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

Toll-like receptor 9 dependent interferon-α release is impaired in severe asthma but is not associated with exacerbation frequency

Patients with asthma and chronic obstructive pulmonary disease (COPD) are susceptible to exacerbations, often caused by microbial pathogens. We hypothesised that intracellular Toll-like receptor (TLR) function in blood mononuclear cells (PBMCs) from these subjects would be impaired and that this impairment is related to exacerbation frequency. PBMCs stimulated with a TLR-9 agonist (but not TLR-3 or 7/8) produced significantly less IFN-α in asthma (26 [3-696]pg/ml) compared to control (943 [164-1651]) and COPD (597 [127-1186]) subjects (p = 0.0019) but this was not related to the number of exacerbations per year in asthma or COPD. In COPD, IFN-α levels were related to KCO (% predicted) in COPD (r = -0.41, p = 0.01). IFN-α was derived from plasmacytoid dendritic cells (pDCs) and their frequency was lower in asthma compared to control subjects (control 0.48% [0.33-0.64] versus asthma 0.29% [0.13-0.34], p = 0.019) whereas pDC function per se was not significantly impaired between groups. The mechanism underlying reduced IFN-α production and the clinical consequences in severe asthma remains to be established.

Heterogeneity in mechanisms influencing glucocorticoid sensitivity: the need for a systems biology approach to treatment of glucocorticoid-resistant inflammation

Glucocorticoids (GCs) have impressive anti-inflammatory and immunosuppressive effects and show a diversity of actions across a variety of cell phenotypes. Implicit in efforts to optimize GCs as anti-inflammatory agents for any or all indications is the notion that the relevant mechanism(s) of action of GCs are fully elucidated. However, recent advances in understanding GC signalling mechanisms have revealed remarkable complexity and contextual dependence, calling into question whether the mechanisms of action are sufficiently well-described to embark on optimization. In the current review, we address evidence for differences in the mechanism of action in different cell types and contexts, and discuss contrasts in mechanisms of glucocorticoid insensitivity, with a focus on asthma and Chronic Obstructive Pulmonary Disease (COPD). Given this complexity, we consider the potential breadth of impact and selectivity of strategies directed to reversing the glucocorticoid insensitivity.

Phenotype of asthmatics with increased airway S-nitrosoglutathione reductase activity

S-Nitrosoglutathione is an endogenous airway smooth muscle relaxant. Increased airway S-nitrosoglutathione breakdown occurs in some asthma patients. We asked whether patients with increased airway catabolism of this molecule had clinical features that distinguished them from other asthma patients. We measured S-nitrosoglutathione reductase expression and activity in bronchoscopy samples taken from 66 subjects in the Severe Asthma Research Program. We also analysed phenotype and genotype data taken from the program as a whole. Airway S-nitrosoglutathione reductase activity was increased in asthma patients (p=0.032). However, only a subpopulation was affected and this subpopulation was not defined by a "severe asthma" diagnosis. Subjects with increased activity were younger, had higher IgE and an earlier onset of symptoms. Consistent with a link between S-nitrosoglutathione biochemistry and atopy: 1) interleukin 13 increased S-nitrosoglutathione reductase expression and 2) subjects with an S-nitrosoglutathione reductase single nucleotide polymorphism previously associated with asthma had higher IgE than those without this single nucleotide polymorphism. Expression was higher in airway epithelium than in smooth muscle and was increased in regions of the asthmatic lung with decreased airflow. An early-onset, allergic phenotype characterises the asthma population with increased S-nitrosoglutathione reductase activity.

Update on reslizumab for eosinophilic asthma

INTRODUCTION

Patients with severe eosinophilic asthma have an unmet need for novel and efficacious treatments. Reslizumab is one of the three monoclonal antibodies targeting the IL-5 pathway and has been found in Phase IIIb clinical trials to reduce asthma exacerbations, control asthma-related symptoms and improve pulmonary function in patients with eosinophilic asthma.

AREAS COVERED

In this article, we discuss the results of asthma clinical trials using reslizumab, beginning with a discussion of the relationship between eosinophils, IL-5 and asthma. We conducted PubMed searches using the terms 'reslizumab', 'anti-IL-5', 'eosinophilic asthma', 'IL-5 asthma'. We also searched ClinicalTrials.gov for 'reslizumab', 'reslizumab asthma', 'SCH 55700', 'SCH 55700 asthma', 'Cinquil' and 'Cinquil asthma'.

EXPERT OPINION

Reslizumab and other anti-IL-5 therapies have seen success in recent trials through more stringent study participant selection targeting eosinophilic inflammation. This selection can now be based on simple blood counts. These drugs have shown a very good safety profile, but long-term safety data are not yet available. Approval for these drugs is eagerly awaited by clinicians and patients alike.

