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Netsanet A Negewo,1 Peter G Gibson,2– 4 Jodie L Simpson,1 Vanessa M McDonald,2– 5 Katherine J Baines1 1Immune Health Research Program, Hunter Medical Research Institute, New Lambton Heights, NSW, Australia; 2Centre of Excellence in Treatable Traits, University of Newcastle, New Lambton Heights, NSW, Australia; 3Department of Respiratory and Sleep Medicine, John Hunter Hospital, Newcastle, NSW, Australia; 4Asthma and Breathing Research Centre, Hunter Medical Research Centre, New Lambton Heights, NSW, Australia; 5School of Nursing and Midwifery, The University of Newcastle, Callaghan, NSW, AustraliaCorrespondence: Katherine J Baines, Hunter Medical Research Institute, Level 2 East Wing, Locked Bag 1000, New Lambton Heights, NSW, 2305, Australia, Tel +61 2 40420090, Fax +61 2 40420046, Email katherine.baines@newcastle.edu.auPurpose: 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.Keywords: COPD, gene expression, inflammation, sputum

Background and objective Low-dose long-term azithromycin is recommended in clinical practice guidelines for obstructive airway diseases (OADs), however, an optimal therapeutic regimen is not yet established. This study aimed to understand the patterns of azithromycin use in OADs, 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 250mg 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% versus 32%; p

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

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

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.

BACKGROUND Monocytes and macrophages are critical innate immune cells of the airways. Despite their differing functions, few clinical studies discriminate between them and little is known about their regulation in asthma. OBJECTIVE We aimed to distinguish and quantify macrophages, monocytes and monocyte subsets in induced sputum and blood and examine their relationship with inflammatory and clinical features of asthma. METHODS We applied flow cytometry to distinguish macrophages, monocytes and subsets in sputum and blood (n = 53; 45 asthma, 8 non-asthma) and a second asthma sputum cohort (n = 26). Monocyte subsets were identified by surface CD14/CD16 (CD14++ CD16- classical, CD14+ CD16+ intermediate and CD14+ CD16++ non-classical monocytes). Surface CD206, a marker of monocyte tissue differentiation, was measured in sputum. Relationship to airway inflammatory phenotype (neutrophilic n = 9, eosinophilic n = 14, paucigranulocytic n = 22) and asthma severity (severe n = 12, non-severe n = 33) was assessed. RESULTS Flow cytometry- and microscope-quantified sputum differential cell proportions were significantly correlated. Sputum macrophage number was reduced (p = .036), while classical monocyte proportion was increased in asthma vs non-asthma (p = .032). Sputum classical monocyte number was significantly higher in neutrophilic vs paucigranulocytic asthma (p = .013). CD206- monocyte proportion and number were increased in neutrophilic vs eosinophilic asthma (p

Background The 6 gene expression signature (6GS) predicts inflammatory phenotype, exacerbation risk, and corticosteroid responsiveness in asthma. In COPD, patterns of airway inflammation are similar, suggesting the 6GS may be useful. This study determines the diagnostic and prognostic ability of 6GS in predicting inflammatory phenotypes and exacerbation risk in COPD. Methods We performed 2 studies: a cross-sectional phenotype prediction study in stable COPD (total N=132; n=34 eosinophilic (E)-COPD, n=42 neutrophilic (N)-COPD, n=39 paucigranulocytic (PG)-COPD, n=17 mixed-granulocytic (MG)-COPD) that assessed 6GS ability to discriminate phenotypes (eosinophilia≥3%; neutrophilia≥61%); and a prospective cohort study (total n=54, n=8 E-COPD; n=18 N-COPD; n=20 PG-COPD; n=8 MG-COPD, n=21 exacerbation prone (≥2/year)) that investigated phenotype and exacerbation prediction utility. 6GS was measured by qPCR and evaluated using multiple logistic regression and area under the curve (AUC). Short-term reproducibility (intra-class correlation) and phenotyping method agreement (κ statistic) were assessed. Results In the phenotype prediction study, 6GS could accurately identify and discriminate patients with E-COPD from N-COPD (AUC=96.4%; p

