Exhaled nitric oxide in children with allergic rhinitis: a potential biomarker of asthma development

Utility of biomarkers in the diagnosis and monitoring of asthmatic children

Asthma imposes a heavy morbidity burden during childhood; it affects over 10% of children in Europe and North America and it is estimated to exceed 400 million people worldwide by the year 2025. In clinical practice, diagnosis of asthma in children is mostly based on clinical criteria; nevertheless, assessment of both physiological and pathological processes through biomarkers, support asthma diagnosis, aid monitoring, and further lead to better treatment outcomes and reduced morbidity. Recently, identification and validation of biomarkers in pediatric asthma has emerged as a top priority across leading experts, researchers, and clinicians. Moreover, the implementation of non-invasive biomarkers for the assessment and monitoring of paediatric patients with asthma, has been prioritized; however, only a proportion of them are currently included in the clinical practise. Although, the use of non-invasive biomarkers is highly supported in recent asthma guidelines for documenting diagnosis and supporting monitoring of asthmatic patients, data on the Pediatric population are limited. In the present report, the Pediatric Asthma Committee of the World Allergy Organization (WAO), aims to summarize and discuss available data for the implementation of non-invasive biomarkers in the diagnosis and monitoring in children with asthma. Information on the most studied biomarkers, including spirometry, oscillometry, markers of allergic sensitization, fractional exhaled nitric oxide, and the most recent exhaled breath markers and "omic" approaches, will be reviewed. Practical limitations and considerations based on both experts' opinion and critical review of the literature, on the utility of all "well-known" and newly introduced non-invasive biomarkers will be presented. A critical commentary on biomarkers' use in diagnosing and monitoring asthma during the COVID-19 pandemic, cost and availability of biomarkers in different settings and in developing countries, the differences on the biomarkers use between Primary Practitioners, Pediatricians, and Specialists and their role on the longitudinal aspect of asthma is provided.

Relationship between exhaled nitric oxide and biomarkers of atopy in children and adolescents with allergic rhinitis

INTRODUCTION

Measurement of the exhaled nitric oxide fraction (FeNO) has been proposed as an indirect and non-invasive method to detect eosinophilic airway inflammation. Allergic rhinitis (AR) is frequently associated with high levels of FeNO. Allergic sensitization can contribute to the recruitment of eosinophils in the airway and the consequent increase in FeNO.

OBJECTIVE

To correlate FeNO values with inflammatory and atopic sensitization biomarkers in patients with AR.

PATIENTS AND METHODS

Observational, analytical, cross-sectional study. Children and adolescents with AR without asthma were included. FeNO, blood eosinophil count, total serum IgE were determined and skin tests with aeroallergens were performed by calculating the scores for PPC1 (number of positive allergens), STS2 (sum of millimeters of positive papules) and the atopy index (ratio between STS2/STS1). Spearman's correlation test was used between FeNO and variables of inflammation and atopy.

RESULTS

Twenty-eight patients between 6 and 17 years old were included. There was a significant positive correlation between FeNO and blood eosinophils (r=.38; p=.047) and between FeNO and the atopy index (r=.40; p=.03). No correlation was found between FeNO and total serum IgE (r=.24; p=.21), STS1 (r=.20; p=.32) and STS2 (r=.34; p=.08).

CONCLUSION

In children and adolescents with AR, FeNO was correlated with the atopy index and the blood eosinophil count. These last biomarkers could be used as alternatives for FeNO as biomarkers of lower airway inflammation in patients with AR.

Prevalence of allergic rhinitis with lower airways inflammation: A new endotype with high risk of asthma development?

AIM

Asthma and allergic rhinitis share common pathophysiological mechanisms. However, while asthma phenotypes and endotypes are defined basing on both clinical and immunological features, rhinitis classification is still based on severity and frequency of symptoms. Recently, fractional exhaled nitric oxide (FeNO) has been suggested as a possible biomarker of rhinitis to asthma development. The aim of our study was to define the prevalence of a high FeNO allergic rhinitis endotype in a paediatric population of children with allergic rhinitis in order to quantify the impact of such patients in general practice.

METHODS

A total of 159 children (aged 7-16 years) with allergic rhinitis and no asthmatic symptoms were enrolled in our study. Severity assessment of rhinitis and asthma was evaluated in accordance with ARIA and GINA guidelines. All patients performed the following assessments: skin prick test (SPT), spirometry and FeNO measurement.

