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RATIONALE The alarmins IL-33 and HMGB1 (high mobility group box 1) contribute to type-2 inflammation and asthma pathogenesis. OBJECTIVES To determine whether P2Y13 receptor (P2Y13-R), a purinergic G protein-coupled receptor (GPCR) and risk allele for asthma, regulates the release of IL-33 and HMGB1. METHODS Bronchial biopsies were obtained from healthy and asthmatic subjects. Primary human airway epithelial cells (AECs), primary mouse (m)AECs, or C57Bl/6 mice were inoculated with various aeroallergens or respiratory viruses, and the nuclear-to-cytoplasmic translocation and release of alarmins measured by immunohistochemistry and ELISA. The role of P2Y13-R in AEC function and in the onset, progression, and an exacerbation of experimental asthma, was assessed using pharmacological antagonists and P2Y13-R gene-deleted mice. MEASUREMENTS AND MAIN RESULTS Aeroallergen-exposure induced the extracellular release of ADP and ATP, nucleotides that activate P2Y13-R. ATP, ADP, aeroallergen (house dust mite, cockroach or Alternaria) or virus exposure induced the nuclear-to-cytoplasmic translocation and subsequent release of IL-33 and HMGB1, and this response was ablated by genetic deletion or pharmacological antagonism of P2Y13. In mice, prophylactic or therapeutic P2Y13-R blockade attenuated asthma onset, and critically, ablated the severity of a rhinovirus-associated exacerbation in a high-fidelity experimental model of chronic asthma. Moreover, P2Y13-R antagonism derepressed antiviral immunity, increasing IFN-λ production and decreasing viral copies in the lung. CONCLUSIONS We identify P2Y13-R as a novel gatekeeper of the nuclear alarmins IL-33 and HMGB1, and demonstrate that the targeting of this GPCR via genetic deletion or treatment with a small-molecule antagonist protects against the onset and exacerbations of experimental asthma.

Rationale: Non–cystic fibrosis bronchiectasis is characterized by airway mucus accumulation and sputum production, but the role of mucus concentration in the pathogenesis of these abnormalities has not been characterized. Objectives: This study was designed to: 1) measure mucus concentration and biophysical properties of bronchiectasis mucus; 2) identify the secreted mucins contained in bronchiectasis mucus; 3) relate mucus properties to airway epithelial mucin RNA/protein expression; and 4) explore relationships between mucus hyperconcentration and disease severity. Methods: Sputum samples were collected from subjects with bronchiectasis, with and without chronic erythromycin administration, and healthy control subjects. Sputum percent solid concentrations, total and individual mucin concentrations, osmotic pressures, rheological properties, and inflammatory mediators were measured. Intracellular mucins were measured in endobronchial biopsies by immunohistochemistry and gene expression. MUC5B (mucin 5B) polymorphisms were identified by quantitative PCR. In a replication bronchiectasis cohort, spontaneously expectorated and hypertonic saline-induced sputa were collected, and mucus/mucin concentrations were measured. Measurements and Main Results: Bronchiectasis sputum exhibited increased percent solids, total and individual (MUC5B and MUC5AC) mucin concentrations, osmotic pressure, and elastic and viscous moduli compared with healthy sputum. Within subjects with bronchiectasis, sputum percent solids correlated inversely with FEV(1) and positively with bronchiectasis extent, as measured by high-resolution computed tomography, and inflammatory mediators. No difference was detected in MUC5B rs35705950 SNP allele frequency between bronchiectasis and healthy individuals. Hypertonic saline inhalation acutely reduced non–cystic fibrosis bronchiectasis mucus concentration by 5%. Conclusions: Hyperconcentrated airway mucus is characteristic of subjects with bronchiectasis, likely contributes to disease pathophysiology, and may be a target for pharmacotherapy.

