Inflammation and infections in unreported chronic obstructive pulmonary disease exacerbations

Purpose: COPD patients often do not report acute exacerbations to healthcare providers – unreported exacerbations. It is not known whether variances in symptoms, airway obstruction, aetiology and inflammatory responses account for differences in reporting of COPD exacerbations. The aims of the study were to compare symptoms, lung function changes, aetiology and inflammatory markers between exacerbations that were reported to healthcare providers or treated, with those that were unreported and untreated. Patients and methods: We recruited a cohort of COPD patients and collected clinical data and blood and airway samples when stable and during acute exacerbations. Virological and bacterial analyses were carried out and inflammatory markers measured. Results: We found no differences in symptoms, lung function, incidence of infection and inflammatory markers between reported and unreported exacerbations. Subjects who reported all exacerbations had higher BODE scores, lower FEV1 and more exacerbations compared with those who did not. Conclusion: The failure to report exacerbations is not related to the severity, aetiology or inflammatory profile of the exacerbation. Patients with less severe COPD and less frequent exacerbations are less likely to report exacerbations. The decision to report an exacerbation is not an objective marker of exacerbation severity and therefore studies that do not count unreported exacerbations will underestimate the frequency of clinically significant exacerbations. A better understanding of the factors that determine non-reporting of exacerbations is required to improve exacerbation reporting

IL-33-dependent Type 2 inflammation during rhinovirus-induced asthma exacerbations in vivo

Rationale: Rhinoviruses are the major cause of asthma exacerbations; however, its underlying mechanisms are poorly understood. We hypothesized that the epithelial cell–derived cytokine IL-33 plays a central role in exacerbation pathogenesis through augmentation of type 2 inflammation. Objectives: To assess whether rhinovirus induces a type 2 inflammatory response in asthma in vivo and to define a role for IL-33 in this pathway. Methods: We used a human experimental model of rhinovirus infection and novel airway sampling techniques to measure IL-4, IL-5, IL-13, and IL-33 levels in the asthmatic and healthy airways during a rhinovirus infection. Additionally, we cultured human T cells and type 2 innate lymphoid cells (ILC2s) with the supernatants of rhinovirusinfected bronchial epithelial cells (BECs) to assess type 2 cytokine production in the presence or absence of IL-33 receptor blockade. Measurements and Main Results: IL-4, IL-5, IL-13, and IL-33 are all induced by rhinovirus in the asthmatic airway in vivo and relate to exacerbation severity. Further, induction of IL-33 correlates with viral load and IL-5 and IL-13 levels. Rhinovirus infection of human primary BECs induced IL-33, and culture of human T cells and ILC2s with supernatants of rhinovirus-infected BECs strongly induced type 2 cytokines. This induction was entirely dependent on IL-33. Conclusions: IL-33 and type 2 cytokines are induced during a rhinovirus-induced asthma exacerbation in vivo. Virus-induced IL-33 and IL-33–responsive T cells and ILC2s are key mechanistic links between viral infection and exacerbation of asthma. IL-33 inhibition is a novel therapeutic approach for asthma exacerbation

Pulmonary innate lymphoid cell responses during rhinovirus-induced asthma exacerbations

Rationale Type 2 innate lymphoid cells (ILC2s) are significant sources of type 2 cytokines, which are implicated in the pathogenesis of asthma and asthma exacerbations. The role of ILC2s in virus-induced asthma exacerbations is not well-characterized. Objectives To characterize pulmonary ILC responses following experimental rhinovirus challenge in patients with moderate asthma and healthy subjects. Methods Patients with moderate asthma and healthy subjects were inoculated with rhinovirus-16, and underwent bronchoscopy at baseline, day 3 and day 8 post-inoculation. Pulmonary ILC1s and ILC2s were quantified in bronchoalveolar lavage (BAL) using flow cytometry. The ratio of BAL ILC2:ILC1 was assessed to determine their relative contributions to the clinical and immune response to rhinovirus challenge. Measurements and Main Results At baseline, ILC2s were significantly higher in patients with asthma than healthy subjects. At day 8, ILC2s significantly increased from baseline in both groups, which was significantly higher in asthma than in healthy subjects (all comparisons P<0.05). In healthy subjects, ILC1s increased from baseline at day 3 (P=0.001), while in patients with asthma, ILC1s increased from baseline at day 8 (P=0.042). Patients with asthma had significantly higher ILC2:ILC1 ratios at baseline (P=0.024) and day 8 (P=0.005). Increased ILC2:ILC1 ratio in asthma correlated with clinical exacerbation severity and type 2 cytokines in nasal mucosal lining fluid. Conclusions An ILC2-predominant inflammatory profile in asthma was associated with increased severity and duration of rhinovirus infection compared with healthy subjects, supporting the potential role of ILC2s in the pathogenesis of virus-induced asthma exacerbations. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT0177359

