The role of non-invasive modalities for assessing inflammation in patients with non-cystic fibrosis bronchiectasis

Biomarkers in bronchiectasis

Bronchiectasis is a heterogeneous disease with multiple aetiologies and diverse clinical features. There is a general consensus that optimal treatment requires precision medicine approaches focused on specific treatable disease characteristics, known as treatable traits. Identifying subtypes of conditions with distinct underlying biology (endotypes) depends on the identification of biomarkers that are associated with disease features, prognosis or treatment response and which can be applied in clinical practice. Bronchiectasis is a disease characterised by inflammation, infection, structural lung damage and impaired mucociliary clearance. Increasingly there are available methods to measure each of these components of the disease, revealing heterogeneous inflammatory profiles, microbiota, radiology and mucus and epithelial biology in patients with bronchiectasis. Using emerging biomarkers and omics technologies to guide treatment in bronchiectasis is a promising field of research. Here we review the most recent data on biomarkers in bronchiectasis.

Increased TGFβ1, VEGF and IFN-γ in the Sputum of Severe Asthma Patients With Bronchiectasis

BACKGROUND

Bronchiectasis is one of the most common comorbidities in severe asthma. However, the mechanisms by which asthma promotes the development and progress of this condition are not well defined. This study aimed to analyze the inflammatory phenotypes and quantify the expression of proinflammatory and remodeling cytokines in asthma patients with and without bronchiectasis.

METHODS

The study sample comprised individuals with severe asthma and bronchiectasis (group AB, n=55) and a control population of individuals with severe asthma without bronchiectasis (group AC, n=45). Induced sputum samples were obtained and cell types determined by differential cell count. Proinflammatory and bronchial remodeling cytokines (IL-8, neutrophilic elastase, TGFβ1, VEGF, IFN-γ, TNF-α, and GM-CSF) were analyzed by immunoassay in sputum supernatant.

RESULTS

Neutrophilic inflammation was the primary phenotype in both asthma groups. Higher levels of TGFβ1, VEGF and IFN-γ were observed in asthma patients with bronchiectasis (group AB) than in controls (group AC) (15 vs 24pg/ml, p=0.014; 183 vs 272pg/ml, p=0.048; 0.85 vs 19pg/ml, p<0.001, respectively). Granulocyte-macrophage colony-stimulating factor (GM-CSF) levels were significantly lower in the AB group than in the AC group (1.2 vs 4.4pg/ml, p<0.001). IL-8, neutrophil elastase and TNF-α did not present significant differences between the groups.

CONCLUSIONS

Raised levels of TGFβ1 and VEGF cytokines may indicate airway remodeling activation in asthma patients with bronchiectasis. The type of inflammation in asthma patients did not differ according to the presence or absence of 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.

High-sensitivity C-reactive protein level in stable-state bronchiectasis predicts exacerbation risk

BACKGROUND

Elevation of systemic inflammatory markers were found to correlate with increased disease extent, reduced lung function and higher risk of future severe exacerbations in patients with bronchiectasis. Although a significant correlation of circulating hs-CRP levels with HRCT scores and resting oxygen saturation in patients with stable-state non-cystic fibrosis (CF) bronchiectasis was suggested, there is little data on the relationship between hs-CRP and the prognosis of bronchiectasis and a lack of data on the role of hs-CRP in predicting bronchiectasis exacerbation.

METHODS

A prospective study was conducted on Chinese patients with non- CF bronchiectasis from 1st October to 31st December 2021. Baseline serum hs-CRP were obtained at stable-state. The follow-up period lasted for one year. Co-primary endpoints were the development of any bronchiectasis exacerbation and hospitalized bronchiectasis exacerbation.

RESULTS

Totally 123 patients were included. Higher hs-CRP was associated with increased risk to develop any bronchiectasis exacerbation, adjusted odds ratio (aOR) of 2.254 (95% CI = 1.040-4.885, p = 0.039), and borderline significantly increased hospitalized bronchiectasis exacerbation with aOR of 1.985 (95% CI = 0.922-4.277, p = 0.080).

CONCLUSION

Baseline serum hs-CRP level at stable-state can predict risk of bronchiectasis exacerbation, which is reflecting chronic low-grade inflammation in bronchiectasis.

Effect of COVID-19 on Bronchiectasis Exacerbation Rates: A Retrospective U.S. Insurance Claims Study

Rationale: Bronchiectasis is a chronic, progressive disease of bronchial dilation, inflammation, and scarring leading to impaired mucociliary clearance and increased susceptibility to infection. Identified causes include previous severe respiratory infections. A small, single-center UK study demonstrated a reduction in bronchiectasis exacerbations during the first year of the coronavirus disease (COVID-19) pandemic. No studies have been conducted in a U.S. (commercially insured) cohort to date. Objectives: To explore the impact of the COVID-19 pandemic on the frequency of exacerbations in a large cohort of commercially insured U.S. patients with bronchiectasis by testing the hypothesis that U.S. patients with bronchiectasis had fewer exacerbations during the pandemic. Methods: This retrospective observational cohort study used health insurance claims data from Optum's deidentified Clinformatics Data Mart database, which included U.S. patients and their covered dependents. Eligible patients were ⩾18 years of age with bronchiectasis; patients with other respiratory conditions were excluded. The main study cohort excluded patients with frequent asthma and/or chronic obstructive pulmonary disease diagnoses. The primary objective was to compare the bronchiectasis exacerbation rates before and during the COVID-19 pandemic. Results: The median number of exacerbations per patient per year decreased significantly from the year before the COVID-19 pandemic to the first year of the pandemic (1 vs. 0; P < 0.01). More patients had zero exacerbations during the first year of the pandemic than the year prior (57% vs. 24%; McNemar's chi-square = 122.56; P < 0.01). Conclusions: In a U.S. population-based study of patients with International Classification of Diseases codes for bronchiectasis, the rate of exacerbations during Year 1 of the COVID-19 pandemic was reduced compared with the 2-year time period preceding the pandemic.

Real-World Investigation of Eosinophilic-Associated Disease Overlap (REVEAL): Analysis of a US Claims Database

PURPOSE

The epidemiology of eosinophil-associated diseases (EADs) is not yet fully understood. While some studies have been conducted on stand-alone eosinophilic diseases, there is scarce evidence on the degree of overlap among rarer conditions.

METHODS

The retrospective Real-world inVestigation of Eosinophilic-Associated disease overLap (REVEAL) study used data from the Optum® Clinformatics® insurance claims database to describe and characterize disease overlap among 11 EADs: allergic bronchopulmonary aspergillosis, atopic dermatitis, chronic rhinosinusitis with nasal polyps, eosinophilic gastritis/gastroenteritis, eosinophilic granulomatosis with polyangiitis, eosinophilic esophagitis, bullous pemphigoid, chronic obstructive pulmonary disorder, chronic spontaneous urticaria, and non-cystic fibrosis bronchiectasis. Patient records with EADs of interest were identified between January 1, 2015, and June 30, 2018.

RESULTS

Overall, 1,326,645 patients were included; 74.4% had 1 EAD, 20.5% had ≥ 2 EADs, and 5.1% had ≥ 3 EADs. Higher rates of disease overlap were associated with older age. Higher blood eosinophil counts were also observed in patients with a greater number of overlapping conditions, suggesting a common role for eosinophilic inflammation in the pathogenesis of multiple diseases. Furthermore, greater disease overlap was associated with higher disease severity in most cohorts.

CONCLUSIONS

Results from this study have implications for quantifying unmet needs and can be used to inform treatment guidelines and raise the awareness of eosinophilic inflammation and EAD overlap among healthcare professionals from a range of disease specialties.

Real-World Effectiveness of IL-5/5Ra Targeted Biologics in Severe Eosinophilic Asthma With Comorbid Bronchiectasis

BACKGROUND

Bronchiectasis is a common comorbidity in patients with asthma and is associated with increased disease severity. In patients with severe eosinophilic asthma, biologics targeting IL-5/5Ra have beneficial effects on oral corticosteroid (OCS) use and exacerbation frequency. However, how coexisting bronchiectasis affects the response to such treatments is unknown.

