altered in asthma. We hypothesised that intercompartment-, immune cell- and/or asthma inflammatory phenotype-dependent regulation could relate to TNF dysregulation in neutrophilic asthma. METHODS: Measurements were made in 45 adults with asthma (36 non-neutrophilic, 9 neutrophilic) and 8 non-asthma controls. Soluble TNF-α, TNF receptor 1 (TNFR1) and TNFR2 were quantified in plasma and sputum supernatant by ELISA, and membrane-bound TNF-α/TNFR1/TNFR2 measured on eosinophils, neutrophils, monocytes, and macrophages in blood and sputum by flow cytometry. Marker expression was compared between inflammatory phenotypes and compartments, and relationship of membrane-bound and soluble TNF markers and immune cell numbers tested by correlation. RESULTS: Soluble sputum TNFR1 and TNFR2 were increased in neutrophilic versus non-neutrophilic asthma (p=0.010 and p=0.029). Membrane-bound TNF-α expression was upregulated on sputum versus blood monocytes, while TNFR1 and TNFR2 levels were reduced on airway versus blood monocytes and neutrophils. Soluble TNFR1 and TNFR2 in sputum significantly correlated with the number of airway monocytes (p=0.016, r=0.358 and p=0.029, r=0.327). CONCLUSION: Our results imply that increased sputum soluble TNF receptor levels observed in neutrophilic asthma relate to the increased recruitment of monocytes and neutrophils into the airways and their subsequent receptor shedding. Monocytes also increase TNF-α ligand expression in the airways. These results suggest an important contribution of airway monocytes to the altered inflammatory milieu in neutrophilic asthma.

The influence of early-life microbial exposures on long-term respiratory health.

Host-microbiome interactions exert a profound influence on human physiology and health outcomes. In particular, certain characteristics of commensal microbiota during a critical period in early life are essential for the establishment of immune tone and metabolic control. An increasing body of evidence suggests that early life exposures that disrupt these interactions can substantially influence life-long risks for respiratory disease. Here, we explore how such early life exposures, including antibiotic exposure, maternal diet, preterm birth, mode of delivery, breastfeeding, and environmental variables shape the infant microbiome, and the mechanisms by such changes can in turn impact respiratory health.

Mepolizumab asthma treatment failure due to refractory airway eosinophilia, which responded to benralizumab.

Monoclonal antibodies directed against interleukin (IL)-5, such as mepolizumab and benralizumab, are an effective and established treatment for severe eosinophilic asthma. Here, we present a patient with eosinophilic asthma with a partial clinical response to mepolizumab initially, as measured by these biomarkers, who when investigated was found to have refractory airway eosinophilia. Escalation of the mepolizumab dose led to further but still only partial response. A treatment trial with benralizumab was more successful and led to suppression of airway eosinophilia. We review the literature, focusing on eosinophil biology at the tissues and the different mechanisms of action of the two agents.

Inhaled budesonide in the treatment of early COVID-19 (STOIC): a phase 2, open-label, randomised controlled trial.

