International ERS/ATS guidelines on definition, evaluation and treatment of severe asthma

Biomarkers to identify sputum eosinophilia in different adult asthma phenotypes

Several biomarkers have been used to assess sputum eosinophilia in asthma. It has been suggested that the diagnostic accuracy of these biomarkers might differ between asthma phenotypes. We investigated the accuracy of biomarkers in detecting sputum eosinophilia (≥3%) in different adult asthma phenotypes.Levels of eosinophils in blood and sputum, exhaled nitric oxide fraction (FeNO) and total immunoglobulin (Ig)E from 336 adult patients, enrolled in three prospective observational clinical trials and recruited at five pulmonology outpatient departments, were analysed. Areas under the receiver operating characteristics curves (AUC) for detecting sputum eosinophilia were calculated and compared between severe and mild, obese and nonobese, atopic and nonatopic and (ex-)smoking and never-smoking asthma patients.Sputum eosinophilia was present in 116 patients (35%). In the total group the AUC was 0.83 (95% CI 0.78-0.87) for blood eosinophils, 0.82 (0.77-0.87) for FeNO and 0.69 (0.63-0.75) for total IgE. AUCs were similar for blood eosinophils and FeNO between different phenotypes. Total IgE was less accurate in detecting sputum eosinophilia in atopic and obese patients than in nonatopic and nonobese patients.Blood eosinophils and FeNO had comparable diagnostic accuracy (superior to total IgE) in identifying sputum eosinophilia in adult asthma patients, irrespective of asthma phenotype such as severe, nonatopic, obese and smoking-related asthma.

Eosinophilia in Pulmonary Disorders

Lung disease associated with marked peripheral blood eosinophilia is unusual and nearly always clinically significant. Once recognized, it is generally easy to manage, albeit with long-term systemic corticosteroids. A failure to respond to oral steroids in the context of good compliance suggests a malignant cause for the eosinophilia. An important development is the introduction of antieosinophil therapies, particularly those directed against the interleukin 5 pathway, which is hoped to provide benefit in the full spectrum of eosinophilic lung disease as well as asthma, reducing the burden of side effects and resultant comorbidities.

A nonmuscle myosin light chain kinase-dependent gene signature in peripheral blood mononuclear cells is linked to human asthma severity and exacerbation status

Asthma is increasingly recognized as a heterogeneous disease influenced by complex genetic and environmental contributions. Myosin light chain kinase (MLCK; gene symbol, MYLK), especially the nonmuscle isoform nmMLCK, is a cytoskeleton protein known to be related to human asthma susceptibility and severity, findings confirmed in preclinical models of asthmatic inflammation. In this study, we define the central capacity for a nmMLCK-influenced gene signature in human peripheral blood mononuclear cells to predict human asthma severity and exacerbation status. We refined this signature from a list of nmMLCK-influenced genes identified in lung tissues of nmMLCK knockout mice exposed to inflammatory stimuli (ventilator-induced lung injury), with subsequent identification of nmMLCK-influenced genes in a list of human asthma severity-related genes expressed in blood. The enriched nmMLCK-influenced gene signature successfully predicted human asthma severity and exacerbation status in both discovery and validation human asthma cohorts. These findings validate the central role played by nmMLCK in asthma susceptibility, severity, and exacerbation and further provide novel gene signatures as effective asthma biomarkers for severity, exacerbation, and prognosis.

A potential immunopathogenic role for reduced IL-35 expression in allergic asthma

OBJECTIVE

Allergic asthma is a chronic airway inflammation resulting from an imbalance of T helper (Th) cell responses to allergens. Interleukin (IL)-35 has been shown to have potent immunoregulatory properties. Whether IL-35 participates in the immunopathogenesis of allergic asthma patients is still unknown.

METHODS

CD4+ T cells and CD4+ CD25- T cells were obtained from peripheral blood mononuclear cells (PBMCs) using magnetic separation. The concentration of IL-35 in plasma was measured by enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of the IL-35 subunits, EBI3 and IL-12p35, were detected by quantitative real-time PCR (qPCR). The proliferative responses of CFSE-labeled CD4+ CD25- T cells in the presence or absence of rhIL-35 were evaluated by flow cytometry. Cytokine production of activated CD4+ CD25- T cells was examined by flow cytometry and ELISA.

RESULTS

IL-35 protein and mRNA levels were decreased in allergic asthmatics. The frequencies of CD4+ CD25+ Foxp3+ Tregs and CD4+ IL-12p35+ T cells in allergic asthma patients were lower than in healthy controls. Moreover, the addition of rhIL-35 suppressed CFSE+ CD4+ CD25- T cell proliferation in vitro in a dose-dependent manner, and the suppression induced by rhIL-35 was associated with decreases in IL-4 but not IFN-γ and IL-17 production of activated CD4+ CD25- T cells. The increased level of Th1/Th2 was observed in allergic asthmatics in the presence of rhIL-35.

CONCLUSIONS

Our data suggest that IL-35 can effectively suppress the proliferation and IL-4 production of activated CD4+ CD25- T cells in allergic asthma, and that IL-35 may be a new immunotherapy for asthma patients.

Computed tomography assessment of airways throughout bronchial tree demonstrates airway narrowing in severe asthma

RATIONALE AND OBJECTIVES

To analyze airway dimensions throughout the bronchial tree in severe asthmatic patients using multidetector row computed tomography (MDCT) focusing on airway narrowing.

MATERIALS AND METHODS

Thirty-two patients with severe asthma underwent automated (BronCare software) analysis of their right lung bronchi, with counts of airways >3 mm long arising from the main bronchi (airway count) and bronchial dimension quantification at segmental and subsegmental levels (lumen area [LA], wall area [WA], and WA%). Focal bronchial stenosis was defined as >50% narrowing of maximal LA on contiguous cross-sectional slices. Severe asthmatics were compared to 13 nonsevere asthmatic patients and nonasthmatic (pooled) subjects (Wilcoxon rank tests, then stepwise logistic regression). Finally, cluster analysis of severe asthmatic patients and stepwise logistic regression identified specific imaging subgroups.

RESULTS

The most significant differences between severe asthmatic patients and the pooled subjects were bronchial stenosis (subsegmental and all bronchi: P < .002) and WA% (P < .0003). Stepwise logistic regression retained WA% as the only explanatory covariable (P = .002). Two identified clusters of severe asthmatic patients differed for parameters characterizing airway narrowing (airway count: P = .0002; focal bronchial stenosis: P = .009). Airway count was as discriminant as forced expiratory volume in 1 second/forced vital capacity (P = .01) to identify patients in each cluster, with both variables being correlated (r = 0.59, P = .005).

