Simultaneously elevated exhaled nitric oxide and serum-eosinophil cationic protein relate to recent asthma events in asthmatics in a cross-sectional population-based study

Respiratory symptoms, exacerbations and sleep disturbances are more common among participants with asthma and chronic airflow limitation: an epidemiological study in Estonia, Iceland and Sweden

BACKGROUND

Chronic airflow limitation (CAL) is a hallmark of chronic obstructive pulmonary disease but is also present in some patients with asthma. We investigated respiratory symptoms, sleep and health status of participants with and without CAL with particular emphasis on concurrent asthma using data from adult populations in Iceland, Estonia and Sweden investigated within the Burden of Obstructive Lung Disease study.

METHODS

All participants underwent spirometry with measurements of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) before and after bronchodilation. CAL was defined as postbronchodilator FEV1/FVC below the lower limit of normal. IgE-sensitisation and serum concentrations of eosinophil-derived neurotoxin (S-EDN) were assessed in a subsample. The participants were divided into four groups: no self-reported doctor's diagnosed asthma or CAL, asthma without CAL, CAL without asthma and asthma and CAL: χ2 test and analysis of variance were used in bivariable analyses and logistic and linear regression when analysing the independent association between respiratory symptoms, exacerbations, sleep-related symptoms and health status towards CAL, adjusting for centre, age, sex, body mass index, smoking history and educational level.

RESULTS

Among the 1918 participants, 190 (9.9%) had asthma without CAL, 127 (6.6%) had CAL without asthma and 50 (2.6%) had CAL with asthma. Having asthma with CAL was associated with symptoms such as wheeze (adjusted OR (aOR) 6.53 (95% CI 3.53 to 12.1), exacerbations (aOR 12.8 (95% CI 6.97 to 23.6), difficulties initiating sleep (aOR 2.82 (95% CI 1.45 to 5.48), nocturnal gastro-oesophageal reflux (aOR 3.98 (95% CI 1.79 to 8.82)) as well as lower physical health status. In these analyses, those with no asthma and no CAL were the reference group. The prevalence of IgE-sensitisation was highest in both asthma groups, which also had higher levels of S-EDN.

CONCLUSION

Individuals with self-reported asthma with CAL suffer from a higher burden of respiratory and sleep-related symptoms, higher exacerbation rates and lower health status when compared with participants with asthma alone or CAL alone.

Exacerbation Profile and Risk Factors in a Type-2-Low Enriched Severe Asthma Cohort: A Clinical Trial to Assess Asthma Exacerbation Phenotypes

Rationale: The past 25 years have seen huge progress in understanding of the pathobiology of type-2 (T2) asthma, identification of measurable biomarkers, and the emergence of novel monoclonal antibody treatments. Although present in a minority of patients with severe asthma, very little is known about the mechanisms underlying T2-low asthma, making it a significant unmet need in asthma research. Objectives: The objective of this study was to explore the differences between study exacerbators and nonexacerbators, to describe physiological changes at exacerbation in those who are T2^HIGH and T2^LOW at the time of exacerbation, and to evaluate the stability of inflammatory phenotypes when stable and at exacerbation. Methods: Exacerbation assessment was a prespecified secondary analysis of data from a 48-week, multicenter, randomized controlled clinical study comparing the use of biomarkers and symptoms to adjust steroid treatment in a T2-low severe asthma-enriched cohort. Participants were phenotyped as T2^LOW (fractional exhaled nitric oxide ⩽ 20 ppb and blood eosinophil count ⩽ 150 cells/µl) or T2^HIGH (fractional exhaled nitric oxide > 20 or blood eosinophil count > 150) at study enrollment and at each exacerbation. Here, we report the findings of the exacerbation analyses, including comparison of exacerbators and nonexacerbators, the physiological changes at exacerbation in those who had evidence of T2 biology at exacerbation versus those that did not, and the stability of inflammatory phenotypes when stable and at exacerbation. Measurements and Main Results: Of the 301 participants, 60.8% (183) had one or more self-reported exacerbations (total of 390). Exacerbators were more likely to be female, have a higher body mass index, and have more exacerbations requiring oral corticosteroid and unscheduled primary care attendances for exacerbations. At enrollment, 23.6% (71) were T2^LOW and 76.4% (230) T2^HIGH. The T2^LOW group had more asthma primary care attendances, were more likely to have a previous admission to HDU (high dependency unit)/ICU and to be receiving maintenance oral corticosteroids. At exacerbation, the T2^LOW events were indistinguishable from T2^HIGH exacerbations in terms of lung function (mean fall in T2^LOW FEV_1, 200 [400] ml vs. T2^HIGH 200 [300] ml; P = 0.93) and symptom increase (ACQ5: T2^LOW, 1.4 [0.8] vs. T2^HIGH, 1.3 [0.8]; P = 0.72), with no increase in T2 biomarkers from stable to exacerbation state in the T2^LOW exacerbations. The inflammatory phenotype within individual patients was dynamic; inflammatory phenotype at study entry did not have a significant association with exacerbation phenotype. Conclusions: Asthma exacerbations demonstrating a T2^LOW phenotype were physiologically and symptomatically similar to T2^HIGH exacerbations. T2^LOW asthma was an unstable phenotype, suggesting that exacerbation phenotyping should occur at the time of exacerbation. The clinically significant exacerbations in participants without evidence of T2 biology at the time of exacerbation highlight the unmet and pressing need to further understand the mechanisms at play in non-T2 asthma. Clinical trial registered with www.clinicaltrials.gov (NCT02717689).