Weekly low-dose methotrexate for reduction of Global Initiative for Asthma Step 5 treatment in severe refractory asthma: study protocol for a randomized controlled trial

BACKGROUND

Patients with chronic severe asthma (CSA) have a crippling disease and current available treatments are not satisfactory. Thus, management of CSA remains a major unmet need. Although the evidence from existing randomized controlled trials fails to support a definite role for immunomodulatory drugs in these patients due to major methodologic drawbacks, findings with low-dose methotrexate (MTX) are encouraging. However, larger and well-designed clinical trials are required to establish the beneficial role of MTX in CSA, and for the detection of the key characteristics of those who are going to respond to this drug.

METHODS/DESIGN

Patients will be recruited from the accessible asthmatic patients lists of tertiary referral centers. All patients will meet the stringent diagnostic criteria for CSA, including the requirement for the regular use of Global Initiative for Asthma (GINA) Global Strategy for Asthma Management and Prevention Step 5 medications (oral prednisone and/or omalizumab). The experimental design of the proposed study will take the form of a double-blind parallel-randomized placebo-controlled trial consisting of a total of eight visits, including run-in and run-out periods. Patients will be randomly allocated to receive either MTX or a matched placebo once a week as an add-on therapy to their existing medication after run-in. Physiological, laboratory and clinical assessments will be measured regularly throughout the study and compared with baseline assessments.

DISCUSSION

We expect that MTX will reduce Step 5 medications dosage in patients with CSA without compromising the overall disease control. Improvement in several indicators of asthma severity and control will be also investigated.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02124226 (assigned 25 April 2014).

Lymphotoxin β receptor signaling induces IL-8 production in human bronchial epithelial cells

Asthma-related mortality has been decreasing due to inhaled corticosteroid use, but severe asthma remains a major clinical problem. One characteristic of severe asthma is resistance to steroid therapy, which is related to neutrophilic inflammation. Recently, the tumor necrosis factor superfamily member (TNFSF) 14/LIGHT has been recognized as a key mediator in severe asthmatic airway inflammation. However, the profiles and intracellular mechanisms of cytokine/chemokine production induced in cells by LIGHT are poorly understood. We aimed to elucidate the molecular mechanism of LIGHT-induced cytokine/chemokine production by bronchial epithelial cells. Human bronchial epithelial cells express lymphotoxin β receptor (LTβR), but not herpesvirus entry mediator, which are receptors for LIGHT. LIGHT induced various cytokines/chemokines, such as interleukin (IL)-6, oncostatin M, monocyte chemotactic protein-1, growth-regulated protein α and IL-8. Specific siRNA for LTβR attenuated IL-6 and IL-8 production by BEAS-2B and normal human bronchial epithelial cells. LIGHT activated intracellular signaling, such as mitogen-activated protein kinase and nuclear factor-κB (NF-κB) signaling. LIGHT also induced luciferase activity of NF-κB response element, but not of activator protein-1 or serum response element. Specific inhibitors of phosphorylation of extracellular signal-regulated kinase (Erk) and that of inhibitor κB attenuated IL-8 production, suggesting that LIGHT-LTβR signaling induces IL-8 production via the Erk and NF-κB pathways. LIGHT, via LTβR signaling, may contribute to exacerbation of airway neutrophilic inflammation through cytokine and chemokine production by bronchial epithelial cells.

Anticholinergics/antimuscarinic drugs in asthma

Anticholinergic alkaloids have been used for thousands of years for the relief of bronchoconstriction and other respiratory symptoms, and their use in the treatment of chronic obstructive pulmonary disease is well established. Acetylcholine, acting through muscarinic receptor (M) receptor, modulates multiple physiologic functions pertinent to asthma including airway muscle tone, mucus gland secretion, and various parameters of inflammation and remodeling. In addition, activation of M receptors may inhibit beta2 adrenoreceptor. These observations offer the rationale for the use of M receptors antagonists in the treatment of asthma. Short-acting antimuscarinic agents may be effective alone or in combination with short-acting beta agonists for the relief of acute symptoms. Long-acting antimuscarinic agents have emerged as potentially useful in the long-term treatment of difficult-to-control asthma. This review will analyze the mechanisms of action and therapeutic role of antimuscarinic agents on asthma including current guidelines regarding antimuscarinic drugs, recent studies in asthma, special populations to consider, and possible predictors of response.

MicroRNA: potential biomarkers and therapeutic targets for allergic asthma?

MicroRNAs are small non-coding RNAs that bind to multiple target mRNAs to control gene expression post-transcriptionally by inhibiting translation. In mammalian cells, microRNAs play important roles in a diverse array of cellular processes (e.g. cell proliferation and differentiation). However, alterations in their levels may compromise cellular function, predisposing to disease. In this review, we discuss microRNAs that have been linked with pathogenesis of asthma and propose functional roles in the regulation of disease. MicroRNAs have the potential to be biomarkers for asthma and provide the platform for the development of new classes of therapeutic compounds.

