Quantification of atopy and the probability of rhinitis in preschool children: a population-based birth cohort study

Component-specific clusters for diagnosis and prediction of allergic airway diseases

BACKGROUND

Previous studies which applied machine learning on multiplex component-resolved diagnostics arrays identified clusters of allergen components which are biologically plausible and reflect the sources of allergenic proteins and their structural homogeneity. Sensitization to different clusters is associated with different clinical outcomes.

OBJECTIVE

To investigate whether within different allergen component sensitization clusters, the internal within-cluster sensitization structure, including the number of c-sIgE responses and their distinct patterns, alters the risk of clinical expression of symptoms.

METHODS

In a previous analysis in a population-based birth cohort, by clustering component-specific (c-s)IgEs, we derived allergen component clusters from infancy to adolescence. In the current analysis, we defined each subject's within-cluster sensitization structure which captured the total number of c-sIgE responses in each cluster and intra-cluster sensitization patterns. Associations between within-cluster sensitization patterns and clinical outcomes (asthma and rhinitis) in early-school age and adolescence were examined using logistic regression and binomial generalized additive models.

RESULTS

Intra-cluster sensitization patterns revealed specific associations with asthma and rhinitis (both contemporaneously and longitudinally) that were previously unseen using binary sensitization to clusters. A more detailed description of the subjects' within-cluster c-sIgE responses in terms of the number of positive c-sIgEs and unique sensitization patterns added new information relevant to allergic diseases, both for diagnostic and prognostic purposes. For example, the increase in the number of within-cluster positive c-sIgEs at age 5 years was correlated with the increase in prevalence of asthma at ages 5 and 16 years, with the correlations being stronger in the prediction context (e.g. for the largest 'Broad' component cluster, contemporaneous: r = .28, p = .012; r = .22, p = .043; longitudinal: r = .36, p = .004; r = .27, p = .04).

CONCLUSION

Among sensitized individuals, a more detailed description of within-cluster c-sIgE responses in terms of the number of positive c-sIgE responses and distinct sensitization patterns, adds potentially important information relevant to allergic diseases.

Understanding the heterogeneity of childhood allergic sensitization and its relationship with asthma

PURPOSE OF REVIEW

To review the current state of knowledge on the relationship between allergic sensitization and asthma; to lay out a roadmap for the development of IgE biomarkers that differentiate, in individual sensitized patients, whether their sensitization is important for current or future asthma symptoms, or has little or no relevance to the disease.

RECENT FINDINGS

The evidence on the relationship between sensitization and asthma suggests that some subtypes of allergic sensitization are not associated with asthma symptoms, whilst others are pathologic. Interaction patterns between IgE antibodies to individual allergenic molecules on component-resolved diagnostics (CRD) multiplex arrays might be hallmarks by which different sensitization subtypes relevant to asthma can be distinguished. These different subtypes of sensitization are associated amongst sensitized individuals at all ages, with different clinical presentations (no disease, asthma as a single disease, and allergic multimorbidity); amongst sensitized preschool children with and without lower airway symptoms, with different risk of subsequent asthma development; and amongst sensitized patients with asthma, with differing levels of asthma severity.

SUMMARY

The use of machine learning-based methodologies on complex CRD data can help us to design better diagnostic tools to help practising physicians differentiate between benign and clinically important sensitization.

Allergic Rhinitis in Preschoolers: A Systematic Review of Diagnostics

BACKGROUND

Most studies that seek to analyze the prevalence of allergic rhinitis do not include preschool children and the diagnosis in this age group is difficult.

OBJECTIVE

Identify complementary tests to the diagnosis of allergic rhinitis in preschool children and verify if there is scientific robustness to propose a diagnostic algorithm for this condition in this age group.

METHODS

Systematic review of the literature in four databases: SCIELO, PubMed/MEDLINE, LILACS and SCOPUS. Each article was initially chosen by title, abstract and by the keywords "allergic rhinitis," "diagnosis" and "preschool." Those articles selected entered the complete reading and data extraction phase. The study was registered in the International Prospective Register of Systematic Reviews under number CRD42020207053.

RESULTS

Fourteen articles were suitable for analysis. In the assessment using Quality Assessment of Diagnostic Accuracy Studies - 2, all studies had at least one domain considered "high risk" or "undetermined risk." Seven reports of nasal cytology, seven of specific IgE, four of immediate hypersensitivity skin test, one of nasal nitric oxide, three of total IgE and one of urinary leukotriene E4 were found. Eight articles evaluated more than one diagnostic test.

CONCLUSION

There are no defined criteria for the diagnosis of allergic rhinitis in preschool children. Nasal cytology, serum specific IgE and immediate hypersensitivity skin test were the most used tests. A reliable diagnostic criterion in this age group is necessary so that in the future it is possible to propose a diagnostic algorithm for allergic rhinitis in preschool children.

The miR-124-3p regulates the allergic airway inflammation and remodeling in an ovalbumin-asthmatic mouse model by inhibiting S100A4

OBJECTIVE

Asthma is a chronic respiratory disease with an increasing incidence every year. microRNAs (miRNAs) have been demonstrated to have implications for asthma. However, limited information is available regarding the effect of miR-124-3p on this disease. Therefore, this study aimed to explore the possible effects of miR-124-3p and S100A4 on inflammation and epithelial-mesenchymal transition (EMT) in asthma using mouse models.

METHOD

Ovalbumin was used to induce asthmatic mouse models. Lung injury in mouse models was assessed, and the bronchoalveolar lavage fluid of mice was collected to determine the number of eosinophilic granulocytes and assess inflammation. The expression levels of miR-124-3p, S100A4, E-cadherin, N-cadherin, Snail1, vimentin, and TGF-β1/Smad2 signaling pathway-related proteins were measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. In vitro experiments, cells were transfected with miR-124-3p mimics or inhibitors to test the expression of S100A4 by RT-qPCR and western blot analysis, and the mutual binding of miR-124-3p and S100A4 was validated by dual-luciferase reporter gene assay.

RESULTS

Overexpression of miR-124-3p or inhibition of S100A4 expression attenuated bronchial mucus secretion and collagenous fibers and suppressed inflammatory cell infiltration. Additionally, upon miR-124-3p overexpression or S100A4 suppression, eosinophilic granulocytes were decreased, interleukin-4 (IL-4) and IL-13 expression levels were reduced in the bronchoalveolar lavage fluid, serum total IgE level was reduced, and the TGF-β1/Smad2 signaling pathway was suppressed. Mechanically, a dual-luciferase reporter gene assay verified the binding relationship between miR-124-3p and S100A4.

CONCLUSION

miR-124-3p can negatively target S100A4 to attenuate inflammation in asthmatic mouse models by suppressing the EMT process and the TGF-β/smad2 signaling pathway.

Temporal Variation and Factors Associated with Allergic Rhinitis in a Cohort of Rural Preschool Children from Sri Lanka

BACKGROUND

Allergic rhinitis is a common chronic childhood disease with a low diagnosis rate, causing poor quality of life, absenteeism, decreased school performance and significant healthcare cost. However, data on the prevalence of allergic rhinitis is sparse in preschoolers of rural geography, especially in developing countries.

AIM

To describe the epidemiology of allergic rhinitis in preschoolers from a rural geography of a developing country.

METHODS

A population-based cross-sectional study was conducted in Anuradhapura district, Sri Lanka using the WHO-30 cluster methodology with probability proportionate to size sampling. The International Study of Asthma and Allergy in Childhood questionnaire was used to assess symptomatology.

RESULTS

The response rate was 91.8%, with 548 (51.7%) male and 512 (48.3%) female participants. The mean age was 4.4 (± 0.7) years. Allergic rhinitis was reported in 123 (11.6%; 95% CI 9.7-13.5), and eye symptoms were reported in 41 (3.9%; 95% CI 2.8-5.2) children. Activities of daily living were disturbed due to nasal symptoms in 113 (10.7%; 95% CI 8.8-12.5). Allergic rhinitis was independently associated with severe asthma (OR 6.26; 95% CI 3.54-11.06), sleeping on the floor (OR 4.79; 95% CI 1.33-17.25) and having cats in the households (OR 1.86; 95% CI 1.18-2.91). Nasal symptoms were more common in January and August to October months. The standardized local highest monthly temperature, lowest monthly temperature, highest monthly humidity and dew point strongly predicted allergic rhinitis symptom exacerbation (F=4.8, p=0.036, adjusted R square=57.8%, VIF≤2.259, DW=2.1).

CONCLUSIONS

Allergic rhinitis affects 1 in 10 preschool children of rural Sri Lanka. The factors associated and environmental factor model developed to predict symptom exacerbation could be used to prevent allergic rhinitis exacerbations.

