Search

BackgroundPatients with chronic obstructive pulmonary disease (COPD) commonly suffer from acute exacerbations (AECOPD) and display varying disease severity. However, there is no available biomarker for the classification of AECOPD. This study is aimed at investigating the sputum cellular profiles to classify patients with AECOPD.MethodsA total of 83 patients with AECOPD and 26 healthy controls were recruited. Their demographic and clinical characteristics were recorded, and their lung function was examined. The phenotypes of sputum inflammatory cells were characterised, and the concentrations of sputum and serum amyloid-A (SAA), C-reactive protein (CRP), interleukin-6 (IL-6), and matrix metalloproteinase-9 (MMP-9) were measured. Based on the sputum inflammatory cell profiles, individual patients were categorized into one of the four subgroups with inflammatory eosinophilic, neutrophilic, paucigranulocytic, and mixed granulocytic AECOPD. Most AECOPD patients were reevaluated within 12-14 months after discharge.ResultsThere were 10 (12%) eosinophilic, 36 (43%) neutrophilic, 5 (6%) mixed granulocytic, and 32 (39%) paucigranulocytic AECOPD patients. The patients with mixed granulocytic or neutrophilic AECOPD had a higher BODE score, more sputum inflammatory cells, lower lung function, and longer hospital stay, accompanied by higher concentrations of sputum MMP-9, IL-6 and CRP, and serum SAA, IL-6 and CRP. Notably, 83% of patients with neutrophilic AECOPD displayed evidence of bacterial infection and many of them responded poorly to standard therapies. In addition, patients with mixed granulocytic or neutrophilic stable COPD remained at lower lung functions and higher levels of inflammation.ConclusionPatients with AECOPD display heterogeneous inflammation, and the profiles of sputum inflammatory cells may be used as valuable biomarkers for the classification of AECOPD patients.

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-1β, 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.

BackgroundThe common cold questionnaire (CCQ) is used to discriminate those with and without a viral infection. Its usefulness in people with acute asthma is unknown. Our aim was to assess the ability of the CCQ to detect viral infection and to monitor recovery during a viral induced asthma exacerbation and confirmed by virological testing.Methodology/principal findingsWe studied subjects (> or =7 yrs) admitted to hospital with acute asthma and diagnosed as positive (n = 63), or negative to viral infection (n = 27) according to molecular and virological testing from respiratory samples. CCQ, asthma history and asthma control questionnaires were completed and repeated 4-6 weeks later. Sensitivity, specificity, and response to change of the CCQ were assessed by receiver operator curve (ROC) analysis and effect size calculation respectively. The CCQ did not discriminate between viral and non-viral infection for subjects with asthma (sensitivity = 76.2%; specificity = 29.6%). ROC analysis could not differentiate between positive or negative virus in subjects with asthma. The CCQ had a large response to change following recovery (effect size = 1.01). 39% of subjects recovering from viral exacerbation remained positive to virological testing at follow-up despite improvement in clinical symptoms. The CCQ reflected clinical improvement in these subjects, thus providing additional information to complement virological testing.Conclusions/significanceThe CCQ is a useful instrument for monitoring response to viral infection in people with asthma. Reliable differentiation between viral and non-viral asthma exacerbations was not achieved with the CCQ and requires specific virological testing. When combined with virological testing, the CCQ should be a useful outcome measure for evaluating therapies in viral-induced asthma.