Breathing exercises for asthma

Educational aims

To summarise the evidence of the role of breathing control approaches in the management of asthma

To provide information on the content of evidence-based breathing exercises programmes

Summary

Asthma is a complex, multi-dimensional condition that affects patients in many ways. Having asthma is inherently stressful and psychological problems are common and associated with poor asthma outcomes. Although most patients in clinical trials can achieve high levels of control with optimised pharmacotherapy, in “real-life” practice, poor control is common, with over-reliance on rescue bronchodilator medication and ongoing symptoms and quality-of-life impairment. Many patients are interested in non-pharmacological treatments to improve asthma control, particularly breathing control exercises but, until recently, the evidence base has been inadequate. The place of breathing exercises has been controversial, partly because some proponents have made exaggerated, implausible claims of effectiveness. Recent evidence, however, has resulted in endorsement of breathing exercises as add-on treatment in asthma in systematic reviews and guidelines.

This review summarises the current evidence of effectiveness of breathing exercises programmes as an adjuvant treatment to pharmacological strategies for people with asthma. The types of breathing training programmes used and the content of effective programmes are discussed. We conclude that patients whose asthma continues to cause symptoms and quality-of-life impairment, despite adequate pharmacological treatment, or who have high bronchodilator use, should be offered access to an effective breathing training programme as a part of holistic, integrated asthma care.

Key points

Asthma is frequently poorly controlled despite effective modern medication

Psychological factors can be as important as physiological ones in affecting symptom perception and disease impact

Breathing exercises can improve patient-reported outcomes and psychological state

Breathing exercises should be offered to all asthma patients with symptoms or impaired quality of life despite standard treatment

The effects of bronchiectasis on asthma exacerbation

BACKGROUND

Bronchiectasis and asthma are different in many respects, but some patients have both conditions. Studies assessing the effect of bronchiectasis on asthma exacerbation are rare. The aim of this study is to investigate the effect of bronchiectasis on asthma exacerbation.

METHODS

We enrolled 2,270 asthma patients who were followed up in our hospital. Fifty patients had bronchiectasis and asthma. We selected fifty age- and sex-matched controls from the 2,220 asthma patients without bronchiectasis, and assessed asthma exacerbation and its severity based on the annual incidence of total asthma exacerbation, annual prevalence of steroid use, and frequency of emergency room visits and hospitalizations due to asthma exacerbation in each group.

RESULTS

Fifty patients (2.2%) had bronchiectasis and asthma. The annual incidence of asthma exacerbation was higher in patients with asthma and bronchiectasis than in patients with asthma alone (1.08±1.68 vs. 0.35±0.42, p=0.004). The annual prevalence of steroid use (0.9±1.54 vs. 0.26±0.36, p=0.006) and the frequency of emergency room visits (0.46±0.84 vs. 0.02±0.13, p=0.001) due to asthma exacerbation were also higher in patients with asthma and bronchiectasis than in patients with asthma alone.

CONCLUSION

Bronchiectasis is associated with difficult asthma control.

Pathobiology of severe asthma

Severe asthma (SA) afflicts a heterogeneous group of asthma patients who exhibit poor responses to traditional asthma medications. SA patients likely represent 5-10% of all asthma patients; however, they have a higher economic burden when compared with milder asthmatics. Considerable research has been performed on pathological pathways and structural changes associated with SA. Although limitations of the pathological approaches, ranging from sampling, to quantitative assessments, to heterogeneity of disease, have prevented a more definitive understanding of the underlying pathobiology, studies linking pathology to molecular markers to targeted therapies are beginning to solidify the identification of select molecular phenotypes. This review addresses the pathobiology of SA and discusses the current limitations of studies, the inflammatory cells and pathways linked to emerging phenotypes, and the structural and remodeling changes associated with severe disease. In all cases, an effort is made to link pathological findings to specific clinical/molecular phenotypes.

Methotrexate as an oral corticosteroid-sparing agent in severe asthma: the emergence of a responder asthma endotype

Background

Sustained use of oral corticosteroids is associated with significant side effects. It is therefore of interest to find a corticosteroid-sparing agent. In two meta-analyses, methotrexate resulted in a rather small reduction in the oral corticosteroid maintenance dose. We have used methotrexate as an oral corticosteroid-sparing agent in consecutive patients with severe bronchial asthma and find a need for a real-life observational study to evaluate the effect of methotrexate in clinical practice.

Methods

We analyzed the clinical data of 13 oral corticosteroid-dependent asthma patients with a mean prednisolone dose of 15 mg/day for up to 8 years. The diagnosis of asthma based on the clinical history, positive bronchodilator reversibility test, and variable airflow obstruction was secured by bronchial biopsies in all patients. We reviewed the literature and found 12 studies evaluating methotrexate as an oral corticosteroid-sparing agent in severe asthma and calculated the mean daily reduction in mg of prednisolone.

Results

Oral corticosteroids could be reduced in 8/13 patients, 61.5% (mean reduction 9.0 mg/day), and stopped in six of these patients. Five patients had no reduction and remained oral corticosteroid-dependent. Patients with the highest oral corticosteroid doses experienced the greatest reductions. Two patients stopped methotrexate due to side effects. FEV1 remained unaffected by methotrexate treatment and corticosteroid reduction.