Expert Opinion on Practice Patterns in Mild Asthma After the GINA 2019 Updates: A Major Shift in Treatment Paradigms from a Long-Standing SABA-Only Approach to a Risk Reduction-Based Strategy with the Use of Symptom-Driven (As-Needed) Low-Dose ICS/LABA

PURPOSE OF REVIEW

This expert opinion, prepared by a panel of chest disease specialists, aims to review the current knowledge on practice patterns in real-life management of mild asthma and to address the relevant updates in asthma treatment by The Global Initiative for Asthma (GINA) to guide clinicians for the best clinical practice in applying these new treatment paradigms.

RECENT FINDINGS

On the basis of the emerging body of evidence suggesting the non-safety of short-acting β2-agonists (SABA)-only therapy and comparable efficacy of the as-needed inhaled corticosteroids (ICS)-formoterol combinations with maintenance ICS regimens, GINA recently released their updated Global Strategy for Asthma Management and Prevention Guide (2019). The new GINA 2019 recommendations no longer support the SABA-only therapy in mild asthma but instead includes new off-label recommendations such as symptom-driven (as-needed) low-dose ICS-formoterol and "low dose ICS taken whenever SABA is taken." The GINA 2019 asthma treatment recommendations include a major shift from long-standing approach of clinical practice regarding the use of symptom-driven SABA treatment alone in the management of mild asthma. This expert opinion supports the transition from a long-standing SABA-only approach to a risk reduction-based strategy, with the use of symptom-driven (as-needed) low-dose ICS/LABA in mild asthma patients, particularly in those with poor adherence to controller medications. The thoughtful and comprehensive approach of clinicians to these strategies is important, given that the exact far-reaching impact of this major change in management of mild asthma in the real-world settings will only be clarified over time.

Identification of novel genes influencing eosinophil-specific protein levels in asthma families

BACKGROUND

Eosinophils play a key role in the asthma allergic response by releasing cytotoxic molecules such as eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN) that generate epithelium damages.

OBJECTIVE

To identify genetic variants influencing ECP and EDN levels in asthma-ascertained families.

METHODS

We performed univariate and bivariate genome-wide association analyses of ECP and EDN levels in 1,018 subjects from EGEA study with follow-up in 153 subjects from SLSJ study and combined the results of these two studies through meta-analysis. We then conducted Bayesian statistical fine-mapping together with quantitative trait locus and functional annotation analyses to identify the most likely functional genetic variants and candidate genes.