CONCLUSIONS

Severe asthma-associated morphologic changes were characterized by focal bronchial stenoses and diffuse airway narrowing; the latter was associated with airflow obstruction. WA%, dependent on airway caliber, is the best parameter to identify severe asthmatic patients from pooled subjects.

Unrecognised psychopathology in patients with difficult asthma: major mental and personality disorders

BACKGROUND

Difficult asthma is a severe subgroup of asthma in which the main feature is uncontrollability of symptoms. Psychopathology is suggested to be prominent in patients with difficult asthma and considered important in its treatment; however, the evidence is scarce.

AIMS

To describe psychopathology in difficult asthma, both major mental and personality disorders, based on diagnostic interviews.

METHOD

This study was conducted in a specialised asthma care centre. A total of 51 patients with difficult asthma were diagnosed at the start of the treatment programme using two structured clinical interviews for both major mental (SCID-I) and personality disorders (SCID-II) according to DSM-IV-TR.

RESULTS

About 55% of the patients with difficult asthma had a psychiatric disorder of which 89% was undiagnosed and untreated before being interviewed. About 49% had a minimum of one major mental disorder of which the cluster of anxiety disorders was the most common cluster of major mental disorders, followed by somatoform disorders. About 20% were diagnosed with a personality disorder. Of the 10 patients with a personality disorder, 9 had an obsessive-compulsive personality disorder.

CONCLUSIONS

This study demonstrates that more than half of patients with difficult asthma had a psychiatric disorder of which 89% was unrecognised. This study highlights the importance of offering patients with difficult asthma a psychiatric diagnostic interview and/or a psychiatric consultation as part of their routine medical examination and provision of appropriate psychiatric treatment. Moreover, it highlights the urgency of further research into the role of psychopathology in the development of difficult asthma.

DECLARATION OF INTEREST

None.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

Analysis of a Panel of 48 Cytokines in BAL Fluids Specifically Identifies IL-8 Levels as the Only Cytokine that Distinguishes Controlled Asthma from Uncontrolled Asthma, and Correlates Inversely with FEV1

We sought to identify cells and cytokines in bronchoalveolar lavage (BAL) fluids that distinguish asthma from healthy control subjects and those that distinguish controlled asthma from uncontrolled asthma. Following informed consent, 36 human subjects were recruited for this study. These included 11 healthy control subjects, 15 subjects with controlled asthma with FEV1≥80% predicted and 10 subjects with uncontrolled asthma with FEV1 <80% predicted. BAL fluid was obtained from all subjects. The numbers of different cell types and the levels of 48 cytokines were measured in these fluids. Compared to healthy control subjects, patients with asthma had significantly more percentages of eosinophils and neutrophils, IL-1RA, IL-1α, IL-1β, IL-2Rα, IL-5, IL-6, IL-7, IL-8, G-CSF, GROα (CXCL1), MIP-1β (CCL4), MIG (CXCL9), RANTES (CCL5) and TRAIL in their BAL fluids. The only inflammatory markers that distinguished controlled asthma from uncontrolled asthma were neutrophil percentage and IL-8 levels, and both were inversely correlated with FEV1. We examined whether grouping asthma subjects on the basis of BAL eosinophil % or neutrophil % could identify specific cytokine profiles. The only differences between neutrophil-normal asthma (neutrophil≤2.4%) and neutrophil-high asthma (neutrophils%>2.4%) were a higher BAL fluid IL-8 levels, and a lower FEV1 in the latter group. By contrast, compared to eosinophil-normal asthma (eosinophils≤0.3%), eosinophil-high asthma (eosinophils>0.3%) had higher levels of IL-5, IL-13, IL-16, and PDGF-bb, but same neutrophil percentage, IL-8, and FEV1. Our results identify neutrophils and IL-8 are the only inflammatory components in BAL fluids that distinguish controlled asthma from uncontrolled asthma, and both correlate inversely with FEV1.

Defining phenotypes in asthma: a step towards personalized medicine

Asthma is a common disease with a complex pathophysiology. It can present in various clinical forms and with different levels of severity. Unbiased cluster analytic methods have unravelled several phenotypes in cohorts representative of the whole spectrum of severity. Clusters of severe asthma include those on high-dose corticosteroid treatment, often with both inhaled and oral treatment, usually associated with severe airflow obstruction. Phenotypes with concordance between symptoms and sputum eosinophilia have been reported, including an eosinophilic inflammation-predominant group with few symptoms and late-onset disease who have a high prevalence of rhinosinusitis, aspirin sensitivity, and exacerbations. Sputum eosinophilia is also a biomarker that can predict therapeutic responses to antibody-based treatments to block the effects of the T-helper (Th)-2 cytokine, interleukin (IL)-5. Low Th2-expression has been predictive of poor therapeutic response to inhaled corticosteroid therapy. Current asthma schedules emphasise a step-up approach to treating asthma in relation to increasing severity, but, in more severe disease, phenotyping or endotyping of asthma will be necessary to determine new treatment strategies as severe asthma is recognized as being a particularly heterogeneous disease. Much less is known about 'non-eosinophilic' asthma. Phenotypic characterisation of corticosteroid insensitivity and chronic airflow obstruction of severe asthma is also needed. Phenotype-driven treatment of asthma will be further boosted by the advent of transcriptomic and proteomic technologies, with the application of systems biology or medicine approaches to defining phenotypes and biomarkers of disease and therapeutic response. This will pave the way towards personalized medicine and healthcare for asthma.

Severe asthma in children

Severe asthma in children is characterized by sustained symptoms despite treatment with high doses of inhaled corticosteroids or oral corticosteroids. Children with severe asthma may fall into 2 categories, difficult-to-treat asthma or severe therapy-resistant asthma. Difficult-to-treat asthma is defined as poor control due to an incorrect diagnosis or comorbidities, or poor adherence due to adverse psychological or environmental factors. In contrast, treatment resistant is defined as difficult asthma despite management of these factors. It is increasingly recognized that severe asthma is a highly heterogeneous disorder associated with a number of clinical and inflammatory phenotypes that have been described in children with severe asthma. Guideline-based drug therapy of severe childhood asthma is based primarily on extrapolated data from adult studies. The recommendation is that children with severe asthma be treated with higher-dose inhaled or oral corticosteroids combined with long-acting β-agonists and other add-on therapies, such as antileukotrienes and methylxanthines. It is important to identify and address the influences that make asthma difficult to control, including reviewing the diagnosis and removing causal or aggravating factors. Better definition of the phenotypes and better targeting of therapy based upon individual patient phenotypes is likely to improve asthma treatment in the future.