Conclusions

Methotrexate has significant oral corticosteroid-sparing effect while maintaining an unaltered asthma control and spirometry. Methotrexate seems an effective oral corticosteroid-sparing agent in a significant proportion of patients with severe asthma. The specific asthma phenotype/endotype that responds needs further study.

The real-life clinical effects of 52 weeks of omalizumab therapy for severe persistent allergic asthma

BACKGROUND

Omalizumab was introduced in Malta in 2011. To date, no local data have been published.

OBJECTIVE

To obtain baseline characteristics of our local cohort, determine effectiveness of omalizumab at 52 weeks, compare clinical outcomes 52 weeks pre- and postomalizumab therapy and to assess its safety and tolerability.

SETTING

The Mater Dei Hospital in Malta.

METHOD

All consented adult patients who were eligible to start treatment with omalizumab for asthma were enrolled in this open, prospective observational real-life study. A questionnaire was completed and an Asthma Control Test and spirometry performed. Patients were reviewed on a regular basis. Any undesirable symptoms were recorded. Treatment effectiveness was evaluated at 16 and 52 weeks, during which a decision was taken whether patients were responders. Outcomes were compared 52 weeks pre- and post- treatment initiation. Main outcome measure To determine effectiveness of treatment following 1 year of omalizumab by assessing its impact on the rate of asthma-related exacerbations and health care utilization including hospitalizations.

RESULTS

Our cohort included 22 patients, all non-smokers (mean age 52.7 ± 11, 64 % males). The mean baseline IgE level was 448.6 ± 444 IU/ml. At week 12, treatment was stopped in one patient due to arthralgias. The drug was stopped in two patients at week 16 due to treatment ineffectiveness. At week 20, treatment was stopped in another patient in view of arthralgias. A significant reduction in the number of asthma exacerbations (p = .03) and number of systemic steroid courses required (p = .03) was identified at 52 weeks. There was a significant improvement in the ACT score (p < .001) after 52 weeks but no significant improvement in FEV1. There was a non-significant decline in the number of hospitalizations (p = .6), asthma-related healthcare visits (p = .2) and days off work (p = .09). Adverse events occurred in 10 % of patients. Costs related to asthma hospital-stay and medicines administered during hospitalisations were decreased by half following 1 year on omalizumab.

CONCLUSION

Omalizumab treatment resulted in an improved asthma control, with a significant reduction in asthma exacerbations and systemic steroid courses required and improvement on ACT score. Adverse events were infrequent and the drug was well tolerated.

25-Hydroxyvitamin D3-deficiency enhances oxidative stress and corticosteroid resistance in severe asthma exacerbation

Oxidative stress plays a significant role in exacerbation of asthma. The role of vitamin D in oxidative stress and asthma exacerbation remains unclear. We aimed to determine the relationship between vitamin D status and oxidative stress in asthma exacerbation. Severe asthma exacerbation patients with 25-hydroxyvitamin D3-deficiency (V-D deficiency) or 25-hydroxyvitamin D-sufficiency (V-D sufficiency) were enrolled. Severe asthma exacerbation with V-D-deficiency showed lower forced expiratory volume in one second (FEV1) compared to that with V-D-sufficiency. V-D-deficiency intensified ROS release and DNA damage and increased TNF-α, OGG1 and NFκB expression and NFκB phosphorylation in severe asthma exacerbation. Supplemental vitamin D3 significantly increased the rates of FEV1 change and decreased ROS and DNA damage in V-D-deficiency. Vitamin D3 inhibited LPS-induced ROS and DNA damage and were associated with a decline in TNF-α and NFκB in epithelial cells. H₂O₂ reduces nuclear translocation of glucocorticoid receptors in airway epithelial cell lines. V-D pretreatment enhanced the dexamethasone-induced nuclear translocation of glucocorticoid receptors in airway epithelial cell lines and monocytes from 25-hydroxyvitamin D3-deficiency asthma patients. These findings indicate that V-D deficiency aggravates oxidative stress and DNA damage, suggesting a possible mechanism for corticosteroid resistance in severe asthma exacerbation.

Bronchial asthma: is personalized therapy on the horizon?

In the last years there is an increasing trend towards personalized medicine for patients with asthma. This is due to the availability of novel specific therapies. These new compounds are supposed to be used in well-defined patient groups, which are likely to respond to these interventions. In addition to already used anti-IgE, novel monoclonal antibodies such as anti-IL-5 and anti-IL-13 are becoming available. Currently clinical trials are ongoing to identify which patient population will respond to these novel therapies.

Interleukin-22 exacerbates airway inflammation induced by short-term exposure to cigarette smoke in mice

AIM

Interleukin-22 (IL-22) exhibits both proinflammatory and anti-inflammatory properties in various biological processes. In this study we explored the effects of exogenous recombinant IL-22 (rIL-22) on cigarette smoke (CS)-induced airway inflammation in mice.

METHODS

Male C57BL/6 mice were divided into groups: (1) CS group exposed to tobacco smoke for 3 consecutive days, (2) rIL-22 group received rIL-22 (100 mg/kg, ip), and (3) CS plus rIL-22 group, received rIL-22 (100 mg/kg, ip) before the CS exposure. The airway resistance (Rn), lung morphology, inflammatory cells in the airways, and inflammatory cytokines and CXCR3 ligands in both bronchoalveolar lavage (BAL) fluids and lung tissues were analyzed.