RESULTS

We identified five genome-wide significant loci (P<5x10^-8) including seven distinct signals associated with ECP and/or EDN levels. The genes targeted by our fine-mapping and functional search include RNASE2 and RNASE3 (14q11) which encode EDN and ECP respectively and four other genes which regulate ECP/EDN levels. These four genes were the following: JAK1 (1p31) a transcription factor with a key role in the immune response and a potential therapeutic target for eosinophilic asthma, ARHGAP25 (2p13) involved in leukocyte recruitment to inflammatory sites, NDUFA4 (7p21) encoding a component of the mitochondrial respiratory chain and involved in cellular response to stress and CTSL (9q22) involved in immune response, extra-cellular remodeling and allergic inflammation.

CONCLUSION

This study demonstrates that the analysis of specific phenotypes produced by eosinophils allows identifying genes with a major role in allergic response and inflammation and offering potential therapeutic targets for asthma.

Dynamic Urinary Proteome Changes in Ovalbumin-Induced Asthma Mouse Model Using Data-Independent Acquisition Proteomics

Background

In this work, we aim to investigate dynamic urinary proteome changes during asthma development and to identify potential urinary protein biomarkers for the diagnosis of asthma.

Methods

An ovalbumin (OVA)-induced mouse model was used to mimic asthma. The urinary proteome from asthma and control mice was determined using data-independent acquisition combined with high-resolution tandem mass spectrometry.

Results

Overall, 331 proteins were identified, among which 53 were differentially expressed (26, 24, 14 and 20 on days 2, 8, 15 and 18, respectively; 1.5-fold change, adjust P<0.05). Gene Ontology annotation of the differential proteins showed that the acute-phase response, innate immune response, B cell receptor signaling pathway, and complement activation were significantly enriched. Protein–protein interaction network revealed that these differential proteins were partially biologically connected in OVA-induced asthma, as a group. On days 2 and 8, after two episodes of OVA sensitization, six differential proteins (CRAMP, ECP, HP, F2, AGP1, and CFB) were also reported to be closely associated with asthma. These proteins may hold the potential for the early screening of asthma. On days 15 and 18, after challenged with 1% OVA by inhalation, seven differential proteins (VDBP, HP, CTSE, PIGR, AAT, TRFE, and HPX) were also reported to be closely associated with asthma. Thus, these proteins hold the potential to be biomarkers for the diagnosis of asthma attack.

Conclusion

Our results indicate that the urinary proteome could reflect dynamic pathophysiological changes in asthma progression.

Performance of Eosinophil Cationic Protein as a Biomarker in Asthmatic Children

BACKGROUND

Although blood eosinophils are a frequently used marker of type 2 inflammation in children with asthma, their sensitivity is relatively poor. Additional markers of type 2 inflammation are needed.

OBJECTIVE

We hypothesized that plasma concentrations of eosinophil cationic protein (ECP), a marker of eosinophil activation, would be useful for detection of type 2 inflammation and would predict poorer asthma outcomes over 1 year.

METHODS

Children and adolescents 6 through 17 years (N = 256) with confirmed asthma completed a baseline visit and a follow-up visit at 12 months. A subset also underwent systemic corticosteroid responsiveness testing with intramuscular triamcinolone. Outcome measures at 12 months included uncontrolled asthma, lung function, and asthma exacerbations treated with systemic corticosteroids.

RESULTS

Plasma ECP concentrations ranged from 0.03 to 413.61 ng/mL (median, 6.95 ng/mL) and were consistently associated with other markers of type 2 inflammation. At baseline, children in the highest ECP tertile had poorer asthma control, more airflow limitation, and more exacerbations, but also had greater symptom improvement with intramuscular triamcinolone. At 12 months, associations between the highest ECP tertile and exacerbations, but not lung function or asthma control, persisted after covariate adjustment. However, the sensitivity of ECP was modest and was not markedly different from that of blood eosinophil counts.

CONCLUSION

Plasma ECP concentrations may be a useful marker of type 2 inflammation in children and may help identify those children at highest risk for recurrent exacerbations who could benefit from corticosteroid treatment. However, additional markers may be needed to improve sensitivity for outcome detection.

Concurrence of elevated FeNO and airway hyperresponsiveness in nonasthmatic adolescents

OBJECTIVES

The aim of this study was to investigate airway responsiveness and eosinophil and neutrophil inflammatory markers in clinically confirmed nonasthmatic adolescents with elevated fractional exhaled nitric oxide (FeNO), a marker of type-2 inflammation in the airways.