The discovery and development of omalizumab for the treatment of asthma

INTRODUCTION

The evolution in immunological methods used to assess human allergic diseases has led to the identification of immunoglobulin E (IgE) as a diagnostic biomarker and a potential therapeutic target. Innovative technologies in molecular biology and immunogenetics contributed to the development of a selective blocking agent, disclosing new therapeutic perspectives in the treatment of allergic asthma. Omalizumab is the most advanced humanized anti-IgE monoclonal antibody that specifically binds serum-free IgE. Omalizumab also interrupts the allergic cascade by preventing binding of IgE with FcεRI receptors on mast cells, basophils, antigen-presenting cells and other inflammatory cells.

AREAS COVERED

This review discusses the discovery strategy and preclinical development of omalizumab. Furthermore, it also provides a clinical overview of the key trials leading to its launch and a detailed analysis of safety and post-marketing data.

EXPERT OPINION

The clinical efficacy of omalizumab in allergic asthma has been well documented in clinical trials, involving adults, adolescents and children with moderate-to-severe and severe allergic asthma. To date, omalizumab has also been approved in chronic idiopathic urticaria for patients 12 years and older who remain symptomatic despite high dosages of H1 antihistamines. Omalizumab has also been investigated in many other different patient populations beyond allergic asthma and may yet have an application to other indications. While omalizumab is the only mAb available for treating allergic asthma, the authors anticipate that new mAbs will emerge in the future that overcome omalizumab's current limitations.

Bronchial thermoplasty in asthma: current perspectives

Bronchial thermoplasty (BT) is a novel therapy for patients with severe asthma. Using radio frequency thermal energy, it aims to reduce the airway smooth muscle mass. Several clinical trials have demonstrated improvements in asthma-related quality of life and a reduction in the number of exacerbations following treatment with BT. In addition, recent data has demonstrated the long-term safety of the procedure as well as sustained improvements in rates of asthma exacerbations, reduction in health care utilization, and improved quality of life. Further study is needed to elucidate the underlying mechanisms that result in these improvements. In addition, improved characterization of the asthma subphenotypes likely to exhibit the largest clinical benefit is a critical step in determining the precise role of BT in the management of severe asthma.

Microbiota in allergy and asthma and the emerging relationship with the gut microbiome

Asthma and atopy, classically associated with hyper-activation of the T helper 2 (Th2) arm of adaptive immunity, are among the most common chronic illnesses worldwide. Emerging evidence relates atopy and asthma to the composition and function of the human microbiome, the collection of microbes that reside in and on and interact with the human body. The ability to interrogate microbial ecology of the human host is due in large part to recent technological developments that permit identification of microbes and their products using culture-independent molecular detection techniques. In this review we explore the roles of respiratory, gut, and environmental microbiomes in asthma and allergic disease development, manifestation, and attenuation. Though still a relatively nascent field of research, evidence to date suggests that the airway and/or gut microbiome may represent fertile targets for prevention or management of allergic asthma and other diseases in which adaptive immune dysfunction is a prominent feature.

Mepolizumab for eosinophilic severe asthma: recent studies

INTRODUCTION

In September 2014 two large clinical studies of the anti-IL-5 monoclonal antibody mepolizumab in severe asthma were published in the New England Journal of Medicine (MENSA and SIRIUS).

AREAS COVERED

Eosinophilic inflammation has long been recognised as a feature of asthma. Identification of IL-5 as a key cytokine specific for eosinophil development and survival lead to development of monoclonal antibody therapy targeting this pathway. These two important new studies suggested that this treatment could reduce exacerbation rates by 50% in asthmatic patients with persistent peripheral blood eosinophilia and persistent symptoms despite high-dose-inhaled corticosteroids and additional controller therapy, and frequent exacerbations. In the second study, mepolizumab was shown to reduce oral steroid requirement by a median of 50% in similar patients who additionally required oral prednisone to control disease.

EXPERT OPINION

This represents an important new treatment option in an area of unmet need, and together with a large dose ranging study (DREAM) published in 2012 form the basis for filing for registration in the USA and Europe.

Asthma-COPD overlap 2015: now we are six

BACKGROUND

The overlap between asthma and COPD is increasingly recognised. This review examines the new insights, treatment and remaining knowledge gaps for asthma-COPD overlap.

METHOD

A systematic literature review of cluster analyses of asthma and COPD was performed. Articles from 2009 to the present dealing with prevalence, morbidity and treatment of asthma-COPD overlap were identified and reviewed.

RESULTS

Asthma-COPD overlap was consistently recognised in studies using a variety of different study designs and sampling. The prevalence was approximately 20% in patients with obstructive airways diseases. Asthma-COPD overlap was associated with increased morbidity and possibly an increased mortality and comorbidity. There was evidence of a heterogeneous pattern of airway inflammation that included eosinophilic (in adult asthma), neutrophilic or mixed patterns (in severe asthma and COPD). Systemic inflammation was present in asthma-COPD overlap and resembled that of COPD. Within asthma-COPD overlap, there is evidence of different subgroups, and recognition using bronchodilator responsiveness has not been successful. Guidelines generally recommend a serial approach to assessment, with treatment recommendations dominated by an asthma paradigm. Research is needed into key clinical features that impact outcome, mechanisms and treatment approaches in asthma-COPD overlap. Identifying and treating disease components by multidimensional assessment shows promise.

CONCLUSIONS

Asthma-COPD overlap has drawn attention to the significant heterogeneity that exists within obstructive airway diseases. It should be replaced by novel approaches that identify and manage the components of this heterogeneity, such as multidimensional assessment and treatment. Future research is needed to test these novel and personalised approaches.

Variability in Asthma Inflammatory Phenotype in Induced Sputum. Frequency and Causes

INTRODUCTION

Recent studies have found variability in asthma inflammatory phenotypes determined by the inflammatory cells in induced sputum (IS). The aim of this study was to determine the frequency and factors affecting inflammatory phenotype variability in IS.

METHODS

Retrospective observational study that included 61 asthmatic patients who underwent at least two IS tests over a period of 5 years. They were classified according to their baseline inflammatory phenotype and subsequently grouped according to phenotype variability (persistent eosinophilic, persistent non-eosinophilic and intermittent eosinophilic). Demographic, clinical and functional data and factors potentially influencing IS variability were collected in all cases.