BACKGROUND: Multiple early reports of patients admitted to hospital with COVID-19 showed that patients with chronic respiratory disease were significantly under-represented in these cohorts. We hypothesised that the widespread use of inhaled glucocorticoids among these patients was responsible for this finding, and tested if inhaled glucocorticoids would be an effective treatment for early COVID-19. METHODS: We performed an open-label, parallel-group, phase 2, randomised controlled trial (Steroids in COVID-19; STOIC) of inhaled budesonide, compared with usual care, in adults within 7 days of the onset of mild COVID-19 symptoms. The trial was done in the community in Oxfordshire, UK. Participants were randomly assigned to inhaled budsonide or usual care stratified for age (≤40 years or >40 years), sex (male or female), and number of comorbidities (≤1 and ≥2). Randomisation was done using random sequence generation in block randomisation in a 1:1 ratio. Budesonide dry powder was delivered using a turbohaler at a dose of 400 µg per actuation. Participants were asked to take two inhalations twice a day until symptom resolution. The primary endpoint was COVID-19-related urgent care visit, including emergency department assessment or hospitalisation, analysed for both the per-protocol and intention-to-treat (ITT) populations. The secondary outcomes were self-reported clinical recovery (symptom resolution), viral symptoms measured using the Common Cold Questionnare (CCQ) and the InFLUenza Patient Reported Outcome Questionnaire (FLUPro), body temperature, blood oxygen saturations, and SARS-CoV-2 viral load. The trial was stopped early after independent statistical review concluded that study outcome would not change with further participant enrolment. This trial is registered with ClinicalTrials.gov, NCT04416399. FINDINGS: From July 16 to Dec 9, 2020, 167 participants were recruited and assessed for eligibility. 21 did not meet eligibility criteria and were excluded. 146 participants were randomly assigned-73 to usual care and 73 to budesonide. For the per-protocol population (n=139), the primary outcome occurred in ten (14%) of 70 participants in the usual care group and one (1%) of 69 participants in the budesonide group (difference in proportions 0·131, 95% CI 0·043 to 0·218; p=0·004). For the ITT population, the primary outcome occurred in 11 (15%) participants in the usual care group and two (3%) participants in the budesonide group (difference in proportions 0·123, 95% CI 0·033 to 0·213; p=0·009). The number needed to treat with inhaled budesonide to reduce COVID-19 deterioration was eight. Clinical recovery was 1 day shorter in the budesonide group compared with the usual care group (median 7 days [95% CI 6 to 9] in the budesonide group vs 8 days [7 to 11] in the usual care group; log-rank test p=0·007). The mean proportion of days with a fever in the first 14 days was lower in the budesonide group (2%, SD 6) than the usual care group (8%, SD 18; Wilcoxon test p=0·051) and the proportion of participants with at least 1 day of fever was lower in the budesonide group when compared with the usual care group. As-needed antipyretic medication was required for fewer proportion of days in the budesonide group compared with the usual care group (27% [IQR 0-50] vs 50% [15-71]; p=0·025) Fewer participants randomly assigned to budesonide had persistent symptoms at days 14 and 28 compared with participants receiving usual care (difference in proportions 0·204, 95% CI 0·075 to 0·334; p=0·003). The mean total score change in the CCQ and FLUPro over 14 days was significantly better in the budesonide group compared with the usual care group (CCQ mean difference -0·12, 95% CI -0·21 to -0·02 [p=0·016]; FLUPro mean difference -0·10, 95% CI -0·21 to -0·00 [p=0·044]). Blood oxygen saturations and SARS-CoV-2 load, measured by cycle threshold, were not different between the groups. Budesonide was safe, with only five (7%) participants reporting self-limiting adverse events. INTERPRETATION: Early administration of inhaled budesonide reduced the likelihood of needing urgent medical care and reduced time to recovery after early COVID-19. FUNDING: National Institute for Health Research Biomedical Research Centre and AstraZeneca.

Hemopexin: A Novel Anti-inflammatory Marker for Distinguishing COPD From Asthma.

PURPOSE: Systemic inflammatory biomarkers can improve diagnosis and assessment of chronic obstructive pulmonary disease (COPD) and asthma. We aimed to validate an airway disease biomarker panel of 4 systemic inflammatory biomarkers, α2-macroglobulin, ceruloplasmin, haptoglobin and hemopexin, to establish their relationship to airway disease diagnosis and inflammatory phenotypes and to identify an optimized biomarker panel for disease differentiation. METHODS: Participants with COPD or asthma were classified by inflammatory phenotypes. Immunoassay methods were used to measure levels of validation biomarkers in the sera of participants with disease and non-respiratory disease controls. Markers were analyzed individually and in combination for disease differentiation and compared to established biomarkers (C-reactive protein, interleukin-6, and white blood cell/blood eosinophil count). RESULTS: The study population comprised of 141 COPD, 127 severe asthma, 54 mild-moderate asthma and 71 control participants. Significant differences in ceruloplasmin, haptoglobin and hemopexin levels between disease groups and between systemic inflammatory phenotypes were observed. However, no differences were found between airway inflammatory phenotypes. Hemopexin was the best performing individual biomarker and could diagnose COPD versus control participants (area under the curve [AUC], 98.3%; 95% confidence interval [CI], 96.7%-99.9%) and differentiate COPD from asthmatic participants (AUC, 97.0%; 95% CI, 95.4%-98.6%), outperforming established biomarkers. A biomarker panel, including hemopexin, haptoglobin and other established biomarkers, could diagnose asthma versus control participants (AUC, 87.5%; 95% CI, 82.8%-92.2%). CONCLUSIONS: Hemopexin can be a novel biomarker with superior diagnostic ability in differentiating COPD and asthma. We propose an anti-inflammatory axis between the airways and systemic circulation, in which hemopexin is a protective component in airway disease.

