Sputum IL-1β Research Articles

Correlation of sputum inflammatory markers with severity and blood inflammatory markers in bronchiectasis.

As a disease characterized by chronic neutrophilic inflammation, various sputum biomarkers have been investigated in the association with the severity and prognosis of bronchiectasis. However, there is lack of data on the association between sputum interleukin-1beta (IL-1β), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α) levels at clinical stable state and the clinical, spirometric and blood inflammatory parameters, as well as prognostic scores. The purpose of the study is to assess the association between sputum IL-1β, IL-8 and TNF-α levels at clinical stable state and various clinical and laboratory parameters in bronchiectasis. A prospective study was conducted in a major regional hospital and tertiary respiratory referral centre in Hong Kong, including 44 Chinese patients with bronchiectasis. The correlation between stable state sputum IL-1β, IL-8 and TNF-α levels with various clinical, laboratory and spirometric parameters in bronchiectasis, as well as FACED [forced expiratory volume in one second (FEV1), age, chronic colonisation by Pseudomonas aeruginosa, radiological extension and dyspnoea]/E-FACED (FACED plus exacerbations) scores were assessed. Baseline sputum IL-1β level was found to have significant moderate positive correlation with baseline blood high sensitivity C-reactive protein (hs-CRP) level with Pearson correlation coefficient (r) of 0.529 (P=0.001). Baseline sputum IL-8 level was found to have significant moderate positive correlation with baseline FACED and E-FACED score with r of 0.574 (P<0.001) and 0.539 (P<0.001) respectively. Baseline sputum TNF-α level was found to have significant moderate positive correlation with baseline FACED score with r of 0.520 (P<0.001). Sputum IL-1β and, IL-8 and TNF-α levels were shown to have significant correlation with various clinical, laboratory and spirometry parameters in bronchiectasis, as well as more severe disease as measured by FACED and E-FACED scores.

Airway IL-1β is related to disease severity and mucociliary function in bronchiectasis.

The inflammasome is a key regulatory complex of the inflammatory response leading to interleukin-1β (IL-1β) release and activation. IL-1β amplifies inflammatory responses and induces mucus secretion and hyperconcentration in other diseases. The role of IL-1β in bronchiectasis has not been investigated. To characterise the role of airway IL-1β in bronchiectasis, including the association with mucus properties, ciliary function, airway inflammation, microbiome and disease severity. Stable bronchiectasis patients were enrolled in an international cohort study (n=269). IL-1β was measured in sputum supernatant. A validation cohort also had sputum rheology and hydration measured (n=53). For analysis, patients were stratified according to the median value of IL-1β in the population (high versus low) to compare disease severity, airway infection, microbiome (16S rRNA sequencing), inflammation and caspase-1 activity. Primary human nasal epithelial cells grown in air-liquid interface culture were used to study the effect of IL-1β on cilia function. Patients with high sputum IL-1β had more severe disease, increased caspase-1 activity and an increased T-helper type 1, T-helper type 2 and neutrophil inflammatory response compared with patients with low IL-1β. The active-dominant form of IL-1β was associated with increased disease severity. High IL-1β was related to higher relative abundance of Proteobacteria in the microbiome and increased mucus solid content and viscoelastic properties. Chronic IL-1β treatment reduced the functionality of cilia and tight junctions of epithelial cells in vitro. A subset of stable bronchiectasis patients show increased airway IL-1β, suggesting pulmonary inflammasome activation is linked with more severe disease, airway infection, mucus dehydration and epithelial dysfunction.