Background Mast cells (MCs) are innate immune cells that regulate atopic and non-atopic inflammation in the airways. MCs play a critical role in the pathogenesis of asthma, yet their relationship to airway and systemic inflammation and clinical characteristics of asthma is poorly understood. Objective To quantify MCs in induced sputum samples and understand their relationship to airway and circulatory immune cells, and clinical variables in asthma. Methods We employed flow cytometry of sputum samples to quantify MCs, basophils and other immune cells in 51 participants (45 asthma and 6 non-asthma controls). Relationship of MCs to airway (n = 45) and blood (n = 19) immune cells, participant demographics, asthma history, spirometry and airways hyperresponsiveness (AHR) to hypertonic saline was determined by correlation and comparison of cut-off-based sputum MC high vs low participants. Results Mast cells, basophils and eosinophils were increased in asthma vs non-asthma control sputum. In asthma sputum, MCs, basophils and eosinophils were significantly intercorrelated, and MCs and basophils were elevated in participants with eosinophilic asthma. MCs and basophils, but not eosinophils, correlated with AHR. Sputum MC high asthma was characterized by an increased proportion of participants with uncontrolled asthma and reduced FEV1 and FVC. Trends towards similar clinical associations with elevated MCs were observed in a paucigranulocytic subpopulation (n = 15) lacking airway eosinophilia or neutrophilia. Receiver operator characteristic (ROC) analysis showed peripheral blood eosinophil (PBE) count predicted elevated sputum eosinophils and basophils, but not MCs. Conclusions and clinical relevance Sputum MCs are elevated in asthma, and their measurement may be useful as they relate to key clinical features of asthma (spirometry, asthma control, AHR). PBE count did not predict airway MC status, suggesting direct measurement of airway MCs by sensitive methods such as flow cytometry should be further developed.

Recently, a survey has been published on the opinions of UK and Europeans specialists regarding the use of biomarkers in asthma [1]. The results highlight that despite the growing body of research, and the wealth of targets in blood, sputum, tissue and breath, there has been little change in the application of biomarkers to clinical practice. While the virtues of precision medicine continue to be extolled, practically there has been little enthusiasm in real-world clinics. To investigate the factors behind this and whether this holds true outside Europe, we have mirrored the approach of Gallagher et al. [1] and conducted a Delphi survey of specialist physicians in Australia to gauge their opinions on the application of biomarkers in severe asthma (Figure 1)., Asthma specialists are interested in adopting biomarkers into clinical practice, but more work needs to be done to support resources towards their use and provide clearer direction on this. This concern is not limited to European specialists. https://bit.ly/2WWEQXb

BackgroundChronic 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.MethodsWe 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.ResultsWe 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-1β) 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.ConclusionsThese 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.

IntroductionBiomarkers are used to select biologic therapies for patients with severe asthma, but not to regularly adjust therapy, especially oral corticosteroids (OCS).ObjectiveOur 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 settingThis 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 outcomeThe coprimary outcomes were number of severe exacerbations and time to first severe exacerbation assessed over 12 months.ResultsThere 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.ConclusionA 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 numberThis trial was registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12616001015437).

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.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.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.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.Oxford National Institute of Health Research Biomedical Research Centre and AstraZeneca.

SummaryVaccinations against SARS-CoV-2 are effective in COVID-19. However, with limited vaccine access, vaccine hesitancy and variant breakthroughs, there is still a need for effective and safe early treatments. Two community-based clinical trials of the inhaled corticosteroid, budesonide, have recently been published showing and improvement in patients with COVID-19 treated early with budesonide1,2. To understand mechanistically how budesonide was beneficial, inflammatory mediators were assessed in the nasal mucosa of patients recruited to the Steroids in COVID (STOIC1) trial and a cohort of SARS-CoV-2 negative individuals. Here we show that in early COVID-19, elevation in viral response proteins and Th1 and Th2 inflammation occurs. Longitudinal sampling in the natural course of COVID-19 showed persistently high interferon levels and elevated concentrations of the eosinophil chemokine, CCL11. In patients who deteriorate, the initial nasal mucosal signal is characterised by a marked suppression of the early inflammatory response, with reduced concentrations of interferon and inflammatory cytokines, but elevated eosinophil chemokines. Systemic inflammation remained altered in COVID-19 patients, implying that even after symptom resolution, changes in immunological mediators do not resolve. Budesonide treatment decreased IL-33 and IFN-γ, implying a reduction in epithelial damage and dampening of the interferon response. Budesonide treatment also increased CCL17 concentrations, suggesting an improved T-cell response; and significantly alters inflammatory pathways giving further insight into how this treatment can accelerate patient recovery.Abstract Figure

