Bacterial interactome disturbance in chronic obstructive pulmonary disease clinical stability and exacerbations.

RATIONALE: Our understanding of airway dysbiosis in chronic obstructive pulmonary disease (COPD) remains incomplete, which may be improved by unraveling the complexity in microbial interactome. OBJECTIVES: To characterize reproducible features of airway bacterial interactome in COPD at clinical stability and during exacerbation, and evaluate their associations with disease phenotypes. METHODS: We performed weighted ensemble-based co-occurrence network analysis of 1742 sputum microbiomes from published and new microbiome datasets, comprising two case-control studies of stable COPD versus healthy control, two studies of COPD stability versus exacerbation, and one study with exacerbation-recovery time series data. RESULTS: Patients with COPD had reproducibly lower degree of negative bacterial interactions, i.e. total number of negative interactions as a proportion of total interactions, in their airway microbiome compared with healthy controls. Evaluation of the Haemophilus interactome showed that the antagonistic interaction networks of this established pathogen rather than its abundance consistently changed in COPD. Interactome dynamic analysis revealed reproducibly reduced antagonistic interactions but not diversity loss during COPD exacerbation, which recovered after treatment. In phenotypic analysis, unsupervised network clustering showed that loss of antagonistic interactions was associated with worse clinical symptoms (dyspnea), poorer lung function, exaggerated neutrophilic inflammation, and higher exacerbation risk. Furthermore, the frequent exacerbators (≥ 2 exacerbations per year) had significantly reduced antagonistic bacterial interactions while exhibiting subtle compositional changes in their airway microbiota. CONCLUSIONS: Bacterial interactome disturbance characterized by reduced antagonistic interactions, rather than change in pathogen abundance or diversity, is a reproducible feature of airway dysbiosis in COPD clinical stability and exacerbations, which suggests that we may target interactome rather than pathogen alone for disease treatment.

Clinical Subtypes of Neutrophilic Asthma: A Cluster Analysis From Australasian Severe Asthma Network.

BACKGROUND: Clinical heterogeneity may exist within asthma subtypes defined by inflammatory markers. However, the heterogeneity of neutrophilic asthma (NA) remains largely unexplored. OBJECTIVE: To explore potential clusters and the stability of NA. METHODS: Participants with NA from the Australasian Severe Asthma Network underwent a multidimensional assessment. They were then asked to participate in a 12-month longitudinal cohort study. We explored potential clusters using a hierarchical cluster analysis and validated the differential future risk of asthma exacerbations in the identified clusters. A decision tree analysis was developed to predict cluster assignments. Finally, the stability of prespecified clusters was examined within 1 month. RESULTS: Three clusters were identified in 149 patients with NA. Cluster 1 (n = 99; 66.4%) was characterized by female-predominant nonsmokers with well-controlled NA, cluster 2 (n = 16; 10.7%) by individuals with comorbid anxiety/depressive symptoms with poorly controlled NA, and cluster 3 by older male smokers with late-onset NA. Cluster 2 had a greater proportion of participants with severe exacerbations (P = .005), hospitalization (P = .010), and unscheduled visits (P = .013) and a higher number of emergency room visits (P = .039) than that of the other two clusters. The decision tree assigned 92.6% of participants correctly. Most participants (87.5%; n = 7) in cluster 2 had a stable NA phenotype, whereas participants of clusters 1 and 3 had variable phenotypes. CONCLUSIONS: We identified three clinical clusters of NA, in which cluster 2 represents an uncontrolled and stable NA subtype with an elevated risk of exacerbations. These findings have clinical implications for the management of NA.

Existing tests vs. novel non-invasive assays for detection of invasive aspergillosis in patients with respiratory diseases.