OBJECTIVE

To evaluate the real-world effectiveness of anti-IL-5/5Ra therapy in patients with severe eosinophilic asthma and comorbid bronchiectasis on exacerbation frequency and daily maintenance and cumulative OCS dose.

METHODS

This real-world study evaluated data from 97 adults with severe eosinophilic asthma and computed tomography-confirmed bronchiectasis from the Dutch Severe Asthma Registry, who initiated anti-IL5/5Ra biologics (mepolizumab, reslizumab, and benralizumab) and had follow-up data for 12 months or greater. The analysis was performed for the total population and subgroups with or without maintenance OCS use.

RESULTS

Anti-IL-5/5Ra therapy significantly reduced exacerbation frequency in patients with maintenance OCS use as well as in those without it. In the year before biologic initiation, 74.5% of all patients had two or more exacerbations, which decreased to 22.1% in the follow-up year (P < .001). The proportion of patients on maintenance OCS decreased from 47% to 30% (P < .001), and in the OCS-dependent patients (n = 45) maintenance OCS dose decreased from median (interquartile range) of 10.0 mg/d (5-15 mg/d) to 2.5 mg/d (0-5 mg/d) after 1 year (P < .001).

CONCLUSIONS

This real-world study shows that anti-IL-5/5Ra therapy reduces exacerbation frequency and daily maintenance as well as the cumulative OCS dose in patients with severe eosinophilic asthma and comorbid bronchiectasis. Although it is an exclusion criterion in phase 3 trials, comorbid bronchiectasis should not preclude anti-IL-5/5Ra therapy in patients with severe eosinophilic asthma.

Association of blood total immunoglobulin E and eosinophils with radiological features of bronchiectasis

BACKGROUND

Our study aimed to investigate whether serum total IgE and blood eosinophils were associated with radiological features of bronchiectasis in a Chinese cohort.

METHODS

We retrospectively enrolled bronchiectasis patients who visited Peking University Third Hospital from Jan 1st, 2012 to Oct 7th, 2021. The clinical, laboratory and chest CT characteristics were analyzed in association with serum total IgE level and blood eosinophil count.

RESULTS

A total of 125 bronchiectasis patients were enrolled, with 50.4% (63/125) female, and a mean age of 62.4 ± 14.1 years. The median serum total IgE level and blood eosinophil count were 47.7 (19.8, 123.0) KU/L and 140 (90, 230) cells/µl, respectively. In patients with a higher than normal (normal range, 0-60 KU/L) total IgE (43.2%, n = 54), more lobes were involved [4 (3, 5) vs. 3 (2, 4), p = 0.008], and mucus plugs were more common (25.9% vs. 9.9%, p =0.017) on HRCT, as compared to those with a normal level of total IgE. The higher IgE group was more likely to have bilateral involvement (p = 0.059), and had numerically higher Smith and Bhalla scores, but the differences were not statistically significant. In patients with an eosinophil count ≥ 150 cells/µl (49.6%, n = 62), the number of lobes involved was greater [4 (3, 5) vs. 3 (2, 4), p = 0.015], and the Smith and Bhalla scores were higher [9 (5, 12) vs. 6 (3, 9), p = 0.009, 7 (5, 11) vs. 5 (3, 9), p = 0.036]. The Smith score was correlated positively with the eosinophil count (r = 0.207, p = 0.020). Fractional exhaled nitric oxide (FeNO) was correlated with total IgE (r = 0.404, p = 0.001) and eosinophil count (r = 0.310, p = 0.014).

CONCLUSIONS

Our study demonstrated that serum total IgE and the blood eosinophil count were associated with the radiological extent and severity of bronchiectasis, necessitating further investigation on the role of T2 inflammation in structural abnormalities of this heterogeneous disease.

The effect of azithromycin on sputum inflammatory markers in bronchiectasis

BACKGROUND

Long term macrolide treatment has been found beneficial in bronchiectasis (BE) -pathogical bronchial dilatation- possibly due to a combined anti-bacterial and immunomodulatory effect. The exact mechanism of inflammatory response is unknown. Here, we investigated the effect of maintenance macrolide treatment on the inflammatory response in BE. In addition, we assessed the inflammatory profile in BE in relation to disease severity.

METHODS

During the BAT randomized controlled trial (investigating the effect of 1 year of azithromycin (AZM) in 83 BE patients), data on BE severity, lung function and sputum microbiology was collected. For the current study, a wide range of inflammatory markers were analysed in 3- monthly sputum samples in all participants.

RESULTS

At baseline, marked neutrophilic but also eosinophilic inflammation was present in both groups, which remained stable throughout the study and was not affected by AZM treatment. Significant upregulation of pro-inflammatory markers correlated with FEV₁ < 50% (TNFα, ECP, IL-21, IL-1, p = 0.01- 0.05), H. influenzae (HI) colonization (MPO, ECP, MIP-1, TNFα, IL-21, Il-8, IL-1, IL-1α, p < 0.001 - 0.04) and number of exacerbations (MPO, ECP, VEGF, MMP-9, p = 0.003 - 0.01). Surprisingly, colonization with P. aeruginosa (PA) was found to correlate with an attenuated inflammatory response compared to non-PA colonized. In placebo-treated patients, presence of an infectious exacerbation was reflected by a significant excessive increase in inflammation as compared to a non-significant upregulation in the AZM-treated patients.

CONCLUSION

One year of AZM treatment did not result in attenuation of the inflammatory response in BE. Increasing disease severity and the presence of an exacerbation were reflected by upregulation of pro-inflammatory markers.

Blood eosinophil percentage as a predictor of response to inhaled corticosteroid in bronchiectasis

INTRODUCTION

The role of inhaled corticosteroid (ICS) among patients with bronchiectasis remains controversial. There is limited evidence of using baseline eosinophil count (absolute and percentage) as a marker to predict the role of ICS among patients with bronchiectasis.

METHODS

A retrospective case-control study was conducted in a major regional hospital and tertiary respiratory referral centre in Hong Kong, including 140 Chinese patients with noncystic fibrosis (CF) bronchiectasis, to investigate the exacerbation risks of bronchiectasis among ICS users and nonusers with different baseline eosinophil counts.

RESULTS

ICS user had significantly lower risk to develop bronchiectasis exacerbation with adjusted odds ratio (OR) of 0.461 (95% confidence interval [CI] 0.225-0.945, p-value 0.035). Univariate logistic regression was performed for different cut-offs of blood eosinophil count (by percentage) from 2% to 4% (with a 0.5% grid each time). Baseline eosinophil 3.5% was found to be the best cut-off among all with adjusted OR of 0.138 (95% CI = 0.023-0.822, p-value = 0.030).

CONCLUSION

Baseline eosinophil count of 3.5% might serve as a marker to predict the benefits of ICS on exacerbation risk among patients with non-CF bronchiectasis.

Bronchiectasis in severe asthma is associated with eosinophilic airway inflammation and activation

Background

Bronchiectasis is a common comorbidity in severe asthma; causative pathogenic mechanisms are not fully understood but may differ from other causes of bronchiectasis. The role of eosinophilic airway inflammation, a classic feature of asthma predominantly driven by IL-5 and IL-13, in bronchiectasis is unclear, but association with disruption of the airway epithelium through eosinophil degranulation and increased mucus production is plausible.

Objective

We sought to describe the prevalence of bronchiectasis in an unselected population of patients with severe asthma, and the association with the airway eosinophilic inflammation and activation.

Methods

All patients with severe asthma according to European Respiratory Society/American Thoracic Society criteria (high-dose inhaled corticosteroids/oral corticosteroids), attending 4 respiratory clinics over a 1-year period, were included. All patients underwent high-resolution computed tomography and induced sputum was collected and analyzed for a cell differential count, free eosinophilic granules, and airway messenger RNA expression of T2 inflammatory pathways.