Background: Bronchiectasis (BE) guidelines recommend long term macrolide treatment for patients with ≥3 exacerbations/year without P aeruginosa infection. Randomized controlled trials (RCTs) suggest that long term macrolide treatment can prevent exacerbations in adult patients with BE but these studies have been too small to conduct meaningful subgroup analyses. Aims: To explore macrolide benefit in subpopulations, including those where macrolide therapy is not currently recommended, using individual patient data (IPD) meta-analysis. Methods: MEDLINE, Embase, the Cochrane Central Register of Controlled Trials and Web of Science were searched to identify RCT’s of macrolide antibiotics for at least 3 months with a primary outcome of BE exacerbations. IPD meta-analysis was performed using fixed effects models adjusting for age, sex, FEV1 and trial. Results: IPD was obtained for 341 participants in 3 RCTs. Macrolides reduced the frequency of exacerbations adjusted incidence rate ratio (IRR) 0.49 95% CI 0.36-0.66,p Conclusions: Long-term macrolide treatment significantly reduces the rate of exacerbations in patients with BE with similar benefits observed in all subgroups based on patient characteristics.

Background: Bronchiectasis guidelines recommend long-term macrolide treatment for patients with three or more exacerbations per year without Pseudomonas aeruginosa infection. Randomised controlled trials suggest that long-term macrolide treatment can prevent exacerbations in adult patients with bronchiectasis, but these individual studies have been too small to do meaningful subgroup analyses. We did a systematic review and individual patient data (IPD) meta-analysis to explore macrolide benefit in subpopulations, including those in which macrolide therapy is not currently recommended. Methods: We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science from Jan 1, 2000, to Sept 30, 2018, to identify double blind, randomised, placebo-controlled trials of macrolide antibiotics in adult patients with bronchiectasis. We applied no language restrictions. Randomised controlled trials were eligible if treatment was defined a priori as long term and had a primary or secondary outcome of bronchiectasis exacerbations. Studies in patients with cystic fibrosis bronchiectasis were excluded. The primary outcome of the meta-analysis was frequency of exacerbations requiring treatment with antibiotics. Secondary endpoints were time to first exacerbation, change in quality of life according to the St George's Respiratory Questionnaire (SGRQ), and change in FEV1. IPD meta-analysis was done using fixed effects models adjusting for age, sex, FEV1, and trial. We did prespecified subgroup analyses for each of the primary and secondary endpoints using one-step meta-analysis only. Subgroups were defined by age, sex, previous exacerbation frequency, smoking status, inhaled corticosteroid use at baseline, body-mass index at baseline, cause, C-reactive protein at baseline, baseline FEV1 percentage of predicted, SGRQ total score, and Pseudomonas aeruginosa in sputum culture at baseline. The meta-analysis is registered with the PROSPERO international register of systematic reviews, number CRD42018102908. Findings: Of 234 identified studies, we included three randomised controlled trials, and IPD was obtained for 341 participants. Macrolide antibiotics reduced the frequency of exacerbations (adjusted incidence rate ratio [IRR] 0·49, 95% CI 0·36 to 0·66; p

Summary Background Long-term macrolide treatment has proven benefit in inflammatory airways diseases, but whether it leads to changes in the composition of respiratory microbiota is unknown. We aimed to assess whether long-term, low-dose erythromycin treatment changes the composition of respiratory microbiota in people with non-cystic fibrosis bronchiectasis. Methods Microbiota composition was determined by 16S rRNA gene sequencing of sputum samples from participants in the BLESS trial, a 12-month, double-blind, placebo-controlled trial of twice-daily erythromycin ethylsuccinate (400 mg) in adult patients with non-cystic fibrosis bronchiectasis and at least two infective exacerbations in the preceding year. The primary outcome was within-patient change in respiratory microbiota composition (assessed by Bray-Curtis index) between baseline and week 48, comparing erythromycin with placebo. The BLESS trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12608000460303. Findings The BLESS trial took place between Oct 15, 2008, and Dec 14, 2011. Paired sputum samples were available from 86 randomly assigned patients, 42 in the placebo group and 44 in the erythromycin group. The change in microbiota composition between baseline and week 48 was significantly greater with erythromycin than with placebo (median Bray-Curtis score 0·52 [IQR 0·14–0·78] vs 0·68 [0·46–0·93]; median difference 0·16, 95% CI 0·01–0·33; p=0·03). In patients with baseline airway infection dominated by Pseudomonas aeruginosa , erythromycin did not change microbiota composition significantly. In those with infection dominated by organisms other than P aeruginosa , erythromycin caused a significant change in microbiota composition (p=0·03 [by analysis of similarity]), representing a reduced relative abundance of Haemophilus influenzae (35·3% [5·5–91·6] vs 6·7% [0·8–74·8]; median difference 12·6%, 95% CI 0·4–28·3; p=0·04; interaction p=0·02) and an increased relative abundance of P aeruginosa (0·02% [0·00–0·33] vs 0·13% [0·01–39·58]; median difference 6·6%, 95% CI 0·1–37·1; p=0·002; interaction p=0·45). Compared with placebo, erythromycin reduced the rate of pulmonary exacerbations over the 48 weeks of the study in patients with P aeruginosa -dominated infection (median 1 [IQR 0–3] vs 3 [2–5]; median difference −2, 95% CI −4 to –1; p=0·01), but not in those without P aeruginosa -dominated infection (1 [0–2] vs 1 [0–3]; median difference 0, –1 to 0; p=0·41; interaction p=0·04). Interpretation Long-term erythromycin treatment changes the composition of respiratory microbiota in patients with bronchiectasis. In patients without P aeruginosa airway infection, erythromycin did not significantly reduce exacerbations and promoted displacement of H influenzae by more macrolide-tolerant pathogens including P aeruginosa . These findings argue for a cautious approach to chronic macrolide use in patients without P aeruginosa airway infection. Funding Mater Adult Respiratory Research Trust Fund.