RESULTS

Of the 61 patients, 31 (50.8%) had a change with respect to baseline inflammatory phenotype. Of these, 16 (51.6%) were eosinophilic, 5 (16.1%) neutrophilic, 1 (3.2%) mixed and 9 (29.1%) paucigranulocytic. According to phenotype variability, 18 patients (29.5%) were classified as persistent eosinophilic, 17 (27.9%) non-persistent eosinophilic, and 26 (42.6%) intermittent eosinophilic. Smoking and recent asthma exacerbation were significantly associated with increased risk of variability of the IS inflammatory phenotype (OR=6.44; p=.013; 95% CI=1.49-27.80 and OR=5.84; p=.022; 95% CI=1.29-26.37, respectively).

CONCLUSION

Half of asthma patients, predominantly those with eosinophilic phenotype, present a change in IS inflammatory phenotype. This variability is associated with smoking and recent asthma exacerbation. Data suggest these factors can modify the classification of IS inflammatory phenotype in clinical practice.

Misdiagnosis Among Frequent Exacerbators of Clinically Diagnosed Asthma and COPD in Absence of Confirmation of Airflow Obstruction

PURPOSE

Clinical diagnosis of severe asthma and chronic obstructive lung disease (COPD) remains a challenge and often flawed with lack of objective confirmation of airflow obstruction (AO). Misdiagnosis of asthma and COPD has been reported in stable disease, data are non-existent in frequent exacerbators. We investigated misdiagnosis and its predictors in frequent exacerbators.

METHODS

The cohort comprised of frequent severe exacerbators (requiring ≥2 emergency room (ER) visits or hospitalizations) of physician diagnosed (PD)-asthma and PD-COPD. All patients underwent a rigorous diagnostic algorithm over a follow-up period of 10 ± 6 months. Two board-certified pulmonologists ascertained final diagnosis. Patients with persistent absence of AO were identified to have misdiagnosis. Multivariate logistic regression analyses were used to identify predictors of misdiagnoses.

RESULTS

Among 333 frequent exacerbators analyzed (171 patients with PD-asthma, 162 with PD-COPD, mean annual exacerbations 3.4 ± 2.8), 24 % of patients had a baseline post-bronchodilator spirometry. Misdiagnosis was found in 26 % (87 of 333) of patients. Another 12 % (41 of 333) of patients had obstructive lung diseases other than asthma and COPD. Independent risk factors for misdiagnosis were spirometry underutilization (PD-asthma: OR = 2.8, 95 % CI 1.16-6.78, p = 0.02 and PD-COPD: OR = 10.7, 95 % CI 2.05-56.27, p = 0.005) and pack years of smoking (PD-COPD: OR = 1.05, 95 % CI 1.01-1.11, p = 0.03).

CONCLUSIONS

Objective confirmation of AO is essential in preventing misdiagnosis in frequent severe exacerbators of clinically diagnosed asthma and COPD, a third of whom have neither. Spirometry utilization is strongly associated with a reduced risk of misdiagnosis. Smoking is associated with increased risk of misdiagnosis in severe COPD, but not asthma.

Evidence for the efficacy and safety of anti-interleukin-5 treatment in the management of refractory eosinophilic asthma

Two recent phase III trials in patients with severe eosinophilic asthma have shown that anti-interleukin 5 (IL-5) therapy with mepolizumab reduces the frequency of asthma attacks, improves symptoms and allows patients to reduce oral glucocorticoid use without loss of control of asthma. An earlier large 616 patient Dose Ranging Efficacy And safety with Mepolizumab in severe asthma (DREAM) study had shown that the only variables associated with treatment efficacy were a prior history of asthma attacks and the peripheral blood eosinophil count. The link between blood eosinophil counts and treatment efficacy is biologically obvious given that IL-5 has a pivotal role in eosinophil production, proliferation and chemotaxis. It is also clinically relevant as the blood eosinophil count is routinely measured and thus readily available in patients with asthma. Recognition of the link between airway or blood eosinophilia and treatment response was also important in the clinical testing of the alternative IL-5 blocker, such as reslizumab, which is currently being evaluated in a phase III randomized controlled trial (RCT) after having shown to improve lung function, improve symptom score and reduce sputum eosinophilia in a smaller phase IIb study. In addition, benralizumab, an IL-5α receptor blocker, has shown good effects in a phase IIb RCT with patients with severe asthma that had sputum eosinophilia and more recently in a phase IIa trial with patients with eosinophilic chronic obstructive pulmonary disease. Therefore anti-IL-5 treatment seems generally effective in eosinophilic asthma, either assessed by blood or airway eosinophilia. This factor together with the impressive clinical efficacy and good safety profile make anti-IL-5 (mepolizumab, reslizumab) and benralizumab (anti-IL-5 receptor α) very promising drugs for the treatment of patients with severe eosinophilic asthma, a subgroup that is in desperate need of better treatments.

Phenotypes of severe asthma among children and adolescents in Brazil: a prospective study

BACKGROUND

The morbidity associated with severe uncontrolled asthma is disproportionately higher in low- and middle-income countries than in high-income countries. The aim of this study was to describe the phenotypic characteristics of difficult-to-treat severe asthma and treatment-resistant severe asthma in a sample of children and adolescents in Brazil.

METHODS

This was a prospective study, conducted between 2010 and 2014, following 61 patients (6-18 years of age) who had been diagnosed with severe uncontrolled asthma. The patients were classified and managed in accordance with the World Health Organization asthma follow-up protocol, which calls for re-evaluations of the diagnosis, level of control (functional and clinical), comorbidities, inhaler technique, and environmental factors, together with adjustment of the treatment to achieve a target level of control. We assessed pulmonary function, measured fractional exhaled nitric oxide, and performed sputum cytology. After the target rate of ≥ 80% adherence to inhaled corticosteroid treatment had been reached and all of the re-evaluations had been performed, the patients incorrectly diagnosed with severe uncontrolled asthma were excluded and the remaining patients were classified as having treatment-resistant or difficult-to-treat severe asthma.

RESULTS

We found that, of the 61 patients evaluated, 10 had been misdiagnosed (i.e., they did not have asthma), 15 had moderate asthma, and 36 had severe uncontrolled asthma. Among those 36 patients, the asthma was classified as treatment-resistant in 20 (55.6%) and as difficult-to-treat in 16 (44.4%). In comparison with the patients with difficult-to-treat severe asthma, those with treatment-resistant severe asthma showed a higher median level of fractional exhaled nitric oxide (40 ppb vs. 12 ppb; P < 0.037) and a lower median forced expiratory volume in one second (61% vs. 87%; P < 0.001).

