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

Current concepts of severe asthma

The term asthma encompasses a disease spectrum with mild to very severe disease phenotypes whose traditional common characteristic is reversible airflow limitation. Unlike milder disease, severe asthma is poorly controlled by the current standard of care. Ongoing studies using advanced molecular and immunological tools along with improved clinical classification show that severe asthma does not identify a specific patient phenotype, but rather includes patients with constant medical needs, whose pathobiologic and clinical characteristics vary widely. Accordingly, in recent clinical trials, therapies guided by specific patient characteristics have had better outcomes than previous therapies directed to any subject with a diagnosis of severe asthma. However, there are still significant gaps in our understanding of the full scope of this disease that hinder the development of effective treatments for all severe asthmatics. In this Review, we discuss our current state of knowledge regarding severe asthma, highlighting different molecular and immunological pathways that can be targeted for future therapeutic development.

Eosinophilic bioactivities in severe asthma

Asthma is clearly related to airway or blood eosinophilia, and asthmatics with significant eosinophilia are at higher risk for more severe disease. Eosinophils actively contribute to innate and adaptive immune responses and inflammatory cascades through the production and release of diverse chemokines, cytokines, lipid mediators and other growth factors. Eosinophils may persist in the blood and airways despite guidelines-based treatment. This review details eosinophil effector mechanisms, surface markers, and clinical outcomes associated with eosinophilia and asthma severity. There is interest in the potential of eosinophils or their products to predict treatment response with biotherapeutics and their usefulness as biomarkers. This is important as monoclonal antibodies are targeting cytokines and eosinophils in different lung environments for treating severe asthma. Identifying disease state-specific eosinophil biomarkers would help to refine these strategies and choose likely responders to biotherapeutics.

Reduced epithelial suppressor of cytokine signalling 1 in severe eosinophilic asthma

Severe asthma represents a major unmet clinical need. Eosinophilic inflammation persists in the airways of many patients with uncontrolled asthma, despite high-dose inhaled corticosteroid therapy. Suppressors of cytokine signalling (SOCS) are a family of molecules involved in the regulation of cytokine signalling via inhibition of the Janus kinase-signal transducers and activators of transcription pathway. We examined SOCS expression in the airways of asthma patients and investigated whether this is associated with persistent eosinophilia.Healthy controls, mild/moderate asthmatics and severe asthmatics were studied. Whole genome expression profiling, quantitative PCR and immunohistochemical analysis were used to examine expression of SOCS1, SOCS2 and SOCS3 in bronchial biopsies. Bronchial epithelial cells were utilised to examine the role of SOCS1 in regulating interleukin (IL)-13 signalling in vitroSOCS1 gene expression was significantly lower in the airways of severe asthmatics compared with mild/moderate asthmatics, and was inversely associated with airway eosinophilia and other measures of T-helper type 2 (Th2) inflammation. Immunohistochemistry demonstrated SOCS1 was predominantly localised to the bronchial epithelium. SOCS1 overexpression inhibited IL-13-mediated chemokine ligand (CCL) 26 (eotaxin-3) mRNA expression in bronchial epithelial cells.Severe asthma patients with persistent airway eosinophilia and Th2 inflammation have reduced airway epithelial SOCS1 expression. SOCS1 inhibits epithelial IL-13 signalling, supporting its key role in regulating Th2-driven eosinophilia in severe asthma.

Airway Inflammation after Bronchial Thermoplasty for Severe Asthma

RATIONALE

Bronchial thermoplasty is an alternative treatment for patients with severe, uncontrolled asthma in which the airway smooth muscle is eliminated using radioablation. Although this emerging therapy shows promising outcomes, little is known about its effects on airway inflammation.

OBJECTIVES

We examined the presence of bronchoalveolar lavage cytokines and expression of smooth muscle actin in patients with severe asthma before and in the weeks after bronchial thermoplasty.

METHODS

Endobronchial biopsies and bronchoalveolar lavage samples from 11 patients with severe asthma were collected from the right lower lobe before and 3 and 6 weeks after initial bronchial thermoplasty. Samples were analyzed for cell proportions and cytokine concentrations in bronchoalveolar lavage and for the presence of α-SMA in endobronchial biopsies.

MEASUREMENTS AND MAIN RESULTS

α-SMA expression was decreased in endobronchial biopsies of 7 of 11 subjects by Week 6. In bronchoalveolar lavage fluid, both transforming growth factor-β1 and regulated upon activation, normal T-cell expressed and secreted (RANTES)/CCL5 were substantially decreased 3 and 6 weeks post bronchial thermoplasty in all patients. The cytokine tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL), which induces apoptosis in several cell types, was increased in concentration both 3 and 6 weeks post bronchial thermoplasty.

CONCLUSIONS

Clinical improvement and reduction in α-SMA after bronchial thermoplasty in severe, uncontrolled asthma is associated with substantial changes in key mediators of inflammation. These data confirm the substantial elimination of airway smooth muscle post thermoplasty in the human asthmatic airway and represent the first characterization of significant changes in airway inflammation in the first weeks after thermoplasty.

Profile of difficult to treat asthma patients referred for systematic assessment

AIM

We determined the proportion of asthma patients under specialist care who remain difficult-to-treat and might benefit from systematic assessment. We additionally report the characteristics and indications for referral in 90 patients who received systematic assessment for difficult asthma.

METHODS

We conducted a three-month prospective audit of our hospital's general asthma clinic. We then analyzed consecutive patients over 18 months referred on for systematic assessment of difficult asthma.

RESULTS

Over 3 months, 22/166 patients (13.3%) in the general asthma clinic were considered likely to benefit from systematic assessment of difficult asthma. These patients had higher inhaled steroid requirements (890 ± 604 mg), lower lung function (FEV1: 65 ± 18%), and more often received GINA step 5 treatment (22.7%). However, 7/22 (32%) of suitable patients were not referred for assessment, mainly due to patient factors. Over 18 months, 90 patients received systematic assessment for difficult asthma, on account of poor symptom control (62%), frequent exacerbations (44%), poor lung function (42%), patient factors (29%), and diagnostic uncertainty (26%). There was a high disease burden with a mean (±SD) asthma control test score and asthma quality of life questionnaire score of 14 ± 5 and 4.26 ± 1.45 respectively. 80% fulfilled criteria for severe asthma. The majority were either atopic (66.7%) or eosinophilic (54.4%); only 15.6% were neither. Patients had a median of three extra-pulmonary comorbidities, of which most were previously unrecognised.

