Bronchiectasis

A profile of brensocatib for non-cystic fibrosis bronchiectasis

INTRODUCTION

Non-cystic-fibrosis bronchiectasis (NCFB) is an airway disorder with a growing worldwide prevalence that affects predominantly older and female individuals and is associated with high symptom burden and significant healthcare expenditure. Brensocatib is a novel orally bioavailable, selective, and reversible dipeptidyl peptidase 1 (DPP1) inhibitor that leads to a sustained inhibition of neutrophil serine protease activity in both whole blood and sputum.

AREAS COVERED

This drug profile summarizes the role of inflammation in the pathophysiology of bronchiectasis. The mechanism of action of brensocatib in reducing neutrophil-related inflammation is described. We then summarize existing efficacy and safety data from Phase 2 and Phase 3 studies of brensocatib in patients with bronchiectasis, in which the rate of exacerbation was the primary endpoint. Finally, we summarize the current marketplace for brensocatib, including the unmet for effective therapies for bronchiectasis, and the status of other potential treatments undergoing clinical trials.

EXPERT OPINION

Brensocatib is a first-in-class DPP1 inhibitor that shows promise as a treatment for patients with bronchiectasis.

PMN‐MDSCs Orchestrate the Immunosuppressive Microenvironment in the Lung and Are Associated With Clinical Outcome in Bronchiectasis

Background and Objective

Myeloid‐derived suppressor cells (MDSCs) participate in the progression of many diseases including chronic lung diseases. However, whether MDSCs are accumulated in the lung and how MDSCs orchestrate the pulmonary microenvironment in bronchiectasis remains unknown. Here, we aim to test a hypothesis that PMN‐MDSCs are accumulated in the lung and play a role in creating an airway immunosuppressive milieu, thereby relating to clinical outcomes in bronchiectasis.

Methods

Flow cytometry and immunofluorescence staining were performed for analysing the frequencies and presence of PMN‐MDSCs, LOX‐1+ neutrophils, and ARG‐1+ PMN‐MDSCs in PBMCs, sputum, and lung tissues. T‐cell proliferation assays were established for evaluating the immunosuppressive activities of PMN‐MDSCs. RNA sequencing was performed to investigate the underlying mechanism of PMN‐MDSCs‐mediated immunosuppression. The relationship of PMN‐MDSCs with the time to next exacerbation and treatment response to antibiotic therapy was analysed.

Results

PMN‐MDSCs are accumulated in the lung and blood in bronchiectasis patients compared to healthy individuals. The majority of neutrophils in the lung of bronchiectasis patients are LOX‐1+ PMN‐MDSCs. Mechanistically, PMN‐MDSCs suppress T cell proliferation via secreting high levels of the enzyme arginase‐1 (ARG‐1). Notably, the frequencies of PMN‐MDSCs in sputum negatively correlate with the time to next exacerbation in bronchiectasis patients. Additionally, antibiotic therapy dramatically decreases PMN‐MDSCs frequencies in the airway of bronchiectasis patients.

Conclusion

These findings suggest that PMN‐MDSCs accumulate and establish an immunosuppressive microenvironment in the lung via ARG‐1 in bronchiectasis, which is associated with clinical outcome and response to antibiotic treatment, highlighting a potential role of PMN‐MDSCs in bronchiectasis progression.

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Sputum microbiology data and related clinical outcomes among adult Aboriginal Australians with bronchiectasis

BACKGROUND

Sputum microbiology is an integral aspect of managing patients with bronchiectasis. Adult Aboriginal Australians have a high bronchiectasis disease burden; however, as yet there is sparce literature detailing the sputum microbiology profile in this population.

AIMS

To assess the sputum microbiology profile among Aboriginal patients aged ≥18 years with chest computed tomography-confirmed bronchiectasis in the Top End Northern Territory of Australia.

METHOD

All available sputum samples processed in a single laboratory service with established protocols for examining and reporting sputum microbiology results between 2011 through 2020 were assessed in relation to demographics, lung function parameters, chest radiology, inhaled pharmacotherapy, hospital admissions restricted to respiratory conditions and all-cause mortality.

RESULTS

Four hundred twenty-eight patients (median age 47 years, 56% female) had sputum cultures available to assess. Haemophilus spp. was the most common (64%), followed by yeast/Candida spp. (53%) and Pseudomonas spp. (36%). Polymicrobial cultures were noted in 92% of patients. There were significant geographic differences on a region-wise and community-wise basis. Patients with yeast/Candida spp. and Pseudomonas spp. recorded more hospitalisations (median 7 (interquartile range (IQR) 3-14) and 8 (IQR 4-16)). In multivariate models, both yeast/Candida spp. (odds ratio (OR) 2.63 (95% confidence interval (CI) 1.68-4.14)) and Pseudomonas spp. (OR 1.95 (95% CI 1.25-3.04)) were associated with increased odds for mortality. Other than higher Pseudomonas spp. isolated with the use of inhaled corticosteroids, no significant association was observed either with lung function or chest radiology.

CONCLUSION

Adult Aboriginal Australians with bronchiectasis harbour a significant microorganism load that may play a role in overall morbidity and mortality.

State-of-the-Art Review: Modern Approach to Nocardiosis-Diagnosis, Management, and Uncertainties

Nocardiosis is an uncommon yet potentially devastating infection. Nocardia tends to affect individuals with chronic lung disease or immunocompromising conditions, 2 groups increasing in number. Incidence of nocardiosis is likely to increase as well, and it is vital to have an approach to this complex disease. Here, we aim to review the presentation, diagnosis, and management of Nocardia in the modern era. We will also highlight areas of uncertainty in our understanding of nocardiosis and propose a general approach to nocardiosis therapy, accounting for response and tolerance of Nocardia treatment.

Phase 3 Trial of the DPP-1 Inhibitor Brensocatib in Bronchiectasis

BACKGROUND

In bronchiectasis, neutrophilic inflammation is associated with an increased risk of exacerbations and disease progression. Brensocatib, an oral, reversible inhibitor of dipeptidyl peptidase 1 (DPP-1), targets neutrophil serine proteases, key mediators of neutrophilic inflammation.

METHODS

In a phase 3, double-blind trial, we randomly assigned patients with bronchiectasis (in a 1:1:1 ratio for adults and a 2:2:1 ratio for adolescents) to receive brensocatib (10 mg or 25 mg once per day) or placebo. The primary end point was the annualized rate of adjudicated pulmonary exacerbations over a 52-week period. The secondary end points, listed in hierarchical testing order, were the time to the first exacerbation during the 52-week period; the percentage of patients remaining exacerbation-free at week 52; the change in forced expiratory volume in 1 second (FEV1); the annualized rate of severe exacerbations; and change in quality of life.

RESULTS

A total of 1721 patients (1680 adults and 41 adolescents) underwent randomization and received brensocatib or placebo. The annualized rate of pulmonary exacerbations was 1.02 in the 10-mg brensocatib group, 1.04 in the 25-mg brensocatib group, and 1.29 in the placebo group (rate ratio, brensocatib vs. placebo, 0.79 [95% confidence interval {CI}, 0.68 to 0.92; adjusted P = 0.004] with the 10-mg dose and 0.81 [95% CI, 0.69 to 0.94; adjusted P = 0.005] with the 25-mg dose). The hazard ratio for the time to the first exacerbation was 0.81 (95% CI, 0.70 to 0.95; adjusted P = 0.02) with the 10-mg dose and 0.83 (95% CI, 0.70 to 0.97; adjusted P = 0.04) with the 25-mg dose. In each brensocatib group, 48.5% of patients remained exacerbation-free at week 52, as compared with 40.3% in the placebo group (rate ratio, 1.20 [95% CI, 1.06 to 1.37; adjusted P = 0.02] with the 10-mg dose and 1.18 [95% CI, 1.04 to 1.34; adjusted P = 0.04] with the 25-mg dose). At week 52, FEV1 had declined by 50 ml with the 10-mg dose, 24 ml with the 25-mg dose, and 62 ml with placebo (least-squares mean difference vs. placebo, 11 ml [95% CI, -14 to 37; adjusted P = 0.38] with the 10-mg dose and 38 ml [95% CI, 11 to 65; adjusted P = 0.04] with the 25-mg dose). The incidence of adverse events was similar across groups, except for a higher incidence of hyperkeratosis with brensocatib.

CONCLUSIONS

Among patients with bronchiectasis, once-daily treatment with brensocatib (10 mg or 25 mg) led to a lower annualized rate of pulmonary exacerbations than placebo, and the decline in FEV1 was less with the 25-mg dose of brensocatib than with placebo. (Funded by Insmed; ASPEN ClinicalTrials.gov number, NCT04594369; EudraCT number, 2020-003688-25.).

Neutrophilic inflammation in bronchiectasis

Noncystic fibrosis bronchiectasis, hereafter referred to as bronchiectasis, is a chronic, progressive lung disease that can affect people of all ages. Patients with clinically significant bronchiectasis have chronic cough and sputum production, as well as recurrent respiratory infections, fatigue and impaired health-related quality of life. The pathophysiology of bronchiectasis has been described as a vicious vortex of chronic inflammation, recurring airway infection, impaired mucociliary clearance and progressive lung damage that promotes the development and progression of the disease. This review describes the pivotal role of neutrophil-driven inflammation in the pathogenesis and progression of bronchiectasis. Delayed neutrophil apoptosis and increased necrosis enhance dysregulated inflammation in bronchiectasis and failure to resolve this contributes to chronic, sustained inflammation. The excessive release of neutrophil serine proteases, such as neutrophil elastase, cathepsin G and proteinase 3, promotes a protease-antiprotease imbalance that correlates with increased inflammation in bronchiectasis and contributes to disease progression. While there are currently no licensed therapies to treat bronchiectasis, this review will explore the evolving evidence for neutrophilic inflammation as a novel treatment target with meaningful clinical benefits.