RESULTS

FeNO was increased in 54 (33.9%) of 159 patients. No significant correlation with age, severity and frequency of rhinitis was evidenced. Positive SPT for house dust mites was related with a higher prevalence of high FeNO (P = 0.04), with no significant correlation with other sensitisations. All patients showed normal spirometric values.

CONCLUSION

A possible new endotype of allergic rhinitis and lower airways inflammation showed to be significantly present in our population. The lack of correlation with allergic rhinitis severity assessment suggests that FeNO could be considered as an independent variable, possibly linked to a higher risk of asthma development in children with no lower airways symptoms and normal spirometry.

Cross-sectional study on exhaled nitric oxide in relation to upper airway inflammatory disorders with regard to asthma and perennial sensitization

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is a well-known marker of type-2 inflammation. FeNO is elevated in asthma and allergic rhinitis, with IgE sensitization as a major determinant.

OBJECTIVE

We aimed to see whether there was an independent association between upper airway inflammatory disorders (UAID) and FeNO, after adjustment for asthma and sensitization, in a multi-centre population-based study.

METHODS

A total of 741 subjects with current asthma and 4155 non-asthmatic subjects participating in the second follow-up of the European Community Respiratory Health Survey (ECRHS III) underwent FeNO measurements. Sensitization status was based on measurement of IgE against airborne allergens; information on asthma, UAID and medication was collected through interview-led questionnaires. Independent associations between UAID and FeNO were assessed in adjusted multivariate regression models and test for interaction with perennial sensitization and asthma on the relation between UAID and FeNO were made.

RESULTS

UAID were associated with higher FeNO after adjusting for perennial sensitization, asthma and other confounders: with 4.4 (0.9-7.9) % higher FeNO in relation to current rhinitis and 4.8 (0.7-9.2) % higher FeNO in relation to rhinoconjunctivitis. A significant interaction with perennial sensitization was found in the relationship between current rhinitis and FeNO (p = .03) and between rhinoconjunctivitis and FeNO (p = .03). After stratification by asthma and perennial sensitization, the association between current rhinitis and FeNO remained in non-asthmatic subjects with perennial sensitization, with 12.1 (0.2-25.5) % higher FeNO in subjects with current rhinitis than in those without.

CONCLUSIONS & CLINICAL RELEVANCE

Current rhinitis and rhinoconjunctivitis was associated with higher FeNO, with an interaction with perennial sensitization. This further highlights the concept of united airway disease, with correlations between symptoms and inflammation in the upper and lower airways and that sensitization needs to be accounted for in the relation between FeNO and rhinitis.

Gender-dependent association between exhaled nitric oxide and the CC16 38AA genotype in young school children

Background

Studies that investigated the association between the CC16 A38G polymorphism and the risk of asthma yielded conflicting results. The aim of this study among schoolchildren was to assess the relationships of CC16 A38G polymorphism with aeroallergen sensitization and fractional exhaled nitric oxide (FeNO), two outcomes predicting asthma later in life.

Methods

The study included 139 children (72 boys), median age of 7.7. Information on each child's health, lifestyle, and environment was collected through a questionnaire completed by their parents. CC16 genotypes were determined using urinary DNA. We measured FeNO, the CC16 protein in urine and nasal lavage fluid and aeroallergen‐specific immunoglobulin E in nasal mucosa fluid.

Results

Children with the homozygous mutant CC16 38AA genotype had higher odds of increased FeNO (>30 ppb) compared with their peers with the wild‐type genotype 38GG (OR, 9.85; 95% CI, 2.09‐46.4; P = .004). This association was female gender specific (P = .002) not being observed in boys (P = .40). It was also independent of allergic sensitization, which yet emerged as the strongest predictor of FeNO along with the use of bleach for house cleaning. Children with the CC16 38AA genotype had lower covariates‐adjusted urinary CC16 levels than those with 38GG (median, μg/L, 1.17 vs 2.08, P = .02).

Conclusion

Our study suggests that the CC16 38AA allele promotes airway inflammation as measured by FeNO through a gender‐dependent association. Deficient levels of CC16 in the deep lung, measured noninvasively in urine, as a possible proxy for serum CC16, might underlie this promoting effect.

Could FeNO Predict Asthma in Patients with House Dust Mites Allergic Rhinitis?