Neutrophils in asthma: the good, the bad and the bacteria.

Airway inflammation plays a key role in asthma pathogenesis but is heterogeneous in nature. There has been significant scientific discovery with regard to type 2-driven, eosinophil-dominated asthma, with effective therapies ranging from inhaled corticosteroids to novel biologics. However, studies suggest that approximately 1 in 5 adults with asthma have an increased proportion of neutrophils in their airways. These patients tend to be older, have potentially pathogenic airway bacteria and do not respond well to classical therapies. Currently, there are no specific therapeutic options for these patients, such as neutrophil-targeting biologics.Neutrophils comprise 70% of the total circulatory white cells and play a critical defence role during inflammatory and infective challenges. This makes them a problematic target for therapeutics. Furthermore, neutrophil functions change with age, with reduced microbial killing, increased reactive oxygen species release and reduced production of extracellular traps with advancing age. Therefore, different therapeutic strategies may be required for different age groups of patients.The pathogenesis of neutrophil-dominated airway inflammation in adults with asthma may reflect a counterproductive response to the defective neutrophil microbial killing seen with age, resulting in bystander damage to host airway cells and subsequent mucus hypersecretion and airway remodelling. However, in children with asthma, neutrophils are less associated with adverse features of disease, and it is possible that in children, neutrophils are less pathogenic.In this review, we explore the mechanisms of neutrophil recruitment, changes in cellular function across the life course and the implications this may have for asthma management now and in the future. We also describe the prevalence of neutrophilic asthma globally, with a focus on First Nations people of Australia, New Zealand and North America.

Neutrophil extracellular traps, disease severity, and antibiotic response in bronchiectasis: an international, observational, multicohort study.

BACKGROUND: Bronchiectasis is predominantly a neutrophilic inflammatory disease. There are no established therapies that directly target neutrophilic inflammation because little is understood of the underlying mechanisms leading to severe disease. Neutrophil extracellular trap (NET) formation is a method of host defence that has been implicated in multiple inflammatory diseases. We aimed to investigate the role of NETs in disease severity and treatment response in bronchiectasis. METHODS: In this observational study, we did a series of UK and international studies to investigate the role of NETs in disease severity and treatment response in bronchiectasis. First, we used liquid chromatography-tandem mass spectrometry to identify proteomic biomarkers associated with disease severity, defined using the bronchiectasis severity index, in patients with bronchiectasis (n=40) in Dundee, UK. Second, we validated these biomarkers in two cohorts of patients with bronchiectasis, the first comprising 175 patients from the TAYBRIDGE study in the UK and the second comprising 275 patients from the BRIDGE cohort study from centres in Italy, Spain, and UK, using an immunoassay to measure NETs. Third, we investigated whether pathogenic bacteria had a role in NET concentrations in patients with severe bronchiectasis. In a separate study, we enrolled patients with acute exacerbations of bronchiectasis (n=20) in Dundee, treated with intravenous antibiotics for 14 days and proteomics were used to identify proteins associated with treatment response. Findings from this cohort were validated in an independent cohort of patients who were admitted to the same hospital (n=20). Fourth, to assess the potential use of macrolides to reduce NETs in patients with bronchiectasis, we examined two studies of long-term macrolide treatment, one in patients with bronchiectasis (n=52 from the UK) in which patients were given 250 mg of azithromycin three times a week for a year, and a post-hoc analysis of the Australian AMAZES trial in patients with asthma (n=47) who were given 500 mg of azithromycin 3 times per week for a year. FINDINGS: Sputum proteomics identified that NET-associated proteins were the most abundant and were the proteins most strongly associated with disease severity. This finding was validated in two observational cohorts, in which sputum NETs were associated with bronchiectasis severity index, quality of life, future risk of hospital admission, and mortality. In a subgroup of 20 patients with acute exacerbations, clinical response to intravenous antibiotic treatment was associated with successfully reducing NETs in sputum. Patients with Pseudomonas aeruginosa infection had a lessened proteomic and clinical response to intravenous antibiotic treatment compared with those without Pseudomonas infections, but responded to macrolide therapy. Treatment with low dose azithromycin was associated with a significant reduction in NETs in sputum over 12 months in both bronchiectasis and asthma. INTERPRETATION: We identified NETs as a key marker of disease severity and treatment response in bronchiectasis. These data support the concept of targeting neutrophilic inflammation with existing and novel therapies. FUNDING: Scottish Government, British Lung Foundation, and European Multicentre Bronchiectasis Audit and Research Collaboration (EMBARC).