Airway microbiota and immune mediator relationships differ in obesity and asthma

Asthma and obesity are both complex conditions characterized by chronic inflammation, and obesity-related severe asthma has been associated with differences in the microbiome. However, whether the airway microbiome and microbiota-immune response relationships differ between obese persons with or without nonsevere asthma is unestablished. We compared the airway microbiome and microbiota-immune mediator relationships between obese and nonobese subjects, with and without mild-moderate asthma. We performed cross-sectional analyses of the airway (induced sputum) microbiome and cytokine profiles from blood and sputum using 16S ribosomal RNA gene and internal transcribed spacer region sequencing to profile bacteria and fungi, and multiplex immunoassays. Analysis tools included QIIME 2, linear discriminant analysis effect size (aka LEfSe), Piphillin, and Sparse inverse covariance estimation for ecological association inference (aka SPIEC-EASI). Obesity, irrespective of asthma status, was associated with significant differences in sputum bacterial community structure and composition (unweighted UniFrac permutational analysis of variance, P= .02), including a higher relative abundance of Prevotella, Gemella, and Streptococcus species. Among subjects with asthma, additional differences in sputum bacterial composition and fungal richness were identified between obese and nonobese individuals. Correlation network analyses demonstrated differences between obese and nonobese asthma in relationships between cytokine mediators, and these together with specific airway bacteria involving blood PAI-1, sputum IL-1β, GM-CSF, IL-8, TNF-α, and several Prevotella species. Obesity itself is associated with an altered sputum microbiome, which further differs in those with mild-moderate asthma. The distinct differences in airway microbiota and immune marker relationships in obese asthma suggest potential involvement of airway microbes that may affect mechanisms or outcomes of obese asthma.

Sputum Interleukin-32 in childhood asthma: correlation with IL-1β

_Background:_ Asthma is an airway disorder where inflammatory cytokines are partly responsible for exacerbating the disease. Interleukin (IL)-32, generally referred to as natural killer cell (NK4) transcript 4, is described as an immunoregulator involved in the stimulation of anti-/pro-inflammatory cytokines. The abnormal presence of IL-32 has been observed during inflammatory diseases, particularly in asthma. This study aims to characterize IL-32 in the inflammatory process in patients with severe asthma. _Methods:_ IL-32 and IL-1β levels in the supernatant of induced sputum obtained from 59 asthma patients (mild: 20 patients; moderate: 20 patients; severe: 19 patients) were measured using ELISA. Sputum IL-32 mRNA expression was measured by RT- PCR. _Results:_ Sputum IL-32 was significantly elevated at the protein (_p= 0.00019_) and mRNA expression (_p &lt; 0.0001_) in asthmatics compared to non-asthmatic controls. IL-32 was elevated in severe asthmatic patients (_p &lt; 0.0001_) compared to mild-moderate asthma. Severe asthmatics allergic to house dust mites expressed higher sputum IL-32 levels than severe asthmatics without allergy (_p = 0.0001_). A significant association was found between sputum IL-32 and IL-32 mRNA (r =0.531_; p = 0.0159_) in severe asthma. In the same way, sputum IL-1β and IL-32 were significantly correlated (r = 0.476; _p = 0.0337_). _Conclusion:_ The level of IL-32 in induced sputum may be associated with asthma severity.

Sputum Interleukin-32 in childhood asthma: correlation with IL-1β

_Background:_ Asthma is an airway disorder where inflammatory cytokines are partly responsible for exacerbating the disease. Interleukin (IL)-32, generally referred to as natural killer cell (NK4) transcript 4, is described as an immunoregulator involved in the stimulation of anti-/pro-inflammatory cytokines. The abnormal presence of IL-32 has been observed during inflammatory diseases, particularly in asthma. This study aims to characterize IL-32 in the inflammatory process in patients with severe asthma. _Methods:_ IL-32 and IL-1β levels in the supernatant of induced sputum obtained from 59 asthma patients (mild: 20 patients; moderate: 20 patients; severe: 19 patients) were measured using ELISA. Sputum IL-32 mRNA expression was measured by RT- PCR. _Results:_ Sputum IL-32 was significantly elevated at the protein (_p= 0.00019_) and mRNA expression (_p &lt; 0.0001_) in asthmatics compared to non-asthmatic controls. IL-32 was elevated in severe asthmatic patients (_p &lt; 0.0001_) compared to mild-moderate asthma. Severe asthmatics allergic to house dust mites expressed higher sputum IL-32 level than severe asthmatics without allergy (_p = 0.0001_). A significant association was found between sputum IL-32 and IL-32 mRNA (r =0.531_; p = 0.0159_) in severe asthma. In the same way, sputum IL-1β and IL-32 were significantly correlated (r = 0.476; _p = 0.0337_). _Conclusion:_ The level of IL-32 in induced sputum may be associated with asthma severity.