Background and Objectives: The evolution of allergic rhinitis to asthma is a part of "atopic march". The aim of this study was to analyze possible predictive markers for asthma occurrence in patients with allergic rhinitis to house dust mites (HDM). Materials and Methods: Fifty-eight patients with persistent allergic rhinitis (PAR) were included. The clinical, biological evaluation and fractionated exhaled nitric oxide (FeNO) measurement were performed at enrolment. The patients were clinically evaluated after one year to determine asthma occurrence. Results: The severity of rhinitis symptoms, levels of total immunoglobulin E (IgE), ICAM-1, VCAM-1, E-selectin and IL-6, but not IL-8 and TNF-α were higher in patients with allergic rhinitis who developed asthma compared to non-asthmatics, but the differences were not significant to considered them as predictive factors for asthma occurrence. The risk of asthma was independently influenced by patients aged over 30 years ((OR-3.74; CI95% 0.86-16.31; p = 0.07), a duration of allergic rhinitis over 12 months ((OR-4.20; CI95% 0.88-20; p = 0.07) and a basal FeNO over 28 parts per billion (pbb) ((OR-18.68; CI95% 3.79-92.05; p < 0.001). Conclusion: Clinical and biological parameters may predict asthma occurrence in patients with persistent allergic rhinitis to HDM. Adult patients with a longer duration of rhinitis symptoms and a high level of FeNO have a greater risk to develop asthma.

Comparison of exhaled nitric oxide levels in pediatric patients with allergic rhinitis

OBJECTIVE

To determine whether the measurement of exhaled nitric oxide (eNO) can help distinguish children with allergic rhinitis (AR) from healthy controls and whether eNO in children with AR correlates with disease severity.

METHODS

From August 2015 to 2016, children aged 5-15 years of age grouped into those with allergic rhinitis (n = 40) and those classified as healthy control subjects (n = 40) had exhaled nitric oxide (eNO) levels measured. The eNO level was additionally compared to the patient's clinical disease severity according to the ARIA (Allergic Rhinitis and its Impact on Asthma) classification.

RESULTS

Mean eNO in children with AR (12.64 ± 14.67 ppb) was significantly higher than that in the healthy control group (7.00 ± 6.33 ppb) (p-value = 0.046). In the persistent AR group (17.11 ± 18.40 ppb), eNO level was significantly higher than individuals in the intermittent AR group (8.59 ± 8.88 ppb, p-value = 0.024) and the healthy control group (7.00 ± 6.33 ppb, p-value = 0.008). Among children with AR, eNo was not significantly different with relationship to gender, age, weight and passive smoking exposure.

CONCLUSIONS

Exhaled nitric oxide may be elevated in children with AR that do not have concomitant asthma. This suggests exhaled nitric oxide may show utility as a parameter to monitor the severity of allergic rhinitis and to monitor the efficacy of the treatment. Physicians should consider comorbid AR when utilizing exhaled nitric oxide as a monitoring parameter in the treatment of asthma.

Nitric Oxide and Biological Mediators in Pediatric Chronic Rhinosinusitis and Asthma

BACKGROUND

In the context of the so-called unified airway theory, chronic rhinosinusitis (CRS) and asthma may coexist. The inflammation underlying these conditions can be studied through the aid of biomarkers. Main body: We described the main biological mediators that have been studied in pediatric CRS and asthma, and, according to the available literature, we reported their potential role in the diagnosis and management of these conditions. As for CRS, we discussed the studies that investigated nasal nitric oxide (nNO), pendrin, and periostin. As for asthma, we discussed the role of fractional exhaled nitric oxide (feNO), the role of periostin, and that of biological mediators measured in exhaled breath condensate (EBC) and exhaled air (volatile organic compounds, VOCs).

CONCLUSION

Among non-invasive biomarkers, nNO seems the most informative in CRS and feNO in asthma. Other biological mediators seem promising, but further studies are needed before they can be applied in clinical practice.

Serum IL-1β can be a biomarker in children with severe persistent allergic rhinitis

Background

Allergic rhinitis (AR) is one of the most common diseases globally and usually persists throughout life. In the present study, we aimed to determine whether the expression of inflammatory biomarkers has a relationship with the severity of allergic rhinitis and with comorbid asthma or other allergic diseases in children.