RESULTS

CS alone significantly elevated IL-22 level in the BAL fluid. Both CS and rIL-22 significantly augmented airway resistance, an influx of inflammatory cells into the airways and lung parenchyma, and significantly elevated levels of pro-inflammatory cytokines (TGFβ1 and IL-17A) and CXCR3 chemokines (particularly CXCL10) at the mRNA and/or protein levels. Furthermore, the effects of rIL-22 on airway resistance and inflammation were synergistic with those of CS, as demonstrated by a further increased Rn value, infiltration of greater numbers of inflammatory cells into the lung, higher levels of inflammatory cytokines and chemokines, and more severe pathological changes in CS plus rIL-22 group as compared to those in CS group.

CONCLUSION

Exogenous rIL-22 exacerbates the airway inflammatory responses to CS exposure in part by inducing expression of several proinflammatory cytokines and CXCR3 ligands.

Heterogeneity of phenotypes in severe asthmatics. The Belgian Severe Asthma Registry (BSAR)

The Belgian severe asthma registry is a web-based registry encompassing demographic, clinical, functional and inflammatory data of severe asthmatics (SA), aiming at improving awareness, knowledge on its natural history and subphenotypes, and offering tools to optimize care of this asthma population.

METHODS

The cross-sectional analyses of this registry included 350 SA as defined by the ATS (2000) from 9 Belgian centres, with at least one year follow up.

RESULTS

Mean age was 55 ± 14 yrs. SA were more frequently female (57%) and atopic (70%). Late-onset asthma (≥40 yr) was observed in 31% of SA. Current smokers represented 12% while 31% were ex-smokers. In addition to high doses ICS + LABA, 65% of patients were receiving LTRA, 27% anti-IgE and 24% maintenance oral corticosteroids (8 mg (Interquartile range-IQR:4-8) methylprednisolone). Despite impaired airflow (median FEV1:67%; IQR: 52-81) only 65% had a post-bronchodilator FEV1/FVC ratio <70%. The median blood eosinophil count was 240/mm³. The median FENO was 26 ppb (IQR: 15-43) and 22% of SA had FENO ≥ 50 ppb. Induced sputum was successful in 86 patients. Eosinophilic asthma (sputum Eos ≥ 3%) was the predominant phenotype (55%) while neutrophilic (sputum Neu ≥ 76%) and paucigranulocytic asthma accounted for 22% and 17% respectively. Comorbidities included rhinitis and chronic rhinosinusitis (49%), nasal polyposis (19%), oesophageal reflux (36%), overweight and obesity (47%) and depression (19%). In addition, 8% had aspirin-induced asthma and 3% ABPA. Asthma was not well-controlled in 83% according to ACT < 20 and 77% with ACQ > 1.5.

CONCLUSION

In this cohort of patients with severe asthma, the majority displayed indices of persistent airflow limitation and eosinophilic inflammation despite high-dose corticosteroids, suggesting potential for eosinophil-targeted biotherapies.

Critical review of bronchial thermoplasty: where should it fit into asthma therapy?

Bronchial thermoplasty is a device-based therapy for treatment of severe refractory asthma that uses radiofrequency energy to reduce airway smooth muscle and decrease bronchoconstriction. BT improves quality of life and decreases the rate of severe exacerbations with no known major long-term complications. The effectiveness of bronchial thermoplasty persists at least 5 years after the treatment is completed. Further investigation is needed to better define the specific subpopulation of patients with severe asthma who would best benefit from this treatment.

Developing and emerging clinical asthma phenotypes

For more than a century, clinicians have attempted to subdivide asthma into different phenotypes based on triggers that cause asthma attacks, the course of the disease, or the prognosis. The first phenotypes that were described included allergic asthma, intrinsic or nonallergic asthma, infectious asthma, and aspirin-exacerbated asthma. These phenotypes are being reviewed elsewhere in this issue of the journal. The present article focuses on developing and emerging clinical asthma phenotypes. First, asthma phenotypes that are associated with environmental exposures (occupational agents, cigarette smoke, air pollution, cold dry air); second, asthma phenotypes that are associated with specific symptoms or clinical characteristics (cough, obesity, adult onset of disease); and third, asthma phenotypes that are based on biomarkers. This latter approach is the most promising because it attempts to identify asthma phenotypes with different underlying mechanisms so that therapies can be better targeted toward disease-specific features and disease outcomes can be improved.

