Quantitative analysis of IgE antibodies to food and inhalant allergens in 4-year-old children reflects their likelihood of allergic disease

Long-term ozone exposure and lung function in middle childhood

BACKGROUND

Ozone (O3) exposure interrupts normal lung development in animal models. Epidemiologic evidence further suggests impairment with higher long-term O3 exposure across early and middle childhood, although study findings to date are mixed and few have investigated vulnerable subgroups.

METHODS

Participants from the CANDLE study, a pregnancy cohort in Shelby County, TN, in the ECHO-PATHWAYS Consortium, were included if children were born at gestational age >32 weeks, completed a spirometry exam at age 8-9, and had a valid residential history from birth to age 8. We estimated lifetime average ambient O3 exposure based on each child's residential history from birth to age 8, using a validated fine-resolution spatiotemporal model. Spirometry was performed at the age 8-9 year study visit to assess Forced Expiratory Volume in the first second (FEV1) and Forced Vital Capacity (FVC) as primary outcomes; z-scores were calculated using sex-and-age-specific reference equations. Linear regression with robust variance estimators was used to examine associations between O3 exposure and continuous lung function z-scores, adjusted for child, sociodemographic, and home environmental factors. Potential susceptible subgroups were explored using a product term in the regression model to assess effect modification by child sex, history of bronchiolitis in infancy, and allergic sensitization.

RESULTS

In our sample (n = 648), O3 exposure averaged from birth to age 8 was modest (mean 26.6 [SD 1.1] ppb). No adverse associations between long-term postnatal O3 exposure were observed with either FEV1 (β = 0.12, 95% CI: -0.04, 0.29) or FVC (β = 0.03, 95% CI: -0.13, 0.19). No effect modification by child sex, history of bronchiolitis in infancy, or allergic sensitization was detected for associations with 8-year average O3.

CONCLUSIONS

In this sample with low O3 concentrations, we did not observe adverse associations between O3 exposures averaged from birth to age 8 and lung function in middle childhood.

Early inhalant allergen sensitization at component level: an analysis in atopic Dutch children

Background

Allergic rhinitis is a common respiratory disease in children and sensitization to inhalant allergens plays a significant role in its development. However, limited knowledge exists regarding sensitization profiles of inhalant allergen components in atopic children, particularly in the very young individuals. Understanding these profiles could provide insights into the early development of allergic rhinitis. The objective of this cross-sectional retrospective study was to evaluate the IgE-sensitization profiles to multiple inhalant allergen components and their clinical relevance in Dutch atopic children, with specific focus on children under the age of 4 years.

Methods

A total of 243 atopic children were included in the study and sensitization profiles were analyzed using multiplex microarray analysis (ISAC). Clinical information was obtained from records of a pediatric allergy outpatient clinic between 2011 and 2020. Specific IgE responses to inhalation allergen components from five allergen sources (grass pollen, tree pollen, house dust mite, cat and dog), were examined. The study encompassed children of different age groups and compared those with and without symptoms.

Results

The results demonstrated that sensitization to inhalant allergen components was present in 92% of the cohort. Sensitization was already evident at a young age (87%), including infancy, with a rapid increase in prevalence after 1 year of age. House dust mite emerged as the most predominant sensitizing allergen in early childhood, followed by tree pollen in later years. Sensitization patterns were similar between symptomatic and asymptomatic children, although symptomatic children exhibited higher frequencies and values. The sensitization profiles in very young children were comparable to those of children across all age groups.

Conclusion

These findings highlight the presence of sensitization to inhalant allergen components and the early onset of allergic rhinitis before the age of 4, including infancy, in Dutch atopic children. Notable allergen molecules in Dutch atopic children under the age of 4 years include Bet v 1, Fel d 1, Der f 1, Der p 1, Der p 10 and Phl p 4, with house dust mite sensitization being the most common among Dutch infants. Moreover, the prevalence of sensitization to inhalant allergens in this Dutch cohort surpassed that of general European populations, emphasizing the importance of early assessment and management of allergic rhinitis in young atopic children.