CONCLUSION

One-in-eight asthma patients already under specialist care were suitable for systematic assessment of difficult asthma, but a third of these were not referred due to patient factors. Diagnostic uncertainty and patient factors were important indications for systematic assessment. Most patients who underwent systematic assessment exhibited severe asthma phenotypes potentially responsive to targeted treatment, but also had multiple comorbidities. Our results highlight the importance of management strategies to address patient factors, severe asthma biology, and concurrent contributory conditions.

Clinical usefulness of mepolizumab in severe eosinophilic asthma

Asthma is a chronic inflammatory disorder of the airways with variable clinical severity from very mild and occasional symptoms to recurrent critical exacerbations, at risk of fatal or near-fatal outcome, in a small percentage of patients. Within the different inflammatory cascades involved in asthma, eosinophils play a central role in the pathogenesis and largely influence disease severity. Interleukin-5 (IL-5) is the main cytokine controlling eosinophil activity and proliferation at the site of inflammation. Mepolizumab was the first biological humanized anti-IL-5 monoclonal antibody tested in randomized clinical trials on eosinophilic asthma and other eosinophilic diseases. On the basis of several positive clinical efficacy data, it has recently been approved by the US Food and Drug Administration for the treatment of severe eosinophilic asthma. Unfortunately, high costs are at present a critical issue. Future studies will probably help in the correct selection of a potential “responder phenotype”, allowing the prescription of this promising therapy to appropriate patients and best define cost-effectiveness issues.

Biomarkers Guided Treatment Strategies in Adult Patients with Asthma: Ready for the Clinical Field?

Asthma is a chronic inflammatory airways disorder mainly characterized by heterogeneity. In the more severe forms, a discordance often exists between symptoms and inflammation. Difficulty in managing asthma derives partly from the multiple phenotypes existing and our inability to recognize them. The use of non-invasive, with main representative the fraction of exhaled nitric oxide, or semi-invasive techniques such as induced sputum are effective tools that can help us to guide asthma treatment. In the latest years, several serum biomarkers related to asthmatic inflammation have been used for the better recognition of asthma sub-phenotypes to achieve optimization of therapy and disease outcome. In patients with mild-moderate asthma, as well as patients with more severe asthma, the use of blood eosinophils revealed an acceptable accuracy for the prediction of airway eosinophilia indicating that in future studies may facilitate both individualized treatment and management of asthma. None of the above techniques have been incorporated in clinical practice although sputum eosinophils can be used in patients with severe asthma particularly in specialized centers with great experience. Of great interest are blood eosinophils since current data support their role either as tool for treatment selections or/and as a biomarker of airway eosinophilia.

Epidemiology and Pulmonary Physiology of Severe Asthma

The epidemiology and physiology of severe asthma are inherently linked because of varying phenotypes and expressions of asthma throughout the population. To understand how to better treat severe asthma, we must use both population data and physiologic principles to individualize therapies among groups with similar expressions of this disease.

How to manage a child with difficult asthma?

INTRODUCTION

Children with difficult asthma have significant morbidity and fail to achieve asthma control despite being prescribed high dose maintenance treatment. If control remains poor after diagnostic confirmation, detailed assessments of the reasons for asthma being difficult-to-control are needed. Underlying modifiable factors including non-adherence to medication, persistent environmental exposures that trigger asthma symptoms and psychosocial factors contribute to poor control in these patients.

AREAS COVERED

The focus of this review is to provide a practical approach to the diagnosis and management of difficult asthma including an overview of long term assessments to identify potential progression to true, severe asthma. A multi-disciplinary team is critical to enable modifiable factors to be identified and addressed. Significant resources are required to manage paediatric difficult asthma optimally and only specialist centres should be tasked with the assessment of these patients. Although this may have an impact on healthcare resources, long term benefits for lung health are significant. Expert commentary: The management of paediatric difficult asthma is not simple and involves numerous professionals with varied expertise. However, if it is not undertaken with the appropriate skills, there is a significant risk of children receiving inappropriate invasive investigations and therapies that will have no impact on morbidity.

The enigmatic role of IL-22 in asthma

Asthma is a complex, heterogeneous disorder with increasing prevalence. It is now recognized that several asthma phenotypes exist, including type 2-high and type 2-low (or non-type 2) subsets. As current research strives to identify subgroups of asthmatics that share disease pathobiology to establish endotypes, efforts to clarify the underlying molecular mechanisms of disease are needed and essential. IL-22 is thought to be a mediator of asthma pathogenesis, but whether this cytokine has a pathologic or beneficial role in the lung during severe disease is still debated. Studies focused on the regulation of this cytokine by its receptors and other inflammatory mediators during allergic airway responses are necessary to clarify its role in disease. Here, we discuss the ambiguity surrounding the role of IL-22 in asthma and considerations for targeting IL-22 therapeutically.

Moving towards precision care for childhood asthma

PURPOSE OF REVIEW

Asthma guidelines recognize the presence of different asthma endotypes and phenotypes but treatment recommendations are limited to age groups rather than phenotypes, as the phenotype literature is regarded as emerging evidence. This review will examine the current evidence regarding the management of asthma in school age children (5-18 years old) by endotype and phenotype.

RECENT FINDINGS

A number of studies have examined the effect of endotypes and phenotypes on response to conventional asthma therapy, omalizumab and specific allergen immunotherapy, and response in children with severe asthma. Emerging therapies, namely biologics and immunomodulators, have attracted considerable attention and appear to have favorable effects in adults with asthma, but additional pediatric studies are needed.

SUMMARY

The optimal treatment strategy for children with asthma is not yet defined and likely dependent on many patient and disease characteristics. Much of the phenotypic response literature presented in this review was constrained by a limited number of pediatric and adult studies available and as such should be regarded as preliminary. Better definition of asthma phenotypes and better targeting of therapy based on individual patient phenotypes are likely to improve asthma treatment in the future.