Background: Multiple early hospital cohorts of coronavirus disease 2019 (COVID-19) showed that patients with chronic respiratory disease were significantly under-represented. We hypothesised that the widespread use of inhaled glucocorticoids was responsible for this finding and tested if inhaled glucorticoids would be an effective treatment for early COVID-19 illness. Methods: We conducted a randomised, open label trial of inhaled budesonide, compared to usual care, in adults within 7 days of the onset of mild Covid-19 symptoms. The primary end point was COVID-19-related urgent care visit, emergency department assessment or hospitalisation. The trial was stopped early after independent statistical review concluded that study outcome would not change with further participant enrolment. Results: 146 patients underwent randomisation. For the per protocol population (n=139), the primary outcome occurred in 10 participants and 1 participant in the usual care and budesonide arms respectively (difference in proportion 0.131, p=0.004). The number needed to treat with inhaled budesonide to reduce COVID-19 deterioration was 8. Clinical recovery was 1 day shorter in the budesonide arm compared to the usual care arm (median of 7 days versus 8 days respectively, logrank test p=0.007). Proportion of days with a fever and proportion of participants with at least 1 day of fever was lower in the budesonide arm. Fewer participants randomised to budesonide had persistent symptoms at day 14 and day 28 compared to participants receiving usual care. Conclusion: Early administration of inhaled budesonide reduced the likelihood of needing urgent medical care and reduced time to recovery following early COVID-19 infection. Trial Registration: ClinicalTrials.gov number, NCT04416399 Funding: Oxford NIHR Biomedical Research Centre and AstraZeneca Declaration of Interests: Dr. Ramakrishnan reports grants and non-financial support from Oxford Respiratory NIHR BRC, during the conduct of the study; non-financial support from AstraZeneca, personal fees from Australian Government Research Training Program, outside the submitted work; . Dr. Nicolau has nothing to disclose. Mrs Langford has nothing to disclose. Mr. Mahdi has nothing to disclose. Mrs Helen Jeffers reports personal fees from AstraZeneca, outside the submitted work; . Miss Mwasuku has nothing to disclose. Mrs Krassowska has nothing to disclose. Dr Fox has nothing to disclose. Dr Binnian has nothing to disclose. Dr Glover has nothing to disclose. Dr Bright has nothing to disclose. Dr. Butler reports grants from National Institute for Health Research (NIHR), Roche Molecular Diagnostics, Janssen Pharmaceuticals, and various public funding bodies for research related to diagnostics and infections. He has revcied personal fees from Pfizer INC, Roche Diagnostics, and Janssen Pharmaceuticals, outside the submitted work. Dr. Cane has nothing to disclose. Mr. Halner has nothing to disclose. Dr. Matthews has nothing to disclose. Dr. Donnelly reports grants from AstraZeneca, from Boehringer-Ingelheim, outside the submitted work; . Dr. Simpson has nothing to disclose. Dr Baker has nothing to disclose. Dr. Fadai has nothing to disclose. Dr. Peterson reports personal fees from AstraZeneca, outside the submitted work; . Mr. Bengtsson reports personal fees from AstraZeneca, outside the submitted work; Dr. Barnes reports grants and personal fees from AstraZeneca, grants and personal fees from Boehringer Ingelheim, personal fees from Teva, personal fees from Covis, during the conduct of the study; Dr. Russell reports grants from AstraZeneca, personal fees from Boehringer Ingelheim, personal fees from Chiesi UK, personal fees from Glaxo-SmithKline, during the conduct of the study; . Dr. Bafadhel reports grants from AstraZeneca, personal fees from AstraZeneca, Chiesi, GSK, other from Albus Health, ProAxsis, outside the submitted work; . Ethics Approval Statement: The trial was sponsored by the University of Oxford, and was approved by the Fulham London Research Ethics Committee (20/HRA/2531) and the National Health Research Authority.The ethical approval number is 20/HRA/2531.