Intact Transition Epitope Mapping—Serological Inspection by Epitope EXtraction (ITEM—SIX)

Precision medicine requests accurate serological inspections to precisely stratify patients for targeted treatment. Intact transition epitope mapping analysis proved surrogate seroconversion of a model organism’s serum when spiked with a monoclonal murine anti-Ovalbumin antibody (mAb) with epitope resolution. Isolation of the IgG fraction from blood serum applied two consecutive protein precipitation steps followed by ultrafiltration and resulted in an ESI-MS analysis-ready IgG preparation. For epitope mapping by epitope extraction, the Ovalbumin antigen was digested with trypsin. After desalting, the peptide mixture was added to the ESI-MS-ready IgG preparation from mAb-spiked serum and the solution was incubated to form an immune complex between the Ovalbumin-derived epitope peptide and the anti-Ovalbumin mAb. Then, the entire mixture of proteins and peptides was directly electrosprayed. Sorting of ions in the mass spectrometer’s gas phase, dissociation of the immune complex ions by collision-induced dissociation, and recording of the epitope peptide ion that had been released from the immune complex proved the presence of the anti-Ovalbumin mAb in serum. Mass determination of the complex-released epitope peptide ion with isotope resolution is highly accurate, guaranteeing high specificity of this novel analysis approach, which is termed Intact Transition Epitope Mapping—Serological Inspections by Epitope EXtraction (ITEM—SIX).

Relevance of low specific IgE levels to egg, milk and peanut in infancy

BACKGROUND

IgE sensitization is usually associated with allergy-related diseases, but may also occur in asymptomatic individuals. The clinical importance of IgE antibody concentrations in the interval 0.1-0.34 kU/L in early life in relation to allergy development is poorly evaluated.

OBJECTIVE

To assess the relevance of low specific IgE (s-IgE) to hen's egg, cow's milk and peanut at 6 months of age for development of sensitization and allergy-related disease during early childhood.

METHODS

s-IgE concentrations to relevant allergens from blood samples taken at 6 months and 1, 2 and 5 years from children in the prospective ALADDIN cohort were divided into three categories: non-sensitized (<0.1 kU/L), low sensitized (0.1-0.34 kU/L) and sensitized (≥0.35 kU/L) and allergy-related disease assessed.

RESULTS

A total of 372 children were included in this study. Compared with non-sensitized children at 6 months of age, children with low levels of allergen specific IgE (0.1-0.34 kU/L) to food allergens, especially to egg, at 6 months of age were associated with development of sensitization to aeroallergens at 5 years of age (10/14 [71%] vs 39/250 [15%]). In addition, children with low levels to egg or milk at 6 months were more often sensitized to the respective allergen at 1 year of age and, regarding low levels to egg, also to the development of eczema (6/18 [33%] vs 29/292 [10%]).

CONCLUSION & CLINICAL RELEVANCE

IgE antibody concentrations in the interval 0.1-0.34 kU/L to food allergens in infancy seem to increase the probability of sensitization to aeroallergens and, regarding low levels to egg, also of eczema during early childhood. Thus, IgE levels during the first year of life, although below 0.35 kU/L, can provide additional allergy-related prognostic information.

Investigating the association between allergen-specific immunoglobulin E, cancer risk and survival

