Assessing Inhaled Corticosteroid Adherence and Responsiveness in Severe Asthma Using Beclometasone Dipropionate/Formoterol NEXThaler Dose-Counting and Nitric Oxide Monitoring

BACKGROUND

Sixty-five percent of people with severe asthma and a fractional exhaled nitric oxide (Feno) greater than or equal to 45 parts per billion (ppb) are nonadherent to inhaled corticosteroids (ICSs). Digital devices recording both time of use and inhaler technique identify nonadherence and ICS responsiveness but are not widely available. As the NEXThaler dose counter activates only at an inspiratory flow rate of 35 L/min, this may provide an alternative to identifying ICS responsiveness.

OBJECTIVE

To assess ICS adherence and responsiveness in severe asthma using beclometasone/formoterol (200/6 μg) NEXThaler (BFN) dose-counting.

METHODS

Patients with severe asthma with a Feno greater than or equal to 45 ppb were invited to use BFN in place of their usual ICS/long-acting β2-agonist. Feno, 6-item Asthma Control Questionnaire score, lung function, and blood eosinophil count were monitored for 3 months. A log10ΔFeno of greater than or equal to 0.24 was used to define Feno suppression as the primary marker of ICS responsiveness at day 28.

RESULTS

Twenty-seven of 48 (56%) patients demonstrated significant Feno suppression at month 1 (median pre-114, post-48 ppb, P < .001). A small but significant reduction occurred in Feno nonsuppressors. The 6-item Asthma Control Questionnaire score fell a median 1.2 units in Feno suppressors (P < .001) and 0.5 units in nonsuppressors (P = .025). These effects were sustained until month 3 in Feno suppressors, with a significant improvement in FEV1 and blood eosinophils. Sixty-seven percent (18 of 27) of those with baseline ICS/long-acting β2-agonist prescription refills of 80% or more were Feno suppressors, suggesting prior nonadherence despite adequate prescription collection. Seventy-nine percent of Feno suppressors did not require biologics within mean 11.4 months from initial dose counting.

CONCLUSIONS

BFN dose-counting identifies ICS responsiveness in severe asthma with the implication that these patients may not need to progress to biological therapies.

Developing Fractional Exhaled Nitric Oxide Predicted and Upper Limit of Normal Values for a Disadvantaged Population

BACKGROUND

Fractional exhaled nitric oxide (Feno), used as a biomarker, is influenced by several factors including ethnicity. Normative data are essential for interpretation, and currently single cutoff values are used in children and adults.

RESEARCH QUESTION

Accounting for factors that influence Feno, (1) what are appropriate predicted and upper limit of normal (ULN) Feno values in an underserved population (First Nations Australians), (2) how do these values compare with age-based interpretive guidelines, and (3) what factors influence Feno and what is the size of the effect?

STUDY DESIGN AND METHODS

Feno data of First Nations Australians (age < 16 years, n = 862; age ≥ 16 years, n = 348) were obtained. Medical history using participant questionnaires and medical records were used to define healthy participants. Flexible regression using spline functions, as used by the Global Lung Function Initiative, were used to generate predicted and ULN values.

RESULTS

Look-up tables for predicted and ULN values using age (4-76 years) and height (100-200 cm) were generated and are supplied with a calculator for clinician use. In healthy First Nations children (age < 18 years), ULN values ranged between 25 and 60 parts per billion (ppb) when considering only biologically plausible age and height combinations. For healthy adults, ULN values ranged between 39 and 88 ppb. Neither the current Feno interpretation guidelines, nor the currently recommended cutoff of 50 ppb for First Nations children 16 years of age or younger were appropriate for use in this cohort. Our modelling revealed that predicted and ULN values of healthy participants varied nonlinearly with age and height.

INTERPRETATION

Because single pediatric, adult, or all-age Feno cutoff values used by current interpretive guidelines to define abnormality fail to account for factors that modify Feno values, we propose predicted and ULN values for First Nations Australians 4 to 76 years of age. Creating age- and height-adjusted predicted and ULN values could be considered for other ethnicities.

Type 2-high asthma is associated with a specific indoor mycobiome and microbiome

Background

The links between microbial environmental exposures and asthma are well documented, but no study has combined deep sequencing results from pulmonary and indoor microbiomes of patients with asthma with spirometry, clinical, and endotype parameters.