Sputum Interleukin-32 in childhood asthma: correlation with IL-1β

_Background:_ Asthma is an airway disorder where inflammatory cytokines are partly responsible for exacerbating the disease. Interleukin (IL)-32, generally referred to as natural killer cell (NK4) transcript 4, is described as an immunoregulator involved in the stimulation of anti-/pro-inflammatory cytokines. The abnormal presence of IL-32 has been observed during inflammatory diseases, particularly in asthma. This study aims to characterize IL-32 in the inflammatory process in patients with severe asthma. _Methods:_ IL-32 and IL-1β levels in the supernatant of induced sputum obtained from 59 asthma patients (mild: 20 patients; moderate: 20 patients; severe: 19 patients) were measured using ELISA. Sputum IL-32 mRNA expression was measured by RT- PCR. _Results:_ Sputum IL-32 was significantly elevated at the protein (_p= 0.00019_) and mRNA expression (_p &lt; 0.0001_) in asthmatics compared to non-asthmatic controls. IL-32 was elevated in severe asthmatic patients (_p &lt; 0.0001_) compared to mild-moderate asthma. Severe asthmatics allergic to house dust mites expressed higher sputum IL-32 level than severe asthmatics without allergy (_p = 0.0001_). A significant association was found between sputum IL-32 and IL-32 mRNA (r =0.531_; p = 0.0159_) in severe asthma. In the same way, sputum IL-1β and IL-32 were significantly correlated (r = 0.476; _p = 0.0337_). _Conclusion:_ The level of IL-32 in induced sputum may be associated with asthma severity.

Nanoparticles in induced sputum - a window to airway inflammation among active smokers.

Aims: To evaluate the role of nanoparticles (NP) in sputum samples of active smokers as markers of inflammation and disease. Materials & methods: 29 active smokers were included (14 with chronic obstructive pulmonary disease [COPD]) and underwent clinical assessment, pulmonary function tests, sputum induction (with NPanalysis) and blood sampling. Results: Higher particle and NP concentrations and smaller mean size directly correlated with clinical parameters such as the COPD Assessment Test score and impulse oscillometry results. Similar correlations were found between NPs and increased sputum IL-1β, IL-6 and TNF-α. Among COPD patients, higher IL-8 and lower IL-10 serum levels also correlated with NP concentrations. Conclusion: This proof-of-concept study shows the potential of sputum NPs as markers of airway inflammation and disease.

Interleukin-1 beta is a potential mediator of airway nitric oxide deficiency in cystic fibrosis

Airway nitric oxide (NO) deficiency is a hallmark of cystic fibrosis (CF), but the reasons for the reduced NO production in CF airways are unclear. Interleukin (IL)-1 pathway activation plays a role in early CF lung disease and is also involved in the regulation of NO synthase activity. Treatment of CF patients with the CFTR-targeting drug ivacaftor, among other beneficial effects, results in an increase in airway NO levels. In this longitudinal observational trial, we show that ivacaftor therapy leads to a significant reduction in sputum IL-1β concentration but not in other IL-1- or Th17-associated cytokines. IL-1β concentrations were closely linked to improvement in pulmonary function, measures of NO metabolism in sputum and exhaled NO. These data therefore suggest a potential interaction between transepithelial chloride conductance, IL-1β and airway NO production.

IL-1\u03b2 augments TGF-\u03b2 inducing epithelial-mesenchymal transition of epithelial cells and associates with poor pulmonary function improvement in neutrophilic asthmatics