How to Choose the Correct Drug in Severe Pediatric Asthma

When a child with severe asthma (asthma defined clinically for the purposes of this review as wheeze, breathlessness, and chest tightness sometimes with cough) does not respond to treatment, it is important to be sure that an alternative or additional diagnosis is not being missed. In school age children, the next step is a detailed protocolized assessment to determine the nature of the problem, whether within the airway or related to co-morbidities or social/environmental factors, in order to personalize the treatment. For example, those with refractory difficult asthma due to persistent non-adherence may benefit from using budesonide and formoterol combined in a single inhaler [single maintenance and reliever treatment (SMART)] as both a reliever and preventer. For those with steroid-resistant Type 2 airway inflammation, the use of biologicals such as omalizumab and mepolizumab should be considered, but for mepolizumab at least, there is a paucity of pediatric data. Protocols are less well developed in preschool asthma, where steroid insensitive disease is much more common, but the use of two simple measurements, aeroallergen sensitization, and peripheral blood eosinophil count, allows the targeted use of inhaled corticosteroids (ICSs). There is also increasing evidence that chronic airway infection may be important in preschool wheeze, increasing the possibility that targeted antibiotics may be beneficial. Asthma in the first year of life is not driven by Type 2 inflammation, so beyond avoiding prescribing ICSs, no evidence based recommendations can be made. In the future, we urgently need to develop objective biomarkers, especially of risk, so that treatment can be targeted effectively; we need to address the scandal of the lack of data in children compared with adults, precluding making evidence-based therapeutic decisions and move from guiding treatment by phenotypes, which will change as the environment changes, to endotype based therapy.

Kids, Difficult Asthma and Fungus

Fungi have many potential roles in paediatric asthma, predominantly by being a source of allergens (severe asthma with fungal sensitization, SAFS), and also directly damaging the epithelial barrier and underlying tissue by releasing proteolytic enzymes (fungal bronchitis). The umbrella term ‘fungal asthma’ is proposed for these manifestations. Allergic bronchopulmonary aspergillosis (ABPA) is not a feature of childhood asthma, for unclear reasons. Diagnostic criteria for SAFS are based on sensitivity to fungal allergen(s) demonstrated either by skin prick test or specific IgE. In children, there are no exclusion criteria on total IgE levels or IgG precipitins because of the rarity of ABPA. Diagnostic criteria for fungal bronchitis are much less well established. Data in adults and children suggest SAFS is associated with worse asthma control and greater susceptibility to asthma attacks than non-sensitized patients. The data on whether anti-fungal therapy is beneficial are conflicting. The pathophysiology of SAFS is unclear, but the epithelial alarmin interleukin-33 is implicated. However, whether individual fungi have different pathobiologies is unclear. There are many unanswered questions needing further research, including how fungi interact with other allergens, bacteria, and viruses, and what optimal therapy should be, including whether anti-neutrophilic strategies, such as macrolides, should be used. Considerable further research is needed to unravel the complex roles of different fungi in severe asthma.

Novel therapeutic targets for allergic airway disease in children

The aim of precision medicine is setting up targeted therapies for selected patients that would ideally have high effectiveness and few side effects. This is made possible by targeted therapy drugs that selectively act on a specific pathway. Precision medicine is spreading to many medical specialties, and there is increasing interest in the context of allergic airway diseases, such as allergic rhinitis, chronic rhinosinusitis, and asthma. This review is an update of new targets in the treatment of childhood allergic upper airway diseases and asthma, including the most recent biologic drugs that have already been licensed or are in the pipeline to be tested with children.

Association of serum specific IgE levels with asthma in autumn pollen-induced allergic rhinitis: A retrospective analysis

BACKGROUND

Artemisia and Humulus pollen are the two most important aeroallergens of autumn allergies in North China. Cross-sectional data in 2001 have shown that allergic rhinitis often preceded or occurred at the same time as asthma in patients with autumn pollinosis in North China.

OBJECTIVE

We used this cross-sectional data to investigate the association of serum specific IgE (sIgE) levels to Humulus and/or Artemisia pollen with the onset of asthma in patients with autumn pollen-induced allergic rhinitis.

METHODS

1096 patients with autumn pollinosis were face-to-face interviewed and underwent sIgE tests to Artemisia and Humulus. The temporal sequence of allergic rhinitis and asthma was documented. 1013 patients were positive to Artemisia and/or Humulus by sIgE. Multinomial logistic regression and survival analysis were used to examine the potential implication of sIgE levels for the progression of asthma in autumn pollen-induced allergic rhinitis.

RESULTS

Of the 1013 participants with a positive sIgE test to Artemisia and/or Humulus, 563 (55.6%) had a history of allergic rhinitis which preceded or occurred at the same time as asthma. 450 (44.4%) had allergic rhinitis alone. After controlling of sex, age at onset of allergic rhinitis, and parental asthma, the risk of developing asthma increased with the levels of sIgE to both Artemisia and Humulus (p < 0.05). In Kaplan-Meier analysis, IgE classes 5-6 to Humulus or Artemisia increased the risk of asthma development (p < 0.05).

CONCLUSION

Autumn pollen-induced allergic rhinitis often coexists with seasonal asthma. The incidence of asthma is more pronounced when the sIgE level was higher.

Immunological Processes Driving IgE Sensitisation and Disease Development in Males and Females

IgE sensitisation has increased significantly over the last decades and is a crucial factor in the development of allergic diseases. IgE antibodies are produced by B cells through the process of antigen presentation by dendritic cells, subsequent differentiation of CD4⁺ Th2 cells, and class switching in B cells. However, many of the factors regulating these processes remain unclear. These processes affect males and females differently, resulting in a significantly higher prevalence of IgE sensitisation in males compared to females from an early age. Before the onset of puberty, this increased prevalence of IgE sensitisation is also associated with a higher prevalence of clinical symptoms in males; however, after puberty, females experience a surge in the incidence of allergic symptoms. This is particularly apparent in allergic asthma, but also in other allergic diseases such as food and contact allergies. This has been partly attributed to the pro- versus anti-allergic effects of female versus male sex hormones; however, it remains unclear how the expression of sex hormones translates IgE sensitisation into clinical symptoms. In this review, we describe the recent epidemiological findings on IgE sensitisation in male and females and discuss recent mechanistic studies casting further light on how the expression of sex hormones may influence the innate and adaptive immune system at mucosal surfaces and how sex hormones may be involved in translating IgE sensitisation into clinical manifestations.

Acquisition, remission, and persistence of eczema, asthma, and rhinitis in children

BACKGROUND

Allergic sensitization is associated with eczema, asthma, and rhinitis. However, it is unknown whether and how allergic sensitization is associated over time with acquisition, remission, and persistence of these diseases and their comorbidity.

OBJECTIVE

To gain a better understanding of factors including allergic sensitization transitions that influence the temporal pattern of asthma, eczema, and rhinitis and their comorbidity during childhood.

METHODS

In the Isle of Wight birth cohort, information on allergic sensitization to common allergens was collected at ages 4, 10, and 18 years along with asthma, rhinitis, and eczema status determined by clinical diagnosis. Logistic regressions were used to estimate subsequent and concurrent odds ratios of diseases transition with allergic sensitization transition status as the main independent variable. Two transition periods were considered, 4 to 10 years of age and 10 to 18 years of age.

RESULTS

The odds of new diagnosis of allergic disease (no-yes) was increased among subjects with acquired or persistent allergic sensitization to common allergens compared to subjects with no sensitization (acquisition of sensitization odds ratio [OR]=3.22, P < .0001; persistence of sensitization, OR=6.33, P < .0001). The odds of remission of allergic diseases (yes-no) was lower among subjects with acquired or sustained allergic sensitization (acquisition, OR=0.18, P = .0001; persistence, OR=0.085, P < .0001), compared to subjects not sensitized. Subjects with acquired or persistent allergic sensitization were also had higher odds for persistence of disease (yes-yes) than subjects not sensitized (acquisition, OR=5.49, P = .0001; persistence, OR=11.79, P < .0001).

CONCLUSION

Transition of allergic sensitizations to common allergens is a prognostic factor for subsequent or concurrent transition of eczema, asthma, and rhinitis. Prevention or reduction in allergic sensitization has a potential to lead to remission of these conditions.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Lung Development and Aging

The onset of chronic obstructive pulmonary disease (COPD) can arise either from failure to attain the normal spirometric plateau or from an accelerated decline in lung function. Despite reports from numerous big cohorts, no single adult life factor, including smoking, accounts for this accelerated decline. By contrast, five childhood risk factors (maternal and paternal asthma, maternal smoking, childhood asthma and respiratory infections) are strongly associated with an accelerated rate of lung function decline and COPD. Among adverse effects on lung development are transgenerational (grandmaternal smoking), antenatal (exposure to tobacco and pollution), and early childhood (exposure to tobacco and pollution including pesticides) factors. Antenatal adverse events can operate by causing structural changes in the developing lung, causing low birth weight and prematurity and altered immunological responses. Also important are mode of delivery, early microbiological exposures, and multiple early atopic sensitizations. Early bronchial hyperresponsiveness, before any evidence of airway inflammation, is associated with adverse respiratory outcomes. Overlapping cohort studies established that spirometry tracks from the preschool years to late middle age, and those with COPD in the sixth decade already had the worst spirometry at age 10 years. Alveolar development is now believed to continue throughout somatic growth and is adversely impacted by early tobacco smoke exposure. Genetic factors are also important, with genes important in lung development and early wheezing also being implicated in COPD. The inescapable conclusion is that the roots of COPD are in early life, and COPD is a disease of childhood adverse factors interacting with genetic factors.