Bronchial thermoplasty: reappraising the evidence (or lack thereof)

Bronchial thermoplasty (BT) involves the application of radiofrequency energy to visible proximal airways to selectively ablate airway smooth muscle. BT is the first nonpharmacologic interventional therapy approved by the US Food and Drug Administration (FDA) for severe asthma. This approval was based on the results of the pivotal Asthma Intervention Research (AIR)-2 trial, which is the only randomized, double-blind, sham-controlled trial of BT. The primary end point of the AIR-2 trial was improvement in the Asthma Quality of Life Questionnaire (AQLQ). The results of the AIR-2 trial have generated enormous interest, controversy, and confusion regarding the true efficacy of BT for severe asthma. Current marketing of BT highlights its use for patients with "severe" asthma, which is interpreted by most practicing clinicians as meaning oral corticosteroid dependence, frequent exacerbations, or a significantly reduced FEV1 with a poor quality of life. Did the AIR-2 trial include patients with a low FEV1, oral steroid dependence, or frequent exacerbations? Did the trial show efficacy for any of the primary or secondary end points? The FDA approved the device based on the reduction in severe asthma exacerbations. However, were the rates of asthma exacerbations, ED visits, or hospitalizations truly different between the two groups, and was this type of analysis even justified given the original study design? This commentary is designed to specifically answer these questions and help the practicing clinician navigate the thermoplasty literature with confidence and clarity. We carefully dissect the design, conduct, and results of the AIR-2 trial and raise serious questions about the efficacy of bronchial thermoplasty.

Oral glucocorticoid-sparing effect of mepolizumab in eosinophilic asthma

BACKGROUND

Many patients with severe asthma require regular treatment with oral glucocorticoids despite the use of high-dose inhaled therapy. However, the regular use of systemic glucocorticoids can result in serious and often irreversible adverse effects. Mepolizumab, a humanized monoclonal antibody that binds to and inactivates interleukin-5, has been shown to reduce asthma exacerbations in patients with severe eosinophilic asthma.

METHODS

In a randomized, double-blind trial involving 135 patients with severe eosinophilic asthma, we compared the glucocorticoid-sparing effect of mepolizumab (at a dose of 100 mg) with that of placebo administered subcutaneously every 4 weeks for 20 weeks. The primary outcome was the degree of reduction in the glucocorticoid dose (90 to 100% reduction, 75 to less than 90% reduction, 50 to less than 75% reduction, more than 0 to less than 50% reduction, or no decrease in oral glucocorticoid dose, a lack of asthma control during weeks 20 to 24, or withdrawal from treatment). Other outcomes included the rate of asthma exacerbations, asthma control, and safety.

RESULTS

The likelihood of a reduction in the glucocorticoid-dose stratum was 2.39 times greater in the mepolizumab group than in the placebo group (95% confidence interval, 1.25 to 4.56; P=0.008). The median percentage reduction from baseline in the glucocorticoid dose was 50% in the mepolizumab group, as compared with no reduction in the placebo group (P=0.007). Despite receiving a reduced glucocorticoid dose, patients in the mepolizumab group, as compared with those in the placebo group, had a relative reduction of 32% in the annualized rate of exacerbations (1.44 vs. 2.12, P=0.04) and a reduction of 0.52 points with respect to asthma symptoms (P=0.004), as measured on the Asthma Control Questionnaire 5 (in which the minimal clinically important difference is 0.5 points). The safety profile of mepolizumab was similar to that of placebo.

CONCLUSIONS

In patients requiring daily oral glucocorticoid therapy to maintain asthma control, mepolizumab had a significant glucocorticoid-sparing effect, reduced exacerbations, and improved control of asthma symptoms. (Funded by GlaxoSmithKline; SIRIUS ClinicalTrials.gov number, NCT01691508.).

Mepolizumab treatment in patients with severe eosinophilic asthma

BACKGROUND

Some patients with severe asthma have frequent exacerbations associated with persistent eosinophilic inflammation despite continuous treatment with high-dose inhaled glucocorticoids with or without oral glucocorticoids.

METHODS

In this randomized, double-blind, double-dummy study, we assigned 576 patients with recurrent asthma exacerbations and evidence of eosinophilic inflammation despite high doses of inhaled glucocorticoids to one of three study groups. Patients were assigned to receive mepolizumab, a humanized monoclonal antibody against interleukin-5, which was administered as either a 75-mg intravenous dose or a 100-mg subcutaneous dose, or placebo every 4 weeks for 32 weeks. The primary outcome was the rate of exacerbations. Other outcomes included the forced expiratory volume in 1 second (FEV1) and scores on the St. George's Respiratory Questionnaire (SGRQ) and the 5-item Asthma Control Questionnaire (ACQ-5). Safety was also assessed.

RESULTS

The rate of exacerbations was reduced by 47% (95% confidence interval [CI], 29 to 61) among patients receiving intravenous mepolizumab and by 53% (95% CI, 37 to 65) among those receiving subcutaneous mepolizumab, as compared with those receiving placebo (P<0.001 for both comparisons). Exacerbations necessitating an emergency department visit or hospitalization were reduced by 32% in the group receiving intravenous mepolizumab and by 61% in the group receiving subcutaneous mepolizumab. At week 32, the mean increase from baseline in FEV1 was 100 ml greater in patients receiving intravenous mepolizumab than in those receiving placebo (P=0.02) and 98 ml greater in patients receiving subcutaneous mepolizumab than in those receiving placebo (P=0.03). The improvement from baseline in the SGRQ score was 6.4 points and 7.0 points greater in the intravenous and subcutaneous mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 4 points), and the improvement in the ACQ-5 score was 0.42 points and 0.44 points greater in the two mepolizumab groups, respectively, than in the placebo group (minimal clinically important change, 0.5 points) (P<0.001 for all comparisons). The safety profile of mepolizumab was similar to that of placebo.