METHODOLOGY

A total of 959 subjects from a general population, aged 12 to 15 years, answered a standardised questionnaire and underwent FeNO measurements at a screening visit at school. Adolescents without asthma, who had elevated FeNO (FeNO₁₀₀  > 15 ppb) (n = 19), and control subjects, with low FeNO (FeNO₁₀₀  < 5 ppb) and without reported symptoms of asthma or allergy (n = 28), participated in a follow-up study where FeNO₅₀ , airway responsiveness to methacholine (PD₂₀ ), blood eosinophil counts, and serum neutrophil lipocalin (HNL) and myeloperoxidase (MPO) levels were measured. Questionnaire follow-ups were performed 4 and 16 years later.

RESULTS

Airway responsiveness (PD₂₀ : 6.94 [1.87, 11.39] vs 11.42 [6.33, 59.4] µmol; P < .05) and blood eosinophil counts (0.31 [0.20, 0.44] vs 0.13 [0.1, 0.22] 10⁹ /L; P < .001) (geometric mean [95% CI]) were higher among cases than controls. A significant correlation between blood eosinophils and FeNO was found (rho = 0.41; P = .005). In contrast, serum HNL and MPO were lower in cases than controls (P < .05 both), and there was a negative correlation between HNL and FeNO (r = -0.31; P = .04). At both follow-ups, a higher proportion of subjects reported allergic symptoms compared with baseline (P = .02, P = .01).

CONCLUSIONS

Elevated FeNO in nonasthmatic adolescents was associated with airway hyperresponsiveness, elevated blood eosinophil counts, and lower systemic activation of neutrophils.

Different endotypes and phenotypes drive the heterogeneity in severe asthma

The identification of sputum eosinophilia indicating corticosteroid responsiveness in subjects with severe asthma heralded the beginning of phenotyping asthmatic subjects based on airways inflammation. Since then, the heterogeneity of severe asthma has been explored and the importance of immunobiology has come sharply into focus with the identification of the key type-2 cytokine pathways driving eosinophilic inflammation. The development of molecules targeting these type-2 pathways has transformed severe asthma treatment, but necessitates robust clinical evaluation, biomarker profiling and assessment of comorbid factors to identify subjects most likely to benefit from these therapies. It has also become clear that targeting these pathways does not eradicate asthma symptoms and exacerbation risk; further work is needed to clarify underlying non-type-2 mechanisms in severe asthma pathways and possible therapeutic targets. This review addresses progress to date in clinical assessment and management of severe asthma and some of the challenges and unmet needs in severe asthma to achieve the goal of delivering individualized patient care.

Immunological biomarkers in severe asthma

Severe asthma is heterogeneous in its clinical presentation, underlying pathophysiology, course and response to therapy. Clinical and physiological assessment of severe asthma is often inadequate in predicting underlying disease mechanisms and or response to medications. With the emergence of novel targeted therapies in severe asthma, the need for reproducible, easily measured biomarkers became obvious but only few are currently available for clinical use. These biomarkers along with the clinical presentation of the patient play an important role in identifying phenotypes and endotypes, predicting the clinical course and prognosis and improving the precision therapeutic approach to asthma.

Biomarkers and asthma management: analysis and potential applications

PURPOSE OF REVIEW

Asthma features a high degree of heterogeneity in both pathophysiology and therapeutic response, resulting in many asthma patients being treated inadequately. Biomarkers indicative of underlying pathological processes could be used to identify disease subtypes, determine prognosis and to predict or monitor treatment response. However, the newly identified as well as more established biomarkers have different applications and limitations.

RECENT FINDINGS

Conventional markers for type 2-high asthma, such as blood eosinophils, fraction of exhaled nitric oxide, serum IgE and periostin, feature limited sensitivity and specificity despite their significant correlations. More distinctive models have been developed by combining biomarkers and/or using omics techniques. Recently, a model with a positive predictive value of 100% for identification of type 2-high asthma based on a combination of minimally invasive biomarkers was developed.