Objective

The goal of this study was to investigate the links between indoor microbial exposures and pulmonary microbial communities and to document the role of microbial exposures on inflammatory and clinical outcomes of patients with severe asthma (SA).

Methods

A total of 55 patients with SA from the national Cohort of Bronchial Obstruction and Asthma cohort were enrolled for analyzing their indoor microbial flora through the use of electrostatic dust collectors (EDCs). Among these patients, 22 were able to produce sputum during “stable” or pulmonary “exacerbation” periods and had complete pairs of EDC and sputum samples, both collected and analyzed. We used amplicon targeted metagenomics to compare microbial communities from EDC and sputum samples of patients according to type 2 (T2)-asthma endotypes.

Results

Compared with patients with T2-low SA, patients with T2-high SA exhibited an increase in bacterial α-diversity and a decrease in fungal α-diversity of their indoor microbial florae, the latter being significantly correlated with fraction of exhaled nitric oxide levels. The β-diversity of the EDC mycobiome clustered significantly according to T2 endotypes. Moreover, the proportion of fungal taxa in common between the sputum and EDC samples was significantly higher when patients exhibited acute exacerbation.

Conclusion

These results illustrated, for the first time, a potential association between the indoor mycobiome and clinical features of patients with SA, which should renew interest in deciphering the interactions between indoor environment, fungi, and host in asthma.

Cough and Eosinophilia

Eosinophilic airway inflammation is observed in 30% to 50% of chronic cough sufferers. It is a common feature of asthma and upper airway cough syndrome, and it is required in the diagnosis of nonasthmatic eosinophilic bronchitis. Our understanding of the mechanisms underlying allergic and nonallergic eosinophilic inflammation have evolved tremendously in the last 2 decades, but the cause of this inflammation in any individual is often uncertain. Inhaled corticosteroids are the mainstay therapy for cough due to asthma or nonasthmatic eosinophilic bronchitis, and response is related to the presence of biomarkers of eosinophilic airway inflammation. In upper airway cough syndrome, nasal topical corticosteroids are beneficial in allergic rhinitis and chronic rhinosinusitis with polyposis. This review will describe the diagnosis, current and possible future treatments, and prognosis of chronic cough in adults with eosinophilic inflammation.

Pragmatic Clinical Perspective on Biologics for Severe Refractory Type 2 Asthma

Patients with severe refractory asthma present a challenging clinical conundrum for practicing clinicians. Biologics that target key mediators in the type 2 inflammation cascade, including IL-4, IL-5, IL-13, and IgE, can be effective strategies for these patients. However, with various biologics available, choosing the optimal one for a particular patient becomes a nuanced decision. We propose a pragmatic algorithm that identifies the optimal biologic class for patients who have specific type 2 disease endotypes. Patients with eosinophilic endotypes fare well with anti-IL-5(rα) medications, comprising mepolizumab, benralizumab, and reslizumab because they have been shown to reduce exacerbations in severe eosinophilic asthma by approximately 50%. In patients with fractional exhaled nitric oxide-high endotypes, anti-IL-4rα such as dupilumab is deemed to be most effective and has demonstrated a 47% reduction in asthma exacerbations. For patients with severe uncontrolled allergic asthma, anti-IgE (omalizumab) is effective and has been shown to confer a 25% reduction in asthma exacerbations. Type 2 comorbidities including chronic rhinosinusitis with nasal polyps, atopic dermatitis, chronic idiopathic urticaria, and eosinophilic esophagitis are important to bear in mind before the prescription of biologics. Further head-to-head studies are indicated to compare biologics in patients with mixed endotypes according to peripheral blood eosinophils, fractional exhaled nitric oxide, and allergic status. The evidence strongly supports endotype-driven prescribing of biologics to achieve clinically relevant outcomes in severe refractory asthma and related comorbidities.

Elevated Testosterone Is Associated with Decreased Likelihood of Current Asthma Regardless of Sex

BACKGROUND

Asthma prevalence decreases postpuberty in males. Testosterone inhibits airway smooth muscle contraction and attenuates type 2 inflammation.

OBJECTIVE

To investigate the relationship between serum testosterone and current asthma prevalence and lung function in a nationally representative data set.