Increased Neutrophil Elastase in Affected Lobes of Bronchiectasis and Correlation of Its Levels between Sputum and Bronchial Lavage Fluid

BACKGROUND

Neutrophil elastase (NE) has been proposed as a potential biomarker for evaluating the severity and prognosis of bronchiectasis. This study aimed to compare bronchial lavage quantification of NE levels and activities with those of sputum.

METHODS

A cross-sectional study was conducted in which 24 Vietnamese adults with bronchiectasis were enrolled from June 2023 to August 2023. All participants underwent bronchoscopy to collect bronchial lavage fluid (BLF) from two bronchial locations: one in the region with the greatest bronchial dilatation and one in the normal bronchi or in patients with all lobes affected, the least abnormal lobe (abnormal BLF [ABLF] and normal BLF [NBLF], respectively). Spontaneously expectorated sputum was also collected.

RESULTS

Out of 24 cases, the prevalence of mild, moderate and severe bronchiectasis was 14/24 (58.4%), 5/24 (20.8%), and 5/24 (20.8%), respectively. NE concentration and activity were significantly higher in sputum and ABLF than in NBLF (p<0.001). Sputum and ABLF were highly correlated (r=0.841, p<0.001) with no significant difference in NE activity between sputum and ABLF. Higher levels of NE activity were seen in more severe bronchiectasis than in mild bronchiectasis in all samples but were only statistically significant for NE activity in sputum (r=0.418, p=0.042).

CONCLUSION

NE activity and concentration are elevated in areas of the lung most affected by bronchiectasis. Sputum is a valid surrogate of pulmonary NE levels, as they correlate strongly with ABLF and confirm in a Vietnamese population the relationship between NE activity and disease severity.

Mucolytics for children with chronic suppurative lung disease

BACKGROUND

Chronic suppurative lung disease (CSLD) is an umbrella term to define the spectrum of endobronchial suppurative lung disease, including bronchiectasis and protracted bacterial bronchitis (PBB), associated with chronic wet or productive cough. Research that explores new therapeutic options in children with CSLD has been identified by clinicians and patients as one of the top research priorities. Mucolytic agents work to improve mucociliary clearance and interrupt the vicious vortex of airway infection and inflammation, hence they have potential as a therapeutic option.

OBJECTIVES

To assess the effects of mucolytics for reducing exacerbations, improving quality of life and other clinical outcomes in children with CSLD (including PBB and bronchiectasis), and to assess the risk of harm due to adverse events.

SEARCH METHODS

An Information Specialist searched the Cochrane Airways Trials Register to June 2022, and a review author searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase databases to 27 September 2024. Other review authors handsearched respiratory journals.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), of both cross-over and parallel design, that compared a mucolytic with a placebo or 'no intervention' control group and included children (aged 18 years and under) with any type of CSLD (including PBB and bronchiectasis). We excluded studies with adult participants and studies in children with cystic fibrosis, empyema, pulmonary abscess or bronchopulmonary fistula.

DATA COLLECTION AND ANALYSIS

Two authors independently reviewed titles and abstracts to assess eligibility for inclusion. The authors then assessed study quality and extracted data. They assessed the quality of the study using the Cochrane risk of bias tool (RoB 2), and used GRADE to assess the certainty of evidence. Outcomes of interest to be analysed included: i) for maintenance or stable state: rate of exacerbations, ii) for exacerbation state: time to resolution of respiratory exacerbation, iii) lung function - forced expiratory volume in one second (FEV1) and forced vital capacity (FVC), iv) quality of life and v) adverse events. Only one study met the inclusion criteria, so we could not perform a meta-analysis. Data were continuous, so we reported outcomes as mean differences.

MAIN RESULTS

The sole included RCT was a cross-over study of 63 children in the total cohort, with reported data and analysis of only 52 children (26 per arm) with non-cystic fibrosis bronchiectasis. The study compared 3% hypertonic saline nebulised before chest physiotherapy with a control arm (physiotherapy alone), with each phase lasting eight weeks. Children in the hypertonic saline arm had a mean age of 9.80 (SD 2.97) years and 42.3% were male; those in the control arm had a mean age of 9.10 (SD 2.40) years and 38.4% were male. Only results of the first arm of the cross-over study were included in this review. The RCT reported a clinically important difference between the groups for our review's primary outcome: rate of respiratory exacerbations. The mean number of exacerbations per child-year was 2.50 (SD 0.64) in the intervention group and 7.80 (SD 1.05) in the control group (mean difference (MD) -5.30, 95% CI -5.77 to -4.83; 1 study, 52 participants; very low-certainty evidence). The RCT also reported that the percentage point improvement in mean % predicted FEV1 and FVC from baseline to week eight was better with hypertonic saline compared to control. Mean FEV1 improvement was 14.15% (SD 5.50) in the intervention group versus 5.04% (SD 5.55) in the control group (MD 9.11%, 95% CI 6.11 to 12.11; 1 study, 52 participants; very low-certainty evidence). While for FVC, the mean improvement was 13.77% (SD 5.73) compared with 7.54% (SD 4.90), respectively (MD 6.23%, 95% CI 3.33 to 9.13; 1 study, 52 participants; very low-certainty evidence). Quality of life measures were not used. We judged the study to have a high risk of bias due to unblinding, missing data, deviation from the intended intervention and reporting bias with measurement and selection of outcome measures. The authors reported that there were no dropouts due to adverse events. No data were available regarding quality of life. The included study assessed mucolytic use during a stable state, and we found no studies of mucolytic use during an exacerbation. We also found no studies assessing oral mucolytics, other inhaled mucolytics, use in PBB, or in settings other than hospital outpatients. We also found two ongoing studies, one using hypertonic saline and one using an oral mucolytic agent erdosteine, which will potentially be included in future updates of this review.

AUTHORS' CONCLUSIONS

This systematic review is limited to a single small study, which we judged to be at high risk of bias. It remains uncertain whether regular nebulised hypertonic saline during a stable state reduces exacerbations or improves lung function. Further multi-centre, well-designed RCTs of longer duration that investigate various mucolytics are required to answer this important clinical question.

The bronchiectasis microbiome: current understanding and treatment implications

PURPOSE OF REVIEW

Advances in DNA sequencing and analysis of the respiratory microbiome highlight its close association with bronchiectasis phenotypes, revealing fresh opportunities for diagnosis, stratification, and personalized clinical intervention. An under-recognized condition, bronchiectasis is increasingly the subject of recent large-scale, multicentre, and longitudinal clinical studies including detailed analysis of the microbiome. In this review, we summarize recent progress in our understanding of the bronchiectasis microbiome within the context of its potential use in treatment decisions.

RECENT FINDINGS

Diverse microbiome profiles exist in bronchiectasis, in line with the established disease heterogeneity including treatment response. Classical microbiology has established Pseudomonas aeruginosa and Haemophilus influenza as two microbial markers of disease, while holistic microbiome analysis has uncovered important associations with less common bacterial taxa including commensal an/or pathobiont species, including the emerging role of the fungal mycobiome, virome, and interactome. Integration of airway microbiomes with other high-dimensional biological and clinical datasets holds significant promise to determining treatable traits and mechanisms of disease related to the microbiome.

SUMMARY

The bronchiectasis microbiome is an emerging and key area of study with significant implications for understanding bronchiectasis, influencing treatment decisions and ultimately improving patient outcomes.

Heart rate recovery after the 6-min walk test in people with bronchiectasis

Background

The cardiac autonomic response to exercise and during recovery has been poorly explored in bronchiectasis.

Methods

A longitudinal study was conducted in adults with bronchiectasis. Sociodemographic and clinical data were collected at baseline and after 12 months of follow-up. The heart rate recovery after the first (HRR1) and second minute (HRR2) of recovery in the six-min walk test (6MWT) was estimated in both assessments. Adjusted regression models were used to identify predictors of a delayed HRR1 (HRR1≤14).

Results

104 participants with a mean±sd age of 64±13 years and mostly women (67%) were included. A delayed HRR1 after the baseline 6MWT was identified in 36% of participants. These participants presented a higher proportion of males, increased body mass index, higher disease severity, more likely to require hospitalisation, more impact on quality of life, lower exercise capacity, lower heart rate at the end of the 6MWT and lower HRR2. Disease severity (β, 95% CI) (moderate and severe versus mild, -0.47 (-0.94 to -0.01)) and distance walked (0.34 (0.11 to 0.56)) were the independent variables associated with HRR1. Of the 45 participants who completed the entire follow-up period, 24% exhibited delayed HRR1. The presence of at least two exacerbations during the follow-up period (OR 16.89, 95% CI 1.44 to 197.48) was the only predictor of a delayed HRR1 in the assessment completed at the end of the study.

Conclusion

HRR1 is related to disease severity and is mainly affected by having severe exacerbations in people with bronchiectasis.

Pulmonary microbiology and microbiota in adults with non-cystic fibrosis bronchiectasis: a systematic review and meta-analysis

BACKGROUND

Non-cystic fibrosis bronchiectasis is associated with frequent and diverse microbial infections, yet an overall understanding of microbial presence across different disease stages is lacking.