SUMMARY

Individualisation of asthma treatment regimens on the basis of biomarkers is necessary to improve asthma control. However, the suboptimal properties of currently available conventional biomarkers limit its clinical utility. Newly identified biomarkers and models based on combinations and/or omics analysis must be validated and standardised before they can be routinely applied in clinical practice. The development of robust biomarkers will allow development of more efficacious precision medicine-based treatment approaches for asthma.

[Correlation between expressions of myeloperoxidase and eosinophil cationic protein in sputum and clinical features of asthma-chronic obstructive pulmonary disease overlap]

OBJECTIVE

To observe the role of myeloperoxidase(MPO)and eosinophilic cationic protein(ECP)in the airway inflammation and their correlation with clinical feature in asthma-COPD overlap (ACO) patients.

METHODS

Twenty patients with COPD, 20 with asthma, 20 with ACO and 20 control subjects underwent pulmonary function test for measurement of forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), peak expiratory flow (PEF), and maximum midexpiratory flow (MMF_25/75). COPD assessment test (CAT) was used to evaluate the clinical symptoms of the patients with COPD and ACO. The asthma control test (ACT) was used to evaluate the asthma control in the patients with asthma and ACO. Induced sputum samples were collected from the subjects for analysis of neutrophil and eosinophil ratios, and enzyme-linked immunosorbent assay was used to determine the expression levels of MPO and ECP in the sputum.

RESULTS

No significant difference was observed in the CAT scores between ACO group and COPD group (P&gt; 0.05). Compared with the asthma group, the patients with ACO had significantly lower ACT scores and lower FEV₁, PEF and MMF_25/75 (P &lt; 0.05). The patients with ACO had significantly higher FVC and sputum eosinophil ratio than those with COPD (P &lt; 0.05), and a higher sputum neutrophil ratio than those with asthma (P &lt; 0.01). In ACO group, the MPO level in sputum was significantly higher than that in the asthma group (P &lt; 0.05), while sputum ECP level was significantly higher than that in both the asthma group and COPD group (P &lt; 0.05 or 0.01). In ACO group, sputum MPO level was positively correlated with sputum neutrophil ratio (r=0.8358, P &lt; 0.01) but was not correlated with CAT score or FEV₁ (P&gt; 0.05); sputum ECP level was positively correlated with sputum eosinophil ratio (r=0.4666, P &lt; 0.05) and was inversely correlated with ACT score (r=-0.4966, P &lt; 0.05) and FEV₁ (r=-0.4610, P &lt; 0.05).

CONCLUSIONS

Both neutrophilic and eosinophilic inflammations occur in the airway of patients with ACO, and their sputum ECP level is negatively correlated with asthma control and obstructive airflow limitation.

Severe Asthma-Perspectives From Adult and Pediatric Pulmonology

Both adults and children with severe asthma represent a small proportion of the asthma population; however, they consume disproportionate resources. For both groups it is important to confirm the diagnosis of severe asthma and ensure that modifiable factors such as adherence have, as far as possible, been addressed. Most children can be controlled on inhaled corticosteroids and long term oral corticosteroid use is rare, in contrast to adults where steroid related morbidity accounts for a large proportion of the costs of severe asthma. Atopic sensitization is very common in children with severe asthma as are other atopic conditions such as allergic rhinitis and hay fever which can impact on asthma control. In adults, the role of allergic driven disease, even in those with co-existent evidence of sensitization, is unclear. There is currently an exciting pipeline of novel biologicals, particularly directed at Type 2 inflammation, which afford the possibility of improved asthma control and reduced treatment side effects for people with asthma. However, not all drugs will work for all patients and accurate phenotyping is essential. In adults the terms T2 high and T2 low asthma have been coined to describe groups of patients based on the presence/absence of eosinophilic inflammation and T-helper 2 (TH₂) cytokines. Bronchoscopic studies in children with severe asthma have demonstrated that these children are predominantly eosinophilic but the cytokine patterns do not fit the T2 high paradigm suggesting other steroid resistant pathways are driving the eosinophilic inflammation. It remains to be seen whether treatments developed for adult severe asthma will be effective in children and which biomarkers will predict response.