Rationale Despite the potentially important roles for infection in adult non-cystic fibrosis (CF) bronchiectasis disease progression, the bacterial species present in the lower airways of these patients is poorly characterised. Objectives To provide a comprehensive cross-sectional analysis of bacterial content of lower airway samples from patients with non-CF bronchiectasis using culture-independent microbiology. Methods Paired induced sputum and bronchoalveolar lavage samples, obtained from 41 adult patients with non-CF bronchiectasis, were analysed by 16S ribosomal RNA gene pyrosequencing. Assessment of species distribution and dispersal allowed ‘core’ and ‘satellite’ bacterial populations to be defined for this patient group. Microbiota characteristics correlated with clinical markers of disease. Measurement and main results 140 bacterial species were identified, including those associated with respiratory tract infections and opportunistic infections more generally. A group of core species, consisting of species detected frequently and in high abundance, was defined. Core species included those currently associated with infection in bronchiectasis, such as Pseudomonas aeruginosa , Haemophilus influenzae and Streptococcus pneumoniae , and many species that would be unlikely to be reported through standard diagnostic surveillance. These included members of the genera Veillonella , Prevotella and Neisseria . The comparative contribution of core and satellite groups suggested a low level of random species acquisition. Bacterial diversity was significantly positively correlated with forced expiratory volume in 1 s (FEV 1 ) and bacterial community composition similarity correlated significantly with FEV 1 , neutrophil count and Leicester cough score. Conclusions Characteristics of the lower airways microbiota of adult patients with non-CF bronchiectasis correlate significantly with clinical markers of disease severity.

Background Non-cystic fibrosis (CF) bronchiectasis is characterised by chronic airway infection and neutrophilic inflammation, which we hypothesised would be associated with Th17 pathway activation. Methods Th17 pathway cytokines were quantified in bronchoalveolar lavage fluid (BALF), and gene expression of IL-17A, IL-1β, IL-8 and IL-23 determined from endobronchial biopsies (EBx) in 41 stable bronchiectasis subjects and 20 healthy controls. Relationships between IL-17A levels and infection status, important clinical measures and subsequent Pseudomonas aeruginosa infection were determined. Results BALF levels of all Th17 cytokines (median (IQR) pg/mL) were significantly higher in bronchiectasis than control subjects, including IL-17A (1.73 (1.19, 3.23) vs. 0.27 (0.24, 0.35), 95% CI 1.05 to 2.21, p

Cystic fibrosis (CF) lung pathology is characterized by excessive neutrophilic inflammation and high tumor necrosis factor-alpha (TNF-α) levels. A cornerstone of CF management is reduction of the inflammatory burden in the lung. We present the case of a 19-year-old CF patient who demonstrated significant clinical improvement in her lung disease associated with a reduction in sputum percent neutrophils, following commencement of etanercept (TNF-α antagonist) for rheumatoid arthritis. She has not had any infectious complications or other significant adverse effects during 2 years of treatment. It may be time to reconsider TNF-α antagonists as potential anti-inflammatory agents for CF lung disease.