CONCLUSIONS

Mepolizumab administered either intravenously or subcutaneously significantly reduced asthma exacerbations and was associated with improvements in markers of asthma control. (Funded by GlaxoSmithKline; MENSA ClinicalTrials.gov number, NCT01691521.).

Stability of phenotypes defined by physiological variables and biomarkers in adults with asthma

BACKGROUND

Although asthma is characterized by variable airways obstruction, most studies of asthma phenotypes are cross-sectional. The stability of phenotypes defined either by biomarkers or by physiological variables was assessed by repeated measures over 1 year in the Pan-European BIOAIR cohort of adult asthmatics.

METHODS

A total of 169 patients, 93 with severe asthma (SA) and 76 with mild-to-moderate asthma (MA), were examined at six or more visits during 1 year. Asthma phenotype clusters were defined by physiological variables (lung function, reversibility and age of onset of the disease) or by biomarkers (eosinophils and neutrophils in induced sputum).

RESULTS

After 1 year of follow-up, the allocation to clusters was changed in 23.6% of all asthma patients when defined by physiological phenotypes and, remarkably, in 42.3% of the patients when stratified according to sputum cellularity (P = 0.034). In the SA cohort, 30% and 48.6% of the patients changed allocation according to physiological and biomarker clustering, respectively. Variability of phenotypes was not influenced by change in oral or inhaled corticosteroid dose, nor by the number of exacerbations. Lower stability of single and repeated measure was found for all evaluated biomarkers (eosinophils, neutrophils and FeNO) in contrast to good stability of physiological variables (FEV1 ), quality of life and asthma control.

CONCLUSION

Phenotypes determined by biomarkers are less stable than those defined by physiological variables, especially in severe asthmatics. The data also imply that definition of asthma phenotypes is improved by repeated measures to account for fluctuations in lung function, biomarkers and asthma control.

Indoor fungal diversity and asthma: a meta-analysis and systematic review of risk factors

BACKGROUND

Indoor dampness increases the risk of indoor fungal growth. A complex interaction between occupant behaviors and the built environment are thought to affect indoor fungal concentrations and species diversity, which are believed to increase the risk of having asthma, exacerbation of asthma symptoms, or both. To date, no systematic review has investigated this relationship.

OBJECTIVE

This review aims to assess the relationship between exposure to indoor fungi identified to the genera or species level on asthma outcomes in children and adults.

METHODS

Ten databases were systematically searched on April 18, 2013, and limited to articles published since 1990. Reference lists were independently screened by 2 reviewers, and authors were contacted to identify relevant articles. Data were extracted from included studies meeting our eligibility criteria by 2 reviewers and quality assessed by using the Newcastle-Ottawa scale designed for assessment of case-control and cohort studies.

RESULTS

Cladosporium, Alternaria, Aspergillus, and Penicillium species were found to be present in higher concentrations in homes of asthmatic participants. Exposure to Penicillium, Aspergillus, and Cladosporium species were found to be associated with increased risk of reporting asthma symptoms by a limited number of studies. The presence of Cladosporium, Alternaria, Aspergillus, and Penicillium species increased the exacerbation of current asthma symptoms by 36% to 48% compared with those exposed to lower concentrations of these fungi, as shown by using random-effect estimates. Studies were of medium quality and showed medium-high heterogeneity, but evidence concerning the specific role of fungal species was limited.

CONCLUSION

Longitudinal studies assessing increased exposure to indoor fungi before the development of asthma symptoms suggests that Penicillium, Aspergillus, and Cladosporium species pose a respiratory health risk in susceptible populations. Increased exacerbation of current asthma symptoms in children and adults were associated with increased levels of Penicillium, Aspergillus, Cladosporium, and Alternaria species, although further work should consider the role of fungal diversity and increased exposure to other fungal species.

Adjuvant-dependent regulation of interleukin-17 expressing γδ T cells and inhibition of Th2 responses in allergic airways disease

Background

Th2 immune responses are linked primarily to mild and moderate asthma, while Th17 cells, Interleukin-17A (IL-17) and neutrophilia have been implicated in more severe forms of disease. How Th2-dependent allergic reactions are influenced by Th17 and IL-17-γδ T cells is poorly understood. In murine models, under some conditions, IL-17 promotes Th2-biased airway inflammatory responses. However, IL-17-γδ T cells have been implicated in the inhibition and resolution of allergic airway inflammation and hyperresponsiveness (AHR).