Results

Bronchiectasis was present in 31% (34 of 108) of patients with severe asthma, and half (52%) of these patients had airway eosinophilia whereas only 16% of patients without bronchiectasis had airway eosinophilia. Patients with bronchiectasis had a significantly higher sputum eosinophil count (5.3 vs 0.8; P = .001) as well as more extensive eosinophil degranulation, compared with those without bronchiectasis (13% vs 2%; P = .05), suggesting a higher degree of eosinophil activation. Pairwise analyses identified significantly higher messenger RNA expression of Charcot-Leyden crystal galectin in patients with bronchiectasis (P = .02).

Conclusions

Bronchiectasis in severe asthma was associated with eosinophilic airway inflammation and eosinophilic degranulation as well as messenger RNA expression of Charcot-Leyden crystal galectin.

Pathophysiology of Chronic Bronchial Infection in Bronchiectasis

Bronchiectasis is a complex and heterogeneous disease. Its pathophysiology is poorly understood, but chronic bronchial infection plays an important role in its natural history, and is associated with poor quality of life, more exacerbations and increased mortality. Pseudomonas aeruginosa, Haemophilus influenzae and Staphylococcus aureus are the most common bacteria related to chronic bronchial infection. Non-tuberculous mycobacteria, fungi and respiratory viruses are also present during clinical stability, and may increase the risk of acute exacerbation. Chronic inflammation is present in bronchiectasis, especially neutrophilic inflammation. However, macrophages and eosinophils also play a key role in the disease. Finally, airway epithelium has innate mechanisms such as mucociliary clearance and antibacterial molecules like mucins and antimicrobial peptides that protect the airways from pathogens. This review addresses how the persistence of microorganisms in the airways and the imbalance of the immune system contribute to the development of chronic bronchial infection in bronchiectasis.

Tiotropium in Patients with Bronchiectasis: A Prospective Cohort Study

PURPOSE

There are limited studies on the use of bronchodilators for the treatment of bronchiectasis. This study investigated the efficacy of tiotropium in patients with bronchiectasis and airflow limitation.

METHODS

This study was a prospective cohort study, including 169 patients with bronchiectasis and airflow limitation from 2015 to 2019. The clinical outcomes observed in our study were the effect of tiotropium on the frequency of moderate exacerbations, the time to the first severe exacerbation, and the annual decline in FEV₁.

RESULTS

After 12 months, the annual decline in the FEV₁ after bronchodilator use was 27.08 ml or 42.9 ml per year in the group with or without tiotropium, respectively. Treatment with tiotropium was associated with a decreased risk of moderate exacerbation of bronchiectasis (Adjusted RR 0.618 95% CI 0.493-0.774; P < 0.005). The time to the first severe acute exacerbation of bronchiectasis in the tiotropium group was longer than the non-tiotropium group (Adjusted HR 0.333 95% CI 0.219-0.506; P < 0.001).

CONCLUSION

In conclusion, prospective cohort study showed that tiotropium effectively ameliorated the annual decline in the FEV_1, with a lower-risk rate of moderate exacerbations and prolonging the time to the first-time severe exacerbation in patients with bronchiectasis and airflow limitation.

Insights into Personalised Medicine in Bronchiectasis

Bronchiectasis is a heterogenous disease with multiple aetiologies resulting in inflammation and dilatation of the airways with associated mucus production and chronic respiratory infection. The condition is being recognised ever more frequently as the availability of computed tomography increases. It is associated with significant morbidity and healthcare-related costs. With new understanding of the disease process, varying endotypes, identification of underlying causes and treatable traits, the management of bronchiectasis can be increasingly personalised.

High Level of Blood Eosinophils and Localization of Bronchiectasis in Patients with Severe Asthma: A Pilot Study

Background. Severe asthma and bronchiectasis are heterogeneous diseases that frequently coexist. The location of bronchiectasis is generally determined by specific underlying pathophysiological mechanisms. The aim of this study was to determine whether in a population suffering from both severe asthma and bronchiectasis there was a correlation between eosinophilic inflammation and localization of bronchiectasis. Methods. We enrolled 41 patients with coexisting bronchiectasis from eight different severe asthma center outpatient clinics and collected the following data: baseline characteristics, Asthma Control Test, Asthma Control Questionnaire, IgE level, blood count, high-resolution computed tomography and bronchiectasis-related parameters, skin prick test, FeNO50 and flow-volume spirometry. The study was retrospectively registered. Results. The presence of eosinophils > 1000 cells/μL was related to distribution of lower pulmonary bronchiectasis (9.1% upper lobes vs. 53.3% lower lobes, p = 0.014). Indeed, the presence of eosinophilic counts > 1000 increased the probability of lower localization of bronchiectasis compared to upper lobes (ODD 0.088 (0.010−0.772), p = 0.028). Conclusions. An increase in blood eosinophils > 1000 cells/μL seems to be associated with lower preferential localization of bronchiectasis with sparing of the upper lung lobes. This could represent a new potential radiological phenotype that could have a dedicated therapeutic strategy in the future.

Simultaneous evaluation of the fractional exhaled nitric oxide and blood eosinophil count of T2-high endotype in patients with non-cystic fibrosis bronchiectasis

OBJECTIVE

Recently, a type 2 inflammation (T2) high endotype in bronchiectasis was identified. The fraction of exhaled nitric oxide (FeNO) and blood eosinophil count (BEC) are recognized as representative biomarkers of T2 inflammation. Herein, we investigate the clinical characteristics of T2-high endotype in non-cystic fibrosis bronchiectasis patients classified by FeNO and BEC.

METHODS

This retrospective study included 164 bronchiectasis patients treated in the First Affiliated Hospital of Sun Yat-sen University from December 2017 to July 2022. Clinical characteristics were analyzed after classifying patients into four groups according to T2 inflammation biomarkers (FeNO ≥25 ppb; BEC ≥200/µL).

RESULTS

Among the 164 bronchiectasis patients, 35.3% (58/164) presented with high FeNO, 30.5% (50/164) presented with high BEC, and 10.4% (17/164) had high FeNO and BEC. Patients with high FeNO and low BEC presented with better lung function, fewer affected lobes, and lower dyspnea prevalence compared with the three other groups. Moreover, decreased FeNO, instead of decreased BEC, is revealed to be an independent predictor for disease severity and airflow obstruction in bronchiectasis.

CONCLUSIONS

Simultaneous evaluation of FeNO and BEC proposed different endotypes of bronchiectasis established that patients with low BEC and high FeNO had better lung function, fewer affected lobes, lower dyspnea prevalence, and less disease severity. This result will contribute to a more comprehensive assessment of the disease severity and lead to more precise treatment of T2 inflammation in bronchiectasis patients.

CC16 as an Inflammatory Biomarker in Induced Sputum Reflects Chronic Obstructive Pulmonary Disease (COPD) Severity

Purpose

The progression of an abnormal inflammatory response plays a crucial role in the lung function decline of chronic obstructive pulmonary disease (COPD) patients. Compared to serum biomarkers, inflammatory biomarkers in induced sputum would be a more reliable reflection of inflammatory processes in the airways.

Patients and Methods

A total of 102 COPD participants were divided into a mild-to-moderate group (FEV1%pred≥ 50%, n=57) and a severe-to-very-severe group (FEV1%pred<50%, n=45). We measured a series of inflammatory biomarkers in induced sputum and analyzed their association with lung function and SGRQ in COPD patients. To evaluate the relationship between inflammatory biomarkers and the inflammatory phenotype, we also analyzed the correlation between biomarkers and airway eosinophilic phenotype.

Results

We found increased mRNA levels of MMP9, LTB4R, and A1AR and decreased levels of CC16 mRNA in induced sputum in the severe-to-very-severe group. After adjustment for age, sex and other biomarkers, CC16 mRNA expression was positively associated with FEV1%pred (r=0.516, p=0.004) and negatively correlated with SGRQ scores (r=-0.3538, p=0.043). As previously known, decreased CC16 was related to the migration and aggregation of eosinophils in airway. It was also found that CC16 had a moderate negative correlation with the eosinophilic inflammation in airway (r=-0.363, p=0.045) in our COPD patients.