METHODS

A meta-analysis assessed lung microbes in adults with non-CF bronchiectasis, collecting data using both culture-based and sequencing approaches through three international databases and three Chinese databases. Subgroups were categorized by disease stage: the stable group (S), the exacerbation group (E), and unclassified data consolidated into the undetermined group (U). Culture data were analysed in random-effects meta-analyses while sequencing data were processed using QIIME 2.

RESULTS

A total of 98 studies were included with data from 54,384 participants worldwide. Pseudomonas aeruginosa was the most frequently isolated bacterium (S: 26[19-34]%, E: 23[20-25]%, U: 20[16-25]%), while not specified Mycobacterium avium complex exhibited the highest mycobacterial prevalence (S: 3[1-5]%, E: 4[2-5]%, U: 15[3-27]%). Aspergillus spp. (S: 15[-10-39]%, E: 2[1-3]%, U: 10[5-15]%) and Candida spp. (S: not applicable, E: 11[2-20]%, U: 10[-8-27]%) were predominant in fungi culture with variable distributions among groups. Rhinovirus was the most commonly detected virus with varying prevalence across airway sample types rather than disease stages (S-sputum: 18[-16-53]%, S-nasopharyngeal: 4[-1-9]%, E-sputum: 22[16-29]%, E-nasopharyngeal: 6[4-8]%). Sequencing results revealed notable antibiotic persistence of Pseudomonas in 16S, and significant domination of Candida in ITS.

CONCLUSION

Our findings indicate consistent bacterial patterns throughout bronchiectasis stages in both culture and sequencing results. Viruses are extensively detected in stable patients but vary across different airway sample types. Lower bacterial diversity and higher fungal diversity may be associated with exacerbation risks.

Spectral Shaping Computed Tomography Applications

Spectral shaping (also known as spectral filtration) has been utilized in some of the latest computed tomography (CT) systems. This technique involves using tin (Sn) or silver (Ag) filters, which selectively absorb low-energy photons. This review aims to demonstrate the utility of spectral shaping across a wide range of protocols and clinical situations. Spectral-shaped CT protocols using tin filters allow for the acquisition of diagnostic images and greatly reduce the radiation dose, metal artifacts, and photon starvation. These features make spectral shaping suitable for various clinical situations in diagnostic and interventional CT imaging.

Incidence and risk factors of serious infections occurred in patients with lung cancer following immune checkpoint blockade therapy

BACKGROUND

Immune checkpoint inhibitors (ICIs) therapy has revolutionized anti-cancer therapy, with lung cancer exhibiting sustained clinical responses to it. However, there remains a lack of research into the risk factors of serious infections in patients with lung cancer following ICIs therapy. Therefore, we aimed to investigate the incidence and risk factors of serious infections in these patients.

METHODS

Medical records were retrospectively collected and reviewed from 710 patients with lung cancer receiving ICIs therapy at Zhongshan Hospital between January 2021 and February 2023. Serious infections were defined as infections requiring hospitalization or parenteral antimicrobials occurring at any time from the initiation of the ICIs therapy to 3 months after its discontinuation.

RESULTS

Among the study population, 191 patients had suffered from serious infections, with an overall infection rate of 26.90% during an average follow-up period of (432.62 ± 377.09) days. The predominant site of infection was the lung (75.61%), and the most prevalent pathogens were bacteria (85.07%), followed by Mycobacterium tuberculosis (6.47%), viruses (4.98%), and fungi (3.48%). In addition to chronic obstructive pulmonary disease (COPD), asthma, and systemic glucocorticoids use, low lymphocyte count and CD4/CD8 ratio were identified as independent risk factors (all p < 0.05).

CONCLUSION

Laboratory parameters may serve as strong predictors for serious infections in patients with lung cancer following ICIs therapy. Chronic airway diseases including COPD and asthma should be managed effectively. Systemic glucocorticoids should be used prudently to prevent serious infections in these patients.

Evaluating elexacaftor/tezacaftor/ivacaftor (ETI; Trikafta™) for treatment of patients with non-cystic fibrosis bronchiectasis (NCFBE): A clinical study protocol

BACKGROUND

Non-cystic fibrosis bronchiectasis (NCFBE) is a disease that exhibits dilatation of airways, airflow obstruction, persistent cough, excessive sputum production, and refractory respiratory infections. NCFBE exhibits clinical and pathological manifestations similar to key features of cystic fibrosis (CF) lung disease. In CF, pathogenesis results from dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR), and diagnosis is made by demonstrating elevated sweat chloride concentrations (typically ≥60 mEq/L), two CFTR mutations known to be causal, multi-organ tissue injury, or combination(s) of these findings.

OBJECTIVE

Based on a considerable body of evidence, we believe many patients with NCFBE have disease likely to benefit from drugs such as elexacaftor/tezacaftor/ivacaftor (ETI) that activate CFTR-dependent ion transport. ETI is currently prescribed solely for treatment of CF and has not been adequately tested or proposed for patients with NCFBE, many of whom exhibit decreased CFTR function. Accordingly, we are conducting a clinical trial of ETI in subjects carrying a diagnosis of NCFBE.

METHODS

Participants will exhibit one disease-causing CFTR mutation and/or sweat chloride measurements of 30-59 mEq/L. Cutaneous punch biopsy or blood samples will be obtained for iPS cell differentiation into airway epithelial monolayers-which will then be tested for response to ETI. Each patient will be given CFTR modulator treatment for approximately four weeks, with monitoring of clinical endpoints that include FEV1 (forced expiratory volume in one second), sweat chloride, quality of life questionnaire, and weight. The study will evaluate response of patients with NCFBE to ETI, and test usefulness of iPSC-derived airway epithelial monolayers as a novel in vitro technology for predicting clinical benefit.

TRIAL REGISTRATION

This trial is registered at clinicaltrials.gov (Identifier: NCT05743946. Date: 02/23/2023).

Outer membrane vesicle contributes to the Pseudomonas aeruginosa resistance to antimicrobial peptides in the acidic airway of bronchiectasis patients

Pseudomonas aeruginosa is the predominant pathogen causing chronic infection in the airway of patients with bronchiectasis (BE), a chronic respiratory disease with high prevalence worldwide. Environmental factors are vital for bacterial successful colonization. Here, with sputa and bronchoalveolar lavage fluids, we determined that the concentration of airway antimicrobial peptide LL-37 and lactate was elevated in BE patients, especially in those infected with P. aeruginosa. The in vitro antibacterial assay revealed the bactericidal activity of LL-37 against the clinical P. aeruginosa isolates, which were dampened in the acidic condition. P. aeruginosa production of outer membrane vesicles (OMVs) enhanced in the lactate-adjusted acidic condition. Transcriptomic analysis suggested that OMVs induce the hyperproduction of the chemical compound 2-heptyl-4-quinolone (HHQ) in the bacterial population, which was verified by high-performance liquid chromatography. The positively charged HHQ interfered with the binding of LL-37 to bacterial cell membrane, potentiating the P. aeruginosa resistance to LL-37. To our knowledge, this is a new resistance mechanism of P. aeruginosa against antimicrobial peptides and may provide theoretical support for the development of new antibacterial therapies.

A novel nomogram for predicting postoperative pneumonia risk in patients with localized bronchiectasis

BACKGROUND

Pneumonia is one of the most common complications after lung resection. However, there are currently no reports of postoperative pneumonia in patients with bronchiectasis.

OBJECTIVES

Our study aims to construct a new nomogram to predict the risk of postoperative pneumonia in patients with localized bronchiectasis.

DESIGN

The clinical data of patients with localized bronchiectasis from April 2012 to August 2022 were retrospectively analyzed.

METHODS

Independent risk factors were identified through simple linear regression and multiple linear regression analysis, and a new nomogram was constructed based on independent risk factors. The validity of the nomogram was evaluated using the consistency index (C-index), receiver operating characteristic curve, calibration chart, and decision curve analysis chart.

RESULTS

The new nomogram prediction model included five independent risk factors: tuberculosis history, smoking history, platelet-lymphocyte ratio (PLR), diffusing capacity of the lung for carbon monoxide, and controlled nutritional status score. The area under the curve of the prediction model is 0.870 (95% CI: 0.750-0.892), showing good discrimination ability, and the probability threshold was set at 0.2013. In addition, the calibration curve shows that the nomogram has good calibration. In the decision curve, the nomogram model showed good clinical net benefit.

CONCLUSION

This study is the first to construct a nomogram prediction model for postoperative pneumonia of localized bronchiectasis, which can more accurately and directly assess the risk probability of postoperative pneumonia, and provide certain help for clinicians in prevention and treatment decisions.

Association between preserved ratio impaired spirometry and 1-year clinical outcomes in patients with bronchiectasis patients: A cohort study

BACKGROUND

Preserved Ratio Impaired Spirometry (PRISm) (defined as the ratio of forced expired volume in the first second to forced vital capacity (FEV1/FVC) greater than 0·70 with a FEV1 of less than 80% predicted) is associated with a higher risk of hospitalizations and mortality in the general population. However, less is known about whether PRISm is associated with adverse clinical outcomes in patients with bronchiectasis. We aimed to investigate whether PRISm is associated with adverse clinical outcomes in bronchiectasis patients.

METHODS

We performed a retrospective cohort study with inpatients admitted with acute exacerbations of bronchiectasis between January 2017 and January 2022. Clinical data including anthropometry, spirometry, laboratory, etiological and radiologic variables were collected. Patients were divided into the normal spirometry group, the PRISm group and the obstructive spirometry group. All patients were followed up for 1 year. The primary outcome was readmission of bronchiectasis at 1 year.