Sputum TNF markers are increased in neutrophilic and severe asthma and are reduced by azithromycin treatment.

BACKGROUND: The AMAZES randomized controlled trial demonstrated that long-term low-dose azithromycin treatment reduces exacerbations of poorly controlled asthma, but the therapeutic mechanisms remain unclear. Dysregulation of the inflammatory tumour necrosis factor (TNF) pathway is implicated in asthma and could be suppressed by azithromycin. We aimed to determine the inflammatory and clinical associations of soluble TNF signalling proteins (TNF receptors [TNFR] 1 and 2, TNF) in sputum and serum, and to test the effect of 48 weeks of azithromycin vs placebo on TNF markers. METHODS: Sputum supernatant and serum TNFR1, TNFR2 (n = 142; 75 azithromycin-treated, 67 placebo-treated) and TNF (n = 48; 22 azithromycin-treated, 26 placebo-treated) were measured by ELISA in an AMAZES trial sub-population at baseline and end of treatment. Baseline levels were compared between sputum inflammatory phenotypes, severe/non-severe asthma and frequent/non-frequent exacerbators. Effect of azithromycin on markers was tested using linear mixed models. RESULTS: Baseline sputum TNFR1 and TNFR2 were significantly increased in neutrophilic vs non-neutrophilic asthma phenotypes, while serum markers did not differ. Sputum TNFR1 and TNFR2 were increased in severe asthma and correlated with poorer lung function, worse asthma control and increasing age. Serum TNFR1 was also increased in severe asthma. Sputum and serum TNFR2 were increased in frequent exacerbators. Azithromycin treatment significantly reduced sputum TNFR2 and TNF relative to placebo, specifically in non-eosinophilic participants. CONCLUSIONS: We demonstrate dysregulation of TNF markers, particularly in the airways, that relates to clinically important phenotypes of asthma including neutrophilic and severe asthma. Suppression of dysregulated TNF signalling by azithromycin could contribute to its therapeutic mechanism.

Molecular markers of type 2 airway inflammation are similar between eosinophilic severe asthma and eosinophilic chronic obstructive pulmonary disease.