Conclusion

Low CC16 mRNA expression levels in induced sputum were associated with low FEV1%pred and a high SGRQ score in COPD patients. Sputum CC16 as a potential biomarker for predicting COPD severity in clinical practice might attribute to the involvement of CC16 in airway eosinophilic inflammation.

Inhaled Corticosteroids in Adults with Non-cystic Fibrosis Bronchiectasis: From Bench to Bedside. A Narrative Review

Due to their potent anti-inflammatory capacity (particularly in predominantly eosinophilic inflammation) and immunosuppressive properties, inhaled corticosteroids (ICSs) are widely used in asthmatic patients and also in individuals with chronic obstructive pulmonary disease (COPD) who suffer multiple exacerbations or have peripheral eosinophilia. However, there is little evidence for their use in non-cystic fibrosis bronchiectasis (hereafter, bronchiectasis). According to data extracted from large databases of bronchiectasis in adults, ICSs are used in more than 50% of patients without any scientific evidence to justify their efficacy and contrary to the recommendations of international guidelines on bronchiectasis that generally advise against their use. Indeed, bronchiectasis is a disease with predominantly neutrophilic inflammation and a high likelihood of chronic bacterial bronchial infection. Furthermore, it is known that due to their immunosuppressive properties, ICSs can induce an increase in bacterial infections. This manuscript aims to review the basic properties of ICSs, how they impact bronchiectasis in adults, the current position of international guidelines on this treatment, and the current indications and future challenges related to ICS use in bronchiectasis.

CXC Chemokines in the Pathogenesis of Pulmonary Disease and Pharmacological Relevance

Chemokines and their receptors play important roles in the pathophysiology of many diseases by regulating the cellular migration of major inflammatory and immune players. The CXC motif chemokine subfamily is the second largest family, and it is further subdivided into ELR motif CXC (ELR+) and non-ELR motif (ELR-) CXC chemokines, which are effective chemoattractants for neutrophils and lymphocytes/monocytes, respectively. These chemokines and their receptors are expected to have a significant impact on a wide range of lung diseases, many of which have inflammatory or immunological underpinnings. As a result, manipulations of this subfamily of chemokines and their receptors using small molecular agents and other means have been explored for potential therapeutic benefit in the setting of several lung pathologies. Furthermore, encouraging preclinical data has necessitated the progression of a few of these drugs into clinical trials in order to make the most effective use of interventions in the development of viable targeted therapeutics. The current review presents the understanding of the roles of CXC ligands (CXCLs) and their cognate receptors (CXCRs) in the pathogenesis of several lung diseases such as allergic rhinitis, COPD, lung fibrosis, lung cancer, pneumonia, and tuberculosis. The potential therapeutic benefits of pharmacological or other CXCL/CXCR axis manipulations are also discussed.

Strong and consistent associations of precedent chronic rhinosinusitis with risk of non-cystic fibrosis bronchiectasis

BACKGROUND

Chronic rhinosinusitis (CRS) and bronchiectasis commonly co-occur, but most prior studies were not designed to evaluate temporality and causality.

OBJECTIVES

In a sample representing the general population in 37 counties in Pennsylvania, and thus the full spectrum of sinonasal and relevant lung diseases, we aimed to evaluate the temporality and strength of associations of CRS with non-cystic fibrosis bronchiectasis.

METHODS

We completed case-control analyses for each of 3 primary bronchiectasis case finding methods. We used electronic health records to identify CRS and bronchiectasis with diagnoses, procedure orders, and/or specific text in sinus or chest computerized tomography scan radiology reports. The controls never had any indication of bronchiectasis and were frequency-matched to the 3 bronchiectasis groups on the basis of age, sex, and encounter year. There were 5,329 unique persons with bronchiectasis and 33,363 without bronchiectasis in the 3 analyses. Important co-occurring conditions were identified with diagnoses, medication orders, and encounter types. Logistic regression was used to evaluate associations (odds ratios [ORs] and 95% CIs) of CRS with bronchiectasis while adjusting for confounding variables.

RESULTS

In adjusted analyses, CRS was consistently and strongly associated with all 3 bronchiectasis definitions. The strongest associations for CRS (ORs and 95% CIs) were those that were based on the text of sinus computerized tomography scan reports; the associations were generally stronger for CRS without nasal polyps (eg, OR = 4.46 [95% CI = 2.09-9.51] for diagnosis-based bronchiectasis). On average, CRS was identified more than 6 years before bronchiectasis.

CONCLUSION

Precedent CRS was strongly and consistently associated with increased risk of bronchiectasis.

Characterization of Eosinophilic Bronchiectasis: A European Multicohort Study

Rationale: Bronchiectasis is classically considered a neutrophilic disorder, but eosinophilic subtypes have recently been described. Objectives: To use multiple datasets available through the European Multicentre Bronchiectasis Audit and Research Collaboration to characterize eosinophilic bronchiectasis as a clinical entity focusing on the impact of eosinophils on bronchiectasis exacerbations. Methods: Patients were included from five countries to examine the relationships between blood eosinophil counts and clinical phenotypes after excluding coexisting asthma. 16S rRNA sequencing was used to examine relationships between eosinophil counts and the sputum microbiome. A post hoc analysis of the PROMIS (Inhaled Promixin in the Treatment of Non-Cystic Fibrosis Bronchiectasis) phase 2 trial was used to examine the impact of blood eosinophil counts on exacerbations in patients with Pseudomonas aeruginosa infection. Measurements and Main Results: A relationship between sputum and blood eosinophil counts was demonstrated in two cohorts. In analysis of 1,007 patients from five countries, 22.6% of patients had blood eosinophil counts of ⩾300 cells/μl. Counts of <100 cells/μl were associated with higher bronchiectasis severity and increased mortality. There was no clear relationship with exacerbations. Blood eosinophil counts of ⩾300 cells/μl were associated with both Streptococcus- and Pseudomonas-dominated microbiome profiles. To investigate the relationship of eosinophil counts with exacerbations after controlling for the confounding effects of infection, 144 patients were studied in a clinical trial after treatment with antipseudomonal antibiotics. Compared with patients with blood eosinophil counts of <100 cells/μl (reference), elevated eosinophil counts of 100-299 cells/μl (hazard ratio, 2.38; 95% confidence interval, 1.33-4.25; P = 0.003) and ⩾300 cells/μl (hazard ratio, 3.99; 95% confidence interval, 2.20-7.85; P < 0.0001) were associated with shorter time to exacerbation. Conclusions: Eosinophilic bronchiectasis affects approximately 20% of patients. After accounting for infection status, raised blood eosinophil counts are associated with shortened time to exacerbation.

Neutrophil extracellular traps in chronic lung disease: implications for pathogenesis and therapy

Neutrophilic inflammation has a key role in the pathophysiology of multiple chronic lung diseases. The formation of neutrophil extracellular traps (NETs) has emerged as a key mechanism of disease in neutrophilic lung diseases including asthma, COPD, cystic fibrosis and, most recently, bronchiectasis. NETs are large, web-like structures composed of DNA and anti-microbial proteins that are able to bind pathogens, prevent microbial dissemination and degrade bacterial virulence factors. The release of excess concentrations of proteases, antimicrobial proteins, DNA and histones, however, also leads to tissue damage, impaired mucociliary clearance, impaired bacterial killing and increased inflammation. A number of studies have linked airway NET formation with greater disease severity, increased exacerbations and overall worse disease outcomes across the spectrum of airway diseases. Treating neutrophilic inflammation has been challenging in chronic lung disease because of the delicate balance between reducing inflammation and increasing the risk of infections through immunosuppression. Novel approaches to suppressing NET formation or the associated inflammation are in development and represent an important therapeutic target. This review will discuss the relationship between NETs and the pathophysiology of cystic fibrosis, asthma, COPD and bronchiectasis, and explore the current and future development of NET-targeting therapies.