Symptomatology Patterns in Children with Allergic Rhinitis

Background

Although allergic rhinitis (AR) is recognized as a growing global health disease with considerable importance for patients’ lives, especially among children and adolescents, there is a lack of population studies concerning symptomatology patterns of the disease. The present study aimed to explore symptoms prevalence among school-aged children, to detect any correlation between allergen sensitivities with symptomatology patterns, and, finally, to evaluate the association of the sensitivity grade score with symptoms severity or seasonality.

Material/Methods

This was a cross-sectional, observational study in a childhood population. The first stage included recruitment of children and parental-completed questionnaires. The second stage included skin-prick tests for the most common allergens. Severity of symptoms was self-evaluated using a scale that ranged from “0” (no symptoms), “1” (mild), and “2” (moderate-to-severe). AR was classified as seasonal (SAR) or perennial (PAR).

Results

The most frequent symptoms were reported for nasal obstruction, sneezing, and rhinorrhea. All nasal symptoms were significantly more profound among children with HDM sensitivity. However, more symptoms, not only nasal, but also ocular and general ones, were detected among patients with grass pollen sensitivity. Patients with PAR reported more severe symptoms. SAR was associated with mild disease. Finally, the sensitivity grade score was significantly correlated with symptom severity.

Conclusions

Our results suggest that allergen sensitivity may be correlated with symptomatology patterns among children who have allergic rhinitis.

A Review of the Safety, Efficacy and Mechanisms of Delivery of Nasal Oxytocin in Children: Therapeutic Potential for Autism and Prader-Willi Syndrome, and Recommendations for Future Research

In this article, we conduct a comprehensive review of existing evidence for the safety and therapeutic potential of intranasal oxytocin in pediatric populations. Unique considerations for dosing and delivery of oxytocin to the nasal passageway in pediatric populations and methods to promote adherence are reviewed. Intranasal oxytocin has been administered to 261 children in three open-label studies and eight randomized controlled trials. To date, the only published results in pediatric populations have focused on autism spectrum disorder (ASD) and Prader-Willi syndrome (PWS). Results regarding efficacy for improving social impairment in ASD are equivocal, partially due to mixed methodological designs, dosing regimens, and outcome measures. At present, there is no randomized controlled evidence that oxytocin provides benefit to individuals with PWS. There is no clear evidence of a link between oxytocin administration and any specific adverse event. Adverse events have been assessed using medical interviews, open reports, checklists, and physiological assessments. Adverse events reports have been largely classified as mild (n = 93), with few moderate (n = 9) or severe (n = 3) events reported. There were 35 additional adverse events reported, without severity ratings. Severe events, hyperactivity and irritability, occurred at first administration in both placebo and oxytocin groups, and subsided subsequent to discontinuation. We note that adverse event monitoring is inconsistent and often lacking, and reporting of its relationship to the study drug is poor. Only one study reported adherence data to suggest high adherence. Recommendations are then provided for the delivery of nasal sprays to the nasal passageway, monitoring, and reporting of efficacy, safety, and adherence for oxytocin nasal spray trials in pediatric populations.

Association of atopy phenotypes with new development of asthma and bronchial hyperresponsiveness in school-aged children

BACKGROUND

Although previous studies have investigated the association between atopy phenotypes and allergic diseases, atopy characterizations in association with the development of allergic diseases remain poorly understood.

OBJECTIVE

To identify atopy phenotypes in school-age children and to evaluate the association between atopy phenotypes and allergic diseases.

METHODS

We enrolled 616 children with atopy defined as 1 or more positive allergen responses on skin prick tests and 665 children without atopy from the Children's Health and Environmental Research (CHEER) study. All children were followed up for 4 years at 2-year intervals. Atopy phenotypes were classified using latent class analysis.

RESULTS

Four atopy phenotypes were characterized: later sensitization to indoor allergens (cluster 1); multiple early sensitization (cluster 2); early sensitization to outdoor allergens, especially Alternaria, and later sensitization to indoor allergens, including Aspergillus (cluster 3); and early sensitization to indoor allergens and later sensitization to outdoor allergens (cluster 4). New cases of asthma during follow-up were increased in clusters 2 and 3 (adjusted odds ratio [aOR], 2.76 and 4.25, respectively). The risk of new-onset bronchial hyperresponsiveness was highest in cluster 3 (aOR, 5.03). Clusters 2 and 4 had an increased risk of allergic rhinitis (aOR, 7.21 and 2.37, respectively).

CONCLUSION

Identification of atopy phenotypes facilitates prediction of the development of asthma and bronchial hyperresponsiveness in school-age children. Our study suggests prevention of additional sensitization is required to modify the progression of allergic diseases.

Allergy in severe asthma

It is well recognized that atopic sensitization is an important risk factor for asthma, both in adults and in children. However, the role of allergy in severe asthma is still under debate. The term 'Severe Asthma' encompasses a highly heterogeneous group of patients who require treatment on steps 4-5 of GINA guidelines to prevent their asthma from becoming 'uncontrolled', or whose disease remains 'uncontrolled' despite this therapy. Epidemiological studies on emergency room visits and hospital admissions for asthma suggest the important role of allergy in asthma exacerbations. In addition, allergic asthma in childhood is often associated with severe asthma in adulthood. A strong association exists between asthma exacerbations and respiratory viral infections, and interaction between viruses and allergy further increases the risk of asthma exacerbations. Furthermore, fungal allergy has been shown to play an important role in severe asthma. Other contributing factors include smoking, pollution and work-related exposures. The 'Allergy and Asthma Severity' EAACI Task Force examined the current evidence and produced this position document on the role of allergy in severe asthma.

Age, sex and the association between skin test responses and IgE titres with asthma

BACKGROUND

Skin prick tests (SPTs) and allergen-specific serum IgE (sIgE) measurements are the main diagnostic tools for confirming atopic sensitization. Results are usually reported as 'positive' or 'negative', using the same arbitrary cut-offs (SPT>3 mm, sIgE>0.35 kUA /l) across different ages and sexes. We investigated the influence of age and sex on the interpretation of allergy test in the context of childhood asthma.

METHODS

In a population-based birth cohort (n = 1051), we ascertained the information on asthma/wheeze (validated questionnaires) and performed SPTs and sIgE measurement to inhalant allergens (dust mite, cat, dog) at follow-ups between ages three and 11 years. We investigated the association between quantitative sensitization (sum of SPT mean wheal diameters [MWD] and sIgE titres to the three allergens) and current wheeze and asthma across ages and sexes.

RESULTS

We observed a significant association between the SPT MWD and sIgE titres and wheeze/asthma at most ages and for both sexes. However, the strength of this association was age- and sex-dependent. For SPTs, the strength of the association between MWD and asthma increased with increasing age; we observed the opposite pattern for sIgE titre. For any given SPT MWD/sIgE titre, boys were significantly more likely to express clinical symptoms, particularly in early life; this difference between males and females diminished with age and was no longer significant by age 11 years.

CONCLUSIONS

Age and sex should be taken into account when interpreting the results of skin tests and sIgE measurement, and age- and sex-specific normative data are needed for these allergy tests.

Severity of rhinitis and wheezing is strongly associated in preschoolers: A population-based study

BACKGROUND

In preschool children, no study assessed the relation between wheezing and rhinitis severity. Our aims were to estimate the prevalence of current wheezing (CW) in preschoolers and to study the association between CW and current rhinitis (CR), considering its severity/persistency.

METHODS

This is a cross-sectional, nationwide, population-based study including a representative sample of 5003 Portuguese children aged 3-5 years. Data were collected by a face-to-face interview with caregivers using an adapted ISAAC questionnaire. CW was defined as presence of ≥1 wheezing episode in the previous 12 months. Rhinitis severity/persistency was classified according to Allergic Rhinitis and its Impact on Asthma.

RESULTS

Current wheezing prevalence was 24.5% [95% CI 23.3-25.7]; 9.4% of the participants had ≥4 wheezing episodes in the previous year. Children with CR had an odds ratio (OR) of 4.0 [95% CI 3.4-4.5] for CW; it was highest for children with moderate-severe persistent rhinitis (11.5 [95% CI 8.1-16.3]), even after adjusting for possible confounders. Wheezers with CR reported more wheezing treatment use (p = 0.024) than those without CR. There was a trend for a higher number of wheezing episodes with more persistent and severe nasal disease - 48.4% of children with moderate-severe persistent rhinitis had >4 wheezing episodes vs. 28.9% in moderate-severe intermittent, 20.0% in mild persistent, 10.8% in mild intermittent, and 3.6% in those without CR; p < 0.001.