Prior findings linking allergy and cancer have been inconsistent, which may be driven by diverse assessment methods. We used serum specific immunoglobulin E (IgE) against common inhalant allergens that was assessed prior to cancer diagnosis in studying this association. We selected 8,727 Swedish men and women who had measurements of serum allergen-specific IgE and total IgE between 1992 and 1996. Multivariable Cox regression using age as a timescale was performed to assess the associations of IgE sensitization, defined by any levels of serum specific IgE ≥35 kU/L, with risk of overall and specific cancers. A test for trend was performed by assigning scores derived from allergen-specific IgE levels at baseline as an ordinal scale. Kaplan-Meier curves and log-rank test were used to assess cancer survival by IgE sensitization status. During a mean follow-up of 16 year, 689 persons were diagnosed with cancer. We found an inverse association between IgE sensitization and cancer risk, with a hazard ratio (HR) of 0.83 and 95% confidence intervals (CI) of 0.70-0.99. A similar trend was seen with specific IgE scores overall (Ptrend = 0.007) and in women (Ptrend = 0.01). Although IgE sensitization was not associated with risk of common site-specific cancers, serum specific IgE scores were inversely associated with melanoma risk in men and women combined, and with risk of female breast and gynecological cancers combined. No association with survival was observed. The association between circulating IgE levels and incident cancer may point toward a role of T-helper 2 (TH2)-biased response in development of some cancers.

House dust-mite allergen exposure is associated with serum specific IgE but not with respiratory outcomes

Exposure to house dust has been associated with asthma in adults, and this is commonly interpreted as a direct immunologic response to dust-mite allergens in those who are IgE sensitized to house dust-mite. Mattress house dust-mite concentrations were measured in a population-based sample of 2890 adults aged between 27 and 56 years living in 22 centers in 10 countries. Generalized linear mixed models were employed to explore the association of respiratory symptoms with house dust-mite concentrations, adjusting for individual and household confounders. There was no overall association of respiratory outcomes with measured house dust-mite concentrations, even in those who reported they had symptoms on exposure to dust and those who had physician-diagnosed asthma. However, there was a positive association of high serum specific IgE levels to HDM (>3.5 kUA /l) with mattress house dust-mite concentrations and a negative association of sensitization to cat with increasing house dust-mite concentrations. In conclusion, there was no evidence that respiratory symptoms in adults were associated with exposure to house dust-mite allergen in the mattress, but an association of house mite with strong sensitization was observed.

Aeroallergen and food IgE sensitization and local and systemic inflammation in asthma

BACKGROUND

We recently reported an independent association between IgE sensitization to food allergens and increased airway inflammation, assessed by fraction of exhaled nitric oxide (FeNO), in a population-based study (J Allergy Clin Immunol, 130, 2012, 397). Similar studies have not been performed in populations with asthma. The aim of the present study was to investigate the allergic sensitization profile in asthmatics and examine FeNO, airway responsiveness and blood eosinophilia in relation to type and degree of IgE sensitization.

METHOD

FeNO, airway responsiveness, blood eosinophil count (B-Eos) and IgE sensitization to food allergens and aeroallergens were determined in 408 subjects with asthma, aged 10-34 years.

RESULTS

Asthmatics had higher prevalence of IgE sensitization against all allergens than controls (P < 0.001). Mite, pollen, furry animal, mould and food sensitizations were each associated with increased FeNO, airway responsiveness and B-Eos in asthmatics. IgE sensitization to mould, furry animals and food allergens was independently related to FeNO (all P < 0.05) after adjustment for age, sex, height, smoking history and medication. IgE sensitization to mould (P < 0.001) and furry animals (P = 0.02) was related to airway responsiveness in a similar model. Finally, IgE sensitization to mould (P = 0.001), furry animals (P < 0.001) and food allergens (P < 0.001) was independently related to B-Eos.

CONCLUSION

Independent effects of IgE sensitization to aeroallergens (furry animals and mould) and food allergens were found on both local and systemic markers of inflammation in asthma. The finding regarding food IgE sensitization is novel, and a clinical implication might be that even food sensitization must be assessed to fully understand inflammation patterns in asthma.

The link between parental allergy and offspring allergic and nonallergic rhinitis

BACKGROUND

Parental allergy-related disease increases the risk for rhinitis, but it remains unknown how different phenotypes of parental allergy affect this risk. The aim of this study was to investigate how parental hay fever, asthma, and eczema affect the risk of allergic rhinitis (AR) and nonallergic rhinitis (NAR) at 8 years of age.