NETs contribute to the pathophysiology of chronic lung disease. Immunomodulating therapies that may reduce inflammatory mediators and NET formation, without compromising bacterial clearance, offer a new treatment path for patients. https://bit.ly/3fyJC6I

Precision medicine in bronchiectasis

Bronchiectasis, due to its highly heterogenous nature, requires an individualised approach to therapy. Patients experience symptoms and exacerbations driven by a combination of impaired mucociliary clearance, airway inflammation and airway infection. Treatment of bronchiectasis aims to enhance airway clearance and to address the underlying causes of inflammation and infection susceptibility. Bronchiectasis has multiple causes and so the pathophysiology leading to individual symptoms and exacerbations are different between individuals. Standardised investigations are recommended by international guidelines to identify the underlying causes of bronchiectasis. The process of identifying the underlying biology within an individual is called “endotyping” and is an emerging concept across chronic diseases. Endotypes that have a specific treatment are referred to as “treatable traits” and a treatable traits approach to managing patients with bronchiectasis in a holistic and evidence-based manner is the key to improved outcomes. Bronchiectasis is an area of intense research. Endotyping allows identification of subsets of patients to allow medicines to be tested differently in the future where trials, rather than trying to achieve a “one size fits all” solution, can test efficacy in subsets of patients where the treatment is most likely to be efficacious.

Bronchiectasis, due to its highly heterogenous nature, requires an individualised approach to therapy. Treatment targets symptoms and exacerbations by aiming to improve mucociliary clearance and to reduce airway inflammation and airway infection.https://bit.ly/3ite4B2

Nationwide survey of refractory asthma with bronchiectasis by inflammatory subtypes

RATIONALE

Bronchiectasis and bronchiolitis are differential diagnoses of asthma; moreover, they are factors associated with worse asthma control.

OBJECTIVE

We determined clinical courses of bronchiectasis/bronchiolitis-complicated asthma by inflammatory subtypes as well as factors affecting them.

METHODS

We conducted a survey of refractory asthma with non-cystic fibrosis bronchiectasis/bronchiolitis in Japan. Cases were classified into three groups, based on the latest fractional exhaled NO (FeNO) level (32 ppb for the threshold) and blood eosinophil counts (320/µL for the threshold): high (type 2-high) or low (type 2-low) FeNO and eosinophil and high FeNO or eosinophil (type 2-intermediate). Clinical courses in groups and factors affecting them were analysed.

RESULTS

In total, 216 cases from 81 facilities were reported, and 142 were stratified: 34, 40 and 68 into the type 2-high, -intermediate and -low groups, respectively. The frequency of bronchopneumonia and exacerbations requiring antibiotics and gram-negative bacteria detection rates were highest in the type 2-low group. Eighty-seven cases had paired latest and oldest available data of FeNO and eosinophil counts; they were analysed for inflammatory transition patterns. Among former type 2-high and -intermediate groups, 32% had recently transitioned to the -low group, to which relatively low FeNO in the past and oral corticosteroid use contributed. Lastly, in cases treated with moderate to high doses of inhaled corticosteroids, the frequencies of exacerbations requiring antibiotics were found to be higher in cases with more severe airway lesions and lower FeNO.

CONCLUSIONS

Bronchiectasis/bronchiolitis-complicated refractory asthma is heterogeneous. In patients with sputum symptoms and low FeNO, airway colonisation of pathogenic bacteria and infectious episodes are common; thus, corticosteroids should be carefully used.

Bronchiectasis in severe asthma and asthmatic components in bronchiectasis

Asthma and bronchiectasis are different diseases; however, differentiating them can be difficult because they share several symptomatic and physiological similarities. Approximately 20% of patients with bronchiectasis have eosinophilic inflammation, 34% show wheezing, and 7-46% have comorbid asthma, although comorbidity with severe asthma may be limited as shown in 3.3% of cases of bronchiectasis. Meanwhile, 25-68% of patients with severe asthma have comorbid bronchiectasis, and at least two phenotypes are present in the accompanying bronchiectasis: eosinophilic bronchiectasis and chronic infectious bronchiolitis/bronchiectasis. Recent studies show that type-2-targeted biologics are effective for eosinophilic bronchiectasis and theoretically effective for some of the remaining cases when used before oral corticosteroids. Further studies are needed to identify treatment strategies for severe asthma with comorbid bronchiectasis and vice versa.

Inhaled Corticosteroid Therapy in Bronchiectasis is Associated with All-Cause Mortality: A Prospective Cohort Study

Background and Objective

Prescribing inhaled corticosteroids (ICS) for bronchiectasis (BE) in the absence of obstructive lung disease is controversial. Studies investigating ICS therapy and impact on morbidity and mortality in BE are sparse.

Methods

This study comprises all patients with BE managed at respiratory outpatient clinics at two university hospitals in the Capital Region of Denmark 2014-2015. Baseline data were obtained from patient medical records, and patients were followed until April 2020.

Results

Out of 264 patients, 122 (46%) were prescribed ICS with no demographic differences between users/non-users of ICS. Among patients prescribed ICS, 21% did not have a concomitant diagnosis of asthma or COPD. Patients prescribed ICS had lower lung function (median FEV1 65.2 vs 80.9%pred, p<0.001) and a higher symptom burden in terms of cough (p 0.028), sputum production (p <0.001) and dyspnea (p <0.001). Pseudomonas-positive sputum cultures were more common in ICS-treated patients (6.5 vs 20%, p 0.010), as were previous severe exacerbations (41% vs 21%, p <0.001). In terms of mortality, high-dose ICS use was associated with increased mortality in multivariable Cox regression adjusted for age, sex, FEV1 and concomitant asthma/COPD (HR 4.93 [95% CI 1.73-14.0], p 0.003).

Conclusion

In this cohort, close to one out of five patients with BE were prescribed ICS despite having no concomitant diagnosis of asthma or COPD. Overall, ICS treatment was associated with higher morbidity and mortality, though causation is difficult to establish.

Pathophysiology of Bronchiectasis

Bronchiectasis is a complex, heterogeneous disorder defined by both a radiological abnormality of permanent bronchial dilatation and a clinical syndrome. There are multiple underlying causes including severe infections, mycobacterial disease, autoimmune conditions, hypersensitivity disorders, and genetic conditions. The pathophysiology of disease is understood in terms of interdependent concepts of chronic infection, inflammation, impaired mucociliary clearance, and structural lung damage. Neutrophilic inflammation is characteristic of the disease, with elevated levels of harmful proteases such as neutrophil elastase associated with worse outcomes. Recent data show that neutrophil extracellular trap formation may be the key mechanism leading to protease release and severe bronchiectasis. Despite the dominant of neutrophilic disease, eosinophilic subtypes are recognized and may require specific treatments. Neutrophilic inflammation is associated with elevated bacterial loads and chronic infection with organisms such as Pseudomonas aeruginosa. Loss of diversity of the normal lung microbiota and dominance of proteobacteria such as Pseudomonas and Haemophilus are features of severe bronchiectasis and link to poor outcomes. Ciliary dysfunction is also a key feature, exemplified by the rare genetic syndrome of primary ciliary dyskinesia. Mucus symptoms arise through goblet cell hyperplasia and metaplasia and reduced ciliary function through dyskinesia and loss of ciliated cells. The contribution of chronic inflammation, infection, and mucus obstruction leads to progressive structural lung damage. The heterogeneity of the disease is the most challenging aspect of management. An understanding of the pathophysiology of disease and their biomarkers can help to guide personalized medicine approaches utilizing the concept of "treatable traits."