BACKGROUND: Although existing mycological tests (bronchoalveolar lavage [BAL] galactomannan [GM], serum GM, serum (1,3)-ß-D-glucan [BDG], and fungal culture) are widely used for diagnosing invasive pulmonary aspergillosis (IPA) in non-hematological patients with respiratory diseases, their clinical utility in this large population is actually unclear. We aimed to resolve this clinical uncertainty by evaluating the diagnostic accuracy and utility of existing tests and explore the efficacy of novel sputum-based Aspergillus assays. METHODS: Existing tests were assessed in a prospective and consecutive cohort of patients with respiratory diseases in West China Hospital between 2016 and 2019 while novel sputum assays (especially sputum GM and Aspergillus-specific lateral-flow device [LFD]) in a case-controlled subcohort. IPA was defined according to the modified European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria. Sensitivity and specificity were computed for each test and receiver operating characteristic (ROC) curve analysis was performed. RESULTS: The entire cohort included 3530 admissions (proven/probable IPA = 66, no IPA = 3464) and the subcohort included 127 admissions (proven/probable IPA = 38, no IPA = 89). Sensitivity of BAL GM (≥1.0 optical density index [ODI]: 86% [24/28]) was substantially higher than that of serum GM (≥0.5 ODI: 38% [39/102]) ( χ2  = 19.83, P   <  0.001), serum BDG (≥70 pg/mL: 33% [31/95]) ( χ2  = 24.65, P  < 0.001), and fungal culture (33% [84/253]) ( χ2  = 29.38, P  < 0.001). Specificity varied between BAL GM (≥1.0 ODI: 94% [377/402]), serum GM (≥0.5 ODI: 95% [2130/2248]), BDG (89% [1878/2106]), and culture (98% [4936/5055]). Sputum GM (≥2.0 ODI) had similar sensitivity (84% [32/38]) (Fisher's exact P  = 1.000) to and slightly lower specificity (87% [77/89]) ( χ2  = 5.52, P  = 0.019) than BAL GM (≥1.0 ODI). Area under the ROC curve values were comparable between sputum GM (0.883 [0.812-0.953]) and BAL GM (0.901 [0.824-0.977]) ( P  = 0.734). Sputum LFD had similar specificity (91% [81/89]) ( χ2  = 0.89, P  = 0.345) to and lower sensitivity (63% [24/38]) ( χ2  = 4.14, P  = 0.042) than BAL GM (≥1.0 ODI), but significantly higher sensitivity than serum GM (≥0.5 ODI) ( χ2  = 6.95, P  = 0.008), BDG ( χ2  = 10.43, P  = 0.001), and fungal culture ( χ2  = 12.70, P  < 0.001). CONCLUSIONS: Serum GM, serum BDG, and fungal culture lack sufficient sensitivity for diagnosing IPA in respiratory patients. Sputum GM and LFD assays hold promise as rapid, sensitive, and non-invasive alternatives to the BAL GM test.

Reduced bronchodilator reversibility correlates with non-type 2 high asthma and future exacerbations: A prospective cohort study.

BACKGROUND: Given that airway obstruction in asthma is not always fully reversible, reduced bronchodilator reversibility (BDR) may be a special asthma phenotype. OBJECTIVE: To explore the characteristics of BDRhigh/low phenotypes (defined using two BDR criteria) and their associations with asthma exacerbations (AEs). METHODS: After baseline assessments, all patients were classified into BDRhigh or BDRlow phenotypes. This study consisted of 2 parts. Part I was a 12-month prospective observational cohort study designed to identify the clinical characteristics and associations with future AEs in BDRhigh/low phenotypes (n = 456). Part II, designed as a post hoc analysis of the data obtained in Part I, was conducted to assess the association between BDRhigh/low phenotypes and treatment responsiveness (n = 360). RESULTS: Subjects with BDRlow phenotypes had better baseline asthma symptom control and was negatively associated with eosinophilic asthma and type 2 (T2) high asthma. During the 12-month follow-up, those with BDRlow phenotypes had a higher risk of severe AEs (SAEs) (guideline-based criterion: RRadj = 2.24, 95% CI = [1.25, 3.68]; Ward's criterion: RRadj = 2.46, 95% CI = [1.40, 4.00]) and moderate-to-severe AEs (MSAEs) (guideline-based criterion: RRadj = 1.83, 95% CI = [1.22, 2.56]; Ward's criterion: RRadj = 1.94, 95% CI = [1.32, 2.68]) in the following year according to logistic regression models. Similar findings were obtained with negative binominal regression models. BDRlow phenotype was a risk factor for an insensitive response to anti-asthma treatment (guideline-based criterion: ORadj = 1.96, 95% CI = [1.05, 3.65]; Ward's criterion: ORadj = 2.01, 95% CI = [1.12, 3.58]). CONCLUSION: We identified that BDRlow phenotype was associated with non-T2 high asthma and future AEs. These findings have clinically relevant implications for asthma management.