METHODS

Serum testosterone and self-reported physician-diagnosed current asthma data were obtained from 7584 participants aged 6 to 80 years from the cross-sectional 2011-2012 National Health and Nutrition Examination Survey. We used logistic regression to test associations between testosterone and current asthma, adjusting for demographic characteristics and stratifying by sex and age; linear regression to evaluate correlations between testosterone and lung function among patients with asthma; and interaction terms to test for effect modification by blood eosinophils and fractional exhaled nitric oxide.

RESULTS

Serum testosterone inversely associated with odds of current asthma in both men and women, but this association was nonlinear. Similar protective effect sizes were observed for both sexes after log₂-transformation of serum testosterone. For every 1-unit increase in log₂ testosterone, the odds of current asthma decreased by 11% in men and 10% in women, although the association was statistically significant in women only among those 12 years or older after multiple imputation. Serum testosterone did not associate with current asthma prevalence among those younger than 12 years. Testosterone associated with increases in FEV₁ in participants with asthma of both sexes. Neither blood eosinophils nor fractional exhaled nitric oxide modified the association between testosterone and current asthma.

CONCLUSIONS

Serum testosterone inversely associates with current asthma prevalence regardless of sex and correlates with better lung function in a nationally representative database. Androgen therapy for asthma should be further investigated.

Characterization of Severe Asthma Worldwide: Data From the International Severe Asthma Registry

BACKGROUND

Clinical characteristics of the international population with severe asthma are unknown. Intercountry comparisons are hindered by variable data collection within regional and national severe asthma registries. We aimed to describe demographic and clinical characteristics of patients treated in severe asthma services in the United States, Europe, and the Asia-Pacific region.

METHODS

The International Severe Asthma Registry retrospectively and prospectively collected data in patients with severe asthma (≥ 18 years old), receiving Global Initiative for Asthma (GINA) Step 5 treatment or with severe asthma remaining uncontrolled at GINA Step 4. Baseline demographic and clinical data were collected from the United States, United Kingdom, South Korea, Italy, and the Severe Asthma Web-based Database registry (including Australia, Singapore, and New Zealand) from December 2014 to December 2017.

RESULTS

We included 4,990 patients. Mean (SD) age was 55.0 (15.9) years, and mean (SD) age at asthma onset was 30.7 (17.7) years. Patients were predominantly female (59.3%) and white (72.6%), had never smoked (60.5%), and were overweight or obese (70.4%); 34.9% were at GINA Step 5; and 57.2% had poorly controlled disease. A total of 51.1% of patients were receiving regular intermittent oral corticosteroids, and 25.4% were receiving biologics (72.6% for those at GINA Step 5). Mean (SD) exacerbation rate was 1.7 (2.7) per year. Intercountry variation was observed in clinical characteristics, prescribed treatments, and biomarker profiles.

CONCLUSIONS

Using a common data set and definitions, this study describes severe asthma characteristics of a large patient cohort included in multiple severe asthma registries and identifies country differences. Whether these are related to underlying epidemiological factors, environmental factors, phenotypes, asthma management systems, treatment access, and/or cultural factors requires further study.

A single intervention for cockroach control reduces cockroach exposure and asthma morbidity in children

BACKGROUND

Exposure to cockroaches is an important asthma trigger, particularly for children with asthma living in inner cities. Integrated pest management is the recommended approach to cockroach abatement; however, it is costly and difficult to implement. The impact of reducing cockroach exposure on asthma outcomes is not known.

OBJECTIVE

We sought to test the use of a single intervention, insecticidal bait, to reduce cockroach exposure in the home of children with asthma in New Orleans and to examine the impact of cockroach reduction on asthma outcomes.

METHODS

One hundred two children aged 5 to 17 years with moderate to severe asthma were enrolled in a 12-month randomized controlled trial testing the use of insecticidal bait on cockroach counts and asthma morbidity. Homes were visited 6 times and asthma symptoms were assessed every 2 months.

RESULTS

After adjustment, intervention homes had significantly fewer cockroaches than did control homes (mean change in cockroaches trapped, 13.14; 95% CI, 6.88-19.39; P < .01). Children in control homes had more asthma symptoms and unscheduled health care utilization in the previous 2 weeks (1.82, 95% CI, 0.14-3.50, P = .03; 1.17, 95% CI, 0.11-2.24, P = .03, respectively) and a higher proportion of children with FEV₁ of less than 80% predicted (odds ratio, 5.74; 95% CI, 1.60-20.57; P = .01) compared with children living in intervention homes.