Simulation of Forced Expiration in a Biophysical Model, With Homogeneous and Clustered Bronchoconstriction

One limitation of forced spirometry is that it integrates the contribution of the complex and dynamic behavior of all of the airways and tissue of the lung into a single exhaling unit, hence, it is not clear how spirometric measures are affected by local changes to the airways or tissue such as the presence of "ventilation defects." Here, we adapt a wave-speed limitation model to a spatially distributed and anatomically based airway tree that is embedded within a deformable parenchyma, to simulate forced expiration in 1 s (FEV1). This provides a model that can be used to assess the consequence of imposed constrictions on FEV1. We first show how the model can be parameterized to represent imaging and forced spirometry data from nonasthmatic healthy young adults. We then compare the effect of homogeneous and clustered bronchoconstriction on FEV1 in six subject-specific models (three male and three female). The model highlights potential sources of normal subject variability in response to agonist challenge, including the interaction between sites of airway constriction and sites of flow limitation at baseline. The results support earlier studies which proposed that the significant constriction of nondefect airways must be present in order to match to clinical measurements of lung function.

[Biomarkers in asthma]

Identifying new biomarkers in asthma is attractive but requires assessing their relevance and their reliability to clinical practice. Beyond fashion, the improvement in identification of new candidate biomarkers benefited of scientific and biologic progresses, biobanks and platforms robustly backed on longitudinal cohorts and registries. Paradoxically, the main issue is now to stress up the good question, in other words to correctly characterize the unmet needs in asthma that might benefit of a biomarker. Chronicity, variability, weakness of diagnostic tools and the heterogeneity of the disease are features of asthma claiming for identifying new biomarkers. Unmet needs in asthma encompass areas such as diagnosis, prognosis, management and follow-up, therapeutic guidance and phenotypic/endotypic identification. FEV1 is an available biomarker largely tested in asthma worth in most of these areas. Albeit, mandatory features required for a new biomarker to emerge, pro/con debates on those already existing and currently used methods for identifying new ones are worth explorations. We reviewed and summarized the current literature focusing biomarkers in asthma.

Bronchial thermoplasty and biological therapy as targeted treatments for severe uncontrolled asthma

Although a small proportion of patients with asthma have severe disease, it accounts for the majority of morbidity related to the illness. Severe asthma comprises a heterogeneous group of phenotypes. Targeted treatments for these phenotypes represent a major advancement in the management of severe asthma. Omalizumab, a monoclonal antibody to IgE, improves asthma control in patients with a predominant allergic phenotype. Monoclonal antibodies targeted to interleukin 4α and interleukin 5 have shown substantial benefit in patients with the eosinophilic asthma phenotype; so too have monoclonal antibodies targeted to interleukin 13 in patients with a type 2 allergic phenotype. Bronchial thermoplasty, a new technique to reduce airway smooth muscle mass, improves symptoms and reduces exacerbations in patients with severe uncontrolled asthma and the chronic airflow obstruction phenotype. While awaiting comparative trials, we can now use a targeted approach with these phenotypes, guiding our treatment selection with the best evidence. This Review will focus on the latest developments in these new treatments and inform the clinician on how to select the appropriate patient for these treatments.

Herbal medicine for adults with asthma: A systematic review

BACKGROUND

Many people with asthma use herbal medicines to help reduce symptoms and improve asthma control.

OBJECTIVE

To update the systematic review and meta-analysis of randomised controlled trials of herbal medicine for adult asthma.

DATA SOURCES

Nine English and Chinese databases were searched (PubMed, Embase, CINAHL, CENTRAL, AMED, CBM, CNKI, CQVIP, Wanfang).

STUDY SELECTIONS

Herbal medicines combined with routine pharmacotherapies compared with the same pharmacotherapies alone or placebo. Cochrane Risk of Bias Tool and GRADE Summary of Findings tables were used to evaluate methodological quality.

RESULTS

Twenty-nine (29) studies involving 3,001 participants were included. Herbal interventions used multi-ingredients such as licorice root, crow-dipper, astragali, and angelica. Compared with routine pharmacotherapies alone, herbal medicines as add-on therapy improved lung function (FEV1: MD 7.81%, 95% CI 5.79, 9.83, I(2) = 63%; PEFR: MD 65.14 L/min, 95% CI 58.87, 71.41, I(2) = 21%); asthma control (MD 2.47 points, 95% CI 1.64, 3.29, I(2) = 55%); reduced salbutamol usage (MD -1.14 puffs/day, 95% CI -2.20, -0.09, I(2) = 92%); and reduced acute asthma exacerbations over one year (MD -1.20, 95% CI -1.82, -0.58, one study). Compared with placebo plus pharmacotherapies herbal medicines as add-on therapy improved lung function (FEV1: MD 15.83%, 95% CI 13.54, 18.12 and PEFR: MD 55.20 L/min, 95% CI 33.41, 76.99). Other outcomes were not reported in these placebo studies. Included studies were low to moderate quality. Adverse events were rare.

CONCLUSIONS

Herbal medicines combined with routine pharmacotherapies improved asthma outcomes greater than pharmacotherapies alone. Included studies did not blind participants therefore more studies that address such weaknesses are warranted.

Case reports - When bronchial obstruction in the young adult is not asthma and inhalers do not help

INTRODUCTION

Localised bronchial obstruction is a rare differential diagnosis to asthma.

CASE STUDY

We describe two younger patients treated unsuccessfully for asthma and eventually diagnosed with localised bronchoconstriction.

RESULTS

Bronchoscopy revealed bronchoconstriction: Tracheobronchomalacia in case 1 and fixed obstruction in case 2.

CONCLUSION

A systematic approach to the asthma patient with absent response to therapy facilitates rational use of therapeutic and diagnostic resources.

Severe eosinophilic asthma treated with mepolizumab stratified by baseline eosinophil thresholds: a secondary analysis of the DREAM and MENSA studies

BACKGROUND

Findings from previous studies showed that mepolizumab significantly reduces the rate of exacerbations in patients with severe eosinophilic asthma. To assess the relationship between baseline blood eosinophil counts and efficacy of mepolizumab we did a secondary analysis of data from two studies, stratifying patients by different baseline blood eosinophil thresholds.