CONCLUSIONS

Current wheezing was present in almost 25% of preschool children and was strongly associated with rhinitis, especially moderate-severe persistent disease. Preschoolers with both CW and rhinitis seem to have a more severe phenotype, emphasizing the need for concurrent evaluation of nasal and bronchial symptoms even in small children.

Airway hyper-responsiveness to mannitol provides a good evaluation of atopy in childhood asthma

AIM

The relationship between airway hyper-responsiveness (AHR) and atopy has been previously investigated, but there are still some issues to be clarified. The aim of this study was to assess the link between AHR and mannitol and atopy in asthmatic children.

METHODS

We evaluated 44 children with asthma, aged 6-16 years of age, using skin prick tests (SPTs), serum total and specific immunoglobulin E (IgE) levels and the mannitol challenge test (MCT).

RESULTS

We found a good correlation between AHR to mannitol and specific IgE against Dermatophagoides pteronissinus (r = -0.66, p < 0.001) and a weak correlation with specific IgE against dog dander (r = -0.33, p = 0.01) and Aspergillus fumigatus (r = -0.23, p = 0.02). Furthermore, we found a weak correlation between AHR to mannitol and serum total IgE (r = -0.30; p = 0.03), the sum of specific IgE to aeroallergens (r = -0.37, p = 0.01) and the number of positive SPTs (r = -0.31, p = 0.02).

CONCLUSION

Measuring AHR with MCT might provide an accurate evaluation of the degree of atopy in children. The patients with a higher degree of atopy were significantly more reactive to mannitol. In clinical practice, these results indicate that children with asthma who are more atopic may require more intensive treatment strategies to reduce AHR.

Evolution pathways of IgE responses to grass and mite allergens throughout childhood

BACKGROUND

Little is known about longitudinal patterns of the development of IgE to distinct allergen components.

OBJECTIVE

We sought to investigate the evolution of IgE responses to allergenic components of timothy grass and dust mite during childhood.

METHODS

In a population-based birth cohort (n = 1184) we measured IgE responses to 15 components from timothy grass and dust mite in children with available samples at 3 time points (ages 5, 8, and 11 years; n = 235). We designed a nested, 2-stage latent class analysis to identify cross-sectional sensitization patterns at each follow-up and their longitudinal trajectories. We then ascertained the association of longitudinal trajectories with asthma, rhinitis, eczema, and lung function in children with component data for at least 2 time points (n = 534).

RESULTS

Longitudinal latent class analysis revealed 3 grass sensitization trajectories: (1) no/low sensitization; (2) early onset; and (3) late onset. The early-onset trajectory was associated with asthma and diminished lung function, and the late-onset trajectory was associated with rhinitis. Four longitudinal trajectories emerged for mite: (1) no/low sensitization; (2) group 1 allergens; (3) group 2 allergens; and (3) complete mite sensitization. Children in the complete mite sensitization trajectory had the highest odds ratios (ORs) for asthma (OR, 7.15; 95% CI, 3.80-13.44) and were the only group significantly associated with comorbid asthma, rhinitis, and eczema (OR, 5.91; 95% CI, 2.01-17.37). Among children with wheezing, those in the complete mite sensitization trajectory (but not other longitudinal mite trajectories) had significantly higher risk of severe exacerbations (OR, 3.39; 95% CI, 1.62-6.67).

CONCLUSIONS

The nature of developmental longitudinal trajectories of IgE responses differed between grass and mite allergen components, with temporal differences (early vs late onset) dominant in grass and diverging patterns of IgE responses (group 1 allergens, group 2 allergens, or both) in mite. Different longitudinal patterns bear different associations with clinical outcomes, which varied by allergen.

Pediatric severe asthma with fungal sensitization is mediated by steroid-resistant IL-33

Background

The mechanism underlying severe asthma with fungal sensitization (SAFS) is unknown. IL-33 is important in fungus-induced asthma exacerbations, but its role in fungal sensitization is unexplored.

Objective

We sought to determine whether fungal sensitization in children with severe therapy-resistant asthma is mediated by IL-33.

Methods

Eighty-two children (median age, 11.7 years; 63% male) with severe therapy-resistant asthma were included. SAFS (n = 38) was defined as specific IgE or skin prick test response positivity to Aspergillus fumigatus, Alternaria alternata, or Cladosporium herbarum. Clinical features and airway immunopathology were assessed. Chronic exposure to house dust mite and A alternata were compared in a neonatal mouse model.

Results

Children with SAFS had earlier symptom onset (0.5 vs 1.5 years, P = .006), higher total IgE levels (637 vs 177 IU/mL, P = .002), and nonfungal inhalant allergen-specific IgE. Significantly more children with SAFS were prescribed maintenance oral steroids (42% vs 14%, P = .02). SAFS was associated with higher airway IL-33 levels. In neonatal mice A alternata exposure induced higher serum IgE levels, pulmonary IL-33 levels, and IL-13⁺ innate lymphoid cell (ILC) and T_H2 cell numbers but similar airway hyperresponsiveness (AHR) compared with those after house dust mite exposure. Lung IL-33 levels, IL-13⁺ ILC numbers, T_H2 cell numbers, IL-13 levels, and AHR remained increased with inhaled budesonide during A alternata exposure, but all features were significantly reduced in ST2^−/− mice lacking a functional receptor for IL-33.

Conclusion

Pediatric SAFS was associated with more oral steroid therapy and higher IL-33 levels. A alternata exposure resulted in increased IL-33–mediated ILC2 numbers, T_H2 cell numbers, and steroid-resistant AHR. IL-33 might be a novel therapeutic target for SAFS.

Rhinitis in the first 18 months of life: exploring the role of respiratory viruses

BACKGROUND

Rhinitis is common in early childhood, but allergic rhinitis is considered a later manifestation of the atopic march. This study aimed to evaluate rhinitis (allergic and non-allergic) in the first 18 months of life, its link with other atopic manifestations and the role of respiratory viruses.

METHODS

Subjects (n = 1237) of the Singapore GUSTO birth cohort were followed up quarterly until 18 months of age with questionnaires to screen for rhinitis symptoms lasting at least 2 wk and with monthly calls to positive subjects to detect prolonged/recurrent rhinitis symptoms (total duration ≥ 4 wk). Anterior nasal swabbing for molecular-based virus detection was conducted during these visits and near (within a month) rhinitis episodes. Skin prick testing to common environmental and food allergens was conducted at the 18 month visit.

RESULTS

Prolonged/recurrent rhinitis was significantly associated with history of parental atopy (mother: aOR = 2.17; father: aOR = 1.82) and atopic comorbidities of eczema (aOR = 2.53) and wheeze (aOR = 4.63) (p < 0.05), though not with allergen sensitization. Although the frequency of nasal respiratory virus detection during scheduled quarterly visits did not differ between prolonged/recurrent rhinitis and matched controls (p > 0.05), virus detection was higher in swabs obtained within a month following rhinitis episodes in prolonged/recurrent rhinitis subjects compared with scheduled visits (adjusted p = 0.04).

CONCLUSIONS

Based on the duration of rhinitis symptoms, this study defined a subset of early childhood rhinitis which was associated with atopic predisposition and comorbidities. Persistent respiratory viral shedding may contribute to the symptomatology. Whether this entity is a precursor of subsequent childhood allergic rhinitis will require longer follow-up.

Traffic pollution is associated with early childhood aeroallergen sensitization

BACKGROUND

No large, prospective, epidemiologic study has investigated the association between diesel exhaust particle (DEP) exposure and early aeroallergen sensitization and allergic rhinitis (AR) at 4 years of age.

OBJECTIVE

To determine how exposure to traffic exhaust during infancy is associated with aeroallergen sensitization and AR at 4 years of age and the predictive utility of the wheal area at 1 to 3 years of age on AR at 4 years of age.

METHODS

Infants born to aeroallergen sensitized parents were evaluated annually with skin prick tests to 15 aeroallergens with measurement of wheal areas. At 4 years of age, AR was defined as at least one positive aeroallergen skin prick test result and the presence of sneezing and a runny nose without a cold or flu. Infant (DEP) exposure was estimated using data from 27 air sampling monitors and a land use regression model.