CONCLUSIONS

Although patients with treatment-resistant severe asthma cannot always be distinguished from those with difficult-to-treat severe asthma on the basis of baseline clinical characteristics, reduced airflow and elevated fractional exhaled nitric oxide are factors that could distinguish the two groups. Patients diagnosed with severe uncontrolled asthma should be re-evaluated on a regular basis, in order to exclude other diagnoses, to reduce exacerbations, and to identify patients with persistent airflow limitation.

Asthma control and exacerbations in patients with severe asthma treated with omalizumab in Portugal

The analysis of outcomes from patients with severe asthma treated with omalizumab, using real-life prospective data, should contribute to future informed decisions about this treatment in Portugal. The aim of this study was to assess the clinical effect of omalizumab in Portuguese patients with severe persistent allergic asthma, considering specifically asthma control and exacerbations. This was an observational, prospective, multicentre study. Data were collected at routine care over a 12-month period. Disease control was defined by Control of Allergic Rhinitis and Asthma Test (CARAT) global score >24. All asthma patients already under treatment with omalizumab in 7 departments from 6 Portuguese hospitals were included (n=48). Most (77%) patients were female and the mean (SD) age was 51.9 (10.2) years old. During the study period, asthma was controlled in 34% of the visits and the 12-month exacerbation rate was 1.7 per patient (0.6 with unscheduled medical care). One-third of the patients needed unscheduled medical care because of asthma and 29% had to start or increase oral corticosteroid. There was still a 41% reduction in the total sum of oral corticosteroids usage from the first to the last trimester of the study. During routine treatment with omalizumab, Portuguese patients with severe asthma achieved asthma control in 1/3 of the visits and only 1/3 needed unscheduled or Emergency Room care because of asthma exacerbations. These outcomes support the maintenance of the clinical effect during treatment with omalizumab in routine care in Portugal.

Phenotype of asthma related with high serum periostin levels

BACKGROUND

Asthma is a heterogeneous disease composed of various phenotypes. Periostin, a molecule inducible with interleukin (IL)-4 or IL-13 in bronchial epithelial cells, is a biomarker of "TH2-high" asthma. The objective of this study is to examine whether the serum periostin concentrations are correlated with the severity, specific phenotype(s), or comorbidity of asthma.

METHODS

Serum concentrations of periostin were measured in 190 Japanese asthmatic patients and 11 healthy controls. The protocol was registered under UMIN 000002980 in the clinical trial registry.

RESULTS

The serum concentrations of periostin were significantly higher (P = 0.014) in asthmatics [70.0 (54.0-93.5) ng/ml] than in healthy subjects [57.0 (39.0-63.0) ng/ml], though we found no correlation between serum periostin concentrations and treatment steps required to control asthma. To characterize "high-periostin" phenotype(s), the patients with asthma were divided among tertiles based on the serum concentrations of periostin. The high-periostin group was older at onset of asthma (P = 0.04), had a higher prevalence of aspirin intolerance (P = 0.04) or concomitant nasal disorders (P = 0.03-0.001), higher peripheral eosinophil counts (P < 0.001), and lower pulmonary function (P = 0.02-0.07). The serum concentrations of periostin were particularly high in asthmatic patients complicated by chronic rhinosinusitis with nasal polyps and olfactory dysfunction. In contrast, neither atopic status, control status of asthma, nor quality of life were related with the "high-periostin" phenotype.

CONCLUSION

Elevated periostin concentrations in serum were correlated with a specific phenotype of eosinophilic asthma, late-onset and often complicated by obstructive pulmonary dysfunction and nasal disorders.

Combining the Mannitol Test and FeNO in the Assessment of Poorly Controlled Asthma

BACKGROUND

International guidelines recommend up-titration of anti-inflammatory treatment in asthmatic patients with poor symptom control, but patients without eosinophilic airway inflammation are less likely to benefit from this. The mannitol bronchoprovocation test and fractional exhaled nitric oxide (FeNO) are increasingly used in the diagnostic assessment of asthma, but the utility of combining these tests has not been evaluated.

AIM

The aim of this study was to determine the value of combining FeNO and the mannitol test to assess patients with asthma referred for specialist assessment because of poor symptom control.

METHODS

All patients referred consecutively over a 12-month period for the assessment of asthma at the Respiratory Outpatient Clinic at Bispebjerg Hospital in Copenhagen were examined with bronchial provocation to mannitol, FeNO, and induced sputum.

RESULTS

Among asthmatic patients with partly controlled or uncontrolled symptoms according to Global Initiative for Asthma criteria, only 23% had sputum eosinophilia (eosinophils >2.99%). A positive mannitol test did not increase the likelihood of airway eosinophilia significantly (positive test: 32% vs negative test: 18%, P = .12). However, a positive mannitol test combined with a FeNO > 25 ppb indicated a high likelihood of airway eosinophilia (73%), compared with FeNO > 25 ppb and a negative mannitol test (29%) (P < .05). In contrast, in patients with FeNO < 25 ppb, a positive mannitol test was not associated with airway eosinophilia (sputum eosinophils > 2.99%: positive mannitol test: 0%, negative test: 11%, ns).

CONCLUSION

Combining the mannitol test and FeNO may aid in the differentiation between eosinophilic and noneosinophilic asthma in patients referred for specialist management because of poorly controlled asthma symptoms.

Translational value of animal models of asthma: Challenges and promises

Asthma is a heterogeneous disease in which various environmental stimuli as well as different genes, cell types, cytokines and mediators are implicated. This chronic inflammatory disorder of the airways is estimated to affect as many as 300 million people worldwide. Animal models of asthma, despite their limitations, have contributed greatly to our understanding of disease pathology and the identification of key processes, cells and mediators in asthma. However, it is less likely to develop an animal model of asthma that takes into account all aspects of human disease. The focus in current asthma research is increasingly on severe asthma because this group of patients is not well treated today. Recent advances in studies of asthma exacerbation are thus considered. We therefore need to develop translational model systems for pharmacological evaluation and molecular target discovery of severe asthma and asthma exacerbations. In this review we attempted to discuss the different animal models of asthma, with special emphasis on ovalbumin and house dust mite models, their merits and their limitations.