RESULTS

Of 487 bronchiectasis patients, we found 142 (29.2%) had normal spirometry, 67 (13.8%) had PRISm and 278 (57.1%) had obstructive spirometry. Patients with obstructive spirometry were more likely to be male and to smoke, had higher fibrinogen values and more lobes affected. Patients with PRISm (HR 1.929, 95% CI 1.049 to 3.546) and obstructive spirometry (HR 2.406, 95%CI 1.506 to 3.845) had a higher risk of readmissions compared with those with normal spirometry after adjustment for potential confounders.

CONCLUSIONS

PRISm was associated with significant increased risk for readmissions in patients with bronchiectasis compared with normal spirometry, which should receive special attention.

Targeting neutrophil serine proteases in bronchiectasis

Persistent neutrophilic inflammation is a central feature in both the pathogenesis and progression of bronchiectasis. Neutrophils release neutrophil serine proteases (NSPs), such as neutrophil elastase (NE), cathepsin G and proteinase 3. When chronically high levels of free NSP activity exceed those of protective antiproteases, structural lung destruction, mucosal-related defects, further susceptibility to infection and worsening of clinical outcomes can occur. Despite the defined role of prolonged, high levels of NSPs in bronchiectasis, no drug that controls neutrophilic inflammation is licensed for the treatment of bronchiectasis. Previous methods of suppressing neutrophilic inflammation (such as direct inhibition of NE) have not been successful; however, an emerging therapy designed to address neutrophil-mediated pathology, inhibition of the cysteine protease cathepsin C (CatC, also known as dipeptidyl peptidase 1), is a promising approach to ameliorate neutrophilic inflammation, since this may reduce the activity of all NSPs implicated in bronchiectasis pathogenesis, and not just NE. Current data suggest that CatC inhibition may effectively restore the protease-antiprotease balance in bronchiectasis and improve disease outcomes as a result. Clinical trials for CatC inhibitors in bronchiectasis have reported positive phase III results. In this narrative review, we discuss the role of high NSP activity in bronchiectasis, and how this feature drives the associated morbidity and mortality seen in bronchiectasis. This review discusses therapeutic approaches aimed at treating neutrophilic inflammation in the bronchiectasis lung, summarising clinical trial outcomes and highlighting the need for more treatment strategies that effectively address chronic neutrophilic inflammation in bronchiectasis.

Disease Severity and Activity in Bronchiectasis: A Paradigm Shift in Bronchiectasis Management

Bronchiectasis has an increasing prevalence and substantial clinical and economic burden. Therefore, physicians should identify patients with bronchiectasis at high risk of disease progression to ensure optimal management in advance. The heterogeneity of bronchiectasis means it is unlikely that any single parameter could identify highrisk patients; therefore, disease severity is usually assessed using validated composite tools, such as the Bronchiectasis Severity Index, FACED, and Bronchiectasis Aetiology Comorbidity Index, to predict long-term outcomes in bronchiectasis. Disease severity, however, implies an advanced process with lung destruction. Earlier intervention may prevent disease progression and improve outcomes. To identify patients at risk, rather than patients with established advanced disease, we need to shift our focus from disease severity to disease activity. Disease activity denotes the activation level of underlying pathophysiological processes and can be measured using clinical presentations and biomarkers. This review discusses a paradigm shift in bronchiectasis management, focusing on disease activity rather than severity, to prevent disease progression.

Infections, autoimmunity and immunodeficiencies are the leading etiologies of non-cystic fibrosis bronchiectasis in adults from the southwest of Colombia

INTRODUCTION

Non-cystic fibrosis bronchiectasis is a complex medical condition with multiple etiologies, characterized by chronic productive cough and radiologic evidence of airway lumen dilation and wall thickening. Associated exacerbations and declining lung function contribute to increasing disability and mortality. There are no data about the prevalence of non-cystic fibrosis bronchiectasis etiologies in the Colombian population.

OBJECTIVE

To investigate non-cystic fibrosis bronchiectasis etiology and clinical characteristics in adults evaluated in the southwest of Colombia.

MATERIALS AND METHODS

We conducted a cross-sectional, non-interventional study. Subjects diagnosed with non-cystic fibrosis bronchiectasis were referred to by their healthcare providers and then enrolled between October 2018 and April 2021. Medical records and radiological studies were evaluated. Participants underwent laboratory tests, including complete blood count, serum immunoglobulin levels, and, in some cases, additional tests.

RESULTS

We included 161 subjects. The average age was 50 years old, and 59% were females. Bronchiectasis etiology was identified in 84.6% of the cases. Postinfectious (34.6%) and immune disorders (25.3%), represented by autoimmunity (13.6%) and immunodeficiency (11.7%), were the leading causes. Gender differences were noted in autoimmune (females: 18.8% versus males: 6.1%, p = 0.021) and immunodeficiency-related bronchiectasis (males: 21.2% versus females 5.2%, p = 0.002). Immunodeficiencies-associated bronchiectases were more frequent in subjects under 50 years of age, while chronic obstructive pulmonary disease-associated bronchiectases were common in subjects over 50 years of age.

DISCUSSION

The etiologies of non-cystic fibrosis bronchiectasis in Colombia are diverse, exhibiting notable differences from other global regions. Serum immunoglobulin levels and clinical immunologist consultation should be prioritized in diagnosing patients with unclear bronchiectasis etiology, particularly those with recurrent sinopulmonary infections.

Prevalence and Clinical Implications of Pulmonary Vein Stenosis in Bronchiectasis: A 3D Reconstruction CT Study

BACKGROUND

Recent studies on bronchiectasis have revealed significant structural abnormalities and pathophysiological changes. However, there is limited research focused on pulmonary venous variability and congenital variation. Through our surgical observations, we noted that coarctation of pulmonary veins and atrophied lung volume are relatively common in bronchiectasis patients. Therefore, we conducted a retrospective study to explore pulmonary venous variation and secondary manifestations in bronchiectasis cases, utilizing 3D reconstruction software (Mimics Innovation Suite 21.0, Materialise Dental, Leuven, Belgium) to draw conclusions supported by statistical evidence.

METHOD

This retrospective study included patients with bronchiectasis and healthy individuals who underwent CT examinations at Beijing Chao-Yang Hospital between January 2017 and July 2023. Chest CT data were reconstructed using Materialise Mimics. Pulmonary veins and lung lobes were segmented from surrounding tissue based on an appropriate threshold determined by local grey values and image gradients. Subsequently, venous cross-sectional areas and lung volumes were measured for statistical analysis.

RESULT

CT data from 174 inpatients with bronchiectasis and 75 cases from the health examination center were included. Three-dimensional reconstruction data revealed a significant reduction in cross-sectional areas of pulmonary veins in the left lower lobe (p < 0.001), the right lower lobe (p = 0.030), and the right middle lobe (p = 0.009) of bronchiectasis patients. Subgroup analyses indicated that approximately 73.5% of localized cases of the left lower lobe exhibited pulmonary vein stenosis, while in the diffuse group, this proportion was only 52.6%. Furthermore, the cross-sectional area of pulmonary veins had a gradually decreasing trend, based on a small sample. Lung function tests showed significant reductions in FEV1, FVC, and FEV1% in bronchiectasis patients, attributed to the loss of lung volume in the left lower lobe, which accounted for 60.9% of the included sample.

CONCLUSIONS

Our recent findings suggest that pulmonary venous stenosis is a common variation in bronchiectasis and is often observed concurrently with reduced lung volume, particularly affecting the left lower lobe. Moreover, localized cases are more likely to suffer from pulmonary venous stenosis, with an ambiguous downtrend as the disease progresses. In conclusion, increased attention to pulmonary venous variation in bronchiectasis is warranted, and exploring new therapies to intervene in the early stages or alleviate obstruction may be beneficial.

Association of short-term exposure to ambient air pollution and temperature with bronchiectasis mortality: a nationwide time-stratified case-crossover study

BACKGROUND

Ambient pollution and non-optimal temperature are major risk factors for respiratory health. However, the relationships between short-term exposure to these factors and bronchiectasis mortality remain unknown.

METHODS

A nationwide, time-stratified case-crossover study across Mainland China was conducted from 2013 to 2019. Records of bronchiectasis deaths were extracted from the National Death Registration Reporting Information System. Daily concentrations of fine particulate matter (PM2.5), coarse particulate matter (PM2.5-10), nitrogen dioxide (NO2), ozone (O3), and daily temperature were obtained from high-resolution prediction models. We utilized conditional logistic regression model and distributed lag nonlinear model to explore the associations of these exposures with bronchiectasis mortality.

FINDINGS

We included a total of 19,320 bronchiectasis deaths. Air pollutant was associated with bronchiectasis mortality within the first 3 days after exposure and the exposure-response relationships were almost linear. An interquartile range increase in PM2.5, PM2.5-10, and O3 was associated with increments of 3.18%, 4.14%, and 4.36% in bronchiectasis mortality at lag 02 d, respectively. Additionally, lower temperature was associated with higher odds of bronchiectasis mortality. Compared to referent temperature (23.6 °C), the odds ratio for bronchiectasis mortality associated with extremely low temperature (P1: -13.4 °C) was 1.54 (95% CI: 1.05, 2.25).

INTERPRETATION

This national study provides compelling evidence, and highlights the necessity and importance of reducing air pollution exposures and keeping warm for susceptible populations.

FUNDING

National Natural Science Foundation of China (81925001; 82330070); Innovation Program of Shanghai Municipal Education Commission (202101070007-E00097); Program of Shanghai Municipal Science and Technology Commission (21DZ2201800); Program of Shanghai Shenkang Development Center (SHDC12023110); and Major Project of National Health Commission of China.