BackgroundNeutrophilic asthmatics (NA) have less response to inhaled corticosteroids. We aimed to find out the predictor of treatment response in NA.MethodsAsthmatics (n = 115) and healthy controls (n = 28) underwent clinical assessment during 6-month follow-up with standardized therapy. Asthmatics were categorized by sputum differential cell count. The mRNA expressions were measured by RT-qPCR for sputum cytokines (IFN-γ, IL-1β, IL-27, FOXP3, IL-17A, and IL-5). The protein of IL-1β in sputum supernatant was detected by ELISA. Reticular basement membranes (RBM) were measured in the biopsy samples. The role and signaling pathways of IL-1β mediating the epithelial-mesenchymal transition (EMT) process were explored through A549 cells.ResultsNA had increased baseline sputum cell IL-1β expression compared to eosinophilic asthmatics (EA). After follow-up, NA had less improvement in FEV1 compared to EA. For all asthmatics, sputum IL-1β mRNA was positively correlated with protein expression. Sputum IL-1β mRNA and protein levels were negatively correlated to FEV1 improvement. After subgrouping, the correlation between IL-1β mRNA and FEV1 improvement was significant in NA but not in EA. Thickness of RBM in asthmatics was greater than that of healthy controls and positively correlated with neutrophil percentage in bronchoalveolar lavage fluid. In vitro experiments, the process of IL-1β augmenting TGF-β1-induced EMT cannot be abrogated by glucocorticoid or montelukast sodium, but can be reversed by MAPK inhibitors.ConclusionsIL-1β level in baseline sputum predicts the poor lung function improvement in NA. The potential mechanism may be related to IL-1β augmenting TGF-β1-induced steroid-resistant EMT through MAPK signaling pathways.Trial registration: This study was approved by the Ethics Committee of Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology (IRB ID: 20150406).

High serum granulocyte-colony stimulating factor characterises neutrophilic COPD exacerbations associated with dysbiosis.

IntroductionCOPD exacerbations are heterogeneous and can be triggered by bacterial, viral, or noninfectious insults. Exacerbations are also heterogeneous in neutrophilic or eosinophilic inflammatory responses. A noninvasive peripheral biomarker of COPD exacerbations characterised by bacterial/neutrophilic inflammation is lacking. Granulocyte-colony stimulating factor (G-CSF) is a key cytokine elevated during bacterial infection and mediates survival, proliferation, differentiation and function of neutrophils.ObjectiveWe hypothesised that high peripheral G-CSF would be indicative of COPD exacerbations with a neutrophilic and bacterial phenotype associated with microbial dysbiosis.MethodsSerum G-CSF was measured during hospitalised exacerbation (day 0 or D0) and after 30 days of recovery (Day30 or D30) in 37 subjects. In a second cohort, serum and sputum cytokines were measured in 59 COPD patients during stable disease, at exacerbation, and at 2-weeks and 6-weeks following exacerbation.ResultsSerum G-CSF was increased during exacerbation in a subset of patients. These exacerbations were enriched for bacterial but not viral or type-2 biologies. The median serum G-CSF level was 1.6-fold higher in bacterial exacerbation compared to nonbacterial exacerbation (22 pg·mL−1 versus 13 pg·mL−1, p=0.0007). Serum G-CSF classified bacterial exacerbations with an area under the curve (AUC) for the receiver operating characteristic (ROC) curve equal to 0.76. Exacerbations with a two-fold or greater increase in serum G-CSF were characterised by neutrophilic inflammation, with increased sputum and blood neutrophils, and high sputum interleukin (IL)-1β, IL-6 and serum amyloid A1 (SAA1) levels. These exacerbations were preceded by dysbiosis, with decreased microbiome diversity and enrichment of respiratory pathogens such as Haemophilus and Moraxella. Furthermore, serum G-CSF at exacerbation classified neutrophilic-dysbiotic exacerbations (AUC for the ROC curve equal to 0.75).ConclusionsHigh serum G-CSF enriches for COPD exacerbations characterised by neutrophilic inflammation with underlying bacterial dysbiosis.

Inflammatory Endotype-associated Airway Microbiome in Chronic Obstructive Pulmonary Disease Clinical Stability and Exacerbations: A Multicohort Longitudinal Analysis.