Methods

For diagnosis of AR, the skin prick test was performed to measure the responses to 18 allergens. Blood levels of eosinophils and immunoglobulin E (IgE) were examined. We classified the patients into 2 groups based on the severity of the condition as Group 1 [intermittent AR (IAR) or mild persistent AR (PAR)] and Group 2 (moderate to severe PAR). To determine the expression of inflammatory biomarkers, in serum and several biomarkers (caspase-1, IL-1β, CCL-11, CCL-24 and IL-33) were measured in the serum using enzyme-linked immunosorbent assay (ELISA). Additionally, we analyzed the correlation between clinical variables and the expression of biomarkers (eosinophils count, IL-1β and CCL-24) and the severity of AR.

Results

We found that eosinophils count, IL-1β, a marker of activation of inflammasomes, and CCL-24 were significantly increased in the moderate to severe PAR group (p = 0.008, p = 0.003, p = 0.039). Additionally, the expressions of eosinophil count, IL-1β and CCL-24 were significantly higher in patients with active asthmatic symptoms than in those without these conditions. On univariate analysis, allergic rhinitis in sibling, paternal allergic rhinitis, high expression of eosinophils count, IL-1β and CCL-24, history of active asthma and atopy correlated with severity of AR. Multivariate analysis showed only paternal allergic rhinitis and high expression of IL-1β as significant risk factors of moderate to severe PAR with 6.4 fold and 4.7 fold-increase in risk, respectively (p = 0.011 and p = 0.030).

Conclusion

In conclusion, this study provides the first evidence that an excessive release of biologically active IL-1β may promote inflammation in severe PAR. It demonstrates that IL-1β can be a biomarker for active allergic diseases such as AR, asthma, and atopy. Moreover, this finding suggests that IL-1B should be investigated as a therapeutic target in severe PAR and other allergic diseases.

The Role of FeNO in Predicting Asthma

Asthma-like symptoms like wheezing and dyspnea affect 1 in every 3 preschool children. An easily available biomarker that predicts later asthma or unfavorable lung growth in these children may be helpful in targeting the right child with the right drugs and avoiding exposure to potentially harmful drugs in others. The fraction of exhaled nitric oxide (FeNO) has been suggested as a marker of eosinophilic inflammation. FeNO can be measured in a standardized way from the age of 4 but several methods have been developed to measure FeNO also in younger children. Several studies have assessed the predictive value of FeNO in preschool wheezing children for asthma later in life. These studies have shown that FeNO may be helpful in defining different preschool wheezing phenotypes, and in assessing the risk of later asthma or impaired lung growth. However, data are conflicting on the added value over clinical parameters. In two studies in school children, high FeNO was predictive for asthma development during follow up and also predicted lower lung function growth. In school children with respiratory symptoms suggestive of asthma, particularly in atopic children, FeNO has diagnostic value for an asthma diagnosis, mostly for ruling in asthma. There are not enough data to assess if FeNO has a predictive value for lung development in school children.

Fractional exhaled nitric oxide and multiple breath nitrogen washout in preschool healthy and asthmatic children

INTRODUCTION

Objectively assessing pulmonary disease is challenging in preschool children with asthma. We evaluated the feasibility of measuring fractional exhaled nitrogen oxide (FeNO) and multiple breath nitrogen washout (N₂MBW) in children. We compared their capacities for discriminating between children with asthma and healthy controls.

METHODS

We measured FeNO and N₂MBW-derived indices of lung clearance (LCI_2.5) and conductive and acinar ventilation heterogeneity (S_cond and S_acin) in 65 preschool children; 35 with physician-diagnosed asthma and 30 healthy. FeNO was measured with a portable device (sampling time, 6 s). We employed data quality control guidelines on N₂MBW. Feasibility was evaluated in a maximum of 8 attempts for both methods. Atopic co-morbidity and first-degree disposition were evaluated with the ISAAC-questionnaire.

RESULTS

FeNO and N₂MBW testing were feasible in 45% and 91% of children, respectively. Feasibility was highly age-dependent. In children under 4 years old, FeNO was not feasible, but N₂MBW was 85% feasible. Children with asthma had significantly elevated S_cond values (median; 95% CI) (0.024; 0.020; 0.029) compared to healthy controls (0.019; 0.016; 0.023), but similar FeNO, LCI_2.5 and S_acinvalues.

CONCLUSION

The feasibility of measuring FeNO was highly age-dependent and not applicable in children under age 4. N₂MBW was feasible in the majority of preschool children. S_cond, but not FeNO, could discriminate between children with asthma and healthy controls.