Characteristics of different pathogenic bacterial infections and their effects on prognosis in adult patients with bronchiectasis

The present study aimed to analyse the types of pathogens infecting adults with bronchiectasis and the effects of different pathogens on the number of acute exacerbations and the length of hospitalization for 1 year in patients with severe bronchiectasis. A total of 522 patients with bronchiectasis admitted to the Department of Respiratory and Critical Care Medicine at the Second Hospital of Jiaxing (Zhejiang, China) between January 2019 and December 2022 were retrospectively analysed. The patients were divided into a mild to moderate group and a severe group according to the bronchiectasis severity index criteria. The basic and clinical information of all the patients was collected. The patients were followed up for 1 year after the day when the sputum or alveolar lavage fluid samples tested positive for pathogens. The follow-up information included the exacerbation of cough symptoms, the number of hospitalizations and the number of days of antibiotic use in patients with bronchiectasis. A total of 522 patients with bronchiectasis were positive for pathogens, including 192 patients with Pseudomonas aeruginosa (P. aeruginosa; 36.8%), 60 patients with Klebsiella pneumoniae (K. pneumoniae; 11.5%), 48 patients with mixed pathogens (≥2 pathogens at the same time; 9.2%), 36 patients with Staphylococcus aureus (6.9%), 33 patients with Aspergillus fumigatus (6.3%), 30 patients with Haemophilus influenzae (5.7%), 15 patients with Acinetobacter baumannii (A. baumannii; 2.9%) and 108 patients with other pathogens (20.7%). Compared with patients with mild to moderate bronchiectasis, patients with severe bronchiectasis were more likely to have P. aeruginosa but less likely to have K. pneumoniae and other pathogens. The length of hospitalization and duration of antibiotic use in the severe group of patients with bronchiectasis caused by P. aeruginosa, A. fumigatus, or A. baumannii were significantly longer than those in the mild to moderate group. During the 1-year follow-up, the number of acute exacerbations and hospitalizations of patients with severe bronchiectasis caused by A. baumannii and P. aeruginosa were significantly greater than those of patients with severe bronchiectasis caused by other pathogens. According to logistic regression analysis, A. baumannii and P. aeruginosa were independent risk factors for acute exacerbation of severe bronchiectasis in the following year. In patients with severe bronchiectasis, the pathogens A. baumannii, P. aeruginosa and A. fumigatus were independent risk factors for future acute exacerbations and increased risk of hospitalization.

Mining single-cell data for cell type-disease associations

A robust understanding of the cellular mechanisms underlying diseases sets the foundation for the effective design of drugs and other interventions. The wealth of existing single-cell atlases offers the opportunity to uncover high-resolution information on expression patterns across various cell types and time points. To better understand the associations between cell types and diseases, we leveraged previously developed tools to construct a standardized analysis pipeline and systematically explored associations across four single-cell datasets, spanning a range of tissue types, cell types and developmental time periods. We utilized a set of existing tools to identify co-expression modules and temporal patterns per cell type and then investigated these modules for known disease and phenotype enrichments. Our pipeline reveals known and novel putative cell type-disease associations across all investigated datasets. In addition, we found that automatically discovered gene co-expression modules and temporal clusters are enriched for drug targets, suggesting that our analysis could be used to identify novel therapeutic targets.

Autologous transplantation of P63+ lung progenitor cells in patients with bronchiectasis: A randomized, single-blind, controlled trial

Non-cystic fibrosis bronchiectasis is a progressive respiratory disease with limited treatment options, prompting the exploration of regenerative therapies. This study investigates the safety and efficacy of autologous P63+ progenitor cell transplantation in a randomized, single-blind, controlled, phase 1/2 trial. Thirty-seven patients receive bronchoscopic airway clearance (B-ACT) (n = 19) or B-ACT plus P63+ progenitor cells (n = 18). Results show that compared to the control group, the change in DLCO levels from baseline to 24 weeks post therapy is significantly higher in the cell treatment group (p value = 0.039). Furthermore, the patients in the cell treatment group demonstrate significantly reduced lung damaged area, improved SGRQ score, and ameliorated BSI and FACED scores within 4-12 weeks post therapy. Transcriptomic analysis reveals that progenitor cells with higher expression of P63 gene have better therapeutic efficacy. These findings suggest that P63+ progenitor cells may offer a promising therapeutic approach for bronchiectasis. This study was registered at ClinicalTrials.gov(NCT03655808).

Analysis of factors influencing bronchiectasis patients with active pulmonary tuberculosis and development of a nomogram prediction model

Background

To identify the risk factors for bronchiectasis patients with active pulmonary tuberculosis (APTB) and to develop a predictive nomogram model for estimating the risk of APTB in bronchiectasis patients.

Methods

A retrospective cohort study was conducted on 16,750 bronchiectasis patients hospitalized at the Affiliated Hospital of Guangdong Medical University and the Second Affiliated Hospital of Guangdong Medical University between January 2019 and December 2023. The 390 patients with APTB were classified as the case group, while 818 patients were randomly sampled by computer at a 1:20 ratio from the 16,360 patients with other infections to serve as the control group. Relevant indicators potentially leading to APTB in bronchiectasis patients were collected. Patients were categorized into APTB and inactive pulmonary tuberculosis (IPTB) groups based on the presence of tuberculosis. The general characteristics of both groups were compared. Variables were screened using the least absolute shrinkage and selection operator (LASSO) analysis, followed by multivariate logistic regression analysis. A nomogram model was established based on the analysis results. The model's predictive performance was evaluated using calibration curves, C-index, and ROC curves, and internal validation was performed using the bootstrap method.

Results

LASSO analysis identified 28 potential risk factors. Multivariate analysis showed that age, gender, TC, ALB, MCV, FIB, PDW, LYM, hemoptysis, and hypertension are independent risk factors for bronchiectasis patients with APTB (p < 0.05). The nomogram demonstrated strong calibration and discrimination, with a C-index of 0.745 (95% CI: 0.715-0.775) and an AUC of 0.744 for the ROC curve. Internal validation using the bootstrap method produced a C-index of 0.738, further confirming the model's robustness.

Conclusion

The nomogram model, developed using common clinical serological characteristics, holds significant clinical value for assessing the risk of APTB in bronchiectasis patients.

[Management of adult bronchiectasis - Consensus-based Guidelines for the German Respiratory Society (DGP) e. V. (AWMF registration number 020-030)]

Bronchiectasis is an etiologically heterogeneous, chronic, and often progressive respiratory disease characterized by irreversible bronchial dilation. It is frequently associated with significant symptom burden, multiple complications, and reduced quality of life. For several years, there has been a marked global increase in the prevalence of bronchiectasis, which is linked to a substantial economic burden on healthcare systems. This consensus-based guideline is the first German-language guideline addressing the management of bronchiectasis in adults. The guideline emphasizes the importance of thoracic imaging using CT for diagnosis and differentiation of bronchiectasis and highlights the significance of etiology in determining treatment approaches. Both non-drug and drug treatments are comprehensively covered. Non-pharmacological measures include smoking cessation, physiotherapy, physical training, rehabilitation, non-invasive ventilation, thoracic surgery, and lung transplantation. Pharmacological treatments focus on the long-term use of mucolytics, bronchodilators, anti-inflammatory medications, and antibiotics. Additionally, the guideline covers the challenges and strategies for managing upper airway involvement, comorbidities, and exacerbations, as well as socio-medical aspects and disability rights. The importance of patient education and self-management is also emphasized. Finally, the guideline addresses special life stages such as transition, family planning, pregnancy and parenthood, and palliative care. The aim is to ensure comprehensive, consensus-based, and patient-centered care, taking into account individual risks and needs.

ACR Appropriateness Criteria® Tracheobronchial Disease

A variety of thoracic imaging modalities and techniques have been used to evaluate diseases of the trachea and central bronchi. This document evaluates evidence for the use of thoracic imaging in the evaluation of tracheobronchial disease, including clinically suspected tracheal or bronchial stenosis, tracheomalacia or bronchomalacia, and bronchiectasis. Appropriateness guidelines for initial imaging evaluation of tracheobronchial disease and for pretreatment planning or posttreatment evaluation are included. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

The battle within: how Pseudomonas aeruginosa uses host-pathogen interactions to infect the human lung

Pseudomonas aeruginosa is a versatile Gram-negative pathogen known for its ability to invade the respiratory tract, particularly in cystic fibrosis patients. This review provides a comprehensive analysis of the multifaceted strategies for colonization, virulence, and immune evasion used by P. aeruginosa to infect the host. We explore the extensive protein arsenal of P. aeruginosa, including adhesins, exotoxins, secreted proteases, and type III and VI secretion effectors, detailing their roles in the infective process. We also address the unique challenge of treating diverse lung conditions that provide a natural niche for P. aeruginosa on the airway surface, with a particular focus in cystic fibrosis. The review also discusses the current limitations in treatment options due to antibiotic resistance and highlights promising future approaches that target host-pathogen protein-protein interactions. These approaches include the development of new antimicrobials, anti-attachment therapies, and quorum-sensing inhibition molecules. In summary, this review aims to provide a holistic understanding of the pathogenesis of P. aeruginosa in the respiratory system, offering insights into the underlying molecular mechanisms and potential therapeutic interventions.