CONCLUSIONS

Previous research has demonstrated improvement in asthma health outcomes using multifaceted interventions. The strategic placement of insecticidal bait, which is inexpensive, has low toxicity, and is widely available, resulted in sustained cockroach elimination over 12 months and was associated with improved asthma outcomes. This single intervention may be an alternative to multifaceted interventions currently recommended to improve asthma morbidity.

Advances in adult asthma diagnosis and treatment in 2013

In 2013, several themes emerged: (1) a dedicated search for new therapies using new mechanisms; (2) the importance of the plasticity of the immune system (eg, that molecules that mediate inflammation in one setting can promote its resolution and return to homeostasis in other circumstances); (3) the complex role of viruses in asthma exacerbations; (4) the similarities and differences among asthma, asthma in smokers, and chronic obstructive pulmonary disease; and (5) the importance of understanding asthma phenotypes and their stability over time. Once new therapeutics pass the initial clinical trials, patient-oriented and real-world research will be needed.

Asthma across the ages: knowledge gaps in childhood asthma

The Eunice Kennedy Shriver National Institute of Child Health and Human Development convened an Asthma Group in response to the Best Pharmaceuticals for Children Act. The overall goal of the Best Pharmaceuticals for Children Act Program is to improve pediatric therapeutics through preclinical and clinical drug trials that lead to drug-labeling changes. Although significant advances have been made in the understanding and management of asthma in adults with appropriately labeled medications, less information is available on the management of asthma in children. Indeed, many medications are inadequately labeled for use in children. In general, the younger the child, the less information there is available to guide clinicians. Because asthma often begins in early childhood, it is incumbent on us to continue to address the primary questions raised in this review and carefully evaluate the medications used to manage asthma in children. Meanwhile, continued efforts should be made in defining effective strategies that reduce the risk of exacerbations. If the areas of defined need are addressed in the coming years, namely prevention of exacerbations and progression of disease, as well as primary intervention, we will see continuing reduction in asthma mortality and morbidity along with improved quality of life for children with asthma.

Advances in in vitro diagnostics in allergy, asthma, and immunology in 2012

Laboratory tests play an increasing role in risk assessment, diagnostics, and disease monitoring. Great advances have been achieved lately, particularly in the field of clinical immunology and allergy. These include neonatal screening of immunodeficiencies and asthma biomarkers and investigation into the role of recombinant allergens in in vitro testing. The latter area has implications for the diagnostics of food allergy, pollen-induced allergies, asthma, and insect allergies.

Mouse allergen is the major allergen of public health relevance in Baltimore City

BACKGROUND

Cockroach and mouse allergens have both been implicated as causes in inner-city asthma morbidity in multicenter studies, but whether both allergens are clinically relevant within specific inner-city communities is unclear.

OBJECTIVE

Our study aimed to identify relevant allergens in Baltimore City.

METHODS

One hundred forty-four children (5-17 years old) with asthma underwent skin prick tests at baseline and had clinical data collected at baseline and 3, 6, 9, and 12 months. Home settled dust samples were collected at the same time points for quantification of indoor allergens. Participants were grouped based on their sensitization and exposure status to each allergen. All analyses were adjusted for age, sex, and serum total IgE level.

RESULTS

Forty-one percent were mouse sensitized/exposed, and 41% were cockroach sensitized/exposed based on bedroom floor exposure data. Mouse sensitization/exposure was associated with acute care visits, decreased FEV1/forced vital capacity percentage values, fraction of exhaled nitric oxide levels, and bronchodilator reversibility. Cockroach sensitization/exposure was only associated with acute care visits and bronchodilator reversibility when exposure was defined by using bedroom floor allergen levels. Mouse-specific IgE levels were associated with poor asthma health across a range of outcomes, whereas cockroach-specific IgE levels were not. The relationships between asthma outcomes and mouse allergen were independent of cockroach allergen. Although sensitization/exposure to both mouse and cockroach was generally associated with worse asthma, mouse sensitization/exposure was the primary contributor to these relationships.