Heterogeneity of Paucigranulocytic Asthma: A Prospective Cohort Study with Hierarchical Cluster Analysis.

BACKGROUND: Asthma, a heterogeneous disease, can be divided into 4 inflammatory phenotypes using induced sputum cell counts-eosinophilic asthma (EA), neutrophilic asthma (NA), mixed granulocytic asthma, and paucigranulocytic asthma (PGA). Although research has focused on EA and NA, there is little known about PGA. OBJECTIVE: To study the heterogeneity of PGA and identify possible PGA clusters to guide clinical treatment. METHODS: Patients with PGA were grouped by hierarchical cluster analysis and enrolled into a prospective cohort study to validate the clusters, relative to future risk of asthma exacerbations in a real-world setting. Clusters were validated by tree analysis in a separate population. Finally, we explored PGA stability. RESULTS: Cluster analysis of 145 patients with PGA identified 3 clusters: cluster 1 (n = 110, 75.9%) was "mild PGA," cluster 2 (n = 20, 13.8%) was "PGA with psychological dysfunction and rhinoconjunctivitis and other allergic diseases," and cluster 3 (n = 15, 10.3%) was "smoking-associated PGA." Cluster 3 had significantly increased risk of severe exacerbation (relative risk [RR] = 6.43, P = .01), emergency visit (RR = 8.61, P = .03), and hospitalization (RR = 12.94, P < .01). Results of the cluster analysis were successfully validated in an independent PGA population classified using decision tree analysis. Although PGA can transform into or develop from other phenotypes, 70% were stable over time. CONCLUSIONS: Among 3 identified PGA clusters, cluster 3 had a higher risk of severe exacerbation. PGA heterogeneity indicates the requirement of novel targeted interventions.

Clinical Phenotypes of Patients Hospitalized for an Asthma Exacerbation: Prognostic Implications.

BACKGROUND: Hospitalization due to acute asthma exacerbation (AE) is a highly detrimental situation requiring critical management to prevent further deterioration, including mechanical ventilation, intensive care unit (ICU) admission, and death. However, patients hospitalized for AEs are highly heterogeneous and remain largely unexplored. OBJECTIVE: To identify clinical and inflammatory phenotypes of AE requiring hospitalization associated with in-hospital outcomes. METHODS: We performed a hierarchical cluster analysis of 825 consecutively recruited patients hospitalized for AEs. Logistic regressions were conducted to quantify the independent associations of the identified phenotypes with in-hospital outcomes. Decision tree analysis was developed to predict cluster assignment. RESULTS: We identified 3 clusters of patients, which had significantly different characteristics associated with in-hospital adverse outcomes. Cluster 1 (n = 526, 63.8%) was a late-onset phenotype, cluster 2 (n = 97, 11.8%) was an early-onset phenotype, and cluster 3 (n = 202, 24.5%) was a phenotype with fewer eosinophils and more comorbidities. Clusters 2 and 3 had an elevated risk of death (relative ratio [RRadj], 18.10 and 19.17, respectively) and mechanical ventilation (RRadj, 2.56 and 5.71, respectively) than did cluster 1. Individuals in cluster 3 had an extended length of hospital stay (11 days), increased hospitalization direct costs (13,481.57 Chinese Yuan), and a higher risk of ICU admission (RRadj, 2.14) than individuals in clusters 1 and 2. The decision tree assigned 90.8% of the participants correctly. CONCLUSIONS: We identified 3 phenotypes with differential clinical and inflammatory characteristics associated with in-hospital adverse outcomes. These new phenotypes might have important and clinically relevant implications for the management of patients hospitalized for AEs.

Identification of asthma phenotypes based on extrapulmonary treatable traits.