Methods

We compared airway responses in Balb/c mice sensitized to OVA with (and without) a Th2-skewing aluminum-based adjuvant and the IL-17 skewing, complete Freund’s adjuvant (CFA). AHR was measured invasively by flexiVent, while serum OVA-IgE was quantified by an enzyme immunoassay. Airway inflammatory and cytokine profiles, and cellular sources of IL-17 were assessed from bronchoalveolar lavage and/or lungs. The role of γδ T cells in these responses was addressed in OVA/CFA sensitized mice using a γδ T cell antibody.

Results

Following OVA challenge, all mice exhibited mixed eosinophilic/neutrophilic airway inflammatory profiles and elevated serum OVA-IgE. Whereas OVA/alum sensitized mice had moderate inflammation and AHR, OVA/CFA sensitized mice had significantly greater inflammation but lacked AHR. This correlated with a shift in IL-17 production from CD4⁺ to γδ T cells. Additionally, OVA/CFA sensitized mice, given a γδ TCR stimulatory antibody, showed increased frequencies of IL-17-γδ T cells and diminished airway reactivity and eosinophilia.

Conclusions

Thus, the conditions of antigen sensitization influence the profile of cells that produce IL-17, the balance of which may then modulate the airway inflammatory responses, including AHR. The possibility for IL-17-γδ T cells to reduce AHR and robust eosinophilic inflammation provides evidence that therapeutic approaches focused on stimulating and increasing airway IL-17-γδ T cells may be an effective alternative in treating steroid resistant, severe asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0090-5) contains supplementary material, which is available to authorized users.

Defining severe asthma - an approach to find new therapies

Asthma is a chronic inflammatory disease that has reached epidemic proportions worldwide. It is treatable in the majority of patients, but there is no cure. Moreover, a proportion of patients suffer from severe, difficult-to-control disease with daily symptoms and high morbidity, making it imperative that we continue to improve our understanding of the underlying mechanisms of this disease. Severe asthma is a heterogeneous condition. A systematic approach to identify specific asthma phenotypes, including clinical characteristics and inflammatory processes, is the first step toward individualized, logical therapy. This review focuses on the need to characterize severe asthma phenotypes and on novel, targeted molecular treatment options currently under development.

Prevalence of severe childhood asthma according to the WHO

BACKGROUND

The World Health Organization (WHO) recently proposed a new definition of severe asthma to facilitate standardized characterization of patients, and enable more accurate estimations of the prevalence of severe asthma. The aim of this study was to estimate the prevalence of severe asthma according to the WHO definition in children aged 12 years, in Stockholm, Sweden.

METHODS

The birth cohort BAMSE enrolled 4089 children during 1994-96. Parental questionnaires provided information on asthma-related symptoms, diagnosis and medication from 3015 enrolled children at the age of 12 years. Severe asthma was defined as the presence of asthma, as well as continuous treatment with inhaled corticosteroids and long-acting beta-2 agonists, based on information from the Swedish prescribed drug register demonstrating prescriptions of at least 800 μg budesonide daily (or equivalent).

RESULTS

The prevalence of asthma was 11% among 12-year-olds (n = 329). Based on information from the Swedish prescribed drug register, seven children with asthma fulfilled the definition of severe asthma. The estimated prevalence corresponds to 0.23% (95% CI, 0.06-0.4) of the population, or 2.1% (95% CI, 0.5-3.7) of children with asthma. Based on assessed markers of asthma control, 3/7 with severe asthma were considered to have controlled asthma and 4/7 had partly or uncontrolled asthma.

CONCLUSION

Severe asthma appears rare both among 12-year-old schoolchildren with asthma and in the general population. Combining self-reported information from a population-based birth cohort with data from a drug register seems trustworthy in estimating severe asthma as defined by the WHO.

Chloride channel blockade relaxes airway smooth muscle and potentiates relaxation by β-agonists

Severe bronchospasm refractory to β-agonists continues to cause significant morbidity and mortality in asthmatic patients. We questioned whether chloride channels/transporters are novel targets for the relaxation of airway smooth muscle (ASM). We have screened a library of compounds, derivatives of anthranilic and indanyloxyacetic acid, that were originally developed to antagonize chloride channels in the kidney. We hypothesized that members of this library would be novel calcium-activated chloride channel blockers for the airway. The initial screen of this compound library identified 4 of 20 compounds that relaxed a tetraethylammonium chloride-induced contraction in guinea pig tracheal rings. The two most effective compounds, compounds 1 and 13, were further studied for their potential to either prevent the initiation of or relax the maintenance phase of an acetylcholine (ACh)-induced contraction or to potentiate β-agonist-mediated relaxation. Both relaxed an established ACh-induced contraction in human and guinea pig ex vivo ASM. In contrast, the prevention of an ACh-induced contraction required copretreatment with the sodium-potassium-chloride cotransporter blocker bumetanide. The combination of compound 13 and bumetanide also potentiated relaxation by the β-agonist isoproterenol in guinea pig tracheal rings. Compounds 1 and 13 hyperpolarized the plasma cell membrane of human ASM cells and blocked spontaneous transient inward currents, a measure of chloride currents in these cells. These functional and electrophysiological data suggest that modulating ASM chloride flux is a novel therapeutic target in asthma and other bronchoconstrictive diseases.