CONCLUSIONS

In a community with high levels of both mouse and cockroach allergens, mouse allergen appears to be more strongly and consistently associated with poor asthma outcomes than cockroach allergen. Community-level asthma interventions in Baltimore should prioritize reducing mouse allergen exposure.

Predictors of asthma control and lung function responsiveness to step 3 therapy in children with uncontrolled asthma

BACKGROUND

Predictors of improvement in asthma control and lung function to step 3 therapy in children with persistent asthma have not been identified despite reported heterogeneity in responsiveness.

OBJECTIVE

We sought to evaluate potential predictors of asthma control and lung function responsiveness to step 3 therapy.

METHODS

A post hoc analysis from the Best Add-On Giving Effective Response (BADGER) study tested the association between baseline biological, asthma control, pulmonary function, and demographic markers and responsiveness to step-up to a higher dose of inhaled corticosteroid (ICS step-up therapy) or addition of leukotriene receptor antagonist (LTRA step-up therapy) or long-acting β₂-agonist (LABA step-up therapy).

RESULTS

In multivariate analyses higher impulse oscillometry reactance area was associated (P = .048) with a differential FEV₁ response favoring LABA over ICS step-up therapy, whereas higher urinary leukotriene E₄ levels were marginally (P = .053) related to a differential FEV₁ response favoring LTRA over LABA step-up therapy. Predictors of differential responses comparing ICS with LTRA step-up therapy were not apparent, probably because of suppression of allergic markers with low-dose ICS treatment. Minimal overlap was seen across FEV₁ and asthma control day predictors, suggesting distinct mechanisms related to lung function and asthma control day responses.

CONCLUSION

Levels of impulse oscillometry reactance area indicating peripheral airway obstruction and urinary leukotriene E₄ levels indicating cysteinyl leukotriene inflammation can differentiate LABA step-up responses from responses to LTRA or ICS step-up therapy. Further studies with physiologic, genetic, and biological markers related to these phenotypes will be needed to predict individual responses to LABA step-up therapy.

Measures of gene expression in sputum cells can identify TH2-high and TH2-low subtypes of asthma

BACKGROUND

The 3-gene signature of periostin, chloride channel accessory 1 (CLCA1), and Serpin β2 (SERPINB2) in airway epithelial brushings is used to classify asthma into TH2-high and TH2-low endotypes. Little is known about the utility of gene profiling in sputum as a molecular phenotyping method.

OBJECTIVE

We sought to determine whether gene profiling in sputum cells can identify T(H)2-high and T(H)2-low subtypes of asthma.

METHODS

In induced sputum cell pellets from 37 asthmatic patients and 15 healthy control subjects, PCR was used to profile gene expression of the epithelial cell signature of IL-13 activation (periostin, CLCA1, and SERPINB2), TH2 genes (IL4, IL5, and IL13), and other genes associated with airway TH2 inflammation.

RESULTS

Gene expression levels of CLCA1 and periostin, but not SerpinB2, were significantly higher than normal in sputum cells from asthmatic subjects. Expression levels of IL-4, IL-5, and IL-13 were also significantly increased in asthmatic patients and highly correlated within individual subjects. By combining the expression levels of IL-4, IL-5, and IL-13 in a single quantitative metric ("T(H)2 gene mean"), 26 (70%) of the 37 asthmatic patients had T(H)2-high asthma, which was characterized by more severe measures of asthma and increased blood and sputum eosinophilia. TH2 gene mean values tended to be stable when initial values were very high or very low but fluctuated above or below the T(H)2-high cutoff when initial values were intermediate.

CONCLUSION

IL-4, IL-5, and IL-13 transcripts are easily detected in sputum cells from asthmatic patients, and their expression levels can be used to classify asthma into T(H)2-high and T(H)2-low endotypes.

Exhaled nitric oxide levels and blood eosinophil counts independently associate with wheeze and asthma events in National Health and Nutrition Examination Survey subjects

BACKGROUND

Fraction of exhaled nitric oxide (Feno) and blood eosinophil count (B-Eos) values, markers of local and systemic eosinophilic inflammation, respectively, are increased in asthmatic patients. Little is known about the relation of these markers to reported wheeze and asthma events in a random population sample.

OBJECTIVES

We sought to determine the individual and independent values of B-Eos and Feno in relation to wheeze, asthma diagnosis, and asthma events in a cross-sectional study.