RESULTS

Complete data were available for 634 children at 4 years of age. Prevalence of AR increased annually from 6.9% to 21.9%. A positive trend was observed for high DEP exposure and aeroallergen sensitization at 2 and 3 years of age (odds ratio, 1.40; 95% confidence interval, 0.97-2.0) and (odds ratio, 1.35; 95% confidence interval, 0.98-1.85) but not with AR. At 2 years of age, every 1-mm(2) increase in the wheal area of timothy and Alternaria significantly increased the odds of AR at 4 years of age. At 3 years of age, every 1-mm(2) increase in the wheal area of fescue, dog, and Penicillium significantly increased the odds of AR at 4 years of age.

CONCLUSION

DEP exposure enhances the risk of early aeroallergen sensitization. Aeroallergen wheal area at 2 and 3 years of age is associated with AR at 4 years of age.

The predictive value of allergen skin prick tests and IgE tests at pre-school age: the PACT study

BACKGROUND

Sensitization toward allergens, as determined by skin prick test (SPT) or specific IgE (sIgE), is a predictor for the later presence of allergy-related disease (atopic eczema, allergic rhinoconjuctivitis and asthma). However, it is not known whether SPT or sIgE should be the preferred test. The aim of this study was to compare the predictive ability of SPT and sIgE when performed in a general population of 2-yr-old children.

METHODS

In a prospective, longitudinal population-based study of children aged 2-6 yr, SPT and sIgE for nine common allergens were performed at 2 yr. Allergy-related disease was evaluated by clinical examination and questionnaire at 2 and 6 yr of age (n = 199).

RESULTS

Skin prick test or sIgE was positive in 10.6% and 21.1% in the 2-yr-old children, respectively. The prevalence of allergy-related disease was 25.6% at 2 yr and 25.1% at 6 yr. Half of the cases at 2 yr were transient. Both SPT and sIgE were statistically significant predictors for later allergy-related disease, OR = 6.5 (95% CI 2.3-18.6) and OR = 4.1 (95% CI 1.9-9.0), respectively. Receiver operating characteristic analysis showed that SPT and sIgE had comparable predictive ability for atopic eczema, asthma or any allergy-related disease, but sIgE had better ability to predict later allergic rhinoconjunctivitis.

CONCLUSION

Sensitization at 2 yr may be useful predictors of allergy-related disease later in childhood. The predictive ability of SPT and sIgE were mainly comparable; however, it may be that sIgE is the preferred choice in young children when the aim is to predict allergic rhinoconjunctivitis.

Impact of rhinitis on asthma severity in school-age children

BACKGROUND

In a population-based sample of school-age children, we investigated factors associated with rhinitis, and differences between allergic and nonallergic rhinitis. Amongst children with asthma, we explored the association between rhinitis and asthma severity.

METHODS

Children participating in a birth cohort study (n = 906) were reviewed at age 8 years. Asthma was defined as at least two of the following three features: physician-diagnosed asthma, currently using asthma medication and current wheeze. We measured lung function (plethysmography and spirometry) and airway hyper-reactivity (AHR; methacholine challenge).

RESULTS

In the analysis adjusted for the presence of asthma, children with rhinitis had significantly higher AHR (P = 0.001). Maternal smoking and absence of breastfeeding were stronger predictors of nonallergic rhinitis, whereas current wheeze and eczema were stronger predictors of allergic rhinitis. Amongst asthmatics (n = 159), when compared to 76 children without rhinitis, those with rhinitis (n = 83) were 2.89-fold (95% CI 1.41-5.91) more likely to experience frequent attacks of wheezing, 3.44-fold (1.19-9.94) more likely to experience severe attacks of wheezing limiting speech, 10.14-fold (1.27-81.21) more likely to have frequent visits to their doctor because of asthma and nine-fold (1.11-72.83) more likely to miss school. Reported use of intranasal corticosteroids resulted in a numerically small, but consistent reduction in risk, rendering the associations between rhinitis and asthma severity nonsignificant.

CONCLUSION

We observed differences in risk factors and severity between allergic and nonallergic rhinitis. In children with asthma, rhinitis had adverse impact on asthma severity. The use of intranasal corticosteroids resulted in a small, but consistent reduction in the risk.

Establishing IMMULITE® 2000 cut-off values for serum allergen-specific immunoglobulin and exploring their relationship to exhaled nitric oxide

Aim

Paediatric cut-off values for serum allergen-specific IgE (sIgE) using the Siemens IMMULITE® 2000 system to diagnose allergic rhinoconjunctivitis have not been established. We aimed to determine cut-off levels for sIgE for 10 common inhalant allergens and to study the relationship between sIgE, total IgE and fractional exhaled nitric oxide (FE_NO).

Methods

We enrolled 243 schoolchildren, including 164 with allergic rhinoconjunctivitis. Parental interviews, skin prick tests, sIgE, total IgE, FE_NO measurements, spirometry and exercise tests were performed.

Results

Cut-off values with the best combined sensitivity and specificity were above the detection limit of the assay for seven of the ten allergens (0.23–1.1 kU/L). The overall accuracy of the IMMULITE® in detecting allergic rhinoconjunctivitis was good. sIgE was superior to total IgE and FE_NO in predicting allergic rhinoconjunctivitis to timothy, birch, mugwort, cat, dog and house dust mite. FE_NO was elevated in children with allergic rhinoconjunctivitis, irrespective of asthma.

Conclusion

Cut-off values for sIgE were dependent on the allergic phenotype and were above the IMMULITE® detection limit for seven of ten inhalant allergens. Consequently, using the detection limit for sIgE as the decision point would result in over-diagnosing allergic rhinoconjunctivitis. When measuring elevated FE_NO in children, allergic rhinoconjunctivitis should be suspected.

Predicting phenotypes of asthma and eczema with machine learning

Background

There is increasing recognition that asthma and eczema are heterogeneous diseases. We investigated the predictive ability of a spectrum of machine learning methods to disambiguate clinical sub-groups of asthma, wheeze and eczema, using a large heterogeneous set of attributes in an unselected population. The aim was to identify to what extent such heterogeneous information can be combined to reveal specific clinical manifestations.

Methods

The study population comprised a cross-sectional sample of adults, and included representatives of the general population enriched by subjects with asthma. Linear and non-linear machine learning methods, from logistic regression to random forests, were fit on a large attribute set including demographic, clinical and laboratory features, genetic profiles and environmental exposures. Outcome of interest were asthma, wheeze and eczema encoded by different operational definitions. Model validation was performed via bootstrapping.

Results

The study population included 554 adults, 42% male, 38% previous or current smokers. Proportion of asthma, wheeze, and eczema diagnoses was 16.7%, 12.3%, and 21.7%, respectively. Models were fit on 223 non-genetic variables plus 215 single nucleotide polymorphisms. In general, non-linear models achieved higher sensitivity and specificity than other methods, especially for asthma and wheeze, less for eczema, with areas under receiver operating characteristic curve of 84%, 76% and 64%, respectively. Our findings confirm that allergen sensitisation and lung function characterise asthma better in combination than separately. The predictive ability of genetic markers alone is limited. For eczema, new predictors such as bio-impedance were discovered.

Conclusions

More usefully-complex modelling is the key to a better understanding of disease mechanisms and personalised healthcare: further advances are likely with the incorporation of more factors/attributes and longitudinal measures.

Challenges in interpreting allergen microarrays in relation to clinical symptoms: a machine learning approach

BACKGROUND

Identifying different patterns of allergens and understanding their predictive ability in relation to asthma and other allergic diseases is crucial for the design of personalized diagnostic tools.

METHODS

Allergen-IgE screening using ImmunoCAP ISAC(®) assay was performed at age 11 yrs in children participating a population-based birth cohort. Logistic regression (LR) and nonlinear statistical learning models, including random forests (RF) and Bayesian networks (BN), coupled with feature selection approaches, were used to identify patterns of allergen responses associated with asthma, rhino-conjunctivitis, wheeze, eczema and airway hyper-reactivity (AHR, positive methacholine challenge). Sensitivity/specificity and area under the receiver operating characteristic (AUROC) were used to assess model performance via repeated validation.

RESULTS

Serum sample for IgE measurement was obtained from 461 of 822 (56.1%) participants. Two hundred and thirty-eight of 461 (51.6%) children had at least one of 112 allergen components IgE > 0 ISU. The binary threshold >0.3 ISU performed less well than using continuous IgE values, discretizing data or using other data transformations, but not significantly (p = 0.1). With the exception of eczema (AUROC~0.5), LR, RF and BN achieved comparable AUROC, ranging from 0.76 to 0.82. Dust mite, pollens and pet allergens were highly associated with asthma, whilst pollens and dust mite with rhino-conjunctivitis. Egg/bovine allergens were associated with eczema.

CONCLUSIONS

After validation, LR, RF and BN demonstrated reasonable discrimination ability for asthma, rhino-conjunctivitis, wheeze and AHR, but not for eczema. However, further improvements in threshold ascertainment and/or value transformation for different components, and better interpretation algorithms are needed to fully capitalize on the potential of the technology.