Purpose To characterize neutrophils in obstructive airway disease by measuring their surface adhesion molecules and oxidative burst along with characterizing them into different subsets as per their adhesion molecule expression. Patients and methods Peripheral blood from adults with COPD (n=17), asthma (n=20), and healthy participants (n=19) was examined for expression of CD16, CD62L, CD11b, CD11c, and CD54, and analyzed by flow cytometry. For oxidative burst and CD62L shedding analysis, CD16 and CD62L stained leukocytes were loaded with Dihydrorhodamine-123 (DHR-123) and stimulated with N-Formylmethionine-leucyl-phenylalanine (fMLF). Neutrophil subsets were characterized based on CD16 and CD62L expression. Marker surface expression was recorded on CD16+ neutrophils as median fluorescence intensity (MFI). Results Neutrophil surface expression of CD62L was significantly reduced in COPD (median (IQR) MFI: 1156 (904, 1365)) compared with asthma (1865 (1157, 2408)) and healthy controls (2079 (1054, 2960)); p=0.028. COPD neutrophils also demonstrated a significant reduction in CD62L expression with and without fMLF stimulation. Asthma participants had a significantly increased proportion and number of CD62Lbright/CD16dim neutrophils (median: 5.4% and 0.14 × 109/L, respectively), in comparison with healthy (3.54% and 0.12 × 109/L, respectively); p Conclusion Reduced CD62L expression suggests blood neutrophils have undergone priming in COPD but not in asthma, which may be the result of systemic inflammation. The increased shedding of CD62L receptor by COPD blood neutrophils suggests a high sensitivity for activation.

COPD is a seriously disabling respiratory condition that inexorably progresses to disability and mortality. It affects approximately 10% of the population globally with a greater prevalence at advanced ages. Airway bacterial infections complicate the disease course in most COPD patients, leading to increased symptoms, more rapid decline in lung function, acute exacerbations and reduced quality of life. With increasing bacterial resistance to antibiotics and adverse effects of conventional treatments, new effective non-antibiotic antimicrobial therapies are urgently needed to manage COPD. Hypoxia-inducible factor (HIF)-1α is an important transcriptional regulator of cellular responses to hypoxia, oxidants and inflammation, and is overexpressed in the lungs of COPD patients. Recent evidence shows that increased HIF-1α expression can upregulate the platelet-activating factor receptor (PAFR) on the airway epithelial surface that is increased in smokers and particularly COPD patients. The receptor is utilized by PAFR-dependent bacteria (Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa) to induce infection in both the respiratory and gastrointestinal (GI) tracts. However, the importance and mechanism of HIF-1α in augmenting PAFR-dependent bacterial infections in COPD are poorly understood. Here, we review the evidence for the roles of local tissue hypoxia-induced inflammation, HIF-1α and PAFR in facilitating bacterial infections in COPD. Blocking PAFR may provide a novel antimicrobial approach to manage bacterial infections in COPD.

Rationale: The macrolide antibiotic azithromycin reduces exacerbations in adults with persistent symptomatic asthma. However, owing to the pleotropic properties of macrolides, unintended bacteriological consequences such as augmented pathogen colonization or dissemination of antibiotic-resistant organisms can occur, calling into question the long-term safety of azithromycin maintenance therapy.Objectives: To assess the effects of azithromycin on the airway microbiota, pathogen abundance, and carriage of antibiotic resistance genes.Methods: 16S rRNA sequencing and quantitative PCR were performed to assess the effect of azithromycin on sputum microbiology from participants of the AMAZES (Asthma and Macrolides: The Azithromycin Efficacy and Safety) trial: a 48-week, double-blind, placebo-controlled trial of thrice-weekly 500 mg oral azithromycin in adults with persistent uncontrolled asthma. Pooled-template shotgun metagenomic sequencing, quantitative PCR, and isolate whole-genome sequencing were performed to assess antibiotic resistance.Measurements and Main Results: Paired sputum samples were available from 61 patients (n = 34 placebo, n = 27 azithromycin). Azithromycin did not affect bacterial load (P = 0.37) but did significantly decrease Faith's phylogenetic diversity (P = 0.026) and Haemophilus influenzae load (P < 0.0001). Azithromycin did not significantly affect levels of Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, or Moraxella catarrhalis. Of the 89 antibiotic resistance genes detected, five macrolide resistance genes and two tetracycline resistance genes were increased significantly.Conclusions: In patients with persistent uncontrolled asthma, azithromycin reduced airway H. influenzae load compared with placebo but did not change total bacterial load. Macrolide resistance increased, reflecting previous studies. These results highlight the need for studies assessing the efficacy of nonantibiotic macrolides as a long-term therapy for patients with persistent uncontrolled asthma.