T2-High Endotype and Response to Biological Treatments in Patients with Bronchiectasis

Although bronchiectasis pathophysiology has been historically understood around the presence of airway neutrophilic inflammation, recent experiences are consistent with the identification of a type 2 inflammation (T2) high endotype in bronchiectasis. In order to evaluate prevalence and clinical characteristics of bronchiectasis patients with a T2-high endotype and explore their response to biologicals, two studies were carried out. In a cross-sectional study, bronchiectasis adults without asthma underwent clinical, radiological, and microbiological assessment, along with blood eosinophils and oral fractional exhaled nitric oxide (FeNO) evaluation, during stable state. Prevalence and characteristics of patients with a T2- high endotype (defined by the presence of either eosinophils blood count ≥300 cells·µL⁻¹ or oral FeNO ≥ 25 dpp) were reported. A case series of severe asthmatic patients with concomitant bronchiectasis treated with either mepolizumab or benralizumab was evaluated, and patients’ clinical data pre- and post-treatment were analyzed up to 2 years of follow up. Among bronchiectasis patients without asthma enrolled in the cross-sectional study, a T2-high endotype was present in 31% of them. These patients exhibited a more severe disease, high dyspnea severity, low respiratory function, and high impact on quality of life. Among the five patients with severe eosinophilic asthma and concomitant bronchiectasis included in the series, treatment with either mepolizumab or benralizumab significantly reduced the exacerbation rate with an effect that persists for up to 2 years of follow up. If validated across different settings, our data suggest the need to design randomized controlled trials on biological treatments targeting the T2-high endotype in bronchiectasis patients.

Comorbidities and mortality risk factors for patients with bronchiectasis

Introduction: Comorbidities in patients with bronchiectasis are common and have a significant impact on clinical outcomes, contributing to lower quality of life, lung function, and exacerbation frequency. At least 13 comorbidities have been associated with a higher risk of mortality in bronchiectasis patients. Nonetheless, the kind of relationship between bronchiectasis and comorbidities is heterogeneous and poorly understood.Areas covered: different biological mechanisms leading to bronchiectasis could have a role in the development of the associated comorbidities. Some comorbidities could have a causal relationship with bronchiectasis, possibly through a variable degree of systemic inflammation, such as in rheumatic disorders and bowel inflammatory diseases. Other comorbidities, such as COPD or asthma, could be associated through airway inflammation and there is an uncertain cause-effect relationship. Finally, shared risk factors could link different comorbidities to bronchiectasis such as in the case of cardiovascular diseases, where the known link between chronic systemic inflammation and pulmonary infection could play a significant role.Expert opinion: Although different tools have been developed to assess the role of comorbidities in bronchiectasis , we believe that the implementation of current strategies to manage them is absolutely necessary and could significantly improve long-term prognosis in patients with bronchiectasis.

Impact of asthma on bronchiectasis severity and risk of exacerbations

OBJECTIVE

Asthma is a frequent comorbidity of bronchiectasis, with possible implications for exacerbation and severity. We investigated the clinical impact of asthma on bronchiectasis in terms of disease severity and exacerbation risk.

METHODS

We collected demographic, clinical, and functional characteristics of patients with a confirmed diagnosis of bronchiectasis. All patients were investigated for concomitant diagnosis of asthma. The Bhalla score was used to assess radiological severity of bronchiectasis, and the Bronchiectasis Severity Index (BSI) was used to assess the clinical severity. Blood and sputum samples were collected to assess blood cell count, erythrocyte sedimentation rate, c-reactive protein, immunological status (IgA, IgE, IgM, IgG, and IgG subclasses), and microbiological analysis.

RESULTS

A total of 106 patients were enrolled in the study; 30.2% had concomitant asthma and were characterized by higher frequency of bronchiectasis exacerbation, despite higher Bhalla score and lower BSI compared to patients without asthma. Pseudomonas aeruginosa was more frequently isolated from the sputum of bronchiectasis patients without asthma. Total serum IgG, IgG1, and IgG3 were lower in patients with asthma. Blood eosinophils and exhaled nitric oxide were higher in patients with associated asthma. The presence of asthma and presence of Pseudomonas in sputum were the only significant determinants of frequent exacerbations in a binary logistic regression analysis.

CONCLUSION

The coexistence of asthma and bronchiectasis is associated with an independent increase in the risk of bronchiectasis exacerbation despite lower radiological and clinical severity indexes. Asthmatic airway inflammation could promote an enhanced "Cole's Cycle" that is responsible for a higher frequency of exacerbations.

Clinical features associated with a doctor-diagnosis of bronchiectasis in the Severe Asthma Network in Italy (SANI) registry

BACKGROUND

Several severe asthma comorbidities have been identified: an emerging one is bronchiectasis. We evaluated the frequency of bronchiectasis on severe asthma in a real-life setting, through the 'Severe Asthma Network Italy' (SANI) registry.

METHODS

SANI registry encompasses demographic, clinical, functional and inflammatory data of Italian severe asthmatics. Data obtained by the enrolled patients were analyzed, focusing the attention on those patients with concomitant clinically relevant bronchiectasis.

RESULTS

About 15.5% patients have bronchiectasis. Bronchiectasis diagnosis was associated with a higher prevalence of chronic rhinosinusitis with nasal polyps (54.6% vs. 38%, p = 0.001) and higher serum IgE levels (673.4 vs. 412.1 kUI/L, p = 0.013). Patients with bronchiectasis had worse asthma control (ACT: 16.7 vs 18.2, p = 0.013), worse quality of life (AQLQ: 4.08 vs. 4.60, p = 0.02) and lower lung function (FEV₁% predicted 67.3 vs. 75.0, p = 0.002). A higher rate of severe asthma exacerbations in the previous 12 months (85.2% vs. 61.5%, p < 0.001) was found in patients with bronchiectasis.

CONCLUSION

severe asthma associated with bronchiectasis represents a particularly severe asthma variant, possibly driven by an eosinophilic endotype. We, therefore, suggest that bronchiectasis should necessarily be assessed in severe asthmatic patients.

Sputum neutrophil elastase associates with microbiota and Pseudomonas aeruginosa in bronchiectasis

INTRODUCTION

Neutrophilic inflammation is a major driver of bronchiectasis pathophysiology, and neutrophil elastase activity is the most promising biomarker evaluated in sputum to date. How active neutrophil elastase correlates with the lung microbiome in bronchiectasis is still unexplored. We aimed to understand whether active neutrophil elastase is associated with low microbial diversity and distinct microbiome characteristics.

METHODS

An observational, cross-sectional study was conducted at the bronchiectasis programme of the Policlinico Hospital in Milan, Italy, where adults with bronchiectasis were enrolled between March 2017 and March 2019. Active neutrophil elastase was measured on sputum collected during stable state, microbiota analysed through 16S rRNA gene sequencing, molecular assessment of respiratory pathogens carried out through real-time PCR and clinical data collected.

RESULTS

Among 185 patients enrolled, decreasing α-diversity, evaluated through the Shannon entropy (ρ -0.37, p<0.00001) and Pielou's evenness (ρ -0.36, p<0.00001) and richness (ρ -0.33, p<0.00001), was significantly correlated with increasing elastase. A significant difference in median levels of Shannon entropy as detected between patients with neutrophil elastase ≥20 µg·mL^-1 (median 3.82, interquartile range 2.20-4.96) versus neutrophil elastase <20 µg·mL^-1 (4.88, 3.68-5.80; p<0.0001). A distinct microbiome was found in these two groups, mainly characterised by enrichment with Pseudomonas in the high-elastase group and with Streptococcus in the low-elastase group. Further confirmation of the association of Pseudomonas aeruginosa with elevated active neutrophil elastase was found based on standard culture and targeted real-time PCR.

CONCLUSIONS

High levels of active neutrophil elastase are associated to low microbiome diversity and specifically to P. aeruginosa infection.