METHODS

We did a post-hoc analysis of data, which was completed on Sept 25, 2015, from two randomised, double-blind, placebo-controlled studies of at least 32 weeks duration (NCT01000506 [DREAM] and NCT01691521 [MENSA]) done between 2009 and 2014. In these studies, mepolizumab (

DREAM

75 mg, 250 mg, or 750 mg intravenously; MENSA: 75 mg intravenously or 100 mg subcutaneously) versus placebo was given at 4-week intervals in addition to standard care (high-dose inhaled corticosteroids plus ≥1 additional controller with or without daily oral corticosteroids) to patients aged 12 years or older with a clinical diagnosis of asthma, a history of at least two exacerbations in the previous year that required systemic corticosteroid treatment, and evidence of eosinophilic airway inflammation. The primary endpoint in both studies was the annual rate of clinically significant exacerbations (defined as worsening of asthma that required the use of systemic corticosteroids, or admission to hospital, or an emergency-room visit, or a combination of these occurrences). In our analysis, the primary outcome was the annualised rate of exacerbations in patients stratified by baseline eosinophil counts (≥150 cells per μL, ≥300 cells per μL, ≥400 cells per μL, and ≥500 cells per μL) and baseline blood eosinophil ranges (<150 cells per μL, ≥150 cells per μL to <300 cells per μL, ≥300 cells per μL to <500 cells per μL, and ≥500 cells per μL). We based our analysis on the intention-to-treat populations of the two original studies, and all mepolizumab doses were combined for analysis.

FINDINGS

Of 1192 patients, 846 received mepolizumab and 346 received placebo. The overall rate of mean exacerbations per person per year was reduced from 1·91 with placebo to 1·01 with mepolizumab (47% reduction; rate ratio [RR] 0·53, 95% CI 0·44-0·62; p<0·0001). The exacerbation rate reduction with mepolizumab versus placebo increased progressively from 52%; 0·48, 0·39-0·58) in patients with a baseline blood eosinophil count of at least 150 cells per μL to 70%; 0·30, 0·23-0·40]) in patients with a baseline count of at least 500 cells per μL. At a baseline count less than 150 cells per μL, predicted efficacy of mepolizumab was reduced.

INTERPRETATION

Our analysis has shown a close relationship between baseline blood eosinophil count and clinical efficacy of mepolizumab in patients with severe eosinophilic asthma and a history of exacerbations. We noted clinically relevant reductions in exacerbation frequency in patients with a count of 150 cells per μL or more at baseline. The use of this baseline biomarker will help to select patients who are likely to achieve important asthma outcomes with mepolizumab.

FUNDING

GlaxoSmithKline.

Lebrikizumab in the treatment of asthma

INTRODUCTION

Severe asthma continues to be a major clinical problem despite the availability of effective asthma medications such as inhaled corticosteroids. Several targeted biologic therapies are emerging to treat patients with severe asthma. Areas Covered: This review provides an update of information on lebrikizumab, a novel monoclonal antibody that targets IL-13 and is currently in advanced stages of development. It describes the role of IL-13, a key effector cytokine in Type 2 (T2) airway inflammation in asthma and discusses the results of recent phase 2 trials investigating lebrikizumab's efficacy and safety in patients with severe asthma. Furthermore, it provides insight into the current ongoing trials with lebrikizumab and outlines future research needs. Expert Opinion: Several emerging therapeutic targets have been identified for patients with severe asthma. By specifically targeting IL-13, lebrikizumab has the potential to block several downstream signals that play a role in disease progression including airway inflammation, mucous hypersecretion and airway remodeling. The effects of lebrikizumab have been more marked in individuals with high serum periostin levels which reflect underlying IL-13 activity and T2 airway inflammation. Ongoing trials with lebrikizumab aim to further examine its long-term safety and efficacy in a larger population and explore its effects on airway inflammation and function.

Mepolizumab for the reduction of exacerbations in severe eosinophilic asthma

Asthma affects over 300 million people worldwide and is severe in 10% of sufferers. Severe asthma is associated with greater morbidity and mortality particularly as a consequence of frequent exacerbations. Advances in approaches to phenotype the heterogeneity of severe asthma has established the importance of eosinophilic inflammation and emerging new therapies are broadly designed to target T2-mediated eosinophilic inflammation with the aim to reduce exacerbation frequency. Here, we summarize the evidence that eosinophilic asthma is an important pheno(endo)type and identifies a group at risk of exacerbations; that established therapies reduce exacerbations, particularly in eosinophilic severe asthma; and discuss the role of mepolizumab, an IL-5 neutralising monoclonal antibody therapy, in reducing exacerbations in severe eosinophilic asthma compared to established and other emerging therapies.

What lies beyond Asthma Control Test: Suggestions for clinical practice

BACKGROUND

Asthma Control Test (ACT ™) validity relies on Global Initiative for Asthma (GINA) definition of control. It includes neither reversibility nor inflammation assessment despite their importance as hallmark of asthma, partially unrelated to symptoms. Furthermore though rhinitis may affect the patient's perception of asthma control, its impact on ACT accuracy has not been systematically evaluated.

OBJECTIVE

To explore ACT validity according to a definition of control including: forced expiratory volume in 1 s (FEV1) ≥ 80%, negative reversibility test, exhaled nitric oxide at a flow rate of 50 ml/s (FeNO) < 50 ppb.

RESULTS

177 asthmatics referring to our Unit have been studied. ACT with cut-off score ≥20 showed a good positive predictive value (83.5%) but low sensitivity (47.8%), specificity (66.7%), and negative predictive value (26.5%). ROC curves analysis indicates that ACT in patients with mild intermittent rhinitis is more reliable (AUC: 0.714; p < 0.05) than in patients with nasal polyposis/chronic rhino-sinusitis (AUC: 0.176; p > 0.05). Considering asthma classification, the probability that ACT detects patients with uncontrolled asthma is significantly higher in moderate persistent asthma subgroup than in mild persistent asthma one (OR 5.464; IC 95%: 2.5-11,9; p < 0.05).

CONCLUSIONS

As ACT mainly relies on patient's reported outcomes, it may not completely reflect the airways inflammation and airways obstruction. The presence and severity of rhinitis may affect ACT outcome. The awareness of the variables that could influence ACT evaluation is much more important in the primary care setting where ACT may often represent the only tool for asthma assessment.

[Severe asthma: Characteristics of patients in clinical practice]

AIM

To provide clinical characteristics of severe asthma (SA) patients encountered in clinical practice.