Rationale: Understanding the role of the airway microbiome in chronic obstructive pulmonary disease (COPD) inflammatory endotypes may help to develop microbiome-based diagnostic and therapeutic approaches.Objectives: To understand the association of the airway microbiome with neutrophilic and eosinophilic COPD at stability and during exacerbations.Methods: An integrative analysis was performed on 1,706 sputum samples collected longitudinally from 510 patients with COPD recruited at four UK sites of the BEAT-COPD (Biomarkers to Target Antibiotic and Systemic COPD), COPDMAP (Chronic Obstructive Pulmonary Disease Medical Research Council/Association of the British Pharmaceutical Industry), and AERIS (Acute Exacerbation and Respiratory Infections in COPD) cohorts. The microbiome was analyzed using COPDMAP and AERIS as a discovery data set and BEAT-COPD as a validation data set.Measurements and Main Results: The airway microbiome in neutrophilic COPD was heterogeneous, with two primary community types differentiated by the predominance of Haemophilus. The Haemophilus-predominant subgroup had elevated sputum IL-1β and TNFα (tumor necrosis factor α) and was relatively stable over time. The other neutrophilic subgroup with a balanced microbiome profile had elevated sputum and serum IL-17A and was temporally dynamic. Patients in this state at stability were susceptible to the greatest microbiome shifts during exacerbations. This subgroup can temporally switch to both neutrophilic Haemophilus-predominant and eosinophilic states that were otherwise mutually exclusive. Time-series analysis on the microbiome showed that the temporal trajectories of Campylobacter and Granulicatella were indicative of intrapatient switches from neutrophilic to eosinophilic inflammation, in track with patient sputum eosinophilia over time. Network analysis revealed distinct host–microbiome interaction patterns among neutrophilic Haemophilus-predominant, neutrophilic balanced microbiome, and eosinophilic subgroups.Conclusions: The airway microbiome can stratify neutrophilic COPD into subgroups that justify different therapies. Neutrophilic and eosinophilic COPD are interchangeable in some patients. Monitoring temporal variability of the airway microbiome may track patient inflammatory status over time.

Visceral obesity is associated with clinical and inflammatory features of asthma: A prospective cohort study.

Background: Although studies have consistently linked obesity and asthma, the potential influence of visceral obesity on asthma has not been well investigated. Objective: To study the associations of visceral fat area (VFA) and clinical and inflammatory features of asthma and to further explore the effects of VFA on the future risk of asthma exacerbation. Methods: A 12-month prospective cohort study based on the Australasian Severe Asthma Network was designed to observe patients with stable asthma grouped by the median value of VFA. The clinical and inflammatory features of asthma were compared between the low VFA (VFAlow) and high VFA (VFAhigh) groups. Relationships between VFA and clinical and inflammatory features of asthma were analyzed by using correlation analysis. Univariate and multivariable negative binomial regression analyses were performed to investigate the association of VFA with exacerbations within a 12-month follow-up period. Results: The patients in the VFAhigh group were older and had a longer asthma duration. Interleukin (IL) 6 and IL-8 in sputum were higher, whereas fractional exhaled nitric oxide (FeNO) and blood eosinophils were lower in the VFAhigh group. Gender-differentiated correlations of VFA with clinical and inflammatory variables were observed in age, FeNO, immunoglobulin E, blood total white cells and neutrophils, and sputum IL-1β and IL-8. Furthermore, compared with the VFAlow group, the VFAhigh group was at significantly increased risk of moderate-to-severe exacerbations (adjusted incidence rate ratio [IRR] 1.55 [95% confidence interval {CI}, 1.06-2.28; p = 0.025), severe exacerbations (adjusted IRR 2.25 [95% CI, 1.26-4.04]; p = 0.007), and emergency visits (adjusted IRR 5.33 [95% CI, 1.78-17.16]; p = 0.003). Conclusion: The level of VFA was associated with specific clinical and inflammatory characteristics of asthma. Furthermore, VFA, as an independent risk factor, was associated with an increased risk of exacerbations. It indicated that VFA would provide more potential clinical implications for asthma management.

Chitinase-like protein YKL-40 correlates with inflammatory phenotypes, anti-asthma responsiveness and future exacerbations