The Link between Asthma and Bronchiectasis: State of the Art

The nonrecognition of asthma-associated comorbidities is often responsible for the therapeutic failure and the worsening of symptoms, and it is associated with frequent exacerbations, higher disease severity, and increased health costs. Bronchiectasis, one of the most frequent asthma-associated comorbidities, can increase airways inflammation and exacerbation rates and cause respiratory functional impairment. The aim of this article is to review the interactions between bronchiectasis and asthma, in order to better identify patients in the overlap between the 2 diseases and to select an "ad hoc" therapy. A literature search on PubMed/MEDLINE was performed using the following search terms: bronchiectasis in asthma, the association between asthma and bronchiectasis, comorbidities in asthma, and severe asthma. This review analyzed the following items: incorrect or underestimated diagnosis of asthma and bronchiectasis, prevalence of bronchiectasis in asthma, the impact of bronchiectasis in asthma, radiological imaging features of the 2 diseases, etiopathogenesis, and common causes (such as gastroesophageal reflux disease, immune deficits, chronic rhinosinusitis and allergic bronchopulmonary aspergillosis, and treatment of asthma and bronchiectasis). The concomitant presence of bronchiectasis and asthma should be suspected and investigated in patients with severe asthma, frequent exacerbations, and not responding to standard therapy. This clinical phenotype, characterized by a more severe disease, worse outcomes, and functional decline, must be readily recognized in order to choose the most appropriate therapeutic approach, able to potentially improve the management of bronchial asthma, to prevent the onset of exacerbations as well the functional decline, and to reduce health costs.

Diagnosis and quantification of bronchiectasis using computed tomography or magnetic resonance imaging: A systematic review

BACKGROUND

Bronchiectasis is an irreversible dilatation of the airways caused by inflammation and infection. To diagnose bronchiectasis in clinical care and to use bronchiectasis as outcome parameter in clinical trials, a radiological definition with exact cut-off values along with image analysis methods to assess its severity are needed. The aim of this study was to review diagnostic criteria and quantification methods for bronchiectasis.

METHODS

A systematic literature search was performed using Embase, Medline Ovid, Web of Science, Cochrane and Google Scholar. English written, clinical studies that included bronchiectasis as outcome measure and used image quantification methods were selected. Criteria for bronchiectasis, quantification methods, patient demographics, and data on image acquisition were extracted.

RESULTS

We screened 4182 abstracts, selected 972 full texts, and included 122 studies. The most often used criterion for bronchiectasis was an inner airway-artery ratio ≥1.0 (42%), however no validation studies for this cut-off value were found. Importantly, studies showed that airway-artery ratios are influenced by age. To quantify bronchiectasis, 42 different scoring methods were described.

CONCLUSION

Different diagnostic criteria for bronchiectasis are being used, but no validation studies were found to support these criteria. To use bronchiectasis as outcome in future studies, validated and age-specific cut-off values are needed.

Is bronchiectasis really a disease?

The definition of a disease requires that distinguishing signs and symptoms are present that are common, and that the constellation of signs and symptoms differentiate the condition from other causes. In bronchiectasis, anatomical changes, airways inflammation and airway infection are the distinguishing features that are common to this disease. However, bronchiectasis is a heterogenous disease: signs and symptoms are shared with other airway diseases, there are multiple aetiologies and certain phenotypes of bronchiectasis have distinct clinical and laboratory features that are not common to all people with bronchiectasis. Furthermore, response to therapeutic interventions in clinical trials is not uniform. The concept of bronchiectasis as a treatable trait has been suggested, but this may be too restrictive in view of the heterogeneity of bronchiectasis. It is our opinion that bronchiectasis should be defined as a disease in its own right, but one that shares several pathophysiological features and "treatable traits" with other airway diseases. These traits define the large heterogeneity in the pathogenesis and clinical features and suggest a more targeted approach to therapy.

Bronchiectasis in Primary Antibody Deficiencies: A Multidisciplinary Approach

Bronchiectasis, the presence of bronchial wall thickening with airway dilatation, is a particularly challenging complication of primary antibody deficiencies. While susceptibility to infections may be the primary factor leading to the development of bronchiectasis in these patients, the condition may develop in the absence of known infections. Once bronchiectasis is present, the lungs are subject to a progressive cycle involving both infectious and non-infectious factors. If bronchiectasis is not identified or not managed appropriately, the cycle proceeds unchecked and yields advanced and permanent lung damage. Severe symptoms may limit exercise tolerance, require frequent hospitalizations, profoundly impair quality of life (QOL), and lead to early death. This review article focuses on the appropriate identification and management of bronchiectasis in patients with primary antibody deficiencies. The underlying immune deficiency and the bronchiectasis need to be treated from combined immunology and pulmonary perspectives, reflected in this review by experts from both fields. An aggressive multidisciplinary approach may reduce exacerbations and slow the progression of permanent lung damage.

Noncystic fibrosis bronchiectasis management: opportunities and challenges

PURPOSE OF REVIEW

Noncystic fibrosis bronchiectasis is a challenging disease which carries a heavy healthcare burden and significant mortality and morbidity. This review highlights the challenges in the diagnosis of bronchiectasis and discusses the management strategies and research opportunities in this field.

RECENT FINDINGS

The challenges in the management of bronchiectasis appear to be multifactorial, arising from both etiological heterogeneity and disease-specific management. Frequent inflammation and infections not only lead to progressive respiratory failure but also increase the risk of cardiovascular complications. No therapies are approved specifically for adult bronchiectasis, but new guidelines and recent studies outline strategies for control of infection and inflammation and for prevention of frequent exacerbations to improve overall prognosis.

SUMMARY

Recent studies in the management of bronchiectasis are encouraging. Advances have been made in understanding both disease heterogeneity and best practices for care; interventions such as daily mucociliary clearance, eradication of colonized microbial organisms, and control of inflammation may result in favorable outcomes.

Bronchiectasis in severe asthma: a distinct phenotype?

PURPOSE OF REVIEW

The presence of bronchiectasis has been described in about 30% of severe asthma patients. The coexistence of these two respiratory conditions poses new challenges from both clinical and research perspectives. We will review the available literature on this topic to discuss the existance of a specific clinical phenotype of asthma.

RECENT FINDINGS

Despite the paucity of literature, the presence of bronchiectasis with severe asthma is associated with older age, chronic bronchial expectoration, rhinosinusitis, more frequent and severe exacerbations, neutrophilic airway inflammation and poor response to usual treatment. Conversely, asthma features are also described in bronchiectasis patients even in the absence of an appropriate diagnosis of asthma. In both cases, there is some evidence supporting the use of bronchodilators, macrolides and respiratory physiotherapy, while the use of inhaled corticosteroids and antibiotics is controversial.

SUMMARY

Based on available evidence on the association between (severe) asthma and bronchiectasis, its pathophysiology, certain clinical aspects and prognosis are largely unclear. Although specific management appears to be required in most cases, in our opinion there is still insufficient evidence to consider it a distinct phenotype of severe asthma. Hopefully, future research will shed more light on this topic and define the best therapeutic approach.

The biology of pulmonary exacerbations in bronchiectasis

Bronchiectasis is a heterogeneous chronic disease. Heterogeneity characterises bronchiectasis not only in the stable state but also during exacerbations, despite evidence on clinical and biological aspects of bronchiectasis, exacerbations still remain poorly understood.Although the scientific community recognises that bacterial infection is a cornerstone in the development of bronchiectasis, there is a lack of data regarding other trigger factors for exacerbations. In addition, a huge amount of data suggest a primary role of neutrophils in the stable state and exacerbation of bronchiectasis, but the inflammatory reaction involves many other additional pathways. Cole's vicious cycle hypothesis illustrates how airway dysfunction, airway inflammation, infection and structural damage are linked. The introduction of the concept of a "vicious vortex" stresses the complexity of the relationships between the components of the cycle. In this model of disease, exacerbations work as a catalyst, accelerating the progression of disease. The roles of microbiology and inflammation need to be considered as closely linked and will need to be investigated in different ways to collect samples. Clinical and translational research is of paramount importance to achieve a better comprehension of the pathophysiology of bronchiectasis, microbiology and inflammation both in the stable state and during exacerbations.

Bronchiectasis and asthma: a dangerous liaison?

PURPOSE OF REVIEW

To explore the latest insight of the literature on the asthma/bronchiectasis phenotype providing an updated overview about epidemiological, clinical and biological evidence linking these two conditions.

RECENT FINDINGS

An increasing body of literature has shown that the association of asthma and bronchiectasis is a frequent phenomenon leading to a more severe disease with frequent exacerbations. The mechanisms by which the two diseases are linked are still not well established but they share several clinical and immunological features and many comorbidities.