Paediatric rhinitis: position paper of the European Academy of Allergy and Clinical Immunology

Rhinitis is a common problem in childhood and adolescence and impacts negatively on physical, social and psychological well-being. This position paper, prepared by the European Academy of Allergy and Clinical Immunology Taskforce on Rhinitis in Children, aims to provide evidence-based recommendations for the diagnosis and therapy of paediatric rhinitis. Rhinitis is characterized by at least two nasal symptoms: rhinorrhoea, blockage, sneezing or itching. It is classified as allergic rhinitis, infectious rhinitis and nonallergic, noninfectious rhinitis. Similar symptoms may occur with other conditions such as adenoidal hypertrophy, septal deviation and nasal polyps. Examination by anterior rhinoscopy and allergy tests may help to substantiate a diagnosis of allergic rhinitis. Avoidance of relevant allergens may be helpful for allergic rhinitis (AR). Oral and intranasal antihistamines and nasal corticosteroids are both appropriate for first-line AR treatment although the latter are more effective. Once-daily forms of corticosteroids are preferred given their improved safety profile. Potentially useful add-on therapies for AR include oral leukotriene receptor antagonists, short bursts of a nasal decongestant, saline douches and nasal anticholinergics. Allergen-specific immunotherapy is helpful in IgE-mediated AR and may prevent the progression of allergic disease. There are still a number of areas that need to be clarified in the management of rhinitis in children and adolescents.

Pediatric asthma and development of atopy

PURPOSE OF REVIEW

There is ongoing controversy about the relationship between atopy and asthma.

RECENT FINDINGS

In clinical practice, specific IgE and skin test results should not be reported as 'positive' or 'negative', but as the level of IgE and the size of skin test wheal diameter. In assessment of children with severe asthma, these tests are not mutually exclusive but complementary, and both should be carried out and quantified. In the near future, their diagnostic accuracy in children with wheezing may be improved by the measurement of allergen-specific IgG. It is becoming increasingly clear that asthma is not a single disease, but a collection of several diseases with similar/same symptoms. These distinct disease entities (endotypes) may share similar observable characteristics (phenotypes), but arise via different pathophysiological mechanisms. Observable phenotypic features (e.g. sputum inflammatory phenotypes) are not stable in children with asthma. The discovery of novel, latent endotypes of asthma will require integration of a time component to take into account the phenotype instability and longitudinal changes. Not only asthma, but also 'atopy' encompasses a number of different endotypes which differ in their association with asthma.

SUMMARY

Novel endotypes of atopy and asthma which better reflect the unique pathophysiological processes underlying different diseases in the atopy and asthma syndromes can be defined through the fusion of computational thinking and novel mathematical approaches with biomedical science. These novel endotypes may be more relevant for epidemiological, genetic and therapeutic studies.

Specific patterns of allergic sensitization in early childhood and asthma & rhinitis risk

BACKGROUND

Specific patterns of allergic sensitization as well as quantification of the in vitro IgE response in early life may provide relevant clinical insight into future rhinitis and asthma risk.

OBJECTIVE

To define relationships among established sensitization to particular aeroallergens, quantitative analyses of allergen-specific IgE levels, pet exposure and sensitization, and asthma and rhinitis risk.

METHODS

Children at high-risk for the development of asthma and allergic diseases were enrolled at birth into the Childhood Origins of ASThma (COAST) study. Allergen-specific IgE was assessed at ages 1, 3, 6, and 9 years by fluoroenzyme immunoassay (Unicap(®) 100; Pharmacia Diagnostics). Current asthma and rhinitis were diagnosed at age 6 and 8 years.

RESULTS

Sensitization to dog was strongly associated with increased asthma risk (P < 0.0001). Sensitization to perennial compared with seasonal allergens was more strongly associated with asthma risk, while sensitization to seasonal allergens was more closely associated with rhinitis risk. Increased levels of specific IgE to perennial allergens were associated with an increased asthma risk (P = 0.05), while any detectable level of IgE to seasonal allergens was associated with increased rhinitis risk (P = 0.0009). While dog and cat sensitization were both independently associated with increased asthma and rhinitis risk, dog exposure at birth was associated with a reduced risk of asthma, regardless of dog sensitization status during the first 6 years of life (P = 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

Analysing specific patterns of an individual's allergic sensitization profile reveals additional relevant associations with asthma and rhinitis risk as opposed to the information gained from characterizing an individual as 'atopic' by the presence of any demonstrable sensitization alone. Furthermore, protective mechanisms of dog exposure with regards to asthma risk appear to be unrelated to the prevention of sensitization.

Multiple atopy phenotypes and their associations with asthma: similar findings from two birth cohorts

BACKGROUND

Although atopic sensitization is one of the strongest risk factors for asthma, its relationship with asthma is poorly understood. We hypothesize that 'atopy' encompasses multiple sub-phenotypes that relate to asthma in different ways.

METHODS

In two population-based birth cohorts (Manchester and Isle of Wight - IoW), we used a machine learning approach to independently cluster children into different classes of atopic sensitization in an unsupervised manner, based on skin prick and sIgE tests taken throughout childhood and adolescence. We examined the qualitative cluster properties and their relationship to asthma and lung function.

RESULTS

A five-class solution best described the data in both cohorts, with striking similarity between the classes across the two populations. Compared with nonsensitized class, children in the class with sensitivity to a wide variety of allergens (~1/3 of children atopic by conventional definition) were much more likely to have asthma (aOR [95% CI0; 20.1 [10.9-40.2] in Manchester and 11.9 [7.3-19.4] in IoW). The relationship between asthma and conventional atopy was much weaker (5.5 [3.4-8.8] in Manchester and 5.8 [4.1-8.3] in IoW). In both cohorts, children in this class had significantly poorer lung function (FEV1 /FVC lower by 4.4% in Manchester and 2.6% in IoW; P < 0.001), most reactive airways, highest eNO and most hospital admissions for asthma (P < 0.001).

CONCLUSIONS

By adopting a machine learning approach to longitudinal data on allergic sensitization from two independent unselected birth cohorts, we identified latent classes with strikingly similar patterns of atopic response and association with clinical outcomes, suggesting the existence of multiple atopy phenotypes.

Allergic rhinitis is associated with otitis media with effusion: a birth cohort study

BACKGROUND

Childhood otitis media with effusion is a common disease and a link to allergic diseases has been suggested.

OBJECTIVE

To investigate the association between atopic disease and otitis media with effusion diagnosed according to strict objective case definitions by age 6 years.

METHODS

We evaluated 291 children in the 6th year of life from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) 2000 birth cohort. Otitis media with effusion was diagnosed based on tympanometric and objective evaluation. Asthma, eczema, allergic- and non-allergic rhinitis was diagnosed prospectively by pre-defined algorithms. Nasal mucosal swelling was assessed using acoustic rhinometry and nasal eosinophilia from scrapings. Analyses were performed using logistic regression and adjusted for dog, cat and smoking exposure, paternal atopy, household income, older siblings, gender and number of acute otitis media episodes.

RESULTS

Otitis media with effusion was diagnosed in 39% of the cohort and was associated with allergic rhinitis (aOR = 3.36, CI = 1.26-8.96, P = 0.02), but not with nasal mucosal swelling, nasal oeosinophilia, non-allergic rhinitis, asthma or eczema.

CONCLUSION

Otitis media with effusion is closely associated with allergic rhinitis presumably caused by allergic inflammation, but not mechanical nasal mucosal swelling. These findings warrant an increased awareness of otitis media with effusion in children with allergic rhinitis.

Trends in cutaneous sensitization in the first 18 years of life: results from the 1989 Isle of Wight birth cohort study

BACKGROUND

Skin prick testing (SPT) is fundamental to the practice of clinical allergy identifying relevant allergens and predicting the clinical expression of disease. There are only limited data on the natural history of SPT results over childhood and adolescence.

OBJECTIVE

We aimed to describe the natural history of SPT and patterns of sensitization over childhood and adolescence.

METHODS

The 1989 Isle of Wight birth cohort (1456 participants) was followed up at 1, 2, 4, 10 and 18 years. SPT was undertaken from 4 years.

RESULTS

SPT was performed on 980 (80%), 1036 (75%) and 853 (65%) of participants at 4, 10 and 18 years. The prevalence of sensitization to any allergen at these time-points was 19.7%, 26.9% and 41.3% respectively. At each time-point, boys were significantly more likely to be sensitized (P < 0.016) and sensitization significantly increased over childhood and adolescence (average annual increase of 7%). Some children outgrew their sensitization. The rate of sensitization to most individual allergens increased over childhood and adolescence. A configural frequency analysis showed that whether an individual was sensitizated was relatively fixed over childhood and adolescence. Cluster analysis at 4 years demonstrated four major groups of individuals with similar co-sensitization to specific allergens. Children who were sensitized at age 4 years generally went onto become sensitized to additional allergens at 10 and 18 years.