Fixed airflow obstruction relates to eosinophil activation in asthmatics

BACKGROUND

Some asthmatics develop irreversible chronic airflow obstruction, for example, fixed airflow obstruction (fixed-AO). This is probably a consequence of airway remodelling, but neither its relation to inflammation nor which asthma biomarkers can be clinically useful are elucidated. We hypothesized that the presence of type 2 inflammation relates to fixed-AO.

OBJECTIVES

To evaluate the presence of four markers for type 2 inflammation in fixed airflow obstruction among asthmatics.

METHODS

This was a cross-sectional study of 403 participants with asthma, aged 17-75 years, from three Swedish centres. Fixed airflow obstruction was defined as forced expiratory volume during the first second (FEV₁ ) over forced vital capacity (FVC) being below the lower limit of normal (LLN). The following type 2 inflammation markers were assessed: exhaled nitric oxide (FeNO), serum periostin, serum eosinophil cationic protein (S-ECP), and urinary eosinophil-derived neurotoxin (U-EDN).

RESULTS

Elevated U-EDN (values in the highest tertile, ≥65.95 mg/mol creatinine) was more common in subjects with fixed-AO vs. subjects without fixed-AO: 55% vs. 29%, P < 0.001. Elevated U-EDN related to increased likelihood of having fixed-AO in both all subjects and never-smoking subjects, with adjusted (adjusted for sex, age group, use of inhaled corticosteroids last week, atopy, early-onset asthma, smoking history, and packyears) odds ratios (aOR) of 2.38 (1.28-4.41) and 2.51 (1.04-6.07), respectively. In a separate analysis, having both elevated S-ECP (>20 μg/L) and U-EDN was related to having the highest likelihood of fixed-AO (aOR (95% CI) 6.06 (2.32-15.75)). Elevated serum periostin or FeNO did not relate to fixed-AO.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings support that type 2 inflammation, and in particular eosinophil inflammation, is found in asthma with fixed-AO. This could indicate a benefit from eosinophil-directed therapies. Further longitudinal studies are warranted to investigate causality and relation to lung function decline.

Implication of fraction of exhaled nitric oxide and blood eosinophil count in severe asthma

BACKGROUND

Severe asthma is a complex disease with heterogeneous features and involves type 2 airway inflammation, including eosinophil accumulation. Surrogate biomarkers, fraction of exhaled nitric oxide (FeNO) and blood eosinophil count (b-EOS), may predict eosinophilic airway inflammation. Here we investigated clinical characteristics of severe asthma phenotype using a combined analysis of FeNO and b-EOS.

METHODS

This retrospective study examined clinical data of patients with severe asthma (N = 107; median age, 64 years) treated at Saitama Medical University Hospital from 2009 to 2016. Thresholds of FeNO and b-EOS for sputum eosinophil ratio ≥2% were determined using receiver operating characteristic curve (ROC) analysis. Clinical characteristics were analyzed after classifying patients into four subgroups according to these thresholds.

RESULTS

Of 39 induced sputum samples examined, ROC area under the curve for predicting sputum eosinophilia was 82.0% (p = 0.001) for b-EOS and 77.0% (p = 0.006) for FeNO at optimal cut-off values of ≥300/μL and ≥25 ppb, respectively. The number of sensitized allergens was higher in the high FeNO/low b-EOS and high FeNO/high b-EOS subgroups (p < 0.05). The prevalence of chronic sinusitis was higher in the low FeNO/high b-EOS and high FeNO/high b-EOS subgroups (p = 0.04). The high FeNO/high b-EOS subgroup included the largest proportion (approximately 40%) of patients experiencing frequent severe exacerbations. Both low FeNO/low b-EOS and high FeNO/low b-EOS subgroups showed less severe exacerbations.

CONCLUSIONS

Combined evaluation of FeNO and b-EOS can identify patients with frequent exacerbations and stratify the appropriate therapy for type 2 inflammation-predominant severe asthma.

IgE sensitization to food allergens and airborne allergens in relation to biomarkers of type 2 inflammation in asthma

BACKGROUND

We have recently reported that sensitization to food allergens and sensitization to airborne allergens had independent associations with increased fraction of exhaled nitric oxide (FeNO) and blood eosinophils in middle-aged adults and in young subjects with asthma.