Diagnostic accuracy of minimally invasive markers for detection of airway eosinophilia in asthma: a systematic review and meta-analysis

BACKGROUND

Eosinophilic airway inflammation is associated with increased corticosteroid responsiveness in asthma, but direct airway sampling methods are invasive or laborious. Minimally invasive markers for airway eosinophilia could present an alternative method, but estimates of their accuracy vary.

METHODS

We did a systematic review and searched Medline, Embase, and PubMed for studies assessing the diagnostic accuracy of markers against a reference standard of induced sputum, bronchoalveolar lavage, or endobronchial biopsy in patients with asthma or suspected asthma (for inception to Aug 1, 2014). Unpublished results were obtained by contacting authors of studies that did not report on diagnostic accuracy, but had data from which estimates could be calculated. We assessed risk of bias with QUADAS-2. We used meta-analysis to produce summary estimates of accuracy.

FINDINGS

We included 32 studies: 24 in adults and eight in children. Of these, 26 (81%) showed risk of bias in at least one domain. In adults, three markers had extensively been investigated: fraction of exhaled nitric oxide (FeNO) (17 studies; 3216 patients; summary area under the receiver operator curve [AUC] 0·75 [95% CI 0·72-0·78]); blood eosinophils (14 studies; 2405 patients; 0·78 [0·74-0·82]); total IgE (seven studies; 942 patients; 0·65 [0·61-0·69]). In children, only FeNO (six studies; 349 patients; summary AUC 0·81 [0·72-0·89]) and blood eosinophils (three studies; 192 patients; 0·78 [0·71-0·85]) had been investigated in more than one study. Induced sputum was most frequently used as the reference standard. Summary estimates of sensitivity and specificity in detecting sputum eosinophils of 3% or more in adults were: 0·66 (0·57-0·75) and 0·76 (0·65-0·85) for FeNO; 0·71 (0·65-0·76) and 0·77 (0·70-0·83) for blood eosinophils; and 0·64 (0·42-0·81) and 0·71 (0·42-0·89) for IgE.

INTERPRETATION

FeNO, blood eosinophils, and IgE have moderate diagnostic accuracy. Their use as a single surrogate marker for airway eosinophilia in patients with asthma will lead to a substantial number of false positives or false negatives.

FUNDING

None.

Low interleukin (IL)-18 levels in sputum supernatants of patients with severe refractory asthma

BACKGROUND

Severe refractory asthma (SRA) is characterized by persistent asthma symptoms, amplified airway inflammation despite treatment with high dose inhaled steroids and increased airway bacterial colonization. Interleukin (IL)-18 is a pleiotropic pro-inflammatory cytokine that modulates airway inflammation. Furthermore, as a product of the inflammasome, IL-18 is involved in host defence against viral and bacterial stimuli by modulating the immune response.

OBJECTIVE

To determine IL-18 levels in sputum supernatants of patients with asthma and to investigate whether underlying severity affects its levels. Furthermore, possible associations with atopy and mediators and cells involved in the inflammatory process of the airways were examined.

METHODS

Forty-five patients with mild intermittent asthma (21 smokers) and 18 patients with SRA in stable state were studied. All subjects underwent lung function tests, skin prick tests, and sputum induction for cell count identification. IL-18 and ECP levels were measured in sputum supernatants. Furthermore, sputum samples were examined for the commonest respiratory pathogens and viruses by real time polymerase chain reaction (RT-PCR).

RESULTS

Patients with SRA had significantly lower IL-18 levels in sputum supernatants compared to mild asthmatics (p < 0.001). Twelve out of eighteen patients with SRA were colonized by viruses and/or bacterial pathogens. IL-18 levels correlated with the percentage of macrophages (r = 0.635, p = 0.026) and inversely correlated with the percentage of neutrophils in sputum (r = -0.715, p = 0.009). No correlations were found between IL-18, ECP and the percentage of eosinophils in the sputum of SRA.

CONCLUSIONS

In SRA IL-18 is possibly involved in chronic airway inflammation through an eosinophil independent pathway. The decreased levels of IL-18 in SRA support the hypothesis of deregulated inflammasome activation, justifying the susceptibility of these patients for bacterial colonization or infection.

Lung abscess as a complication of bronchial thermoplasty

BACKGROUND

Bronchial thermoplasty (BT) is an emerging treatment modality for patients with difficult to treat asthma. It has been shown to be beneficial for symptom control and improves quality of life and reduces frequency of hospitalization. Safety data from the two major trials of BT indicate that patients who undergo these procedures are most likely to experience adverse respiratory events in the first six weeks post treatment. Lung abscess has never been reported as a direct complication of BT. In this case; we report a lung abscess as an immediate complication of BT, which we believe may be the first case.

CASE PRESENTATION

We describe a forty three year old Caucasian female presented three days post-bronchial thermoplasty with left sided chest pain radiating to the back associated with shortness of breath, wheeze and dry cough. She had also started to feel hot and cold and generally unwell.

CONCLUSION

It remains unclear why this patient developed a lung abscess so acutely post BT treatment. It is important that safety data continues to be collated and published as the procedure becomes more widely available with further long term follow-up in particular.

Distinct endotypes of steroid-resistant asthma characterized by IL-17A(high) and IFN-γ(high) immunophenotypes: Potential benefits of calcitriol

Background

A small population of patients with severe asthma does not respond to glucocorticoids (steroid resistant [SR]). They have high morbidity, highlighting an urgent need for strategies to enhance glucocorticoid responsiveness.

Objective

We investigated the immunologic differences between steroid-sensitive (SS) and SR asthmatic patients and the effect on immunophenotype of oral calcitriol treatment because it has been previously shown to beneficially modulate the clinical response to glucocorticoids in patients with SR asthma.

Methods

CD8-depleted PBMCs were isolated from 12 patients with SS and 23 patients with SR asthma and cultured for 7 days with anti-CD3 and IL-2 with or without dexamethasone. Cytokine production was assessed in supernatants by using the Cytometric Bead Array. Patients with SR asthma were subsequently randomized to oral calcitriol or placebo therapy, and identical studies were repeated.

Results

Patients with SR asthma produced significantly increased IL-17A and IFN-γ levels compared with those in patients with SS asthma, although it was evident that cells from individual patients might overproduce one or the other of these cytokines. Production of IL-17A was inversely and production of IL-13 was positively associated with the clinical response to prednisolone. Oral calcitriol, compared with placebo, therapy of the patients with SR asthma significantly improved dexamethasone-induced IL-10 production in vitro while suppressing dexamethasone-induced IL-17A production. This effect mirrored the previously demonstrated improvement in clinical response to oral glucocorticoids in calcitriol-treated patients with SR asthma.