Background Both obesity and high dietary fat intake activate the nucleotide oligomerization domain–like receptor protein 3 (NLRP3) inflammasome. Objective We aimed to examine NLRP3 inflammasome activity in the airways of obese asthmatic patients after macronutrient overload and in immune cells challenged by inflammasome triggers. Methods Study 1 was a cross-sectional observational study of nonobese (n = 51) and obese (n = 76) asthmatic adults. Study 2 was a randomized, crossover, acute feeding study in 23 asthmatic adults (n = 12 nonobese and n = 11 obese subjects). Subjects consumed 3 isocaloric meals on 3 separate occasions (ie, saturated fatty acid, n-6 polyunsaturated fatty acid, and carbohydrate) and were assessed at 0 and 4 hours. For Studies 1 and 2, airway inflammation was measured based on sputum differential cell counts, IL-1β protein levels (ELISA), and sputum cell gene expression (Nanostring nCounter). In Study 3 peripheral blood neutrophils and monocytes were isolated by using Ficoll density gradient and magnetic bead separation and incubated with or without palmitic acid, LPS, or TNF-α for 24 hours, and IL-1β release was measured (ELISA). Results In Study 1 NLRP3 and nucleotide oligomerization domain 1 (NOD1) gene expression was upregulated, and sputum IL-1β protein levels were greater in obese versus nonobese asthmatic patients. In Study 2 the saturated fatty acid meal led to increases in sputum neutrophil percentages and sputum cell gene expression of Toll-like receptor 4 (TLR4) and NLRP3 at 4 hours in nonobese asthmatic patients. In Study 3 neutrophils and monocytes released IL-1β when challenged with a combination of palmitic acid and LPS or TNF-α. Conclusion The NLRP3 inflammasome is a potential therapeutic target in asthmatic patients. Behavioral interventions that reduce fatty acid exposure, such as weight loss and dietary saturated fat restriction, warrant further exploration.

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 to 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 colonisation 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/β-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.

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., 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, although with refractory airway eosinophilia, who did not fully respond to dose escalation. A treatment trial with benralizumab was more successful and led to suppression of airway eosinophilia.

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.

Summary 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.

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.

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., Monocytes modify the inflammatory milieu in neutrophilic asthma. Blood and sputum analysis reveal TNF pathway dysregulation relating to altered TNF-α ligand and receptor expression by monocytes and their increased airway recruitment in neutrophilic asthma. https://bit.ly/3onJ1s7