Eosinophilic Bronchiectasis: Prevalence, Severity, and Associated Features-A Cohort Study

Background: Bronchiectasis (BE) has been traditionally associated with neutrophilic inflammation, but eosinophilic bronchiectasis (EB) has recently emerged. Data about prevalence, clinical features, and disease severity are lacking. This study aimed to assess the EB prevalence, compare EB with non-EB, evaluate the Type-2 (T2) high endotype in BE (T2-high EB) versus non-T2-high EB, and identify EB predictors. Methods: We conducted a prospective study involving 153 BE patients. The data collected included clinical, radiological, and microbiological findings. BE severity was assessed using the bronchiectasis severity index (BSI), FACED and E-FACED scores, and the bronchiectasis etiology and comorbidity index (BACI). EB was defined as a blood eosinophil count (BEC) ≥ 300 cells/μL, and T2-high EB as BEC ≥ 300 cells/μL with fractional exhaled nitric oxide (FeNO) ≥ 25 ppb. Results: Prevalence was 27% for EB and 20% for T2-high EB. EB patients exhibited poorer lung function and more severe radiologic features, with significantly higher severity scores [BSI, FACED, E-FACED, BACI (p < 0.05)], and a higher median exacerbation rate [4 (2-5) in EB vs. 2 (1-4) in non-EB, p = 0.0002], compared with non-EB patients. T2-high EB patients showed higher severity scores [BSI, FACED, E-FACED (p < 0.05)], as well as worse lung function parameters [FEV1%, FVC%, FEF 25-75% (p < 0.05)] compared with non-T2-high EB patients. In our study, patients with EB exhibited notably worsened lung function and higher BE severity scores compared with their non-EB counterparts, with exacerbations playing a major role in these differences. We found statistically significant positive correlations between BEC and disease severity scores, such as BSI, FACED, and mMRC, as well as an inverse relationship with pulmonary function. The likelihood of EB being present was significantly higher in association with mMRC ≥ 1 (OR = 2.53; 95% CI, 1.26-5.64), exacerbations/year ≥ 1 (OR = 1.27; 95% CI, 1.0-1.63), and chronic PA colonization (OR = 3.9; 95% CI, 1.08-15.8). Conclusions: EB is a distinct endotype. Dyspnea, exacerbations, and PA colonization may be predictive of EB, emphasizing the importance of early detection for improved outcomes. BEC could serve as a useful biomarker of disease severity to consider when diagnosing EB.

Novel cathepsin C inhibitor, BI 1291583, intended for treatment of bronchiectasis: Phase I characterization in healthy volunteers

Novel treatments are needed to reduce inflammation, improve symptoms, address exacerbations, and slow disease progression in bronchiectasis. Cathepsin C (CatC) inhibition promises to achieve this through reduction of neutrophil-derived serine protease (including neutrophil elastase [NE] and proteinase 3 [PR3]) activation. Here, we present the phase I characterization of the novel CatC inhibitor, BI 1291583. Five phase I trials of BI 1291583 in healthy subjects are presented: a single-rising-dose study (NCT03414008) and two multiple-rising-dose studies (NCT03868540 and NCT04866160) assessing the safety, tolerability, pharmacodynamics, and pharmacokinetics of BI 1291583; a food effect study (NCT03837964); and a drug-drug interaction study (NCT03890887) of BI 1291583 and itraconazole. BI 1291583 was safe and well tolerated across the doses tested in these trials. Most adverse events (AEs) were mild or moderate in intensity, with no serious AEs, AEs of special interest or deaths reported in any trial. Drug-related skin exfoliation was not reported more frequently in subjects treated with BI 1291583 compared with placebo. BI 1291583 was readily absorbed, and pharmacokinetics were supra-proportional over the dose ranges assessed. Additionally, BI 1291583 inhibited CatC in a dose-dependent manner, inhibited downstream NE activity, and decreased PR3 levels. No food effect was observed. Co-administration of multiple doses of itraconazole increased BI 1291583 exposure approximately twofold. Due to these promising phase I results, a multinational phase II program of BI 1291583 in adults with bronchiectasis is ongoing (Airleaf™ [NCT05238675], Clairafly™ [NCT05865886], and Clairleaf™ [NCT05846230]).

Dry Powder Inhaler Formulation of Lactobacillus rhamnosus GG Targeting Pseudomonas aeruginosa Infection in Bronchiectasis Maintenance Therapy

The inhaled delivery of lactic acid bacteria (LAB) probiotics has been demonstrated to exert therapeutic benefits to the lungs due to LAB's immunomodulatory activities. The development of inhaled probiotics formulation, however, is in its nascent stage limited to nebulized LAB. We developed a dry powder inhaler (DPI) formulation of lactobacillus rhamnosus GG (LGG) intended for bronchiectasis maintenance therapy by spray freeze drying (SFD). The optimal DPI formulation (i.e., LGG: mannitol: lactose: leucine = 35: 45: 15: 5 wt.%) was determined based on the aerosolization efficiency (86% emitted dose and 26% respirable fraction) and LGG cell viability post-SFD (7 log CFU/mL per mg powder). The optimal DPI formulation was evaluated and compared to lyophilized naked LGG by its (1) adhesion capacity and cytotoxicity to human lung epithelium cells (i.e., A549 and 16HBE14o- cells) as well as its (2) effectiveness in inhibiting the growth and adhesion of Pseudomonas aeruginosa to lung cells. The optimal DPI of LGG exhibited similar non-cytotoxicity and adhesion capacity to lung cells to naked LGG. The DPI of LGG also inhibited the growth and adhesion of P. aeruginosa to the lung cells as effectively as the naked LGG. The present work established the feasibility of delivering the LAB probiotic by the DPI platform without adversely affecting LGG's anti-pseudomonal activities.

Microbiological characteristics of the lower airway in adults with bronchiectasis: a prospective cohort study

BACKGROUND

Microbial infection and colonization are frequently associated with disease progression and poor clinical outcomes in bronchiectasis. Identification of pathogen spectrum is crucial for precision treatment at exacerbation of bronchiectasis.

METHODS

We conducted a prospective cohort study in patients with bronchiectasis exacerbation onset and stable state. Bronchoalveolar lavage fluid (BALF) was collected for conventional microbiological tests (CMTs) and metagenomic Next-Generation Sequencing (mNGS). Bronchiectasis patients were monitored for documenting the time to the next exacerbation during longitudinal follow-up.

RESULTS

We recruited 168 eligible participants in the exacerbation cohorts, and 38 bronchiectasis patients at stable state at longitudinal follow-up. 141 bronchiectasis patients at exacerbation onset had definite or probable pathogens via combining CMTs with mNGS reports. We identified that Pseudomonas aeruginosa, non-tuberculous mycobacteria, Haemophilus influenzae, Nocardia spp, and Staphylococcus aureus were the top 5 pathogens with a higher detection rate in our cohorts via combination of CMTs and mNGS analysis. We also observed strong correlations of Pseudomonas aeruginosa, Haemophilus influenzae, non-tuberculous mycobacteria with disease severity, including the disease duration, Bronchiectasis Severity Index, and lung function. Moreover, the adjusted pathogenic index of potential pathogenic microorganism negatively correlated (r = -0.7280, p < 0.001) with the time to the next exacerbation in bronchiectasis.

CONCLUSION

We have revealed the pathogenic microbial spectrum in lower airways and the negative correlation of PPM colonization with the time to the next exacerbation in bronchiectasis. These results suggested that pathogens contribute to the progression of bronchiectasis.

Bronchiectasis in Asia: a review of current status and challenges

Recent bronchiectasis studies from large-scale multinational, multicentre registries have demonstrated that the characteristics of the disease vary according to geographic region. However, most perspectives on bronchiectasis are dominated by data from Western countries. This review intends to provide an Asian perspective on the disease, focusing on the established registries in India, Korea and China. Asian patients with bronchiectasis are less likely to show female predominance and experience exacerbations, are more likely to be younger, have milder disease, and have fewer options for guideline-recommended treatment than those living in other global regions. Furthermore, Asian bronchiectasis patients demonstrate different comorbidities, microbiological profiles and unique endophenotypes, including post-tuberculosis and dry bronchiectasis. Notably, each Asian region reveals further geographic variations and inter-patient differences. Future studies are warranted to better characterise Asian patients with bronchiectasis.

A Bispecific Monoclonal Antibody Targeting Psl and PcrV Enhances Neutrophil-Mediated Killing of Pseudomonas aeruginosa in Patients with Bronchiectasis

Rationale: Pseudomonas aeruginosa infection is associated with worse outcomes in bronchiectasis. Impaired neutrophil antimicrobial responses contribute to bacterial persistence. Gremubamab is a bivalent, bispecific monoclonal antibody targeting Psl exopolysaccharide and the type 3 secretion system component PcrV. Objectives: This study evaluated the efficacy of gremubamab to enhance killing of P. aeruginosa by neutrophils from patients with bronchiectasis and to prevent P. aeruginosa-associated cytotoxicity. Methods: P. aeruginosa isolates from a global bronchiectasis cohort (n = 100) underwent whole-genome sequencing to determine target prevalence. Functional activity of gremubamab against selected isolates was tested in vitro and in vivo. Patients with bronchiectasis (n = 11) and control subjects (n = 10) were enrolled, and the effect of gremubamab in peripheral blood neutrophil opsonophagocytic killing (OPK) assays against P. aeruginosa was evaluated. Serum antibody titers to Psl and PcrV were determined (n = 30; 19 chronic P. aeruginosa infection, 11 no known P. aeruginosa infection), as was the effect of gremubamab treatment in OPK and anti-cytotoxic activity assays. Measurements and Main Results: Psl and PcrV were conserved in isolates from chronically infected patients with bronchiectasis. Seventy-three of 100 isolates had a full psl locus, and 99 of 100 contained the pcrV gene, with 20 distinct full-length PcrV protein subtypes identified. PcrV subtypes were successfully bound by gremubamab and the monoclonal antibody-mediated potent protective activity against tested isolates. Gremubamab increased bronchiectasis patient neutrophil-mediated OPK (+34.6 ± 8.1%) and phagocytosis (+70.0 ± 48.8%), similar to effects observed in neutrophils from control subjects (OPK, +30.1 ± 7.6%). No evidence of competition between gremubamab and endogenous antibodies was found, with protection against P. aeruginosa-induced cytotoxicity and enhanced OPK demonstrated with and without addition of patient serum. Conclusions: Gremubamab enhanced bronchiectasis patient neutrophil phagocytosis and killing of P. aeruginosa and reduced virulence.