Conclusions

IL-17A^high and IFN-γ^high immunophenotypes exist in patients with SR asthma. These data identify immunologic pathways that likely underpin the beneficial clinical effects of calcitriol in patients with SR asthma by directing the SR cytokine profile toward a more SS immune phenotype, suggesting strategies for identifying vitamin D responder immunophenotypes.

Recurrent lung atelectasis from fibrin plugs as a very early complication of bronchial thermoplasty: a case report

BACKGROUND

Bronchial thermoplasty (BT) is a new therapeutic option for severe refractory asthma not controlled despite high dose inhaled corticosteroids plus long-acting bronchodilators and omalizumab in selected cases. Risk of pulmonary atelectasis after BT in severe asthma has been described in literature, but no details have been reported on the possible mechanisms of the complication.

CASE PRESENTATION

A 49-year-old male with severe uncontrolled asthma was referred to BT. One hour after the first procedure, acute respiratory failure occurred with PaO2/FiO2 < 300. A CT scan showed atelectasis of the right lower and middle lobes. A new bronchoscopy was performed under non-invasive ventilation; the right lower and middle lobe bronchus were occluded by bronchus-shaped plugs, that were very difficult to remove despite repeated saline washings and fragmentation with forceps. The patient had a rapid resolution of respiratory failure. Four weeks later, 6 hours after the second session of BT, severe bronchospasm occurred with respiratory failure. Chest X-Ray showed atelectasis of the left lower lobe, prompting to perform a new flexible bronchoscopy on non-invasive ventilation. The exam showed again a plug occluding the left lower lobar bronchus, removed with forceps and washings. The histological analysis of the plugs demonstrated the massive presence of fibrin with mucus debris, rare Charcot-Leyden crystals, scattered macrophages, neutrophils, eosinophils and bronchial epithelial cells.

CONCLUSION

The originality of our case report is related to the recurrence of bronchial plugging with lobar atelectasis within one and five hours respectively, after two sequential BT procedures. At the histological evaluation the bronchial plugs appeared very different from the typical mucoid asthma plugs, being composed prevalently by fibrin. It can be hypothesized that intense thermal stimulation of the bronchial mucosa may represent a strong boost for inflammation in susceptible patients, with microvascular alteration induced directly by heat or through the release of mediators. Although in severe asthma a risk of atelectasis from the classical asthma mucoid plugs may be expected, the peculiarity of our case resides in the formation of fibrin plugs whose direct correlation with BT should be considered.

Cysteine oxidation impairs systemic glucocorticoid responsiveness in children with difficult-to-treat asthma

BACKGROUND

The mechanisms underlying glucocorticoid responsiveness are largely unknown. Although redox regulation of the glucocorticoid receptor (GR) has been reported, it has not been studied in asthmatic patients.

OBJECTIVE

We characterized systemic cysteine oxidation and its association with inflammatory and clinical features in healthy children and children with difficult-to-treat asthma. We hypothesized that cysteine oxidation would be associated with increased markers of oxidative stress and inflammation, increased features of asthma severity, decreased clinically defined glucocorticoid responsiveness, and impaired GR function.

METHODS

PBMCs were collected from healthy children (n = 16) and children with asthma (n = 118) aged 6 to 17 years. Children with difficult-to-treat asthma underwent glucocorticoid responsiveness testing with intramuscular triamcinolone. Cysteine, cystine, and inflammatory chemokines and reactive oxygen species generation were quantified, and expression and activity of the GR were assessed.

RESULTS

Cysteine oxidation was present in children with difficult-to-treat asthma and accompanied by increased reactive oxygen species generation and increased CCL3 and CXCL1 mRNA expression. Children with the greatest extent of cysteine oxidation had more features of asthma severity, including poorer symptom control, greater medication use, and less glucocorticoid responsiveness despite inhaled glucocorticoid therapy. Cysteine oxidation also modified the GR protein by decreasing available sulfhydryl groups and decreasing nuclear GR expression and activity.

CONCLUSIONS

A highly oxidized cysteine redox state promotes a posttranslational modification of the GR that might inhibit its function. Given that cysteine oxidation is prevalent in children with difficult-to-treat asthma, the cysteine redox state might represent a potential therapeutic target for restoration of glucocorticoid responsiveness in this population.

Why aren't we doing better in asthma: time for personalised medicine?

After decades of improvement, asthma outcomes have stalled. Mortality, hospitalisations, exacerbations and symptom control remain sub-optimal. In controlled trials, most patients gain high levels of control, but in ‘real-life’ routine clinical practice most patients do not. Avoidable factors are found in most asthma deaths and hospital admissions. This perspective paper considers and contextualises the factors underlying poor asthma outcomes, and it suggests approaches that could improve the situation. Factors discussed include severe, therapy-resistant disease and the role of new and upcoming pharmacological therapies in improving outcomes. These are likely to be beneficial when targeted on patients with severe disease and discrete phenotypic characteristics, identified through biomarkers. However, for the majority of patients treated in the community, they are unlikely to be used widely, and better use of current therapy classes will be more important. Non-adherence with regular inhaled corticosteroid treatment and over-use of rescue bronchodilators are common, and many patients have poor inhaler technique. Self-management is frequently poor, particularly in those with psychosocial disadvantages and co-morbidities. Communication between clinicians and patients is sometimes poor, with failure to detect avoidable poor control and non-adherence, and failure to provide the necessary information and education to support efficient self-management. Strategies for improving monitoring and clinician–patient interactions to allow personalised treatment are considered. These strategies have the potential to allow individual patient needs to be recognised and efficient targeting of the variety of effective pharmacological and non-pharmacological interventions that we possess, which has the potential to improve both individual and population outcomes.

Usefulness of noninvasive methods for the study of bronchial inflammation in the control of patients with asthma

Bronchial asthma is one of the most prevalent respiratory conditions. Although it is defined as an inflammatory disease, the current guidelines for both diagnosis and follow-up of patients are based only on clinical and lung function parameters. Current research is focused on finding markers that can accurately predict future risk, and on assessing the ability of these markers to guide medical treatment and thus improve prognosis. The use of noninvasive methods to study airway inflammation is gaining increasing support. The study of eosinophils in induced sputum has proved useful for the diagnosis of asthma; however, its clinical implementation is complex. Some studies have shown that the measurement of exhaled nitric oxide (FeNO) may also be useful to establish disease phenotypes and improve control. Others have found that the measurement of pH and certain markers of oxidative stress, cytokines and prostanoids in exhaled breath condensate (EBC) may also be useful as well as the measurement of the temperature of exhaled breath and the analysis of volatile organic compounds (VOCs). In conclusion, since asthma is an inflammatory disease, it seems appropriate to try to control it through the study of airway inflammation using noninvasive methods. In this regard, the analysis of induced sputum cells has proved very useful, although the clinical implementation of this technique seems difficult. Other techniques such as temperature measurement, the analysis of FeNO, the analysis of the VOCs in exhaled breath, or the study of certain biomarkers in EBC require further study in order to determine their clinical applicability.