SUBJECTS AND METHODS

A cross-sectional cohort study was performed to cover 119 outpatients aged 22-82 years. SA was diagnosed according to the ERS/ATS criteria (2014). Spirometry and bronchodilator reversibility testing were carried out; fractional exhaled nitric oxide (FeNO) was measured; inhalant allergen hypersensitivity (skin prick and blood specific IgE testing) and peripheral blood eosinophil counts were estimated. Asthma control and asthma-related quality of life were assessed.

RESULTS

77% of the patients were found to have allergic asthma; in this case, house dust mites were leading allergens in the spectrum of sensitization. 82% of the patients were observed to have uncontrolled asthma and 76% had incompletely reversible bronchial obstruction. The airway eosinophilic inflammation markers (FeNO more than 25 ppb and eosinophil counts of more than 150 cells/µ) were elevated in 63% of the patients. Good compliance was noted in 61% of the patients. There were 27% of active smokers who had lower lung function and FeNO levels. The smokers showed a low compliance with inhaled glucocorticosteroid treatment. SA was concurrent with chronic obstructive pulmonary disease in 37% of the cases.

CONCLUSION

SA is a heterogeneous disease. Traditional treatment is not always effective, as many patients, despite their treatment, have uncontrolled SA and continuously increased markers of airways eosinophilic inflammation. Monoclonal antibody therapy may promote success in treating this cohort of patients.

Airway smooth muscle enlargement is associated with protease-activated receptor 2/ligand overexpression in patients with difficult-to-control severe asthma

BACKGROUND

Asthma is a complex disease with heterogeneous features of airway inflammation and remodeling. The increase in airway smooth muscle (ASM) mass is an essential component of airway remodeling in patients with severe asthma, yet the pathobiological mechanisms and clinical outcomes associated with ASM enlargement remain elusive.

OBJECTIVE

We sought to compare ASM area in control subjects and patients with mild-to-moderate or severe asthma and to identify specific clinical and pathobiological characteristics associated with ASM enlargement.

METHODS

Bronchial biopsy specimens from 12 control subjects, 24 patients with mild-to-moderate asthma, and 105 patients with severe asthma were analyzed for ASM area, basement membrane thickness, vessels, eosinophils, neutrophils, T lymphocytes, mast cells, and protease-activated receptor 2 (PAR-2). In parallel, the levels of several ASM mitogenic factors, including the PAR-2 ligands, mast cell tryptase, trypsin, tissue factor, and kallikrein (KLK) 5 and KLK14, were assessed in bronchoalveolar lavage fluid. Data were correlated with asthma severity and control both at inclusion and after 12 to 18 months of optimal management and therapy.

RESULTS

Analyses across ASM quartiles in patients with severe asthma demonstrated that patients with the highest ASM quartile (median value of ASM area, 26.3%) were younger (42.5 vs ≥50 years old in the other groups, P ≤ .04) and had lower asthma control after 1 year of optimal management (P ≤ .006). ASM enlargement occurred independently of features of airway inflammation and remodeling, whereas it was associated with PAR-2 overexpression and higher alveolar tryptase (P ≤ .02) and KLK14 (P ≤ .03) levels.

CONCLUSION

Increase in ASM mass, possibly involving aberrant expression and activation of PAR-2-mediated pathways, characterizes younger patients with severe asthma with poor asthma control.

Airway Microbiota in Severe Asthma and Relationship to Asthma Severity and Phenotypes

BACKGROUND

The lower airways harbor a community of bacterial species which is altered in asthma.

OBJECTIVES

We examined whether the lower airway microbiota were related to measures of asthma severity.

METHODS

We prospectively recruited 26 severe asthma, 18 non-severe asthma and 12 healthy subjects. DNA was extracted from induced sputum and PCR amplification of the V3-V5 region of bacterial 16S rRNA gene was performed.

RESULTS

We obtained 138,218 high quality sequences which were rarefied at 133 sequences/sample. Twenty OTUs had sequences ≥1% of total. There were marked differences in the distribution of Phyla between groups (P = 2.8x10-118). Bacteroidetes and Fusobacteria were reduced in non-severe and severe asthmatic groups. Proteobacteria were more common in non-severe asthmatics compared to controls (OR = 2.26; 95% CI = 1.94-2.64) and Firmicutes were increased in severe asthmatics compared to controls (OR = 2.15; 95%CI = 1.89-2.45). Streptococcal OTUs amongst the Firmicutes were associated with recent onset asthma, rhinosinusitis and sputum eosinophilia.

CONCLUSIONS

Sputum microbiota in severe asthma differs from healthy controls and non-severe asthmatics, and is characterized by the presence of Streptococcus spp with eosinophilia. Whether these organisms are causative for the pathophysiology of asthma remains to be determined.

Asthma-COPD Overlap Syndrome (ACOS): Single disease entity or not? Could exhaled nitric oxide be a useful biomarker for the differentiation of ACOS, asthma and COPD?

Asthma and chronic obstructive pulmonary disease (COPD) represent two major public health problems. However, there is a significant proportion of patients with a mixed asthma-COPD phenotype. This condition is defined as asthma-COPD overlap syndrome (ACOS). Since there are no internationally accepted criteria for the diagnosis of that syndrome, its management remains difficult. Given the fact that patients with ACOS have an increased risk of exacerbation and hospitalization, there is a pressing need for a more targeted approach and better management. We propose that fractional exhaled nitric oxide (FeNO), a marker of eosinophilic inflammation, could help clinicians differentiate ACOS from asthma and COPD. We evaluate this hypothesis, using data derived from the existing literature.

Assessment of corticosteroid response in pediatric patients with severe asthma by using a multidomain approach

BACKGROUND

There is no agreed upon definition of systemic corticosteroid response in asthmatic children. Moreover, pediatric severe therapy-resistant asthma (STRA) is heterogeneous, and thus response to steroids is unlikely to be uniform in all patients.

OBJECTIVE

We sought to evaluate the utility of a multidomain approach incorporating symptoms, lung function, and inflammation to determine steroid responsiveness in pediatric patients with STRA.

METHODS

Eighty-two children (median age, 12 years) with STRA received a clinically indicated dose of intramuscular steroid. Changes in 4 separate domains were assessed 4 weeks after intramuscular triamcinolone acetonide: normalization of (1) symptoms (Asthma Control Test score, >19/25 or 50% increase), (2) spirometric results (FEV1 ≥80% of predicted value or ≥15% increase), (3) fraction of exhaled nitric oxide levels (<24 ppb), and (4) sputum eosinophil counts (<2.5%). Fifty-four of 82 children had complete data in all 4 domains.