BackgroundMultiple early hospital cohorts of coronavirus disease 2019 (COVID-19) showed that patients with chronic respiratory disease were significantly under-represented. We hypothesised that the widespread use of inhaled glucocorticoids was responsible for this finding and tested if inhaled glucorticoids would be an effective treatment for early COVID-19 illness.MethodsWe conducted a randomised, open label trial of inhaled budesonide, compared to usual care, in adults within 7 days of the onset of mild Covid-19 symptoms. The primary end point was COVID-19-related urgent care visit, emergency department assessment or hospitalisation. The trial was stopped early after independent statistical review concluded that study outcome would not change with further participant enrolment.Results146 patients underwent randomisation. For the per protocol population (n=139), the primary outcome occurred in 10 participants and 1 participant in the usual care and budesonide arms respectively (difference in proportion 0.131, p=0.004). The number needed to treat with inhaled budesonide to reduce COVID-19 deterioration was 8. Clinical recovery was 1 day shorter in the budesonide arm compared to the usual care arm (median of 7 days versus 8 days respectively, logrank test p=0.007). Proportion of days with a fever and proportion of participants with at least 1 day of fever was lower in the budesonide arm. Fewer participants randomised to budesonide had persistent symptoms at day 14 and day 28 compared to participants receiving usual care.ConclusionEarly administration of inhaled budesonide reduced the likelihood of needing urgent medical care and reduced time to recovery following early COVID-19 infection.(Funded by Oxford NIHR Biomedical Research Centre and AstraZeneca;ClinicalTrials.govnumber,NCT04416399)Research in contextEvidence before this studyThe majority of interventions studied for the COVID-19 pandemic are focused on hospitalised patients. Widely available and broadly relevant interventions for mild COVID-19 are urgently needed.Added value of this studyIn this open label randomised controlled trial, inhaled budesonide, when given to adults with early COVID-19 illness, reduces the likelihood of requiring urgent care, emergency department consultation or hospitalisation. There was also a quicker resolution of fever, a known poor prognostic marker in COVID-19 and a faster self-reported and questionnaire reported symptom resolution. There were fewer participants with persistent COVID-19 symptoms at 14 and 28 days after budesonide therapy compared to usual care.Implications of all the available evidenceThe STOIC trial potentially provides the first easily accessible effective intervention in early COVID-19. By assessing health care resource utilisation, the study provides an exciting option to help with the worldwide pressure on health care systems due to the COVID-19 pandemic. Data from this study also suggests a potentially effective treatment to prevent the long term morbidity from persistent COVID-19 symptoms.

Introduction Asthma is a common, chronic lung disease marked by reversible airflow obstruction driven by inflammation. There is increasing evidence for a neutrophil-dominant inflammatory endotype1 with clear mechanistic potential for neutrophil elastase (NE) to cause clinical manifestations of disease. However, the relationship between neutrophil proteinases and asthma pathophysiology remains uncertain. We hypothesised that patients with a neutrophilic-endotype would have increased NE activity compared to other asthma endotypes and healthy smokers. Methods Patients with respiratory physician-confirmed asthma diagnosis were recruited. Controls without asthma were age-matched with normal lung function and no symptoms suggestive of asthma/alternative respiratory disease Asthma patients were divided into endotypes by analysis of sputum cellular composition as previously described.1 NE activity was measured in plasma using an ELISA based on specific fibrinogen-cleavage product Aα–Val360.2 Results Forty-five asthma patients (Mean (SD): age 60.6 years (10.3); 40% male) and 45 controls (age 60.2 years (10.1); 51% male) were recruited. Asthma patients had evidence of airflow obstruction (mean (SD): FEV1/FVC% predicted asthma 64.3 (11.7) versus controls 77.5 (6.3), p When considered together, patients with asthma had a significantly higher NE activity footprint than controls (mean (SD): asthma 12.7 nM (5.7), control 9.4 nM (3.1), p=0.0011) When divided into phenotypes, patients with neutrophil-dominant asthma (n=15) had increased activity footprint compared to a specifically age-matched sub-group of controls (n=15, Mean (SD): asthma 15.0 nM (5.9), control 8.9 nM (2.9), p=0.0034). There were no differences between the NE activity footprint comparing patients with eosinophilic (n=11, 11.4 nM (5.5) p>0.9999) or paucigranulocytic (n=14, 10.3 nM (5.4) p>0.9999) endotypes to controls. In neutrophilic asthma, there was no correlation between NE activity and neutrophils in sputum (%) (R2=0.02677, p=0.5601), age (R2=0.08626, p=0.2880), FEV1/FVC% (R2=0.04410, p=0.4911), or smoking exposure (R2=0.5515, p=0.4766). Conclusions These findings suggest that there is a differing systemic proteolytic enzyme activity in neutrophil–dominant asthma patients compared to controls and between neutrophilic asthma and paucigranulocytic asthma, which may influence disease pathophysiology. References Simpson JL, et al. ERJ 2014. Carter RI, et al. Thorax 2015.

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.