Usefulness of Impulse Oscillometry in Predicting the Severity of Bronchiectasis

BACKGROUND

Bronchiectasis is a chronic respiratory disease that leads to airway inflammation, destruction, and airflow limitation, which reflects its severity. Impulse oscillometry (IOS) is a non-invasive method that uses sound waves to estimate lung function and airway resistance. The aim of this study was to assess the usefulness of IOS in predicting the severity of bronchiectasis.

METHODS

We retrospectively reviewed the IOS parameters and clinical characteristics in 145 patients diagnosed with bronchiectasis between March 2020 and May 2021. Disease severity was evaluated using the FACED score, and patients were divided into mild and moderate/severe groups.

RESULTS

Forty-four patients (30.3%) were in the moderate/severe group, and 101 (69.7%) were in the mild group. Patients with moderate/severe bronchiectasis had a higher airway resistance at 5 Hz (R5), a higher difference between the resistance at 5 and 20 Hz (R5-R20), a higher resonant frequency (Fres), and a higher area of reactance (AX) than patients with mild bronchiectasis. R5 ≥0.43, resistance at 20 Hz (R20) ≥0.234, R5-R20 ≥28.3, AX ≥1.02, reactance at 5 Hz (X5) ≤-0.238, and Fres ≥20.88 revealed significant univariable relationships with bronchiectasis severity (p<0.05). Among these, only X5 ≤-0.238 exhibited a significant multivariable relationship with bronchiectasis severity (p=0.039). The receiver operating characteristic curve for predicting moderate- to-severe bronchiectasis of FACED score based on IOS parameters exhibited an area under the curve of 0.809.

CONCLUSION

The IOS assessed by the disease severity of FACED score can effectively reflect airway resistance and elasticity in bronchiectasis patients and serve as valuable tools for predicting bronchiectasis severity.

Infection and the microbiome in bronchiectasis

Bronchiectasis is marked by bronchial dilatation, recurrent infections and significant morbidity, underpinned by a complex interplay between microbial dysbiosis and immune dysregulation. The identification of distinct endophenotypes have refined our understanding of its pathogenesis, including its heterogeneous disease mechanisms that influence treatment and prognosis responses. Next-generation sequencing (NGS) has revolutionised the way we view airway microbiology, allowing insights into the "unculturable". Understanding the bronchiectasis microbiome through targeted amplicon sequencing and/or shotgun metagenomics has provided key information on the interplay of the microbiome and host immunity, a central feature of disease progression. The rapid increase in translational and clinical studies in bronchiectasis now provides scope for the application of precision medicine and a better understanding of the efficacy of interventions aimed at restoring microbial balance and/or modulating immune responses. Holistic integration of these insights is driving an evolving paradigm shift in our understanding of bronchiectasis, which includes the critical role of the microbiome and its unique interplay with clinical, inflammatory, immunological and metabolic factors. Here, we review the current state of infection and the microbiome in bronchiectasis and provide views on the future directions in this field.

Total sputum nitrate/nitrite is associated with exacerbations and Pseudomonas aeruginosa colonisation in bronchiectasis

Background

Sputum nitrate/nitrite, which is the main component of reactive nitrogen species, is a potential biomarker of disease severity and progression in bronchiectasis. This study aimed to determine the association between nitrate/nitrite and exacerbations and airway microbiota in bronchiectasis.

Methods

We measured total nitrate/nitrite concentration in sputum samples collected from 85 patients with stable bronchiectasis, performed 16S ribosomal RNA sequencing of sputum samples and predicted the denitrification ability of airway microbiota using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Relationships between sputum total nitrate/nitrite and disease severity, exacerbations and airway microbiota were examined.

Results

Higher total sputum nitrate/nitrite was associated with more severe bronchiectasis defined by E-FACED (exacerbation, forced expiratory volume in 1 s, age, chronic colonisation by Pseudomonas aeruginosa, radiological extension and dyspnoea) (p=0.003) or Bronchiectasis Severity Index (p=0.006) and more exacerbations in the prior 12 months (p=0.005). Moreover, total sputum nitrate/nitrite was significantly higher in patients with worse cough score (p=0.03), worse sputum purulence score (p=0.01) and worse Medical Research Council dyspnoea score (p=0.02). In addition, the total sputum nitrate/nitrite of the P. aeruginosa colonised (PA) group was higher than that of the non-P. aeruginosa colonised (NPA) group (p=0.04), and the relative abundance of P. aeruginosa was positively correlated with total nitrate/nitrite (r=0.337, p=0.002). Denitrification module (M00529) was also significantly enriched in the PA group compared to the NPA group through PICRUSt analyses. Using receiver-operating characteristic analysis, total nitrate/nitrite was associated with exacerbations during 1-year follow-up (area under the curve 0.741, p=0.014).

Conclusions

Sputum nitrate/nitrite is a biomarker of disease severity and associated with P. aeruginosa colonisation in bronchiectasis.

Bronchiectasis

Non-cystic fibrosis bronchiectasis, a condition that remains relatively underrecognized, has garnered increasing research focus in recent years. This scientific interest has catalyzed advancements in diagnostic methodologies, enabling comprehensive clinical and molecular profiling. Such progress facilitates the development of personalized treatment strategies, marking a significant step toward precision medicine for these patients. Bronchiectasis poses significant diagnostic challenges in both clinical settings and research studies. While computed tomography (CT) remains the gold standard for diagnosis, novel alternatives are emerging. These include artificial intelligence-powered algorithms, ultra-low dose chest CT, and magnetic resonance imaging (MRI) techniques, all of which are becoming recognized as feasible diagnostic tools. The precision medicine paradigm calls for refined characterization of bronchiectasis patients by analyzing their inflammatory and molecular profiles. Research into the underlying mechanisms of inflammation and the evaluation of biomarkers such as neutrophil elastase, mucins, and antimicrobial peptides have led to the identification of distinct patient endotypes. These endotypes present variable clinical outcomes, necessitating tailored therapeutic interventions. Among these, eosinophilic bronchiectasis is notable for its prevalence and specific prognostic factors, calling for careful consideration of treatable traits. A deeper understanding of the microbiome's influence on the pathogenesis and progression of bronchiectasis has inspired a holistic approach, which considers the multibiome as an interconnected microbial network rather than treating pathogens as solitary entities. Interactome analysis therefore becomes a vital tool for pinpointing alterations during both stable phases and exacerbations. This array of innovative approaches has revolutionized the personalization of treatments, incorporating therapies such as inhaled mannitol or ARINA-1, brensocatib for anti-inflammatory purposes, and inhaled corticosteroids specifically for patients with eosinophilic bronchiectasis.

Lung microbiome: new insights into bronchiectasis' outcome

The present treatments for bronchiectasis, which is defined by pathological dilatation of the airways, are confined to symptom relief and minimizing exacerbations. The condition is becoming more common worldwide. Since the disease's pathophysiology is not entirely well understood, developing novel treatments is critically important. The interplay of chronic infection, inflammation, and compromised mucociliary clearance, which results in structural alterations and the emergence of new infection, is most likely responsible for the progression of bronchiectasis. Other than treating bronchiectasis caused by cystic fibrosis, there are no approved treatments. Understanding the involvement of the microbiome in this disease is crucial, the microbiome is defined as the collective genetic material of all bacteria in an environment. In clinical practice, bacteria in the lungs have been studied using cultures; however, in recent years, researchers use next-generation sequencing methods, such as 16S rRNA sequencing. Although the microbiome in bronchiectasis has not been entirely investigated, what is known about it suggests that Haemophilus, Pseudomonas and Streptococcus dominate the lung bacterial ecosystems, they present significant intraindividual stability and interindividual heterogeneity. Pseudomonas and Haemophilus-dominated microbiomes have been linked to more severe diseases and frequent exacerbations, however additional research is required to fully comprehend the role of microbiome in the evolution of bronchiectasis. This review discusses recent findings on the lung microbiota and its association with bronchiectasis.

Bronchiectasis management in adults: state of the art and future directions

Formerly regarded as a rare disease, bronchiectasis is increasingly recognised. A renewed interest in this disease has led to significant progress in bronchiectasis research. Randomised clinical trials (RCTs) have demonstrated the benefits of airway clearance techniques, inhaled antibiotics and long-term macrolide therapy in bronchiectasis patients. However, the heterogeneity of bronchiectasis remains one of the most challenging aspects of management. Phenotypes and endotypes of bronchiectasis have been identified to help find "treatable traits" and partially overcome disease complexity. The goals of therapy for bronchiectasis are to reduce the symptom burden, improve quality of life, reduce exacerbations and prevent disease progression. We review the pharmacological and non-pharmacological treatments that can improve mucociliary clearance, reduce airway inflammation and tackle airway infection, the key pathophysiological features of bronchiectasis. There are also promising treatments in development for the management of bronchiectasis, including novel anti-inflammatory therapies. This review provides a critical update on the management of bronchiectasis focusing on treatable traits and recent RCTs.