BackgroundAsthma is a heterogeneous chronic airway disease, which may be classified into different phenotypes. YKL-40 is a chitin-binding glycoprotein with unclear functions, but its expression is associated with inflammation and tissue remodeling. However, few studies have explored whether YKL-40 is associated with inflammatory phenotypes of asthma.MethodsThe study had two parts. Study I (n = 115) was a one-year prospective cohort designed to explore the relationship of serum YKL-40 levels with inflammatory phenotypes of asthma at baseline, and during exacerbations. Study II (n = 62) was a four-week prospective cohort designed to define whether serum YKL-40 levels could predict responses to a fixed anti-asthma regimen. YKL-40, IL-6 and CCL22 levels were detected using ELISA, and a sputum inflammatory panel (including IL-1β, IL-5, IL-8 and TNF-α) was assessed using Luminex-based MILLIPLEX assay.ResultsStudy I: Serum YKL-40 levels in non-eosinophilic asthma (NEA) i.e. neutrophilic (47.77 [29.59, 74.97] ng/mL, n = 40) and paucigranulocytic (47.36 [28.81, 61.68] ng/mL, n = 31) were significantly elevated compared with eosinophilic asthma (31.05 [22.41, 51.10] ng/mL, n = 44) (P = 0.015). Serum YKL-40levels positively correlated with blood neutrophils, sputum IL-1β and plasma IL-6 but negatively correlated with serum IgE and blood eosinophils (all P ≤ 0.05). Baseline YKL-40 levels predicted moderate to severe exacerbations within a one-year period (aOR = 4.13, 95% CI = [1.08, 15.83]). Study II: Serum YKL-40 was an independent biomarker of negative responses to anti-asthma regimens (adjusted Odds Ratio [aOR] = 0.82, 95% CI = [0.71, 0.96].ConclusionsThese studies show that YKL-40 is a non-type 2 inflammatory signature for NEA, which could predict responsiveness or insensitivity to anti-asthma medications and more exacerbations. Further studies are needed to assess whether monitoring YKL-40 levels could provide potential implications for clinical relevance.

Saturated fatty acids, obesity, and the nucleotide oligomerization domain–like receptor protein 3 (NLRP3) inflammasome in asthmatic patients

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

Sputum transcriptomics reveal upregulation of IL-1 receptor family members in patients with severe asthma

Sputum analysis in asthmatic patients is used to define airway inflammatory processes and might guide therapy. We sought to determine differential gene and protein expression in sputum samples from patients with severe asthma (SA) compared with nonsmoking patients with mild/moderate asthma. Induced sputum was obtained from nonsmoking patients with SA, smokers/ex-smokers with severe asthma, nonsmoking patients with mild/moderate asthma (MMAs), and healthy nonsmoking control subjects. Differential cell counts, microarray analysis of cell pellets, and SOMAscan analysis of sputum analytes were performed. CRID3 was used to inhibit the inflammasome in a mouse model of SA. Eosinophilic and mixed neutrophilic/eosinophilic inflammation were more prevalent in patients with SA compared with MMAs. Forty-two genes probes were upregulated (>2-fold) in nonsmoking patients with severe asthma compared with MMAs, including IL-1 receptor (IL-1R) family and nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing 3 (NRLP3) inflammasome members (false discovery rate<0.05). The inflammasome proteins nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 1 (NLRP1), NLRP3, and nucleotide-binding oligomerization domain (NOD)-like receptor C4 (NLRC4) were associated with neutrophilic asthma and with sputum IL-1β protein levels, whereas eosinophilic asthma was associated with an IL-13-induced TH2 signature and IL-1 receptor-like 1 (IL1RL1) mRNA expression. These differences were sputum specific because no activation of NLRP3 or enrichment of IL-1R family genes in bronchial brushings or biopsy specimens in patients with SA was observed. Expression of NLRP3 and of the IL-1R family genes was validated in the Airway Disease Endotyping for Personalized Therapeutics cohort. Inflammasome inhibition using CRID3 prevented airway hyperresponsiveness and airway inflammation (both neutrophilia and eosinophilia) in a mouse model of severe allergic asthma. IL1RL1 gene expression is associated with eosinophilic SA, whereas NLRP3 inflammasome expression is highest in patients with neutrophilic SA. TH2-driven eosinophilic inflammation and neutrophil-associated inflammasome activation might represent interacting pathways in patients with SA.

A Sputum Proteomic Signature That Associates with Increased IL-1β Levels and Bacterial Exacerbations of COPD.