SUMMARY

The early identification of bronchiectasis through high-definition computer tomography in patients with severe asthma is crucial in order to provide an adequate treatment for both diseases and therefore to better control symptoms, exacerbations and infections.

Bronchiectasis insanity: Doing the same thing over and over again and expecting different results?

Bronchiectasis is an increasingly common disease with a significant impact on quality of life and morbidity of affected patients. It is also a very heterogeneous disease with numerous different underlying etiologies and presentations. Most treatments for bronchiectasis are based on low-quality evidence; consequently, no treatments have been approved by the US Food and Drug Administration or the European Medicines Agency for the treatment of bronchiectasis. The last several years have seen numerous clinical trials in which the investigational agent, thought to hold great promise, did not demonstrate a clinically or statistically significant benefit. This commentary will review the likely reasons for these disappointing results and a potential approach that may have a greater likelihood of defining evidence-based treatment for bronchiectasis.

Severe uncontrolled asthma with bronchiectasis: a pilot study of an emerging phenotype that responds to mepolizumab

Background

Asthma and bronchiectasis are different conditions that frequently coexist. The prevalence of bronchiectasis rises considerably in subjects with severe asthma (25%–51%).

Objective

We evaluated the clinical and biological efficacy of mepolizumab on our pilot population of severe uncontrolled asthmatics with bronchiectasis not related to other pathologies.

Patients and methods

Four patients with severe uncontrolled asthma and diagnosed as bronchiectasis were recruited and started biological treatment with mepolizumab. Standard investigations were performed in all four patients at baseline (T0), after 3 months (T1) and after 1 year (T2) of treatment.

Results

After 1 year (T2) of therapy with mepolizumab, patients showed a significant increment of asthma control test value (12±1.1 vs 24.5±0.3, P<0.01), a reduction of the number of exacerbations/year (5±0.7 vs 0.75±0.75, P<0.01), an increase of pre-bronchodilator FEV₁ (1,680±500 vs 1,860±550 mL, P<0.01) and a reduction of eosinophils in blood (0.75±0.14 vs 0.12±0.02 cells/µL, P<0.01), in the sputum (9.6%±2.1% vs 5.6%±2.7%, P<0.05) and in nasal cytology (++ vs +).

Conclusion

The efficacy of mepolizumab in terms of reduction of inflammation and increase of control that we observed in our patients might suggest that targeting the IL-5 in severe eosinophilic asthma with bronchiectasis may be a good therapeutic strategy.

Bronchiectasis

Bronchiectasis refers to abnormal dilatation of the bronchi. Airway dilatation can lead to failure of mucus clearance and increased risk of infection. Pathophysiological mechanisms of bronchiectasis include persistent bacterial infections, dysregulated immune responses, impaired mucociliary clearance and airway obstruction. These mechanisms can interact and self-perpetuate, leading over time to impaired lung function. Patients commonly present with productive cough and recurrent chest infections, and the diagnosis of bronchiectasis is based on clinical symptoms and radiological findings. Bronchiectasis can be the result of several different underlying disorders, and identifying the aetiology is crucial to guide management. Treatment is directed at reducing the frequency of exacerbations, improving quality of life and preventing disease progression. Although no therapy is licensed for bronchiectasis by regulatory agencies, evidence supports the effectiveness of airway clearance techniques, antibiotics and mucolytic agents, such as inhaled isotonic or hypertonic saline, in some patients. Bronchiectasis is a disabling disease with an increasing prevalence and can affect individuals of any age. A major challenge is the application of emerging phenotyping and endotyping techniques to identify the patient populations who would most benefit from a specific treatment, with the goal of better targeting existing and emerging treatments and achieving better outcomes.

Inhaled corticosteroids for bronchiectasis

BACKGROUND

Bronchiectasis is being increasingly diagnosed and recognised as an important contributor to chronic lung disease in both adults and children in high- and low-income countries. It is characterised by irreversible dilatation of airways and is generally associated with airway inflammation and chronic bacterial infection. Medical management largely aims to reduce morbidity by controlling the symptoms, reduce exacerbation frequency, improve quality of life and prevent the progression of bronchiectasis. This is an update of a review first published in 2000.

OBJECTIVES

To evaluate the efficacy and safety of inhaled corticosteroids (ICS) in children and adults with stable state bronchiectasis, specifically to assess whether the use of ICS: (1) reduces the severity and frequency of acute respiratory exacerbations; or (2) affects long-term pulmonary function decline.

SEARCH METHODS

We searched the Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Register of trials, MEDLINE and Embase databases. We ran the latest literature search in June 2017.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing ICS with a placebo or no medication. We included children and adults with clinical or radiographic evidence of bronchiectasis, but excluded people with cystic fibrosis.

DATA COLLECTION AND ANALYSIS

We reviewed search results against predetermined criteria for inclusion. In this update, two independent review authors assessed methodological quality and risk of bias in trials using established criteria and extracted data using standard pro forma. We analysed treatment as 'treatment received' and performed sensitivity analyses.

MAIN RESULTS

The review included seven studies, involving 380 adults. Of the 380 randomised participants, 348 completed the studies.Due to differences in outcomes reported among the seven studies, we could only perform limited meta-analysis for both the short-term ICS use (6 months or less) and the longer-term ICS use (> 6 months).During stable state in the short-term group (ICS for 6 months or less), based on the two studies from which data could be included, there were no significant differences from baseline values in the forced expiratory volume in the first second (FEV₁) at the end of the study (mean difference (MD) -0.09, 95% confidence interval (CI) -0.26 to 0.09) and forced vital capacity (FVC) (MD 0.01 L, 95% CI -0.16 to 0.17) in adults on ICS (compared to no ICS). Similarly, we did not find any significant difference in the average exacerbation frequency (MD 0.09, 95% CI -0.61 to 0.79) or health-related quality of life (HRQoL) total scores in adults on ICS when compared with no ICS, though data available were limited. Based on a single non-placebo controlled study from which we could not extract clinical data, there was marginal, though statistically significant improvement in sputum volume and dyspnoea scores on ICS.The single study on long-term outcomes (over 6 months) that examined lung function and other clinical outcomes, showed no significant effect of ICS on any of the outcomes. We could not draw any conclusion on adverse effects due to limited available data.Despite the authors of all seven studies stating they were double-blind, we judged one study (in the short duration ICS) as having a high risk of bias based on blinding, attrition and reporting of outcomes. The GRADE quality of evidence was low for all outcomes (due to non-placebo controlled trial, indirectness and imprecision with small numbers of participants and studies).

AUTHORS' CONCLUSIONS

This updated review indicates that there is insufficient evidence to support the routine use of ICS in adults with stable state bronchiectasis. Further, we cannot draw any conclusion for the use of ICS in adults during an acute exacerbation or in children (for any state), as there were no studies.

Autoinflammatory disease in the lung

Ascertaining the dominant cell type driving an immunological disease is essential to understanding the causal pathology and, therefore, selecting or developing an effective treatment. Classifying immunological diseases in this way has led to successful treatment regimens for many monogenic diseases; however, when the dominant cell type is unclear and there is no obvious causal genetic mutation, then identifying the correct disease classification and appropriate therapy can be challenging. In this review we focus on pulmonary immunological diseases where an innate immune signature has been identified as a predominant aspect of the immunopathology. We describe the molecular pathology of 'autoinflammatory diseases of the lung' and propose that small molecule and biological therapies, including recombinant interleukin-1 receptor antagonist, that target key innate immune pathways, are likely be beneficial in the control of pulmonary and systemic inflammation in these conditions. In addition, the successful use of macrolide antibiotics to treat lung infections in these conditions further confirms that the innate immune system is the key conductor of inflammation in these pulmonary diseases, as there is a strong body of evidence that macrolides are able to modulate the NLRP3 inflammasome and interleukin-1β and interleukin-18 secretion, both of which are central players in the innate immune response. Throughout this review we highlight the published evidence of autoinflammatory disease in chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis and rheumatoid lung disease and suggest that the fundamental pathology of these diseases places them towards the autoinflammatory pole of the immunological disease continuum.