METHODS

Feno and B-Eos values were measured in 12,408 subjects aged 6 to 80 years from the National Health and Nutrition Examination Survey 2007-2008 and 2009-2010. Current wheeze and asthma diagnosis, as well as asthma attacks and asthma-related emergency department (ED) visits within the last 12 months, were assessed by means of questionnaires.

RESULTS

Intermediate or high Feno values and intermediate or high B-Eos values were independently associated with having asthma, wheeze, and asthma attacks. However, only intermediate and high B-Eos values were independently associated with asthma-related ED visits. High Feno (≥ 50 ppb) and B-Eos (≥ 500 cells/mm(3)) values rendered an adjusted odds ratio of 4.5 of having wheeze, 5.1 of having asthma, 5.4 for asthma attacks, and 2.9 for asthma-related ED visits compared with normal Feno (<25 ppb) and B-Eos (<300 cells/mm(3)) values.

CONCLUSIONS

Exhaled nitric oxide and B-Eos values offered independent information in relation to the prevalence of wheeze, asthma diagnosis, and asthma events in this random population sample. The clinical importance of these findings in asthmatic patients with regard to phenotyping and individualized treatment, considering both local and systemic eosinophilic inflammation, needs to be determined.

Severe adult-onset asthma: A distinct phenotype

BACKGROUND

Some patients with adult-onset asthma have severe disease, whereas others have mild transient disease. It is currently unknown whether patients with severe adult-onset asthma represent a distinct clinical phenotype.

OBJECTIVE

We sought to investigate whether disease severity in patients with adult-onset asthma is associated with specific phenotypic characteristics.

METHODS

One hundred seventy-six patients with adult-onset asthma were recruited from 1 academic and 3 nonacademic outpatient clinics. Severe refractory asthma was defined according to international Innovative Medicines Initiative criteria, and mild-to-moderate persistent asthma was defined according to Global Initiative for Asthma criteria. Patients were characterized with respect to clinical, functional, and inflammatory parameters. Unpaired t tests and χ(2) tests were used for group comparisons; both univariate and multivariate logistic regression were used to determine factors associated with disease severity.

RESULTS

Apart from the expected high symptom scores, poor quality of life, need for high-intensity treatment, low lung function, and high exacerbation rate, patients with severe adult-onset asthma were more often nonatopic (52% vs 34%, P = .02) and had more nasal symptoms and nasal polyposis (54% vs 27%, P ≤ .001), higher exhaled nitric oxide levels (38 vs 27 ppb, P = .02) and blood neutrophil counts (5.3 vs 4.0 10(9)/L, P ≤ .001) and sputum eosinophilia (11.8% vs 0.8%, P ≤ .001). Multiple logistic regression analysis showed that increased blood neutrophil (odds ratio, 10.9; P = .002) and sputum eosinophil (odds ratio, 1.5; P = .005) counts were independently associated with severe adult-onset disease.

CONCLUSION

The majority of patients with severe adult-onset asthma are nonatopic and have persistent eosinophilic airway inflammation. This suggests that severe adult-onset asthma has a distinct underlying mechanism compared with milder disease.

Dose-ranging study of lebrikizumab in asthmatic patients not receiving inhaled steroids

BACKGROUND

Asthma is a disease with marked heterogeneity in its clinical course and response to treatment. IL-13 is central to type 2 inflammation, which contributes to many key features of asthma. Lebrikizumab is an anti-IL-13 mAb previously reported to significantly improve lung function in patients with inadequately controlled asthma despite inhaled corticosteroid therapy, especially in periostin-high patients.

OBJECTIVE

This phase II study investigated the efficacy and safety of IL-13 blockade with different doses of lebrikizumab in asthmatic patients not receiving inhaled corticosteroids.

METHODS

Patients were randomized to receive 125, 250, or 500 mg of lebrikizumab or placebo subcutaneously monthly for 12 weeks with an 8-week follow-up period. The primary efficacy end point was the relative change in prebronchodilator FEV1 from baseline to week 12.