OBJECTIVE

To investigate the relation between IgE sensitization and several type 2 inflammation biomarkers in adult asthmatics.

METHODS

FeNO, urinary eosinophil-derived neurotoxin (U-EDN), serum eosinophil cationic protein (S-ECP) and periostin were measured in 396 asthmatics, aged 17-76 years, from the Swedish GA2LEN study. Sensitization to airborne allergens was examined with skin prick tests (≥3 mm wheal) and sensitization to food allergens with measurement of specific IgE (≥0.35 kU/L).

RESULTS

Asthmatics sensitized to food allergens had higher FeNO, 22.3 ppb (18.6, 26.7) vs 16.1 ppb (14.2, 18.2) (P = .005), S-ECP, 17.7 mg/L (14.8, 21.1) vs 12.8 mg/L (10.9, 14.9) (P = .01), and periostin, 73.7 (67.5, 80.3) ng/mL vs 59.9 (55.8, 64.2) ng/mL (P = .003), than non-sensitized subjects. Periostin levels in this group were also significantly higher than in the group sensitized only to airborne allergens (P = .01). Sensitization to food allergens related independently to FeNO (P = .02), S-ECP (P = .006) and periostin (P = .004), whereas sensitization only to airborne allergens related only to FeNO (P = .02) after adjustments for age, sex, height, weight and smoking history. FeNO correlated weakly with S-ECP (r = .17, P < .001), periostin (r = .19, P < .001) and U-EDN (0.16, P < .001). S-ECP also correlated weakly with U-EDN (r = .12, P = .02). None of the correlations between the remaining pairs of markers of type 2 inflammation were significant.

CONCLUSIONS & CLINICAL RELEVANCE

Sensitization to food allergens related to several local and systemic type 2 inflammation markers, such as FeNO, S-ECP and periostin. Assessing the profile of allergic sensitization, including to food allergens, might improve the understanding and interpretation of inflammatory markers and potentially improve asthma management.

Biomarkers for severe allergic asthma in children: could they be useful to guide disease control and use of omalizumab?

INTRODUCTION

Although symptom controls in asthmatic children can be achieved through compliant use of conventional medication, some children have uncontrolled severe persistent asthma, especially if they are allergic. For these children, omalizumab (approved by the EMA and FDA in children aged > 6 years) could be a therapeutic option. However, response to omalizumab varies from one child to another. Predictive biomarkers of omalizumab effectiveness could be useful to monitor response to treatment. Area covered: The authors searched in the PubMed database for publications related to the use of biomarkers in allergic asthma. Supported by their own experience in phenotyping asthma in children, they analyzed whether these biomarkers could be useful in assessing response to omalizumab. Expert commentary: Th2 inflammation in children with allergic asthma can be assessed by measuring several biomarkers (blood eosinophil, serum ECP or periostin, FeNO). While a single measurement may be insufficient, a combination of biomarkers assessments may improve the follow-up of children treated by omalizumab.

Effect of the S-nitrosoglutathione reductase inhibitor N6022 on bronchial hyperreactivity in asthma

RATIONALE

Patients with asthma demonstrate depletion of the endogenous bronchodilator GSNO and upregulation of GSNOR.

OBJECTIVES

An exploratory proof of concept clinical study of N6022 in mild asthma to determine the potential bronchoprotective effects of GSNOR inhibition. Mechanistic studies aimed to provide translational evidence of effect.

METHODS

Fourteen mild asthma patients were treated with intravenous N6022 (5 mg) or placebo and observed for 7 days, with repeated assessments of the provocative dose of methacholine causing a 20% fall in FEV1 (methacholine PC₂₀ FEV1), followed by a washout period and crossover treatment and observation. In vitro studies in isolated eosinophils investigated the effect of GSNO and N6022 on apoptosis.