Gene expression in relation to exhaled nitric oxide identifies novel asthma phenotypes with unique biomolecular pathways

RATIONALE

Although asthma is recognized as a heterogeneous disease associated with clinical phenotypes, the molecular basis of these phenotypes remains poorly understood. Although genomic studies have successfully broadened our understanding in diseases such as cancer, they have not been widely used in asthma studies.

OBJECTIVES

To link gene expression patterns to clinical asthma phenotypes.

METHODS

We used a microarray platform to analyze bronchial airway epithelial cell gene expression in relation to the asthma biomarker fractional exhaled nitric oxide (FeNO) in 155 subjects with asthma and healthy control subjects from the Severe Asthma Research Program (SARP).

MEASUREMENTS AND MAIN RESULTS

We first identified a diverse set of 549 genes whose expression correlated with FeNO. We used k-means to cluster the patient samples according to the expression of these genes, identifying five asthma clusters/phenotypes with distinct clinical, physiological, cellular, and gene transcription characteristics-termed "subject clusters" (SCs). To then investigate differences in gene expression between SCs, a total of 1,384 genes were identified that highly differentiated the SCs at an unadjusted P value < 10(-6). Hierarchical clustering of these 1,384 genes identified nine gene clusters or "biclusters," whose coexpression suggested biological characteristics unique to each SC. Although genes related to type 2 inflammation were present, novel pathways, including those related to neuronal function, WNT pathways, and actin cytoskeleton, were noted.

CONCLUSIONS

These findings show that bronchial epithelial cell gene expression, as related to the asthma biomarker FeNO, can identify distinct asthma phenotypes, while also suggesting the presence of underlying novel gene pathways relevant to these phenotypes.

No evidence for altered intracellular calcium-handling in airway smooth muscle cells from human subjects with asthma

Background

Asthma is characterized by airway hyper-responsiveness and variable airflow obstruction, in part as a consequence of hyper-contractile airway smooth muscle, which persists in primary cell culture. One potential mechanism for this hyper-contractility is abnormal intracellular Ca²⁺ handling.

Methods

We sought to compare intracellular Ca²⁺ handling in airway smooth muscle cells from subjects with asthma compared to non-asthmatic controls by measuring: i) bradykinin-stimulated changes in inositol 1,4,5-trisphosphate (IP₃) accumulation and intracellular Ca²⁺ concentration, ii) sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) expression, iii) mechanisms of cytoplasmic Ca²⁺ clearance assessed following instantaneous flash photolytic release of Ca²⁺ into the cytoplasm.

Results

We found no differences in airway smooth muscle cell basal intracellular Ca²⁺ concentrations, bradykinin-stimulated IP₃ accumulation or intracellular Ca²⁺ responses. Quantification of SERCA2 mRNA or protein expression levels revealed no differences in ASM cells obtained from subjects with asthma compared to non-asthmatic controls. We did not identify differences in intracellular calcium kinetics assessed by flash photolysis and calcium uncaging independent of agonist-activation with or without SERCA inhibition. However, we did observe some correlations in subjects with asthma between lung function and the different cellular measurements of intracellular Ca²⁺ handling, with poorer lung function related to increased rate of recovery following flash photolytic elevation of cytoplasmic Ca²⁺ concentration.

Conclusions

Taken together, the experimental results reported in this study do not demonstrate major fundamental differences in Ca²⁺ handling between airway smooth muscle cells from non-asthmatic and asthmatic subjects. Therefore, increased contraction of airway smooth muscle cells derived from asthmatic subjects cannot be fully explained by altered Ca²⁺ homeostasis.

Guidelines for severe uncontrolled asthma

Since the publication, 9 years ago, of the latest SEPAR (Spanish Society of Pulmonology and Thoracic Surgery) Guidelines on Difficult-to-Control Asthma (DCA), much progress has been made in the understanding of asthmatic disease. These new data need to be reviewed, analyzed and incorporated into the guidelines according to their level of evidence and recommendation. Recently, consensus documents and clinical practice guidelines (CPG) addressing this issue have been published. In these guidelines, specific mention will be made of what the previous DCA guidelines defined as "true difficult-to-control asthma". This is asthma that remains uncontrolled after diagnosis and a systematic evaluation to rule out factors unrelated to the disease itself that lead to poor control ("false difficult-to-control asthma"), and despite an appropriate treatment strategy (Spanish Guidelines for the Management of Asthma [GEMA] steps 5 and 6): severe uncontrolled asthma. In this respect, the guidelines propose a revised definition, an attempt to classify the various manifestations of this type of asthma, a proposal for a stepwise diagnostic procedure, and phenotype-targeted treatment. A specific section has also been included on DCA in childhood, aimed at assisting healthcare professionals to improve the care of these patients.

Nasal IL-17F is related to bronchial IL-17F/neutrophilia and exacerbations in stable atopic severe asthma

Severe asthma (SA) is associated with neutrophil recruitment and T helper (TH )17 chemokine overexpression in bronchial biopsies. We aimed to evaluate IL-17A and IL-17F expression in nasal/bronchial lamina propria of atopic mild-to-severe asthmatics and controls in relation to neutrophilia and asthma exacerbations. Cryostat sections of nasal/bronchial biopsies obtained from 14 SA and 14 mild asthma (MA) stable atopic patients with rhinitis, and seven healthy controls were analyzed by immunohistochemistry for neutrophils, IL-17A and IL-17F expression. Atopic SA showed an increase in asthma exacerbations number, IL-17F and IL-17A expression in nasal/bronchial lamina propria compared to MA and controls, and a higher expression of bronchial neutrophils in SA compared to MA and controls. In all asthmatics, significant relationships were found between bronchial IL-17F and neutrophils/FEV1 , nasal IL-17F and bronchial neutrophil/IL-17 markers and between the latter and exacerbations, suggesting that nasal IL-17F might be informative on bronchial IL17-driven neutrophilia in atopic SA.