Introduction: Biomarkers are used to select patients for therapy in severe asthma, but not to regularly adjust therapy, especially oral corticosteroids (OCS). Our goal was to test the efficacy of an algorithm to guide the titration of OCS in adults with severe asthma using blood eosinophil count and fraction of exhaled nitric oxide levels (FeNO). Methods: This proof-of-concept randomized controlled trial assigned severe asthma participants (n=32) to an inflammation arm; where OCS dose was adjusted based on blood eosinophil count and FeNO, or a best-practice clinical care arm. The primary outcome was number of severe exacerbations and time to first severe exacerbation assessed over 12 months. Results: The relative risk of a severe exacerbation in the inflammation versus control arms was 0.88 (Adj.; 95%CI:0.47, 1.62; p=0.675) with a mean exacerbation rate per year of 2.5 and 3.5, respectively. There was a trend toward a longer median time to first severe exacerbation in the inflammation arm (73 vs. 32 days, Adj. HR:0.714; 95%CI:0.25, 2.06; p=0.533). The odds ratio of an emergency department (ED) or hospital admission in the inflammation management arm was 0.177 (Adj; 95%CI: 0.023, 1.361; p=0.0961). There was no significant difference in mean OCS dose used over the course of the study between the two groups, with both groups decreasing their doses by 0.1mg/day/visit. Conclusion: A treatment algorithm to adjust oral corticosteroids using blood eosinophil count and FeNO is feasible in a clinical setting and resulted in a longer time to exacerbation and reduced odds of a hospital admission or ED visit. This warrants further study to optimize the use of oral corticosteroids in the future.

Sputum mast cells associate with clinical and inflammatory features of asthma: Despite their known pathogenic role, the relationship of mast cells (MCs) to inflammatory and clinical features of asthma is poorly understood. We aimed to quantify sputum MCs and examine their relationship to airway and circulatory immune cells and clinical variables in asthma. We conducted flow cytometric analysis of induced sputum to quantify MCs, basophils and other immune cells (n=45 asthma, n=6 non-asthma). Relationship of MCs to sputum and blood (n=19) immune cells in asthma, participant demographics, asthma history, spirometry and dose response slope (DRS) to hypertonic saline was determined. Eosinophilic asthma (EA) was defined by ≥3% sputum eosinophils. Sputum MCs, basophils and eosinophils were significantly intercorrelated and increased in asthma vs non-asthma. MCs and basophils were elevated in EA. MCs and basophils, but not eosinophils, correlated with DRS. Cutoff-based comparison of MC high vs low asthma showed more uncontrolled asthma and reduced FEV1 and FVC in MC high asthma. Similar clinical associations with MC high status were observed in a subpopulation (n = 15) lacking airway eosinophilia or neutrophilia. ROC analysis showed peripheral blood eosinophil (PBE) count predicted elevated sputum eosinophils (AUC=86.7%, P=0.02) or basophils (AUC=82.8%, P=0.016), but not MCs (AUC=52.4%, P=0.87). Sputum MCs are elevated in asthma and they relate to key clinical features of asthma (asthma control, DRS, spirometry). Discord between MCs and PBE suggests MCs are regulated by discrete mechanisms to eosinophils. The clinical significance of elevated MCs in a subset of non-eosinophilic asthma merits further investigation.

Background Severe asthma is a complex heterogeneous disease typically requiring advanced therapies. Underlying the treatment of all asthma, however, is the consistent recommendation across international guidelines to ensure that adherence to therapy is adequate. Currently, there is no consensus on an objective marker of adherence. Methods We performed a prospective observational study of 17 participants taking oral prednisolone using serum prednisolone levels as a marker of adherence, and sputum eosinophilia as a marker of control of type 2 airway inflammation. Based on these biomarkers, we classified participants into a non-adherent and an adherent cohort, and further stratified by the presence of ongoing sputum eosinophilia. Results We identified 3 non-adherent participants and 14 who were adherent, based on their serum prednisolone levels. Stratification using sputum eosinophil counts identified one participant as having ongoing sputum eosinophilia in the setting of non-adherence, while six were identified as steroid resistant with ongoing sputum eosinophilia despite adherence to oral prednisolone therapy. Conclusion Serum prednisolone can be used an objective marker of adherence in those patients with severe asthma taking daily oral prednisolone. In combination with sputum eosinophil counts, a steroid resistant cohort can be distinguished from one with ongoing inflammation in the setting of non-adherence. This information can then be used by clinicians to differentiate the optimal next steps for treatment in these specific populations. Trial registration Participants were recruited as part of the Markers of Inflammation in the Management of Severe Asthma (MIMOSA) study, trial registration ACTRN12616001015437, 02 August 2016.