RESULTS

Twenty-three (43%) of 54 children had a symptom response, 29 (54%) of 54 had a lung function response, 28 (52%) of 54 had a fraction of exhaled nitric oxide response, and 29 (54%) of 54 had a sputum eosinophil response. Although a similar proportion of children responded to systemic corticosteroids in each domain, there were no reliable predictors of a response pattern. Seven (13%) of 54 were complete responders (response in all domains), 8 (15%) of 54 were nonresponders (no response in any domain), and 39 (72%) of 54 were partial responders (response in ≥1 domain).

CONCLUSIONS

A multidomain evaluation of systemic steroid responsiveness using pragmatic clinical assessments confirms childhood STRA is heterogeneous and that a complete response in symptoms and inflammatory and physiologic parameters is rare. Individual response patterns to systemic steroids might be useful in guiding the choice of add-on therapies in each child as a step toward achieving personalized medicine.

The management of asthma in the phenotype and biomarker era: The proposal of a new diagnostic-therapeutic model

Treatment goals in asthma patients are the achievement of a good control of symptoms and the reduction of the risk of exacerbation. However, a "one-size-fits-all" therapeutic strategy is no longer appropriate to effectively pursue these goals, due to the heterogeneity of asthma. To make the treatment scenario even more complex, asthma patients often present comorbidities that may alter response to therapy. In addition, adherence to asthma treatment is poor. Given this complex and heterogeneous picture, the management of asthma is highly challenging. A clear diagnostic-therapeutic model of patients' care and the definition of the specific responsibilities of different healthcare providers appear necessary to improve clinical outcomes and better allocate healthcare resources. We present here a proposal for this model.

The cytokine interleukin-26 as a biomarker in pediatric asthma

In this pilot study, we examined associations between local interleukin (IL)-26, disease severity and biomarkers of Th2-mediated inflammation in a well-defined cohort of pediatric patients (14 years median age, 41 % females) with controlled (n = 28) or uncontrolled (n = 48) asthma. Sputum IL-26 protein concentrations (ELISA) reflected disease control in patients without local (low exhaled nitric oxide) or systemic (low blood eosinophils) signs of eosinophilic inflammation. Moreover, sputum-IL-26 concentrations correlated with those of blood neutrophils. Our study indicates that IL-26 is a potential biomarker of disease severity in pediatric asthma without signs of Th2-mediated inflammation.

Challenges in the pharmacological treatment of geriatric asthma

Asthma in older populations is characterized by frequent comorbid conditions, which increase the risk of side effects and of detrimental interactions between respiratory and non-respiratory drugs. These observations lead to the need to manage asthma in older populations by applying a multidimensional assessment and a multidisciplinary treatment; therefore, we favor the use of the 'geriatric' term to define asthma in the elderly. Geriatric asthma is a complex disease, which may not necessarily imply that it is also complicated, although the two conditions may often coexist. On this basis, the switch from an organ-driven management to the holistic approach may be the key factor to attain optimal control of the disease in this age range. The current review discusses the age-related factors affecting asthma treatment in the oldest individuals, such as the comorbid conditions, and age-related changes of metabolism and excretion that can impair the efficacy and safety of drugs.

Diagnosis and investigation in the severe asthma clinic

Severe asthma is recognised as an important and emerging area of unmet need in asthma. The assessment of severe asthma should include three steps; (1) determining the diagnosis of asthma, including verification that the disease is severe asthma, (2) assessing comorbidities and contributing factors that will impact on clinical severity, as well as (3) assessing asthma phenotypes. These steps recognize the importance of heterogeneity in asthma as a key factor that determines the disease course and increasingly the choice of successful therapy. This assessment should be undertaken systematically and is best done by an expert multidisciplinary team. Here, we will outline the important aspects that should be included in the clinical assessment of the patient in the severe asthma clinic, including diagnosis, clinical history, the assessment of important comorbidities and the key investigations needed to support them.

Toll-Like Receptor 7-Targeted Therapy in Respiratory Disease

Allergic asthma and allergic rhinitis are inflammatory diseases of the respiratory tract characterized by an excessive type-2 T helper cell (Th2) immune response. Toll-like receptor 7 (TLR7) is a single-stranded viral RNA receptor expressed in the airway that initiates a Th1 immune response and has garnered interest as a novel therapeutic target for treatment of allergic airway diseases. In animal models, synthetic TLR7 agonists reduce airway hyperreactivity, eosinophilic inflammation, and airway remodeling while decreasing Th2-associated cytokines. Furthermore, activation of TLR7 rapidly relaxes airway smooth muscle via production of nitric oxide. Thus, TLR7 has dual bronchodilator and anti-inflammatory effects. Two TLR7 ligands with promising pharmacologic profiles have entered clinical trials for the treatment of allergic rhinitis. Moreover, TLR7 agonists are potential antiviral therapies against respiratory viruses. TLR7 agonists enhance influenza vaccine efficacy and also reduce viral titers when given during an active airway infection. In this review, we examine the current data supporting TLR7 as a therapeutic target in allergic airway diseases.

Advances in Bronchial Thermoplasty

Bronchial thermoplasty (BT) is a therapeutic intervention that delivers targeted thermal energy to the airway walls with the goal of ablating the smooth muscle in patients with severe persistent asthma. Since the publication of the original preclinical studies, three large randomized clinical trials evaluating its impact on asthma control have been performed. These trials have shown improvements in asthma-related quality of life and a reduction in asthma exacerbations following treatment with BT. However, there remains significant controversy regarding the true efficacy of BT and the interpretation of these studies, particularly the Asthma Intervention Research 2 trial. In this article, we will discuss these controversies and present the latest evidence on the use of BT in asthma, specifically the 5-year longitudinal evaluation of patients. In addition, we will discuss new insights into the histopathologic changes that occur in the airways following BT, as well as the feasibility of performing the procedure in patients with very severe asthma. We also will discuss the ongoing translational and clinical investigations regarding the underlying mechanism of action and methods to improve patient selection for this procedure.