CONCLUSIONS AND CLINICAL RELEVANCE

Allergic sensitization continues to increase over childhood into adolescence although the majority of children who were not sensitized at 4 years remain non-sensitized throughout childhood and adolescence. The presence of sensitization at 4 years predicted later sensitization to additional allergens.

Prevalence of allergic sensitization versus allergic rhinitis symptoms in an unselected population

BACKGROUND

Allergic rhinitis (AR) is the most common allergic disorder and its prevalence has significantly increased worldwide, nowadays affecting up to 40% of the population in young adults. The objective of the present survey was to evaluate the prevalence of allergic sensitization and the prevalence of clinically diagnosed AR in a sample of the Belgian population, and to estimate the effect of age and gender.

METHODS

We performed a cross-sectional population-based study at an annual public fair in Ghent. Participants underwent a skin prick test (SPT) to 3 aeroallergens: a mix of trees (hazel, alder, and birch), grass pollen, and house dust mite (HDM). The clinical relevance of sensitization was assessed by relating relevant symptoms of AR to the corresponding SPT.

RESULTS

A total of 2,320 participants (1,475 females, median age 44.7 years, range 3-86) were included in this study. The standardized prevalence rates of sensitization were 13.2% for tree mix, 25.9% for grass pollen, and 25.9% for HDM. Sensitization to at least one of the allergens was present in 40.3% of the subjects. Symptomatic sensitization related to trees was reported in 9.7% of cases, grass-related AR was 17.6%, and HDM-related AR was 17.1%. The overall prevalence of AR was 30.9%.

CONCLUSION

In this study we demonstrated a 40.3% prevalence of a positive SPT to one or more common aeroallergens. A clinical diagnosis of AR was present in 30.9% of cases, peaking in the third and fourth decades of life. It is to be expected that in the next decades, when this generation grows older, the general AR prevalence will further increase.

Increased exhaled nitric oxide predicts new-onset rhinitis and persistent rhinitis in adolescents without allergic symptoms

BACKGROUND

The fraction of nitric oxide in exhaled air (FE(NO)) is increased in rhinitis and asthma. We have previously suggested that elevated FE(NO) levels in the absence of asthma symptoms may be a sign of 'early asthma'. In the present study, we hypothesize that elevated exhaled NO levels may also precede rhinitis symptoms.

OBJECTIVE

To investigate in a cohort of adolescents whether or not increased exhaled NO levels at the age of 13-14 years predicted new-onset or persistent rhinitis within a 4-year period.

METHODS

A total of 959 randomly selected adolescents (13-14 years) completed a questionnaire on respiratory symptoms at baseline and follow-up, 4 years later. Exhaled NO was measured at baseline. After exclusion of subjects with asthma diagnosis or asthma symptoms at baseline, 657 participants were eligible for the present study.

RESULTS

Higher FE(NO) levels at baseline were associated with increased risk for new-onset (P = 0.009) and persistent rhinitis (P = 0.03) within a 4-year period. The risk of new-onset rhinitis was 2.32 (1.23, 4.37) [OR (95% CI)] times higher if FE(NO) > 90th percentile of the group without rhinitis at baseline. This increased risk for new-onset rhinitis was significant [2.49 (1.24, 5.01)] after excluding subjects with allergic symptoms. The risk of persistent rhinitis was 5.11 (1.34, 19.57) times higher if FE(NO) > 90th percentile of the group without rhinitis at baseline.

CONCLUSION

Elevated exhaled nitric oxide levels predicted incident and persistent rhinitis in this population-based study of adolescents. Moreover, these findings were consistent after excluding subjects with allergic symptoms. Thus, it appears that elevation of exhaled NO precedes airway symptoms and predicts development of rhinitis in subjects without allergic symptoms or family history of allergic disease.

Quantification of atopy, lung function and airway hypersensitivity in adults

BACKGROUND

Studies in children have shown that concentration of specific serum IgE (sIgE) and size of skin tests to inhalant allergens better predict wheezing and reduced lung function than the information on presence or absence of atopy. However, very few studies in adults have investigated the relationship of quantitative atopy with lung function and airway hyperresponsiveness (AHR).

OBJECTIVE

To determine the association between lung function and AHR and quantitative atopy in a large sample of adults from the UK.

METHODS

FEV1 and FVC (% predicted) were measured using spirometry and airway responsiveness by methacholine challenge (5-breath dosimeter protocol) in 983 subjects (random sample of 800 parents of children enrolled in a population-based birth cohort enriched with 183 patients with physician-diagnosed asthma). Atopic status was assessed by skin prick tests (SPT) and measurement of sIgE (common inhalant allergens). We also measured indoor allergen exposure in subjects' homes.

RESULTS

Spirometry was completed by 792 subjects and 626 underwent methacholine challenge, with 100 (16.0%) having AHR (dose-response slope>25). Using sIgE as a continuous variable in a multiple linear regression analysis, we found that increasing levels of sIgE to mite, cat and dog were significantly associated with lower FEV1 (mite p = 0.001, cat p = 0.0001, dog p = 2.95 × 10-8). Similar findings were observed when using the size of wheal on skin testing as a continuous variable, with significantly poorer lung function with increasing skin test size (mite p = 8.23 × 10-8, cat p = 3.93 × 10-10, dog p = 3.03 × 10-15, grass p = 2.95 × 10-9). The association between quantitative atopy with lung function and AHR remained unchanged when we repeated the analyses amongst subjects defined as sensitised using standard definitions (sIgE>0.35 kUa/l, SPT-3 mm>negative control).

CONCLUSIONS

In the studied population, lung function decreased and AHR increased with increasing sIgE levels or SPT wheal diameter to inhalant allergens, suggesting that atopy may not be a dichotomous outcome influencing lung function and AHR.

Rhinitis in children less than 6 years of age: current knowledge and challenges

Rhinitis is a disease of the upper airway characterized by runny and/or blocked nose and/or sneezing. Though not viewed as a life threatening condition, it is also recognized to impose significant burden to the quality of life of sufferers and their caretakers and imposes an economic cost to society. Through a PubMed online search of the literature from 2006 to September 2011, this paper aims to review the published literature on rhinitis in young children below the age of 6 years. It is apparent from epidemiology studies that rhinitis in this age group is a relatively common problem. The condition has a heterogenous etiology with classification into allergic and non-allergic rhinitis. Respiratory viral infections may play a role in the pathogenesis of long standing rhinitis, but definitive studies are still lacking. Treatment guidelines for management are lacking for this age group, and is a significant unmet need. Although the consensus is that co-morbidities including otitis media with effusion, adenoidal hypertrophy and asthma, are important considerations of management of these children. Pharmacotherapy is limited for young children especially for those below the age of 2 years. This review underscores the lack of understanding of rhinitis in early childhood and therefore the need for further research in this area.

An explorative study of low levels of allergen-specific IgE and clinical allergy symptoms during early childhood

BACKGROUND

Early identification of children at risk for later development of allergic disease is essential for early intervention and initiation of proper treatment and management.

OBJECTIVE

To investigate the relationship between low levels (0.1-0.7 kU(A) /l) of IgE sensitization to food and inhalant allergens and symptoms of eczema, rhinitis, and asthma from birth to 5 years of age.

METHODS

Children (268) were followed prospectively from birth to 5 years of age with physical examinations and measurements of s-IgE at 6, 12, 24, and 60 months of age.

RESULTS

Seventy-four percent of the children with low levels of s-IgE to egg and/or milk at the age of 6 months were still sensitized to one or more allergens at age 2 years. Eighty-four percent of the children with low levels of s-IgE to any of the studied allergens at 12 months of age were still sensitized at age 5. The low levels of egg and milk s-IgE also significantly increased the risk for eczema at the same age and also increased the risk for eczema at 2 years of age.

CONCLUSION

Low levels of s-IgE can be detected from the age of 6 months and are related to further IgE sensitization. The low levels seem to be of importance for both the association to present symptoms and for prediction of future allergic symptoms, especially eczema during early infancy. A detectable s-IgE level, albeit low, could be a clear signal that the immune system is alerted and should be followed.

Allergy-related outcomes in relation to serum IgE: results from the National Health and Nutrition Examination Survey 2005-2006

BACKGROUND

The National Health and Nutrition Examination Survey (NHANES) 2005-2006 was the first population-based study to investigate levels of serum total and allergen-specific IgE in the general US population.

OBJECTIVE

We estimated the prevalence of allergy-related outcomes and examined relationships between serum IgE levels and these outcomes in a representative sample of the US population.