Asthma is a heterogeneous and complex disease, and a description of asthma phenotypes based on extrapulmonary treatable traits has not been previously reported.The objective of this study was to identify and characterise clusters based on clinical, functional, anthropometrical and psychological characteristics in participants with moderate-to-severe asthma.This was a cross-sectional multicentre study involving centres from Brazil and Australia. Participants (n=296) with moderate-to-severe asthma were consecutively recruited. Physical activity and sedentary time, clinical asthma control, anthropometric data, pulmonary function and psychological and health status were evaluated. Participants were classified by hierarchical cluster analysis and the clusters compared using ANOVA, Kruskal--Wallis and Chi-squared tests. Multiple logistic and linear regression models were performed to evaluate the association between variables.We identified four clusters: 1) participants with controlled asthma who were physically active; 2) participants with uncontrolled asthma who were physically inactive and more sedentary; 3) participants with uncontrolled asthma and low physical activity, who were also obese and experienced anxiety and/or depression symptoms; and 4) participants with very uncontrolled asthma who were physically inactive, more sedentary, obese and experienced anxiety and/or depression symptoms. Higher levels of sedentary time, female sex and anxiety symptoms were associated with increased odds of exacerbation risk, while being more active showed a protective factor for hospitalisation. Asthma control was associated with sex, the occurrence of exacerbation, physical activity and health status.Physical inactivity, obesity and symptoms of anxiety and/or depression were associated with worse asthma outcomes, and closely and inextricably associated with asthma control. This cluster analysis highlights the importance of assessing extrapulmonary traits to improve personalised management and outcomes for people with moderate and severe asthma.

Depressive symptom-associated IL-1ß and TNF-α release correlates with impaired bronchodilator response and neutrophilic airway inflammation in asthma.

BACKGROUND: Depressive symptoms worsen asthma outcomes; however, the mechanism remains largely unexplored. OBJECTIVE: This study aimed to determine whether depressive symptom-associated immune inflammation correlates with impaired bronchodilator response (BDR) and airway inflammatory phenotypes. METHODS: Eligible adults with asthma (n = 198) underwent clinical assessment, sputum induction and blood sampling. Depressive symptoms were defined by scores on the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D). Pre- and post-bronchodilator spirometry was performed for BDR. Airway inflammatory phenotypes were defined by sputum cell counts. CRP, IL-1ß, IL-5, IL-6, IL-8, TNF-α, IFN-γ, CCL17 and CCL22 in serum and sputum were detected. RESULTS: Compared with the non-depressive group (n = 174), the depressive group (n = 24) exhibited impaired BDR (P = 0.032) and increased sputum neutrophils (P = 0.023), which correlated with the HADS-D scores (P = 0.027 and P = 0.029). Levels of IL-1ß, TNF-α and IFN-γ in the serum and those of IL-1ß and IFN-γ in the sputum were elevated in the depressive group compared to those in the non-depressive group (all P < 0.05). Multiple regression models indicated that TNF-α in the sputum and IL-1ß, IL-6 and IFN-γ in both the serum and sputum were inversely associated with BDR; TNF-α in the sputum and IL-1ß in both the serum and sputum were positively correlated with sputum neutrophils. Mediation analyses revealed that IL-1ß and TNF-α in the sputum and IL-1ß in both the serum and sputum mediate the correlations of the HADS-D scores with BDR and sputum neutrophils, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Asthma patients with depressive symptoms present worse asthma control, which is most likely explained by impaired BDR and neutrophilic airway inflammation. IL-1ß and TNF-α, which are two key pro-inflammatory cytokines that mediate the correlation of depressive symptoms with impaired BDR and neutrophilic airway inflammation, may serve as targeted biomarkers in the neuropsychological phenotype of asthma; however, this result needs to be further validated.

Montelukast for prevention and treatment of asthma exacerbations in adults: Systematic review and meta-analysis.