CXC chemokine superfamily induced by Interferon-γ in asthma: a cross-sectional observational study

Background

Asthma is a disease encompassing a variety of contributing factors. Phenotyping of asthma based on the profile of accumulated granulocytes in the airways has been performed to explore the mediators involved in allergic bronchial inflammation. The aim of this study was to clarify the characteristics of the CXC chemokine superfamily induced by IFN-γ, namely CXCR3 ligands, in the airways of patients with asthma stratified by the differential proportion of granulocytes in sputum.

Methods

Sputum was induced in 39 adult patients with asthma and 12 healthy subjects. Sputum samples were analyzed for total cell counts and differentials, and concentrations of IFN-γ–inducible protein 10 kDa (IP-10, CXCL10), monokine induced by IFN-γ (Mig, CXCL9), IFN-inducible T cell a chemoattractant (I-TAC, CXCL11), and IL-8 in the supernatants were assayed by ELISA.

Results

Sputum concentrations of IP-10, Mig, and IL-8 were significantly higher in asthma than in healthy subjects. IP-10, Mig, and IL-8 were significantly higher in the mixed granulocyte subtype (eosinophils ≥ 2 % and neutrophils ≥ 40 % in sputum) than in healthy subjects. Additionally, IP-1 0 was significantly higher in the mixed granulocyte subtype than in eosinophil-predominant or neutrophil-predominant subtype (eosinophil percentage ≥ 2 % or neutrophil percentage ≥ 40 %). Mig and IL-8 were significantly higher in the mixed granulocyte subtype than in the paucigranulocyte subtype (eosinophils < 2 % and neutrophils < 40 % in sputum). I-TAC was not different between healthy subjects and asthmatics or granulocyte subtypes. All CXCR3 ligands were significantly associated with the composite of the eosinophil and neutrophil ratio in patients with asthma. Only Mig was significantly correlated with the total eosinophil and neutrophil ratio in patients with asthma on adjusted partial correlation analysis. Mig and IL-8 were significantly negatively correlated with forced expiratory volume in 1 s % predicted (% FEV₁) in patients with asthma.

Conclusions

CXCR3 ligands may serve as potent promoters in eosinophilic and neutrophilic airway inflammation in asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s40733-016-0021-y) contains supplementary material, which is available to authorized users.

Challenges in the management of severe allergic asthma in the elderly

Little is known about the features of asthma and allergy in the elderly. A significant number of elderly patients with asthma have uncontrolled and severe asthma. This review aims to provide an analysis of the literature on the assessment and phenotype of severe allergic asthma in the elderly. Gaps and pitfalls in diagnostic and therapeutic approaches, as well as management of severe allergic asthma in the elderly, are also discussed.

Airway lipoxin A4/formyl peptide receptor 2-lipoxin receptor levels in pediatric patients with severe asthma

BACKGROUND

Lipoxins are biologically active eicosanoids with anti-inflammatory properties. Lipoxin A4 (LXA4) signaling blocks asthmatic responses in human and experimental model systems. There is evidence that patients with respiratory diseases, including severe asthma (SA), display defective generation of lipoxin signals despite glucocorticoid therapy.

OBJECTIVE

We investigated airway levels of formyl peptide receptor 2-lipoxin receptor (FPR2/ALXR), LXA4, and its counterregulatory compound, leukotriene B4 (LTB4), in patients with childhood asthma. We addressed the potential interplay of the LXA4-FPR2/ALXR axis and glucocorticoids in the resolution of inflammation.

METHODS

We examined LXA4 and LTB4 concentrations in induced sputum supernatants from children with intermittent asthma (IA), children with SA, and healthy control (HC) children. In addition, we investigated FPR2/ALXR expression in induced sputum cells obtained from the study groups. Finally, we evaluated in vitro the molecular interaction between LXA4 and glucocorticoid receptor-based mechanisms.

RESULTS

We found that children with SA have decreased LXA4 concentrations in induced sputum supernatants in comparison with children with IA. In contrast to decreases in LXA4 concentrations, LTB4 concentrations were increased in children with asthma independent of severity. LXA4 concentrations negatively correlated with LTB4 concentrations and with exacerbation numbers in children with SA. FPR2/ALXR expression was reduced in induced sputum cells of children with SA compared with that seen in HC subjects and children with IA. Finally, we describe in vitro the existence of crosstalk between LXA4 and glucocorticoid receptor at the cytosolic level mediated by G protein-coupled FPR2/ALXR in peripheral blood granulocytes isolated from HC subjects, children with IA, and children with SA.

CONCLUSION

Our findings provide evidence for defective LXA4 generation and FPR2/ALXR expression that, associated with increased LTB4, might be involved in a reduction in the ability of inhaled corticosteroids to impair control of airway inflammation in children with SA.

Clinically relevant subgroups in COPD and asthma

As knowledge of airways disease has grown, it has become apparent that neither chronic obstructive pulmonary disease (COPD) nor asthma is a simple, easily defined disease. In the past, treatment options for both diseases were limited; thus, there was less need to define subgroups. As treatment options have grown, so has our need to predict who will respond to new drugs. To date, identifying subgroups has been largely reported by detailed clinical characterisation or differences in pathobiology. These subgroups are commonly called "phenotypes"; however, the problem of defining what constitutes a phenotype, whether this should include comorbid diseases and how to handle changes over time has led to the term being used loosely. In this review, we describe subgroups of COPD and asthma patients whose clinical characteristics we believe have therapeutic or major prognostic implications specific to the lung, and whether these subgroups are constant over time. Finally, we will discuss whether the subgroups we describe are common to both asthma and COPD, and give some examples of how treatment might be tailored in patients where the subgroup is clear, but the label of asthma or COPD is not.

Control of asthma in real life: still a valuable goal?

Although studies show that control of asthma can be achieved in the majority of patients, surveys repeatedly show that this is not the case in real life. Important measures to implement in order to achieve asthma control are trained healthcare professionals, a good patient–doctor relationship, patient education, avoidance of exposure to triggers, personalised management and adherence to treatment. These measures help the majority of asthma patients but have not yet been widely implemented and there should be a concerted action for their implementation. Moreover, further and focused research is needed in severe/refractory asthma.