METHODS

Information on 2413 children from a population-based birth cohort was used combining questionnaire data and IgE to inhalant allergens. Logistic regression was used to estimate the association between parental allergy-related disease and AR and NAR. In addition, cluster analysis was used to search for latent phenotypes of heredity likely to be associated with AR and NAR.

RESULTS

At age 8 years, 13.8% of the children had AR, while 6.4% had NAR. Parental isolated hay fever increased the odds of AR (OR 2.2, 95% CI 1.6-3.2), whereas isolated asthma or eczema did not. The odds of NAR increased when one parent had two or more allergy-related diseases. In the cluster analysis, the highest proportion of AR, 37.5%, was seen in a cluster where both parents had hay fever and pollen allergy and that of NAR, 11.0%, in a cluster where one parent had hay fever, pollen allergy, and eczema.

CONCLUSIONS

Parental allergy-related disease may be an important risk factor for NAR as well as AR, and the risk is comparable for maternal and paternal allergy. Parental hay fever seems to be the dominating hereditary risk factor for AR.

Prevalence of IgE sensitization in Danish children with suspected asthma

OBJECTIVE

The aim of this article was to estimate the prevalence of IgE sensitization in Danish children with suspected asthma and to characterize the pattern of sensitization.

STUDY DESIGN

We performed a cross-sectional study including 1744 children from 0 to 15 yr suspected of asthma who were referred to pediatric outpatient clinics in the region of southern Denmark from 2003 to 2005. The children were subjected to an extensive questionnaire-based interview, clinical examination, and both skin prick testing (SPT) and IgE measurements for 17 allergens.

RESULTS

Asthma was confirmed in 1024 of the 1744 children. Among the children in whom the asthma diagnosis was confirmed, sensitization to one or more of the 17 allergens tested was found in 67.5% by either SPT or s-IgE ≥ class 2. Sensitization to any food allergen was found in 31.1%, to any outdoor allergen in 36.2%, and to any indoor allergen in 51.8%. Sensitization to cockroach and latex was rare. We found a weak correlation between SPT and s-IgE among food allergens and a more distinct correlation among inhalant allergens. Surprisingly, 30.1% of children in whom the asthma diagnosis was disproven used inhaled corticosteroids (ICS). On the contrary, 32.5% of the children for whom the asthma diagnosis was verified were not treated with ICS.

CONCLUSION

We have found a high prevalence of sensitization among children with verified asthma. Our study supports relevant allergy testing in all children with verified asthma and emphasizes the importance of a thorough asthma diagnosis before prescribing continuous inhaled corticosteroids to children.

Mammalian-derived respiratory allergens - implications for diagnosis and therapy of individuals allergic to furry animals

Furry animals cause respiratory allergies in a significant proportion of the population. A majority of all mammalian allergens are spread as airborne particles, and several have been detected in environments where furry animals are not normally kept. The repertoire of allergens from each source belongs to a restricted number of allergen families. Classification of allergen families is particularly important for the characterization of allergenicity and cross-reactivity of allergens. In fact, major mammalian allergens are taken from only three protein families, i.e. the secretoglobin, lipocalin and kallikrein families. In particular, the lipocalin superfamily harbours major allergens in all important mammalian allergen sources, and cross-reactivity between lipocalin allergens may explain cross-species sensitization between mammals. The identification of single allergen components is of importance to improve diagnosis and therapy of allergic patients using component-resolved diagnostics and allergen-specific immunotherapy (ASIT) respectively. Major disadvantages with crude allergen extracts for these applications emphasize the benefits of careful characterization of individual allergens. Furthermore, detailed knowledge of the characteristics of an allergen is crucial to formulate attenuated allergy vaccines, e.g. hypoallergens. The diverse repertoires of individual allergens from different mammalian species influence the diagnostic potential and clinical efficacy of ASIT to furry animals. As such, detailed knowledge of individual allergens is essential for adequate clinical evaluation. This review compiles current knowledge of the allergen families of mammalian species, and discusses how this information may be used for improved diagnosis and therapy of individuals allergic to mammals.