Inflammation and infections in unreported chronic obstructive pulmonary disease exacerbations

Maria Adelaide Calderazzo,1 Maria-Belen Trujillo-Torralbo,1,2 Lydia Joanne Finney,1 Aran Singanayagam,1 Eteri Bakhsoliani,1 Vijay Padmanaban,2 Tatiana Kebadze,1 Julia Aniscenko,1 Sarah L Elkin,1,2 Sebastian L Johnston,1,2 Patrick Mallia1,21National Heart and Lung Institute, Imperial College, London, UK; 2Department of Respiratory Medicine, Imperial College Healthcare NHS Trust, London, UKPurpose: COPD patients often do not report acute exacerbations to healthcare providers &ndash; unreported exacerbations. It is not known whether variances in symptoms, airway obstruction, aetiology and inflammatory responses account for differences in reporting of COPD exacerbations. The aims of the study were to compare symptoms, lung function changes, aetiology and inflammatory markers between exacerbations that were reported to healthcare providers or treated, with those that were unreported and untreated.Patients and methods: We recruited a cohort of COPD patients and collected clinical data and blood and airway samples when stable and during acute exacerbations. Virological and bacterial analyses were carried out and inflammatory markers measured.Results: We found no differences in symptoms, lung function, incidence of infection and inflammatory markers between reported and unreported exacerbations. Subjects who reported all exacerbations had higher BODE scores, lower FEV1 and more exacerbations compared with those who did not.Conclusion: The failure to report exacerbations is not related to the severity, aetiology or inflammatory profile of the exacerbation. Patients with less severe COPD and less frequent exacerbations are less likely to report exacerbations. The decision to report an exacerbation is not an objective marker of exacerbation severity and therefore studies that do not count unreported exacerbations will underestimate the frequency of clinically significant exacerbations. A better understanding of the factors that determine non-reporting of exacerbations is required to improve exacerbation reporting.Trial registration: ClinicalTrials.gov Identifier: NCT01376830. Registered June 17, 2011Keywords: chronic obstructive pulmonary disease, acute exacerbations, unreported exacerbation

Cytokine responses to rhinovirus and development of asthma, allergic sensitization and respiratory infections during childhood

BACKGROUND: Immunophenotypes of anti-viral responses, and their relationship with asthma, allergy and lower respiratory tract infections (LRTIs) are poorly understood. We characterized multiple cytokine responses of peripheral-blood mononuclear cells to rhinovirus stimulation, and their relationship with clinical outcomes. METHODS: In a population-based birth cohort, we measured 28 cytokines post-stimulation with rhinovirus-16 in 307 children aged 11 years. We used machine learning to identify patterns of cytokine responses, and related these patterns to clinical outcomes using longitudinal models. We also ascertained phytohaemagglutinin-induced TH2-cytokine responses [PHA-TH2]. RESULTS: We identified six clusters of children based on their rhinovirus-16 responses, which were differentiated by the expression of four cytokine/chemokine groups: interferon-related-(IFN); pro-inflammatory-(Inflam); TH2-chemokine-(TH2-chem); regulatory-(Reg). Clusters differed in their clinical characteristics. Children with IFNmodInflamhighestTH2-chemhighestReghighestrhinovirus-16-induced pattern had PHA-TH2lowresponse, and a very low asthma risk (OR:0.08 [95%CI 0.01-0.81], P=0.03). Two clusters had high risk of asthma and allergic sensitization, but with different trajectories from infancy to adolescence. The IFNlowestInflamhighTH2-chemlowRegmodcluster exhibited PHA-TH2lowestresponse, and was associated with early-onset asthma and sensitization, and the highest risk of asthma exacerbations (1.37 [1.07-1.76], P=0.014) and LRTI hospitalizations (2.40 [1.26-4.58], P=0.008) throughout childhood. In contrast, cluster with IFNhighestInflammodTH2-chemmodReghighrhinovirus-16-cytokine pattern was characterized by PHA-TH2highestresponse, and a low prevalence of asthma/sensitization in infancy which increased sharply to become the highest among all clusters by adolescence (but with low risk of asthma exacerbations). CONCLUSIONS: Early-onset troublesome asthma with early-life sensitization, later-onset milder allergic asthma, and disease protection are each associated with different patterns of rhinovirus-induced immune responses