Activation of the interleukin-1β (IL-1β) signaling pathway has been implicated in COPD, but the proportion of COPD subjects whose disease is principally driven by activation of this pathway is poorly understood. In this study, we sought to differentiate an IL-1β-associated sputum signature from other inflammation-associated COPD phenotypes. Luminex-multiplex assays were used to study IL-1β-mediated signature proteins within airway epithelium, smooth muscle, and vascular endothelial cell cultures. The IL-1β-mediated signature was tested in a longitudinal study comprising of 35 paired stable-COPD and acute exacerbation (AECOPD) sputum samples. The presence of respiratory pathogens (H. influenzae, M. catarrhalis, S. pneumoniae, and P. aeruginosa) was evaluated by sputum cultures. Five proteins namely TNF-α, GCSF, IL-6, CD-40L, and MIP-1β were found to be IL-1β-regulated across all donors and cell types. All five of these IL-1β-mediated proteins were significantly increased (p<0.05) in sputum corresponding to AECOPD events showing at least a twofold increase in IL-1β (IL-1β(+) events, 18 of 35 total events), relative to preceding stable-COPD state. Sputum IL-1β levels showed no significant association (p>0.05, spearman) with known markers of other major COPD inflammation phenotypes. In addition, there was a significant association with bacterial presence in sputum culture with an odds ratio of 9 (95% CI 1.56, 51.9) in IL-1β(+) events versus IL-1β(-) events. Our findings provide insights into potential markers of IL-1β-associated AECOPD, and reaffirm association between IL-1β pathway activation and airway bacterial infection in COPD. Taken together, our findings could help identify COPD patient subsets who may benefit from therapies targeting IL-1β pathway.

The Role of Viral Infection in Pulmonary Exacerbations of Bronchiectasis in Adults: A Prospective Study

BACKGROUNDAlthough viral infections are a major cause of exacerbations in patients with chronic airway diseases, their roles in triggering bronchiectasis exacerbations in adults remain unclear. Therefore, we prospectively investigated the incidence and clinical impacts of viral infection in adults with bronchiectasis exacerbations.METHODSThe study cohort of 119 adults with bronchiectasis was followed up prospectively for 12 months. Nasopharyngeal swabs and sputum samples were assayed for 16 respiratory viruses, using polymerase chain reaction assays. Symptoms, spirometry, quality of life, bacterial cultures, and inflammatory markers were assessed during steady-state bronchiectasis and exacerbations.RESULTSA total of 100 exacerbations were captured from 58 patients during 1-year follow-up. Respiratory viruses were found more frequently in nasopharyngeal swabs and sputum during bronchiectasis exacerbations (49 of 100, 49.0') than during steady state (11 of 58, 18.9'; P < .001). The most common viruses found in patients experiencing exacerbations were coronavirus (19 of 65, 39.2'), rhinovirus (16 of 65, 24.6'), and influenza A/B viruses (16 of 65, 24.6'). Virus-positive exacerbations were associated with a greater increase in markers of systemic and airway inflammation (serum IL-6 and tumor necrosis factor-α; sputum IL-1β and tumor necrosis factor-α) compared with virus-negative exacerbations, but the differences in spirometric indexes, quality of life, and bacterial density were unremarkable. In receiver operating characteristics analysis, serum interferon-γ-induced protein 10 yielded an area under curve of 0.67 (95' CI, 0.53-0.77; P = .018). Furthermore, a greater proportion of patients with virus-positive exacerbations received IV antibiotics.CONCLUSIONSPrevalence of viral infections, detected by polymerase chain reaction assay, is higher in cases of bronchiectasis exacerbations than in steady-state bronchiectasis, suggesting that respiratory viruses play crucial roles in triggering bronchiectasis exacerbations. The potential mechanisms of virus-induced bronchiectasis exacerbations merit further investigations.TRIAL REGISTRYClinicalTrials.gov; No.: NCT01801657; www.clinicaltrials.gov

Damage-associated molecular pattern and innate cytokine release in the airways of competitive swimmers.

Daily intensive exercise by elite athletes can result in exercise-induced asthma especially in elite swimmers and this may be linked to epithelial damage. To study airway epithelial damage and release of damage-associated molecular patterns (DAMPs) after intensive exercise in elite athletes and controls. We recruited competitive swimmers (n=26), competitive indoor athletes (n=13) and controls (n=15) without any history of asthma. Lung function was measured before, immediately after and 24h after a 90-min intensive exercise protocol. Sputum induction was performed at baseline and 24h after exercise. Exercise-induced bronchoconstriction (EIB) was assessed by the eucapnic voluntary hyperventilation test. Baseline sputum uric acid, high mobility group box-1, CXCL8 mRNA, sputum neutrophils and serum Clara cell protein-16 (CC-16) were significantly higher in competitive swimmers compared with controls. Intensive swimming for 90min resulted in an increase of sputum IL-1β, IL-6 and TNF mRNA in competitive swimmers, and of sputum IL-6 mRNA and sputum neutrophils in controls. Although all participants were asymptomatic, seven competitive swimmers, one indoor athlete and one control met the criteria for EIB. Our findings show that the intensive training combined with exposure to by-products of chlorination induces airway epithelial damage in competitive swimmers. This is associated with increased damage-associated molecular patterns, innate cytokine release and neutrophilic airway inflammation.