METHODS

Data for this cross-sectional analysis were obtained from NHANES 2005-2006. Study subjects aged 6 years and older (n = 8086) had blood taken for measurement of total IgE and 19 specific IgE levels against common aeroallergens, including Alternaria alternata, Aspergillus fumigatus, Bermuda grass, birch, oak, ragweed, Russian thistle, rye grass, cat dander, cockroach, dog dander, dust mite (Dermatophagoides farinae and Dermatophagoides pteronyssinus), mouse and rat urine proteins, and selected foods (egg white, cow's milk, peanut, and shrimp). Serum samples were analyzed for total and allergen-specific IgE by using the Pharmacia CAP System. Information on allergy-related outcomes and demographics was collected by questionnaire.

RESULTS

In NHANES 2005-2006, 6.6% reported current hay fever, and 23.5% had current allergies. Allergy-related outcomes increased with increasing total IgE levels (adjusted odds ratios for a 10-fold increase in total IgE level of 1.86 [95% CI, 1.44-2.41] for hay fever and 1.64 [95% CI, 1.41-1.91] for allergies). Increased levels of plant-, pet-, and mold-specific IgE contributed independently to allergy-related symptoms. The greatest increase in odds was observed for hay fever and plant-specific IgE (adjusted odds ratio, 4.75; 95% CI, 3.83-5.88).

CONCLUSION

In the US population self-reported allergy symptoms are most consistently associated with increased levels of plant-, pet-, and mold-specific IgE.

Allergen-specific IgG antibody levels modify the relationship between allergen-specific IgE and wheezing in childhood

BACKGROUND

An increase in IgE antibody levels to inhalant allergens is associated with an increased likelihood of wheezing. The role of allergen-specific IgG and IgG4 in relation to wheezing is yet to be determined.

OBJECTIVE

We sought to investigate whether Fel d 1-specific IgG and IgG4 antibodies modify the association between cat allergen-specific IgE and childhood wheezing.

METHODS

We used data from 2 population-based birth cohorts (United Kingdom [UK], n = 473; Australia, n = 1336). Current wheeze was defined as wheezing in the previous 12 months at age 5 (UK) and 14 (Australia) years. We determined cat allergen-specific IgE (whole extract) and IgG and IgG4 antibody (purified rFel d 1) levels and used logistic regression to estimate the relationship between wheeze and the quantitative allergen antibody levels.

RESULTS

In the univariate analysis risk of wheezing increased significantly with increasing cat-specific IgE levels (UK: odds ratio [OR], 1.56; 95% CI, 1.28-1.90; Australia: OR, 1.29; 95% CI, 1.19-1.40). rFel d 1-specific IgG or IgG4 had no significant effect on wheeze in either population. However, a different pattern of the relationship between antibody levels and wheezing emerged in the multivariate analysis. In the UK cat-specific IgE increased the risk of wheeze (OR, 2.01; 95% CI, 1.29-3.12; P = .002), whereas rFel d 1-specific IgG decreased the risk (OR, 0.46; 95% CI, 0.21-0.99; P = .05). This finding was replicated in Australia (IgE: OR, 1.46; 95% CI, 1.28-1.68; P < .001; IgG: OR, 0.66; 95% CI, 0.44-0.99; P = .049). There was no significant association between IgG4 antibody levels and wheezing in either population.

CONCLUSIONS

rFel d 1-specific IgG but not IgG4 antibody levels significantly modify the association between cat-specific IgE and childhood wheezing, with the risk of symptoms decreasing with increasing IgG levels.

Mite component-specific IgE repertoire and phenotypes of allergic disease in childhood: the tropical perspective

Sensitization to perennial aeroallergens correlates with the risk of persistent asthma (AS) in children. In tropical Singapore, multiple codominant species of mites abound in the indoor environment, and preferential species-specific sensitization has been associated with different phenotypes of allergic disease. We investigated the pattern of mite component-specific IgE (mcsIgE) in children with different phenotypes of clinical allergic disease in an environment with multiple mite species exposure. A prospective evaluation of newly diagnosed patients with clinical diagnosis of allergic rhinitis (AR), atopic dermatitis (AD), or AS and sensitization to one or more aeroallergens were performed. Sera were tested for specific IgE against an extensive panel of Dermatophagoides pteronyssinus and Blomia tropicalis allergens. A total of 253 children were included, mean age 7.3 yr, 79% fulfilled criteria for AR, 46% AS, 71% AD, and 31% for all three. Sensitization to one or both mites was observed in 91% of children, 89% were sensitized to D. pteronyssinus, and 70% to B. tropicalis. The most common mite allergens recognized by these atopic children were Der p 1 (64%), Der p 2 (71%), Blo t 5 (45%), Blo t 7 (44%), and Blo t 21 (56%). Specific IgE responses to an increased number of distinct mite allergens correlated with the complexity of the allergic phenotype. In multivariate analysis, an increased risk for the multi-systemic phenotype (AR + AS + AD) was associated with sensitization to an increased repertoire of mite components (three or more) (OR 4.3, 95% CI 2.1-8.8, p = 0.001) and a positive parental history of AS (OR 2.4, 95% CI 1.2-2.9, p = 0.013). A highly pleiomorphic IgE response to the prevalent indoor mites is associated with the presence of a multi-systemic allergic phenotype in childhood in a tropical environment.

Alternaria sensitization and allergic rhinitis with or without asthma in the French Six Cities study

BACKGROUND

Allergic sensitization to Alternaria has been related to asthma in various studies, but its association with allergic rhinitis is still controversial.

OBJECTIVES

The aim of this study was to assess at the population level the relationships in childhood between Alternaria sensitization and 'past-year rhinoconjunctivitis' (PYRC), 'ever hay fever' (EHF) and 'ever allergic rhinitis caused by allergens other than pollens' (EAR) according to the presence or the absence of asthma.

METHODS

This study is part of the Six Cities Study, the French contribution to the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II. Children underwent skin prick test (SPT) to Alternaria and parents filled a standardized medical questionnaire.

RESULTS

Some 6726 children with a mean age of 10 years were examined. The overall prevalence of Alternaria sensitization was 2.8%, 0.8% for monosensitization. Prevalences of symptoms in sensitized children were 27.7% for PYRC, 27.0% for EHF and 30.4% for EAR. Adjusted Odds Ratios (OR) between Alternaria sensitization and allergic rhinitis phenotypes were 2.34 (95% confidence interval: 1.51-3.63) for PYRC, 2.40 (1.65-3.50) for EHF and 2.95 (2.05-4.23) for EAR. The relationship still remained in the case of monosensitization to Alternaria for both PYRC and EAR when excluding the asthmatic children [OR = 3.87 (1.54-9.78) and 2.88 (1.10-7.55) respectively].

CONCLUSION

In our population-based sample of children, we found a link between Alternaria sensitization and allergic rhinitis, independently of asthma, which is compatible with the mechanisms of deposition of Alternaria in the upper airways.

Establishing the incidence and prevalence of clinician-diagnosed allergic conditions in children and adolescents using routinely collected data from general practices

BACKGROUND

There remains a need to better characterize the epidemiology of allergic disorders, particularly in relation to describing the incidence, natural history and co-morbidity of allergic conditions.

OBJECTIVES

To estimate the incidence and prevalence of clinician-diagnosed eczema, asthma and rhinitis, alone and in combination, in children and adolescents in the United Kingdom.

METHODS

Using the national General Practice Research Database (GPRD) - one of the largest validated databases of routinely collected healthcare data in the world aggregating 3.6 million individuals - we constructed a retrospective birth cohort of 43,473 children born in the year 1990 and registered with a UK general practice within a year of birth. The cohort was followed until 2008 or the longest available follow-up period to determine the cumulative and age-specific incidence and prevalence rates of clinician-diagnosed eczema, asthma and rhinitis, and an 18-year prevalence of these conditions, alone and in combination.

RESULTS

Eczema had the highest incidence density of 226.9 per 10,000 person-years [95% confidence interval (CI): 225.8-228.0] followed by asthma [136.6;(95% CI: 135.7-137.5)] and rhinitis [61.4;(95% CI: 60.8-62.0)], by the age of 18 years. The incidence densities of suffering from one, two or all three allergic conditions were 323.2 (95% CI: 322.0-324.4), 206.4 (95% CI: 205.7-207.1) and 141.9 (95% CI: 141.4-142.4) per 10,000 person-years, respectively. Among the 24 112 children with a complete 18-year follow-up, eczema had the highest 18-year prevalence of clinician-diagnosed condition at 36.5% (95% CI: 35.9-37.2%) followed by asthma [22.9;(95% CI: 22.3-23.4%)] and rhinitis[11.4;(95% CI: 11.0-11.8%)]. The 18-year prevalence of more than one and all three conditions was 16.1% (95% CI: 15.6-16.6%) and 2.5% (95% CI: 2.4-2.8%), respectively.

CONCLUSIONS

This is one of the first studies to provide national estimates on the age-specific incidence and age-specific prevalence of the major allergic disorders showing clinician-diagnosed eczema, asthma and rhinitis to have high incidence rates in early childhood. A significant proportion of children experience and are diagnosed with multiple allergic conditions in early childhood.