Background Chronic Obstructive Pulmonary Disease (COPD) is a progressive airway disease characterised by neutrophilic airway inflammation or bronchitis. Neutrophilic bronchitis is associated with both bacterial colonisation and lung function decline and is common in exacerbations of COPD. Despite current available therapies to control inflammation, neutrophilic bronchitis remains common. This study tested the hypothesis that azithromycin treatment, as an add-on to standard medication, would significantly reduce airway neutrophil and neutrophils chemokine (CXCL8) levels, as well as bacterial load. We conducted a randomised, double-blind, placebo-controlled study in COPD participants with stable neutrophilic bronchitis. Methods Eligible participants (n = 30) were randomised to azithromycin 250 mg daily or placebo for 12 weeks in addition to their standard respiratory medications. Sputum was induced at screening, randomisation and monthly for a 12 week treatment period and processed for differential cell counts, CXCL8 and neutrophil elastase assessment. Quantitative bacteriology was assessed in sputum samples at randomisation and the end of treatment visit. Severe exacerbations where symptoms increased requiring unscheduled treatment were recorded during the 12 week treatment period and for 14 weeks following treatment. A sub-group of participants underwent chest computed tomography scans (n = 15). Results Nine participants with neutrophilic bronchitis had a potentially pathogenic bacteria isolated and the median total bacterial load of all participants was 5.22×107 cfu/mL. Azithromycin treatment resulted in a non-significant reduction in sputum neutrophil proportion, CXCL8 levels and bacterial load. The mean severe exacerbation rate was 0.33 per person per 26 weeks in the azithromycin group compared to 0.93 exacerbations per person in the placebo group (incidence rate ratio (95%CI): 0.37 (0.11,1.21), p = 0.062). For participants who underwent chest CT scans, no alterations were observed. Conclusions In stable COPD with neutrophilic bronchitis, add-on azithromycin therapy showed a trend to reduced severe exacerbations sputum neutrophils, CXCL8 levels and bacterial load. Future studies with a larger sample size are warranted. Trial Registration Australian New Zealand Clinical Trials Registry ACTRN12609000259246

A subset of patients with stable asthma has prominent neutrophilic and reduced eosinophilic inflammation, which is associated with attenuated airways hyper-responsiveness (AHR). Haemophilus influenzae has been isolated from the airways of neutrophilic asthmatics; however, the nature of the association between infection and the development of neutrophilic asthma is not understood. Our aim was to investigate the effects of H. influenzae respiratory infection on the development of hallmark features of asthma in a mouse model of allergic airways disease (AAD). BALB/c mice were intraperitoneally sensitized to ovalbumin (OVA) and intranasally challenged with OVA 12–15 days later to induce AAD. Mice were infected with non-typeable H. influenzae during or 10 days after sensitization, and the effects of infection on the development of key features of AAD were assessed on day 16. T-helper 17 cells were enumerated by fluorescent-activated cell sorting and depleted with anti-IL-17 neutralizing antibody. We show that infection in AAD significantly reduced eosinophilic inflammation, OVA-induced IL-5, IL-13 and IFN-γ responses and AHR; however, infection increased airway neutrophil influx in response to OVA challenge. Augmented neutrophilic inflammation correlated with increased IL-17 responses and IL-17 expressing macrophages and neutrophils (early, innate) and T lymphocytes (late, adaptive) in the lung. Significantly, depletion of IL-17 completely abrogated infection-induced neutrophilic inflammation during AAD. In conclusion, H. influenzae infection synergizes with AAD to induce Th17 immune responses that drive the development of neutrophilic and suppress eosinophilic inflammation during AAD. This results in a phenotype that is similar to neutrophilic asthma. Infection-induced neutrophilic inflammation in AAD is mediated by IL-17 responses., Author Summary Approximately 50% of asthmatics have non-eosinophilic inflammation, and 20% of these patients have severe neutrophilic inflammation and increased IL-8 levels. These so-called neutrophilic asthmatics have persistent airway colonization with bacteria, and Haemophilus influenzae is one of the bacteria most commonly isolated. However, how H. influenzae is associated with the pathogenesis of neutrophilic asthma is unknown. In this study we used mouse models to investigate the relationship between H. influenzae infection and allergic airways disease (AAD). We showed that infection promoted the development of hallmark features of neutrophilic asthma. Infection suppressed Th2 cytokines, eosinophilic inflammation, and AHR in AAD, while increasing neutrophilic inflammation and IL-17 responses. Importantly, inhibition of IL-17 during AAD reduced airway neutrophils and neutrophil chemokines, suggesting that infection drives the development of neutrophilic inflammation through an IL-17-mediated mechanism. This provides novel insights into the mechanisms that may underpin infection-induced neutrophilic asthma. These data also suggest that treatments targeting infection may lead to improved management of neutrophilic asthma.