It has proven efficacy in reducing asthma exacerbations, but the effect size of montelukast (a leukotriene receptor antagonist) for varied severity of asthma exacerbations is not systematically assessed. This study was designed to systematically explore the evidence for montelukast, as first-line or add-on therapy, in preventing and treating asthma exacerbations in adult patients with asthma. Randomized controlled trials were searched in PubMed, CENTRAL, Web of Science, Embase, and OVID up to March 2013, where montelukast prevented or treated asthma exacerbations in adults. Primary outcomes were the number of patients experiencing exacerbations in chronic asthma and hospitalizations in acute asthma. Odds ratio (OR) with 95% confidence intervals (CI), risk difference, and number needed to treat (NNT) were calculated and pooled. Adverse events were also assessed in chronic asthma. Twenty trials for chronic asthma and six for acute asthma were identified. In comparison with placebo, adults with chronic asthma receiving montelukast had significantly reduced number of exacerbations (OR = 0.60 and 95% CI, 0.49, 0.74; NNT = 17 and 95% CI, 12, 29). However, montelukast was inferior to inhaled corticosteroids (ICSs) (OR = 1.63; 95% CI, 1.29, 2.0) and ICS plus long-acting beta2-agonist (LABA; OR = 3.94; 95% CI, 1.64, 9.48) as the first-line therapies and LABA (OR = 1.22; 95% CI, 1.05, 1.42) as the add-on therapies in reducing asthma exacerbations. In acute asthma, montelukast could statistically improve peak expiratory flow percent predicted (p = 0.008) and reduce systemic corticosteroid intake (p = 0.005). Montelukast had low risk in hoarseness and insomnia. Our meta-analysis suggests that montelukast significantly reduces mild, moderate, and part of severe exacerbations in chronic mild to moderate asthma, but it has inferior efficacy to ICS or ICS plus LABA.

The Asthma Control Test and Asthma Control Questionnaire for assessing asthma control: Systematic review and meta-analysis.

BACKGROUND: Currently, the cornerstone of asthma management is the achievement and maintenance of optimal asthma control, but the diagnostic performances of the Asthma Control Test (ACT) and Asthma Control Questionnaire (ACQ) have not been evaluated systematically. OBJECTIVE: We explored the diagnostic performances of and statistically compared the ACT and ACQ. METHODS: Studies that examined the accuracy of the ACT, ACQ, or both in the assessment of asthma control were found by searching PubMed, CENTRAL, Web of Science, Ovid, and Embase. Summary estimates of sensitivity, specificity, and diagnostic odds ratios for the different levels of asthma control were determined by using bivariate random-effects models and hierarchical summary receiver operating characteristic models. RESULTS: Twenty-one studies with 11,141 subjects assessed with the ACT and 12,483 assessed with the ACQ were identified. The ACT had good diagnostic accuracy for assessment of controlled and not well-controlled asthma, and the ACQ (ACQ-7 and ACQ-6) had good diagnostic accuracy for assessment of not well-controlled asthma at prespecified cutoff points. The ACT and ACQ had significant differences in the assessment of controlled and not well-controlled asthma after adjusting for potential factors (P = .001 and P = .015). For assessment of uncontrolled asthma, the ACT had poor accuracy, with a hierarchical summary receiver operating characteristic area under the curve of 0.69, and the cutoff point for the ACQ has not been established. CONCLUSION: The ACT is preferable to the ACQ in clinical practice, and the ACQ requires further cross-validation. Moreover, neither the ACT nor the ACQ is useful for the assessment of uncontrolled asthma.