MEASUREMENTS AND MAIN RESULTS

This was a negative trial as it failed to reach its primary endpoint, which was change from baseline in methacholine PC₂₀ FEV1 at 24 h. However, our exploratory analysis demonstrated significantly more two dose-doubling increases in PC₂₀ FEV1 for N6022 compared with placebo (21% vs 6%, P < 0.05) over the 7-day observation period. Furthermore, a significant treatment effect was observed in the change in PC₂₀ FEV1 from baseline averaged over the 7-day observation period (mean change: +0.82 mg/ml [N6022] from 1.34 mg/ml [baseline] vs -0.18 mg/ml [placebo] from 1.16 mg/ml [baseline], P = 0.023). N6022 was well tolerated in mild asthmatics. In vitro studies demonstrated enhanced eosinophilic apoptosis with N6022.

CONCLUSIONS

In this early phase exploratory proof of concept trial in asthma, N6022 did not significantly alter methacholine PC₂₀ FEV1 at 24 h, but did have a treatment effect at 7 days compared to baseline. Further investigation of the efficacy of S-nitrosoglutathione reductase inhibition in a patient population with eosinophilic asthma is warranted.

Blood biomarkers in chronic airways diseases and their role in diagnosis and management

INTRODUCTION

The complexity and heterogeneous nature of asthma and chronic obstructive pulmonary disease (COPD) results in difficulties in diagnosing and treating patients. Biomarkers that can identify underlying mechanisms, identify patient phenotypes and to predict treatment response could be of great value for adequate treatment. Areas covered: Biomarkers play an important role for the development of novel targeted therapies in airways disease. Blood biomarkers are relatively non-invasive, easy to obtain and easy to apply in routine care. Several blood biomarkers are being used to diagnose and monitor chronic airways diseases, as well as to predict response to treatment and long-term prognosis. Blood eosinophils are the best studied biomarker, the most applied in clinical practice, and until now the most promising of all blood biomarkers. Other blood biomarkers, including serum periostin, IgE and ECP and plasma fibrinogen are less studied and less relevant in clinical practice. Recent developments include the use of antibody assays of many different cytokines at the same time, and 'omics' techniques and systems medicine. Expert commentary: With the exception of blood eosinophils, the use of blood biomarkers in asthma and COPD has been rather disappointing. Future research using new technologies like big-data analysis of blood samples from real-life patient cohorts will probably gain better insight into underlying mechanisms of different disease phenotypes. Identification of specific molecular pathways and associated biomarkers will then allow the development of new targets for precision medicine.

Developments in the field of allergy in 2016 through the eyes of Clinical and Experimental Allergy

In this article, we described the development in the field of allergy as described by Clinical and Experimental Allergy in 2016. Experimental models of allergic disease, basic mechanisms, clinical mechanisms, allergens, asthma and rhinitis, and clinical allergy are all covered.

Cellular and noncellular bloodborne biomarkers in asthma

OBJECTIVE

To provide an overview of studied cellular and noncellular blood-derived asthma biomarkers.

DATA SOURCES

PubMed literature review.

STUDY SELECTIONS

Articles discussing cellular and noncellular bloodborne asthma biomarkers.

RESULTS

Discussed asthma biomarkers include peripheral blood cell counts of T cells, fibrocytes, or granulocytes, as well as levels of cytokines, periostin, IgE, and lipid mediators with or without stimulation. Moreover, this article summarizes the association of various blood biomarkers with the type of airway inflammation, presence of atopy, and dominance of specific T-cell subsets and associated pathways in asthma. Furthermore, biomarkers are here listed according to their proposed clinical use, such as diagnosis, disease phenotyping, classification of severity, assessment of disease control, and monitoring of and predicting treatment response.

CONCLUSION

Further research on asthma biomarkers may improve asthma endotyping and ultimately lead to personalized treatment.

Asthma phenotypes in childhood

INTRODUCTION

Asthma is no longer thought of as a single disease, but rather a collection of varying symptoms expressing different disease patterns. One of the ongoing challenges is understanding the underlying pathophysiological mechanisms that may be responsible for the varying responses to treatment. Areas Covered: This review provides an overview of our current understanding of the asthma phenotype concept in childhood and describes key findings from both conventional and data-driven methods. Expert Commentary: With the vast amounts of data generated from cohorts, there is hope that we can elucidate distinct pathophysiological mechanisms, or endotypes. In return, this would lead to better patient stratification and disease management, thereby providing true personalised medicine.