Mucosal type 2 innate lymphoid cells are a key component of the allergic response to aeroallergen

RATIONALE: Newly characterised type 2 innate lymphoid cells display potent type 2 effector functionality, however their contribution to allergic airways inflammation and asthma is poorly understood. Mucosal biopsy used to characterise the airway mucosa is invasive, poorly tolerated and does not allow sequential sampling. OBJECTIVES: To assess the role of type 2 innate lymphoid cells during nasal allergen challenge in subjects with allergic rhinitis, using novel non-invasive methodology. METHODS: We used a human experimental allergen challenge model, with flow cytometric analysis of nasal curettage samples, to assess the recruitment of type 2 innate lymphoid cells and granulocytes to the upper airways of atopic and healthy subjects following allergen provocation. Soluble mediators in the nasal lining fluid were measured using nasosorption. MEASUREMENTS AND MAIN RESULTS: Following allergen challenge, atopic subjects displayed rapid induction of upper airway symptoms, an enrichment of type 2 innate lymphoid cells, eosinophils and neutrophils, along with increased production of interleukin-5, prostaglandin D2, and eosinophil and T-helper type 2 cell chemokines compared to healthy subjects. The most pronounced type 2 innate lymphoid cell recruitment was observed in patients with elevated serum IgE and airway eosinophilia. CONCLUSIONS: The rapid recruitment of type 2 innate lymphoid cells to the upper airways of allergic rhinitis patients, and their association with key type 2 mediators, highlights their likely important role in the early allergic response to aeroallergen in the airways. The novel methodology described herein enables the analysis of rare cell populations from non-invasive, serial tissue sampling

Antiviral immunity is impaired in COPD patients with frequent exacerbations

Patients with frequent exacerbations represent a chronic obstructive pulmonary disease (COPD) sub-group requiring better treatment options. The aim of this study was to determine the innate immune mechanisms that underlie susceptibility to frequent exacerbations in COPD. We measured sputum expression of immune mediators and bacterial loads in samples from patients with COPD at stable state and during virus-associated exacerbations. In vitro immune responses to rhinovirus infection in differentiated primary bronchial epithelial cells (BECs) sampled from patients with COPD were additionally evaluated. Patients were stratified as frequent exacerbators (>2 exacerbations in the preceding year) or infrequent exacerbators (<2 exacerbations in the preceding year) with comparisons made between these groups. Frequent exacerbators had reduced sputum cell mRNA expression of the anti-viral immune mediators type I and III interferons and reduced interferon-stimulated gene (ISG) expression when clinically stable and during virus-associated exacerbation. A role for epithelial cell-intrinsic innate immune dysregulation was identified: induction of interferons and ISGs during in vitro RV-infection was also impaired in differentiated BECs from frequent exacerbators. Frequent exacerbators additionally had increased sputum bacterial loads at 2 weeks following virus-associated exacerbation onset. These data implicate deficient airway innate immunity involving epithelial cells in the increased propensity to exacerbations observed in some patients with COPD. Therapeutic approaches to boost innate anti-microbial immunity in the lung could be a viable strategy for prevention/treatment of frequent exacerbations