Innate immune responses are increased in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterised by irreversible airflow obstruction, neutrophilic airway inflammation and chronic bacterial colonisation, however the role of the innate immune response in the pathogenesis of COPD remains unclear. METHODS: Induced sputum was obtained from adults with COPD (n=22), and healthy controls (n=29) and was processed for differential cell counts. The sputum supernatant was assayed for innate immune mediators using ELISA, whilst sputum gene expression was measured using real-time PCR. Peripheral blood neutrophils were isolated and their response to lipopolysaccaride (LPS) stimulation was assessed in a subgroup of participants with COPD (n=13) and healthy controls (n=21). RESULTS: Participants with COPD had significantly higher protein levels of interleukin (IL)-8, and neutrophil elastase (NE) and detection of oncostatin M (OSM) compared to healthy controls. Gene expression for toll-like receptor (TLR) 2, IL-8 and OSM were also significantly higher in COPD participants. The level of IL-1ß, surfactant protein (SP)-A, matrix metalloproteinase (MMP)-9 and TLR4 mRNA was not significantly different between groups. The level of innate immune response markers were highly associated with the presence of sputum neutrophils, each other and the degree of airflow limitation (FEV1/FVC). Peripheral blood neutrophils from participants with COPD had an increased response to stimulation by LPS; with a greater fold increase in the production of IL-8 and MMP-9 protein, and gene expression of IL-8, TLR2 and TLR4. CONCLUSIONS: The innate immune response is increased in the airways and circulating neutrophils in COPD, and may be an important mechanism involved in disease pathogenesis.

Inflammatory phenotypes in adult asthma: clinical applications.

BACKGROUND: The pattern of granulocyte infiltration can be used to identify different inflammatory phenotypes in asthma. Recognized granulocyte phenotypes using induced sputum are eosinophilic (EA), neutrophilic, mixed granulocytic and paucigranulocytic asthma. METHODS: The recognition and importance of inflammatory phenotype analysis using induced sputum in adult asthma are reviewed using published literature. RESULTS: Knowledge of inflammatory phenotype is useful because it relates to treatment response, mechanistic pathways involved in disease pathogenesis and future disease risk. The population attributable risk of asthma because of eosinophilic inflammation is about 50%, and conversely, this means that up to 50% of asthma cannot be attributed to eosinophilic inflammation, and represents asthma associated with non-eosinophilic processes. In these patients, bronchial biopsy shows significantly fewer eosinophils in the bronchial mucosa than subjects with EA. This confirms that non-eosinophilic asthma is a consistent pattern/phenotype in the airway lumen and the airway mucosa. A key aspect of asthma inflammatory phenotype analysis is that it can be applied to individual patients. The underlying principle relates to the association between a clinical response to corticosteroids and the presence of a selective sputum eosinophilia. CONCLUSIONS: Clinically useful applications of induced sputum analysis are the detection of non-adherence to corticosteroid therapy, assessment of adequacy of inhaled corticosteroid therapy, long-term therapy management in asthma, oral corticosteroid dose adjustment in refractory asthma and assessment of occupational asthma.

Anti-inflammatory effect of itraconazole in stable allergic bronchopulmonary aspergillosis: a randomized controlled trial.

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) complicates chronic asthma and results from hypersensitivity to the fungus Aspergillus fumigatu s, causing an intense systemic immune response and progressive lung damage. OBJECTIVE: We sought to determine whether treatment with the antifungal agent itraconazole reduced eosinophilic airway inflammation in subjects with ABPA. METHODS: A randomized, double-blind, placebo-controlled trial was performed in stable subjects with ABPA (n = 29). Subjects received 400 mg of itraconazole per day (n = 15) or placebo (n = 14) for 16 weeks. All subjects were reviewed monthly with history, spirometry, and sputum induction to measure airway inflammation, serum total IgE and IgG levels to A fumigatu s, and blood eosinophil counts. RESULTS: By using regression analysis in a random-effects model, subjects receiving itraconazole had a decrease in sputum eosinophils of 35% per week, with no decrease seen in the placebo arm (P <.01). Sputum eosinophil cationic protein levels decreased with itraconazole treatment by 42% per week compared with 23% in the placebo group (P <.01). Itraconazole reduced systemic immune activation, leading to a decrease in serum IgE levels (310 IU/mL) compared with levels seen in the placebo group (increase of 18 IU/mL, P <.01) and a decrease in IgG levels to A fumigatu s (15.4 IU/mL) compared with levels seen in the placebo group (increase of 3.7 IU/mL, P =.03). There were fewer exacerbations requiring oral cortico-steroids in those treated with itraconazole compared with in the placebo group (P =.03). CONCLUSION: Itraconazole treatment of subjects with stable ABPA reduces eosinophilic airway inflammation, systemic immune activation, and exacerbations. These results imply that itraconazole is a potential adjunctive treatment for ABPA.