Achieving asthma control requires implementation of evidence-based guidelines and further research into severe asthmahttp://ow.ly/KzrOp

Pathogenesis and prevention strategies of severe asthma exacerbations in children

PURPOSE OF REVIEW

Exacerbations of asthma in children are most frequently precipitated by respiratory infections with a seasonal pattern. However, management takes little account of the underlying infective or other precipitant abnormality.

RECENT FINDINGS

Interactions between environmental triggers, the airway microbiome and innate immune responses are key determinants of exacerbations. Elevated innate cytokines interleukin (IL)-33 and IL-25, and abnormal molecular responses in the interferon pathway are associated with rhinoviral infections. Exacerbations caused by fungal allergens also induce IL-33, highlighting this as an attractive therapeutic target. An equal contribution of bacterial and viral infection during exacerbations, particularly in preschool children, has become increasingly apparent, but some organisms may be protective. Investigation of mechanisms underlying infection-related exacerbations especially in preschool children is needed.Progressive loss of lung function from exacerbations is most pronounced in children aged 6-11 years, and low FEV1 is now recognized as a key predictor for the development of chronic obstructive pulmonary disease and premature death. Although prevention of exacerbations is critical, suboptimal patient education, prescription and adherence to maintenance therapy, and a lack of predictive biomarkers, remain key unaddressed issues in children.

SUMMARY

Precipitants and predictors of exacerbations, together with the child's age and clinical phenotype, need to be used to achieve individualized management in preference to the current uniform approach for all.

Asthma control and exacerbations: two different sides of the same coin

PURPOSE OF REVIEW

Optimal asthma management includes both the control of asthma symptoms and reducing the risk of future asthma exacerbations. Traditionally, treatment has been adjusted largely on the basis of symptoms and lung function and for many patients, this approach delivers both excellent symptom control and reduced risk. However, the relationship between these two key components of the disease may vary between different asthmatic phenotypes and disease severities and there is increasing recognition of the need for more individualized treatment approaches.

RECENT FINDINGS

A number of factors which predict exacerbation risk have been identified including demographic and behavioural features and specific inflammatory biomarkers. Type-2 cytokine-driven eosinophilic airways inflammation predisposes to frequent exacerbations and predicts response to corticosteroids, and the usefulness of sputum eosinophilia as both a marker of exacerbation risk and biomarker for adjustment of corticosteroid treatment has been established for some time. However, attempts to develop surrogate markers, which would be more straightforward to deliver in the clinic, have been challenging.

SUMMARY

Some patients with asthma have persistent symptoms in the absence of type-2 cytokine driven-eosinophilic airways inflammation due to noncorticosteroid responsive mechanisms (T2-low disease). Composite biomarker strategies using easily measured surrogate indicators of type-2 inflammation (such as fractional exhaled nitric oxide, blood eosinophil count and serum periostin levels) may predict exacerbation risk better but it is unclear if they can be used to adjust corticosteroid treatment. Biomarkers will be used to target novel biologic treatments but additionally may be used to optimize corticosteroid treatment dose and act as prognostics for exacerbation risk and potentially other important longer term asthma outcomes.

Role of T2 inflammation biomarkers in severe asthma

PURPOSE OF REVIEW

Severe asthma is a heterogeneous syndrome. Classification of asthma into phenotypes and endotypes can improve understanding and treatment of the disease. Identification and utilization of biomarkers, particularly those linked to T2 inflammation, can help group patients into phenotypes, predict those who will respond to a specific therapy, and assess the response to treatment.

RECENT FINDINGS

Biomarkers are present in sputum, exhaled breath, and blood of patients with asthma. These include sputum eosinophils and neutrophils, fractional excretion of nitric oxide, blood eosinophilia, IgE, and periostin. Many of these biomarkers are associated with eosinophilic inflammation propagated mainly by T2 cytokines such as IL-5 and IL-13, which are released from Th2 cells and Type 2 innate lymphoid cells. Biomarkers have been utilized in recent trials of novel biologic agents targeted at T2 inflammation and may contribute to the defining population who would respond to these therapies.

SUMMARY

Despite advances in the identification and utilization of asthma biomarkers, further studies are needed to better clarify the role of biomarkers, individually or in combination, in the diagnosis and treatment of severe asthma. Future therapeutic trials should include the use of biomarkers in their design, which may lead to a more personalized approach to therapy and improved outcomes.

Asthma phenotypes and endotypes: a personalized approach to treatment

PURPOSE OF REVIEW

Asthma is quite common and is better described as a syndrome with a heterogeneous presentation than as a single disease. Although most individuals can be effectively managed using a guideline-directed approach to care, those with the most severe illness may benefit from a more targeted therapy. The review describes our current understanding of how asthma phenotypes (observable characteristics) and endotypes (specific biologic mechanisms) can be employed to gain insight into asthma pathobiology and personalized therapy.

RECENT FINDINGS

Our understanding of the heterogeneity of asthma is increasing. The concept of asthma phenotype has become more complex, incorporating both clinical and biologic features. Several asthma endotypes (e.g., allergic bronchopulmonary mycosis, aspirin-exacerbated respiratory disease, severe late-onset hypereosinophilic asthma, etc.) have been proposed, but further research is needed to delineate specific mechanisms underlying asthma pathogenesis. Several biologic therapies targeting certain phenotypes are in development and are expected to broaden our armamentarium for treatment of severe asthma.

SUMMARY

Asthma is a heterogeneous condition with diverse characteristics and biologic mechanisms. Severe asthma is associated with significant morbidity and even mortality and represents a major unmet need. Stratification of asthma subtypes into phenotypes and endotypes should move the field forward in terms of more effective and personalized treatment.

Targeting the JAK-STAT pathway in the treatment of 'Th2-high' severe asthma

Severe asthma is a heterogeneous disease characterized by reversible airway obstruction, chronic inflammation and airway remodeling. Phenotyping and/or endotyping can lead to a more personalized treatment strategy, improving the efficacy of novel drugs. Atopic asthma is associated with high levels of Th2 cells, implicated in a number of inflammatory responses. Differentiation of these cells from naive T cells occurs primarily via the JAK-STAT signaling pathway. Targeting this pathway through inhibition of activating cytokines (IL-4 and IL-13) and their receptors, the JAKs or the STATs, has been shown to have a therapeutic effect on asthma pathology. There are a number of novel drugs currently in development, which target various pathway components; these include both biologics and small molecules at various stages of development.