Importance Macrolide antibiotics such as erythromycin may improve clinical outcomes in non–cystic fibrosis (CF) bronchiectasis, although associated risks of macrolide resistance are poorly defined. Objective To evaluate the clinical efficacy and antimicrobial resistance cost of low-dose erythromycin given for 12 months to patients with non-CF bronchiectasis with a history of frequent pulmonary exacerbations. Design, Setting, and Participants Twelve-month, randomized (1:1), double-blind, placebo-controlled trial of erythromycin in currently nonsmoking, adult patients with non-CF bronchiectasis with a history of 2 or more infective exacerbations in the preceding year. This Australian study was undertaken between October 2008 and December 2011 in a university teaching hospital, with participants also recruited via respiratory physicians at other centers and from public radio advertisements. Interventions Twice-daily erythromycin ethylsuccinate (400 mg) or matching placebo. Main Outcome Measures The primary outcome was the annualized mean rate of protocol-defined pulmonary exacerbations (PDPEs) per patient. Secondary outcomes included macrolide resistance in commensal oropharyngeal streptococci and lung function. Results Six-hundred seventy-nine patients were screened, 117 were randomized (58 placebo, 59 erythromycin), and 107 (91.5%) completed the study. Erythromycin significantly reduced PDPEs both overall (mean, 1.29 [95% CI, 0.93-1.65] vs 1.97 [95% CI, 1.45-2.48] per patient per year; incidence rate ratio [IRR], 0.57 [95% CI, 0.42-0.77]; P = .003), and in the prespecified subgroup with baseline Pseudomonas aeruginosa airway infection (mean difference, 1.32 [95% CI, 0.19-2.46]; P = .02). Erythromycin reduced 24-hour sputum production (median difference, 4.3 g [interquartile range [IQR], 1 to 7.8], P = .01) and attenuated lung function decline (mean absolute difference for change in postbronchodilator forced expiratory volume in the first second of expiration, 2.2 percent predicted [95% CI, 0.1% to 4.3%]; P = .04) compared with placebo. Erythromycin increased the proportion of macrolide-resistant oropharyngeal streptococci (median change, 27.7% [IQR, 0.04% to 41.1%] vs 0.04% [IQR, −1.6% to 1.5%]; difference, 25.5% [IQR,15.0% to 33.7%]; P Conclusion and Relevance Among patients with non-CF bronchiectasis, the 12-month use of erythromycin compared with placebo resulted in a modest decrease in the rate of pulmonary exacerbations and an increased rate of macrolide resistance. Trial Registration anzctr.org.au Identifier: ACTRN12609000578202

Background: Macrolide antibiotics are increasingly prescribed for subjects with non-cystic fibrosis (CF) bronchiectasis, an empiric extension of their proven efficacy in CF. Widespread, injudicious use of long-acting macrolides, particularly azithromycin, risks significantly increasing population antimicrobial resistance. Methods: In an attempt to power a definitive randomised-controlled trial (RCT), an uncontrolled evaluation of the impact of long-term, low-dose oral erythromycin therapy upon pulmonary exacerbation frequency in non-CF bronchiectasis subjects was performed. Adult bronchiectasis subjects with at least 2 infective exacerbations in the preceding 12 months were followed for 12 months following commencement of prophylactic oral erythromycin 250 mgs daily. The co-primary outcome measures, comparing the 12 month erythromycin and pre-erythomycin periods, were numbers of infective exacerbations and days of antibiotic therapy for infective exacerbations. Results: In the 24 evaluable subjects completing a minimum of 12 months of therapy, erythromycin was associated with halving of both the median (range) annual number of infective exacerbations (2 (0-8) vs 4 (2-11), 95% CI 1.5 to 3.5, p < 0.0001) and annual days of antibiotic use (21 (0-78) vs 44 (15-138), 95% CI 18 to 40, p < 0.0001) compared with the preceding 12 month period. Conclusions: Low-dose erythromycin may have a robust effect upon exacerbation frequency in non-CF bronchiectasis subjects with frequent exacerbations and this warrants proceeding to a definitive intervention study. These data have enabled powering of an RCT of long-term, low-dose erythromycin, which is now underway and also incorporates bronchoscopic evaluation for pathophysiologic data.