Improving the Diagnosis and Treatment of Paediatric Bronchiectasis Through Research and Translation

Bronchiectasis, particularly in children, is an increasingly recognised yet neglected chronic lung disorder affecting individuals in both low-to-middle and high-income countries. It has a high disease burden and there is substantial inequity within and between settings. Furthermore, compared with other chronic lung diseases, considerably fewer resources are available for children with bronchiectasis. The need to prevent bronchiectasis and to reduce its burden also synchronously aligns with its high prevalence and economic costs to health services and society. Like many chronic lung diseases, bronchiectasis often originates early in childhood, highlighting the importance of reducing the disease burden in children. Concerted efforts are therefore needed to improve disease detection, clinical management and equity of care. Modifiable factors in the causal pathways of bronchiectasis, such as preventing severe and recurrent lower respiratory infections should be addressed, whilst also acknowledging the role played by social determinants of health. Here, we highlight the importance of early recognition/detection and optimal management of bronchiectasis in children, and outline our research, which is attempting to address important clinical knowledge gaps discussed in a recent workshop. The research is grouped under three themes focussing upon primary prevention, improving diagnosis and disease characterisation, and providing better management. Our hope is that others in multiple settings will undertake additional studies in this neglected field to further improve the lives of people with bronchiectasis. We also provide a resource list with links to help inform consumers and healthcare professionals about bronchiectasis and its recognition and management.

Impact of Rheumatoid Arthritis and Seropositivity on the Risk of Non-Cystic Fibrosis Bronchiectasis

BACKGROUND

Despite the coexistence of bronchiectasis and rheumatoid arthritis (RA) and the poor prognosis associated with the combination of conditions, to our knowledge, no longitudinal studies that comprehensively evaluated whether patients with RA have a higher risk of bronchiectasis compared with those without RA have been published. Whether seropositivity is associated with an increased risk of bronchiectasis in RA is the subject of ongoing controversy.

RESEARCH QUESTION

Does RA influence the development of bronchiectasis? Is seropositivity associated with an increased risk of bronchiectasis in RA?

STUDY DESIGN AND METHODS

The incidence of bronchiectasis was compared between individuals with RA (n = 50,651; seropositive rheumatoid arthritis [SPRA]: n = 35,879 and seronegative rheumatoid arthritis [SNRA]: n = 14,772) and 1:5 age- and sex-matched control patients (n = 253,255) enrolled between 2010 and 2017 in the Korean National Health Insurance Service database. The participants were followed from 1 year after RA diagnosis or the corresponding index date to the date of bronchiectasis incidence, censored date, or December 2019.

RESULTS

The cumulative incidence of bronchiectasis at 9 years of follow-up was approximately 7% in participants with RA. During a median follow-up of 4.3 years (interquartile range, 2.6-6.3 years), participants with RA showed a 2.12-fold higher risk of developing bronchiectasis than matched control participants, even after adjusting for potential confounders related to bronchiectasis development (95% CI, 2.00-2.25). In an analysis of RA serologic status using a fully adjusted model, participants with SPRA and those with SNRA showed 2.34-fold (95% CI, 2.20-2.49) and 1.56-fold (95% CI, 1.40-1.73) increased risks, respectively, compared with matched control participants.

INTERPRETATION

Individuals with RA had approximately twice the risk of developing bronchiectasis than matched control individuals, even after adjusting for potential confounders. The increased risk was more evident in individuals with SPRA than in those with SNRA, implying that rheumatic inflammation plays a major role in the development of RA-bronchiectasis overlap.

Erdosteine in children and adults with bronchiectasis (BETTER trial): study protocol for a multicentre, double-blind, randomised controlled trial

INTRODUCTION

Bronchiectasis is a worldwide chronic lung disorder where exacerbations are common. It affects people of all ages, but especially Indigenous populations in high-income nations. Despite being a major contributor to chronic lung disease, there are no licensed therapies for bronchiectasis and there remain relatively few randomised controlled trials (RCTs) conducted in children and adults. Our RCT will address some of these unmet needs by evaluating whether the novel mucoactive agent, erdosteine, has a therapeutic role in children and adults with bronchiectasis.Our primary aim is to determine in children and adults aged 2-49 years with bronchiectasis whether regular erdosteine over a 12-month period reduces acute respiratory exacerbations compared with placebo. Our primary hypothesis is that people with bronchiectasis who regularly use erdosteine will have fewer exacerbations than those receiving placebo.Our secondary aims are to determine the effect of the trial medications on quality of life (QoL) and other clinical outcomes (exacerbation duration, time-to-next exacerbation, hospitalisations, lung function, adverse events). We will also assess the cost-effectiveness of the intervention.

METHODS AND ANALYSIS

We are undertaking an international multicentre, double-blind, placebo-RCT to evaluate whether 12 months of erdosteine is beneficial for children and adults with bronchiectasis. We will recruit 194 children and adults with bronchiectasis to a parallel, superiority RCT at eight sites across Australia, Malaysia and Philippines. Our primary endpoint is the rate of exacerbations over 12 months. Our main secondary outcomes are QoL, exacerbation duration, time-to-next exacerbation, hospitalisations and lung function.

ETHICS AND DISSEMINATION

The Human Research Ethics Committees (HREC) of Children's Health Queensland (for all Australian sites), University of Malaya Medical Centre (Malaysia) and St. Luke's Medical Centre (Philippines) approved the study. We will publish the results and share the outcomes with the academic and medical community, funding and relevant patient organisations.

TRIAL REGISTRATION NUMBER

ACTRN12621000315819.

Dental management of Kartagener syndrome: A case report

BACKGROUND

Kartagener syndrome (KS) is recognized as an inherited, autosomal recessive disorder characterized by a combination of chronic sinusitis, bronchiectasis, and situs inversus. It affects one in 12,500-50,000 live births worldwide.

AIM

This paper aims to discuss the dental management of patients diagnosed with KS.

CASE REPORT

A 31-year-old male with KS manifests by impaired cilia motility which increases the risk of a frequent lung infection. The dental examination revealed that the patient required comprehensive oral hygiene care which included patient education and nonsurgical periodontal therapy under local anesthesia.

CONCLUSIONS

Dental care providers should ask affected patients with KS about their signs and symptoms of cardiac and pulmonary disease and seek consultation with their attending physician regarding these health concerns before the initiation of general anesthesia and perhaps conscious sedation administration. Patients with KS with emerging cardiac and/or respiratory impairment should be referred promptly for medical assessment.

Human nasal microbiota shifts in healthy and chronic respiratory disease conditions

BACKGROUND

An increasing number of studies investigate various human microbiotas and their roles in the development of diseases, maintenance of health states, and balanced signaling towards the brain. Current data demonstrate that the nasal microbiota contains a unique and highly variable array of commensal bacteria and opportunistic pathogens. However, we need to understand how to harness current knowledge, enrich nasal microbiota with beneficial microorganisms, and prevent pathogenic developments.

RESULTS

In this study, we have obtained nasal, nasopharyngeal, and bronchoalveolar lavage fluid samples from healthy volunteers and patients suffering from chronic respiratory tract diseases for full-length 16 S rRNA sequencing analysis using Oxford Nanopore Technologies. Demographic and clinical data were collected simultaneously. The microbiome analysis of 97 people from Lithuania suffering from chronic inflammatory respiratory tract disease and healthy volunteers revealed that the human nasal microbiome represents the microbiome of the upper airways well.

CONCLUSIONS

The nasal microbiota of patients was enriched with opportunistic pathogens, which could be used as indicators of respiratory tract conditions. In addition, we observed that a healthy human nasal microbiome contained several plant- and bee-associated species, suggesting the possibility of enriching human nasal microbiota via such exposures when needed. These candidate probiotics should be investigated for their modulating effects on airway and lung epithelia, immunogenic properties, neurotransmitter content, and roles in maintaining respiratory health and nose-brain interrelationships.

Pathophysiology of non-cystic fibrosis bronchiectasis in children and adolescents with asthma: A protocol for systematic review and meta-analysis

BACKGROUND

The pathophysiological mechanisms by which asthma and bronchiectasis are associated are still unclear. The association of these two diseases can result in more severe symptoms and a greater number of exacerbations.

OBJECTIVE

The aim of this systematic review is to collect evidence of the pathophysiology of non-cystic fibrosis bronchiectasis with associated asthma in children and adolescents, aged 6-18 years old.

METHODS

A systematic and comprehensive search will be performed using eight main databases, PubMed, PubMed PMC, BVS/BIREME, Scopus, EMBASE, Cochrane Library, Scielo and Web of Science. Articles will be searched from the earliest available time to July 2023. The studied population will be composed of children and adolescents with asthma and non-cystic fibrosis bronchiectasis. From the data obtained, all articles found will be transferred to the Rayyan platform. Study selection will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols Checklist (PRISMA P-2015). In addition, if sufficient data are available, a meta-analysis will be conducted. Two independent reviewers will conduct the studies selection, data extraction, and risk of bias assessment. The outcome measures will be to analyze if non-cystic fibrosis bronchiectasis is related to a specific inflammatory profile.

DISCUSSION

A systematic review will provide better knowledge about the etiopathogenesis and causes of the association between asthma and bronchiectasis and its role in the severity and control of asthma. Identifying, selecting and critically evaluating studies on asthma and bronchiectasis, would be possible to illuminate the characteristics of children and adolescents with associated diagnoses and provide information to help individualized treatments in order to control and prevent complications. The findings of this study will be published in a peer-reviewed journal.

SYSTEMATIC REVIEW REGISTRATION

The systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) in July 2023 (registration number CRD42023440355).