Prevalence of high fractional exhaled nitric oxide among US youth with asthma

BACKGROUND

High fractional exhaled nitric oxide (FeNO) is an indicator of poor asthma control and has been proposed as a non-invasive assessment tool to guide asthma management.

OBJECTIVE

We aimed to describe the prevalence of and factors associated with high FeNO among US youth with asthma.

METHODS

Data from 716 children and adolescents with asthma ages 6-19 years who participated in the 2007-2012 National Health and Nutrition Examination Survey were analyzed. Using American Thoracic Society guidelines, high FeNO was defined as >50 ppb for ages 12-19 years and >35 ppb for ages 6-11 years. Multivariate logistic regression examined associations between high FeNO and age, sex, race/Hispanic origin, income status, weight status, tobacco smoke exposure, and other factors associated with asthma control (recent use of inhaled corticosteroids, recent respiratory illness, asthma-related respiratory signs/symptoms, and spirometry).

RESULTS

About 16.5% of youth with asthma had high FeNO. The prevalence of high FeNO was higher among non-Hispanic black (27%, P < 0.001) and Hispanic (20.2%, P = 0.002) youth than non-Hispanic white (9.7%) youth. Differences in high FeNO prevalence by sex (girls < boys), weight status (obese < normal weight), tobacco smoke exposure (smokers < home exposure < no exposure), and FEV1/FVC (normal < abnormal) were also observed. No differences were noted between categories for the remaining covariates.

CONCLUSION

High FeNO was observed to be associated with sex, race/Hispanic origin, weight status, tobacco smoke exposure, and abnormal FEV1/FVC, but was not associated with asthma-related respiratory symptoms. These findings may help inform future research and clinical practice guidelines on the use of high FeNO in the assessment of asthma control.

Subclinical lower airways correlates of chronic allergic and non-allergic rhinitis

The upper and lower airways behave as a physiological and pathophysiological unit. Subclinical lower airways abnormalities have been described in patients with rhinitis without asthma. These are expressed as bronchial hyperreactivity, abnormalities in lung function and bronchial inflammation, likely as a result of the same phenomenon with systemic inflammatory impact that reaches both the nose and the lungs, which for unknown reasons does not always have a full clinical expression. Patients with rhinitis are at increased risk of developing asthma; therefore, most authors suggest a careful clinical evaluation and monitoring of these patients, especially if symptoms related to inflammation in the lower airways are observed. Although current treatments, such as H1-antihistamines, intranasal steroids and allergen immunotherapy, are quite effective for the management of rhinitis, it is difficult to prove their capacity to prevent asthma among subjects with rhinitis. Evidence showing that the treatment of rhinitis has a favourable impact on indicators of bronchial hyperreactivity and inflammation among subjects that have no symptoms of asthma is more frequently described. In this review, we address the frequency and characteristics of lower airway abnormalities in subjects with rhinitis, both in paediatric and adult populations, their likely predictive value for the development of asthma and the possibilities for therapeutic intervention that could modify the risk of subjects with rhinitis towards presenting asthma.

Fractional Exhaled Nitric Oxide: A Potential Biomarker in Allergic Rhinitis?

BACKGROUND

The fractional concentration of exhaled nitric oxide (FeNO) is a surrogate biomarker for Th2-dependent bronchial inflammation. The present study investigated whether FeNO may characterize allergic rhinitis (AR) patients.

METHODS

A total of 553 AR patients (497 males, mean age 28.8 years) were evaluated. Those patients with a high FeNO underwent a 2-year follow-up.

RESULTS

Increased FeNO was associated with a significantly longer AR duration, impaired lung function, more severe symptoms, and more frequent bronchial hyperresponsiveness (BHR). At follow-up, 22 out of 82 patients (26.8%) with high FeNO levels (>50 ppb) developed asthma.

CONCLUSIONS

AR patients may frequently have high FeNO values, exceeding 50 ppb. This might be associated with an initial impaired lung function, BHR, a perceived worsening of respiratory symptoms, and potential progression to asthma.

Asthma and allergic rhinitis in childhood: what's new

Novel approaches are currently offered for the diagnostic workup and therapeutic management of allergic rhinitis and asthma. New predictive biomarkers of allergy and asthma are available. Primary and secondary prevention, earlier intervention, and modification of the natural history of allergic rhinitis and asthma are being intensively investigated. This review highlights advances in the understanding of the etiology, diagnosis, and management of atopic airway diseases in childhood, as well as prenatal and early-life risk factors and strategies for prevention.