RESULTS

A total of 212 patients were randomized. The mean relative change in FEV1 was numerically higher in all lebrikizumab dose groups versus the placebo group, although the difference was neither statistically nor clinically significant. There were no meaningful differences in changes in FEV1 between the dose groups and the placebo group by the periostin subgroup. Lebrikizumab treatment was associated with a reduced risk of treatment failure at all doses versus placebo (P < .001), and results were similar by the periostin subgroup, with no apparent differences between doses of lebrikizumab. Lebrikizumab was generally well tolerated.

CONCLUSION

Blocking IL-13, a single cytokine, in this population of asthmatic patients is insufficient to improve lung function. There is evidence that IL-13 blockade may improve disease control, as measured by prevention of protocol-defined treatment failure in these patients.

The chitinase-like protein YKL-40: a possible biomarker of inflammation and airway remodeling in severe pediatric asthma

BACKGROUND

Problematic severe childhood asthma includes a subgroup of patients who are resistant to therapy. The specific mechanisms involved are unknown, and novel biomarkers are required to facilitate treatment and diagnosis of therapy-resistant asthma. The chitinase-like protein YKL-40 has been related to asthma and airway remodeling.

OBJECTIVES

To compare serum YKL-40 levels in children with severe, therapy-resistant asthma (n = 34), children with controlled persistent asthma (n = 39), and healthy controls (n = 27), and to investigate correlations with biomarkers of inflammation and airway remodeling.

METHODS

The study protocol included questionnaires, measurement of exhaled nitric oxide in exhaled air, blood sampling for inflammatory biomarkers, and high-resolution computed tomography of the lungs to identify bronchial wall thickening (therapy-resistant only). Serum YKL-40 levels were measured by ELISA, and all asthmatic children were genotyped for a CHI3L1 promoter single nucleotide polymorphism (rs4950928).

RESULTS

Serum YKL-40 levels were significantly higher in children with therapy-resistant asthma than in healthy children (19.2 ng/mL vs 13.8 ng/mL, P = .03). Among children with severe, therapy-resistant asthma, YKL-40 levels correlated with fraction of exhaled nitric oxide in exhaled air (r = 0.48, P = .004), blood neutrophils (r = 0.63, P < .001), and bronchial wall thickening on high-resolution computed tomography (r = 0.45, P = .01). Following adjustment for CHI3L1 genotype, significantly greater levels of YKL-40 were found in children with therapy-resistant asthma than in children with controlled asthma.

CONCLUSIONS

YKL-40 levels are increased in children with severe, therapy-resistant asthma compared to healthy children, and also compared to children with controlled asthma following correction for genotype.

Exhaled breath condensate eicosanoid levels associate with asthma and its severity

BACKGROUND

The relationship between anti-inflammatory lipoxins and proinflammatory leukotrienes might be important in the pathobiology and severity of asthma.

OBJECTIVE

We sought to investigate whether exhaled breath condensate (EBC) lipoxin and leukotriene measurements can noninvasively characterize the asthmatic diathesis and its severity.

METHODS

We measured lipoxin A4 (LXA4) and leukotriene B4 (LTB4) levels in EBC collected from patients with asthma of different severities and from healthy control subjects.

RESULTS

EBC LXA4 and LTB4 levels are increased in asthmatic patients compared with those seen in healthy control subjects (LXA4: 31.40 vs 2.41 pg/mL EBC, respectively [P < .001]; LTB4: 45.62 vs 3.82 pg/mL EBC, respectively [P < .001]). Although levels of both eicosanoids are increased in asthmatic patients, the LXA4/LTB4 ratio decreases with increasing asthma severity. It is 41% lower in patients with severe versus moderate asthma (0.52 vs 0.88, P = .034). EBC LXA4 levels correlate with the degree of airflow obstruction measured by using FEV1 (r = 0.28, P = .018). An LXA4 cutoff value of 7 pg/mL EBC provides 90% sensitivity and 92% specificity for the diagnosis of asthma (area under the curve, 0.96; P < .001). An LTB4 cutoff value of 11 pg/mL EBC provides 100% sensitivity and 100% specificity for the diagnosis of asthma (area under the curve, 1; P < .001).

CONCLUSIONS

Proresolving and proinflammatory eicosanoids are generated in the airways of all asthmatic patients. The proportion of proresolving compounds decreases with asthma severity. These findings support the role for EBC eicosanoid measurements in the noninvasive diagnosis of asthma and suggest that proresolving eicosanoid pathways are dysregulated in patients with severe asthma.