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.

Role of biomarkers in understanding and treating children with asthma: towards personalized care

Asthma is one of the most common chronic diseases affecting children. Despite publicized expert panels on asthma management and the availability of high-potency inhaled corticosteroids, asthma continues to pose an enormous burden on quality of life for children. Research into the genetic and molecular origins of asthma are starting to show how distinct disease entities exist within the syndrome of "asthma". Biomarkers can be used to diagnose underlying molecular mechanisms that can predict the natural course of disease or likely response to drug treatment. The progress of personalized medicine in the care of children with asthma is still in its infancy. We are not yet able to apply stratified asthma treatments based on molecular phenotypes, although that time may be fast approaching. This review discusses some of the recent advances in asthma genetics and the use of current biomarkers that can help guide improved treatment. For example, the fraction of expired nitric oxide and serum Immunoglobulin E (IgE) (including allergen-specific IgE), when evaluated in the context of recurrent asthma symptoms, are general predictors of allergic airway inflammation. Biomarker assays for secondhand tobacco smoke exposure and cysteinyl leukotrienes are both promising areas of study that can help personalize management, not just for pharmacologic management, but also education and prevention efforts.

Prevalence and co-occurrence of parentally reported possible asthma and allergic manifestations in pre-school children

Background

The aim of this study was to make an in-depth analysis of the prevalence and co-occurrence in pre-school children of possible asthma and atopic manifestations.

Methods

In Sweden 74%-84% of preschool children, depending on age, attend municipality organised day-care centres. Parents of 5,886 children 1–6 years of age, sampled from day-care centres in 62 municipalities all over Sweden, responded to a postal questionnaire regarding symptoms indicating prevalent possible asthma, allergic rhinitis, eczema, and food, furred pet and pollen allergy and other data in their children. Possible asthma was defined as any of the four criteria wheezing four times or more during the last year, physician diagnosis and current wheezing, ever had asthma and current wheezing, and current use of inhalation steroids, all based on questionnaire responses.

Results

The overall prevalence of possible asthma was 8.9%, of eczema 21.7%, of rhinitis 8.1%, and of food allergy 6.6%. There was a highly significant co-occurrence between possible asthma and all atopic manifestations, 35.7% having any of the manifestations. Presence of pet allergy was the manifestation showing the closest co-occurrence with presence of possible asthma, presence of pollen allergy with presence of rhinitis, and presence of food allergy with presence of eczema. Assessed from plots of age-specific prevalence of possible asthma, rhinitis, eczema and food allergy, the prevalence of all manifestations increased from one to three years of age and then decreased, except for rhinitis where the prevalence increased until six years of age, indicating no specific ordered sequence.

Conclusions

Parentally reported possible asthma, eczema and food allergy had a curvilinear prevalence course across age with a maximum at age 3, while rhinitis prevalence increased consistently with age. Co-occurrence between possible asthma and atopic manifestations was common, and some combinations were more common than others, but there was no evidence of a specific ordered onset sequence.

Direct and indirect exposure to horse: risk for sensitization and asthma

Most studies on the sensitization to horse allergens in populations without professional exposure have been carried out in geographical areas where the rate of horse ownership is high and horse riding is popular. Very few studies have been carried out in populations living in large urban areas. This gap in the literature probably reflects the widespread view that prevalence of horse-related allergy is low in urban populations because the latter are not regularly exposed to horses. On the contrary, we suggest that urban areas constitute a model useful to study potential modalities of exposure and sensitization to horse allergen by other routes of exposure than horse-riding. In this article, we describe the risks related to various modalities of exposure to horse allergen, clinical aspects of airway sensitization to horse allergens in patients living in urban areas, and non-occupational exposure to horse allergen. In addition, we illuminate some aspects related to dispersion of horse allergens from sources such as stables to indoor environments.