Biological clustering supports both “Dutch” and “British” hypotheses of asthma and chronic obstructive pulmonary disease

BackgroundAsthma and chronic obstructive pulmonary disease (COPD) are heterogeneous diseases.ObjectiveWe sought to determine, in terms of their sputum cellular and mediator profiles, the extent to which they represent distinct or overlapping conditions supporting either the “British” or “Dutch” hypotheses of airway disease pathogenesis.MethodsWe compared the clinical and physiological characteristics and sputum mediators between 86 subjects with severe asthma and 75 with moderate-to-severe COPD. Biological subgroups were determined using factor and cluster analyses on 18 sputum cytokines. The subgroups were validated on independent severe asthma (n = 166) and COPD (n = 58) cohorts. Two techniques were used to assign the validation subjects to subgroups: linear discriminant analysis, or the best identified discriminator (single cytokine) in combination with subject disease status (asthma or COPD).ResultsDiscriminant analysis distinguished severe asthma from COPD completely using a combination of clinical and biological variables. Factor and cluster analyses of the sputum cytokine profiles revealed 3 biological clusters: cluster 1: asthma predominant, eosinophilic, high TH2 cytokines; cluster 2: asthma and COPD overlap, neutrophilic; cluster 3: COPD predominant, mixed eosinophilic and neutrophilic. Validation subjects were classified into 3 subgroups using discriminant analysis, or disease status with a binary assessment of sputum IL-1β expression. Sputum cellular and cytokine profiles of the validation subgroups were similar to the subgroups from the test study.ConclusionsSputum cytokine profiling can determine distinct and overlapping groups of subjects with asthma and COPD, supporting both the British and Dutch hypotheses. These findings may contribute to improved patient classification to enable stratified medicine.

A Novel Microbiota Stratification System Predicts Future Exacerbations in Bronchiectasis

Although airway microbiota composition correlates with clinical measures in non-cystic fibrosis bronchiectasis, these data are unlikely to provide useful prognostic information at the individual patient level. A system enabling microbiota data to be applied clinically would represent a substantial translational advance. This study aims to determine whether stratification of patients according to the predominant microbiota taxon can provide improved clinical insight compared with standard diagnostics. The presence of bacterial respiratory pathogens was assessed in induced sputum from 107 adult patients by culture, quantitative PCR, and, in 96 samples, by ribosomal gene pyrosequencing. Prospective analysis was performed on samples from 42 of these patients. Microbiological data were correlated with concurrent clinical measures and subsequent outcomes. Microbiota analysis defined three groups: Pseudomonas aeruginosa dominated (n = 26), Haemophilus influenzae dominated (n = 34), and other taxa dominated (n = 36). Patients with P. aeruginosa- and H. influenzae-dominated communities had significantly worse lung function, higher serum levels of C-reactive protein (CRP), and higher sputum levels of IL-8 and IL-1β. Predominance of P. aeruginosa, followed by Veillonella species, was the best predictor of future exacerbation frequency, with H. influenzae-dominated communities having significantly fewer episodes. Detection of P. aeruginosa was associated with poor lung function and exacerbation frequency, irrespective of analytical strategy. Quantitative PCR revealed significant correlations between H. influenzae levels and sputum IL-8, IL-1β, and serum CRP. Genus richness was negatively correlated with 24-hour sputum weight, age, serum CRP, sputum IL-1β, and IL-8. Stratification of patients with non-cystic fibrosis bronchiectasis on the basis of predominant bacterial taxa is more clinically informative than either conventional culture or quantitative PCR-based analysis. Further investigation is now required to assess the mechanistic basis of these associations.