BACKGROUND: Airway and systemic eosinophilia are important treatable traits in both severe asthma and COPD. The molecular basis of eosinophilia in COPD is poorly understood but could involve type 2 cytokines (IL5, IL13) and prostaglandin D2 (PGD2 ). METHODS: This study included non-obstructive airways disease (OAD) controls (n = 19), a COPD cohort (n = 96) and a severe asthma cohort (n = 84). Demographics, exacerbation history, disease impact (SGRQ) and spirometry were assessed. Participants were categorized as eosinophilic using either sputum eosinophil proportion (≥3%) or blood eosinophil count (≥300/µL). Sputum type 2 inflammatory measures included PGD2 by ELISA and gene expression (qPCR) of IL5, IL13 and the haematopoietic PGD2 synthase (HPGDS). RESULTS: Type 2 markers did not differ across groups except HPGDS mRNA which was highest in non-OAD controls and lowest in COPD. IL5 and IL13 mRNA and PGD2 levels were significantly increased in eosinophilic vs non-eosinophilic severe asthma but did not differ between eosinophilic COPD and eosinophilic severe asthma or non-eosinophilic COPD. HPGDS expression was higher in eosinophilic severe asthma compared with eosinophilic COPD. Results were similar using sputum or blood eosinophil cut-offs. Sputum IL5 and IL13 were highly intercorrelated in severe asthma (r = 0.907, p < 0.001) and COPD (r = 0.824, p < 0.001), were moderately correlated with sputum eosinophils in severe asthma (IL5 r = 0.440, p < 0.001; IL13 r = 0.428, p < 0.001) and were weakly correlated in COPD (IL5 r = 0.245, p < 0.05; IL13 r = 0.317, p < 0.05). CONCLUSIONS: Molecular markers of type 2 airway inflammation do not differ between eosinophilic asthma and eosinophilic COPD; however, the relationship between eosinophilia and type 2 airway markers appears weaker in COPD than in severe asthma.

Add-on azithromycin reduces sputum cytokines in non-eosinophilic asthma: an AMAZES substudy.

Add-on azithromycin (AZM) significantly reduces exacerbations in poorly controlled asthma irrespective of disease phenotype. In a predefined substudy of the original AMAZES protocol (500 mg, three times a week for 48 weeks), we report that AZM treatment reduces key sputum inflammatory proteins (interleukin (IL)-6, IL-1ß and extracellular DNA), which is more evident in non-eosinophilic asthma (NEA). Moreover, AZM reduced Haemophilus influenzae load only in NEA. Our data support the anti-inflammatory effects of AZM in poorly controlled asthma. Prospective studies are required to identify patients that derive greatest benefit from AZM add-on therapy.

Outcomes of protracted bacterial bronchitis in children: A 5-year prospective cohort study.

BACKGROUND AND OBJECTIVE: Long-term data on children with PBB has been identified as a research priority. We describe the 5-year outcomes for children with PBB to ascertain the presence of chronic respiratory disease (bronchiectasis, recurrent PBB and asthma) and identify the risk factors for these. METHODS: Prospective cohort study was undertaken at the Queensland Children's Hospital, Brisbane, Australia, of 166 children with PBB and 28 controls (undergoing bronchoscopy for symptoms other than chronic wet cough). Monitoring was by monthly contact via research staff. Clinical review, spirometry and CT chest were performed as clinically indicated. RESULTS: A total of 194 children were included in the analysis. Median duration of follow-up was 59 months (IQR: 50-71 months) post-index PBB episode, 67.5% had ongoing symptoms and 9.6% had bronchiectasis. Significant predictors of bronchiectasis were recurrent PBB in year 1 of follow-up (ORadj = 9.6, 95% CI: 1.8-50.1) and the presence of Haemophilus influenzae in the BAL (ORadj = 5.1, 95% CI: 1.4-19.1). Clinician-diagnosed asthma at final follow-up was present in 27.1% of children with PBB. A significant BDR (FEV1 improvement >12%) was obtained in 63.5% of the children who underwent reversibility testing. Positive allergen-specific IgE (ORadj = 14.8, 95% CI: 2.2-100.8) at baseline and bronchomalacia (ORadj = 5.9, 95% CI: 1.2-29.7) were significant predictors of asthma diagnosis. Spirometry parameters were in the normal range. CONCLUSION: As a significant proportion of children with PBB have ongoing symptoms at 5 years, and outcomes include bronchiectasis and asthma, they should be carefully followed up clinically. Defining biomarkers, endotypes and mechanistic studies elucidating the different outcomes are now required.