Allergy Diagnosis in Children and Adults: Performance of a New Point-of-Care Device, ImmunoCAP Rapid

BACKGROUND

: Allergy is a serious problem affecting approximately 1 of 4 individuals. The symptoms with and without allergy etiology are often difficult to distinguish from each other without using an IgE antibody test. The aim of this study was to investigate the performance of a new point-of-care (POC) test for IgE antibodies to relevant allergens in Europe.

METHODS

: IgE antibodies from children and adults with allergies recruited from allergy clinics in Sweden and Spain were analyzed for 10 allergens, suitable for the age groups, using the new POC test and ImmunoCAP laboratory test. The IgE antibody level best discriminating between positive and negative results (the cutoff point) for the different allergens of the POC test and the efficacy of the POC and the ImmunoCAP laboratory tests for diagnosing allergy compared with that of clinical diagnosis were investigated.

RESULTS

: The estimated cutoffs for the different allergens in the POC test ranged from 0.70 to 2.56 kUA/L. Taking into account all positive allergen results in a given patient, the POC test could identify 95% of the patients with allergies. Seventy-eight percent of the allergen-specific physicians' diagnoses were identified and 97% of the negative ones. Most allergens exhibited good performance, identifying about 80% of clinically relevant cases. However, dog, mugwort, and wall pellitory would benefit from improvement.

CONCLUSIONS

: The POC test will be a valuable adjunct in the identification or exclusion of patients with allergies and their most likely offending allergens, both in specialist and general care settings.

Impact of atopy on asthma and allergic rhinitis in the cohort for reality and evolution of adult asthma in Korea

PURPOSE

Atopy is an important cause of asthma. Few data on the prevalence of atopy or comparisons with clinical characteristics of asthma in Korean patients have been published. We evaluated the effects of atopy on clinical profiles and airway inflammation in Korean asthmatics.

METHODS

We retrospectively enrolled 1,492 asthmatics from the Cohort for Reality and Evolution of Adult Asthma in Korea (COREA) cohort who had undergone skin prick tests for aeroallergens. The patients' clinical characteristics, lung function, PC20, and sputum and blood inflammatory cell counts were compared based on the presence or absence of atopy. Atopy was defined as one or more positive reactions (A/H ratio >1) on a skin prick test.

RESULTS

Among 11 aeroallergens, house dust mites (Dermatophagoides farinae and Dermatophagoides pteronyssinus) were the most prevalent cause of a positive skin prick test. As compared with non-atopic asthmatics, atopic asthmatics showed early onset of the disease. Atopic patients with asthma had a higher FEV1, FVC, and FEV1/FVC as compared with non-atopic patients with asthma. In addition, asthmatics without atopy had more uncontrolled asthma (P=0.001) and severe rhinitis (P<0.05) as compared with atopic asthmatics. Smoking, as measured in pack years, was higher in the non-atopic asthmatics than in the atopic asthmatics. The erythrocyte sedimentation rate was higher in non-atopic asthmatics than in the atopic asthmatics and patients with non-atopic asthma had a higher sputum neutrophil count than did those with atopic asthma.

CONCLUSIONS

Our data indicate that atopic asthmatics had an early onset of disease and high IgE levels, while the non-atopic asthmatics had decreased lung function and a high sputum neutrophil count, suggesting that a different approach is needed to treat atopic asthma.

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.

Asthma outcomes: biomarkers

BACKGROUND

Measurement of biomarkers has been incorporated within clinical research studies of asthma to characterize the population and associate the disease with environmental and therapeutic effects.

OBJECTIVE

National Institutes of Health institutes and federal agencies convened an expert group to propose which biomarkers should be assessed as standardized asthma outcomes in future clinical research studies.

METHODS

We conducted a comprehensive search of the literature to identify studies that developed and/or tested asthma biomarkers. We identified biomarkers relevant to the underlying disease process progression and response to treatment. We classified the biomarkers as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Ten measures were identified; only 1, multiallergen screening to define atopy, is recommended as a core asthma outcome. Complete blood counts to measure total eosinophils, fractional exhaled nitric oxide (Feno), sputum eosinophils, urinary leukotrienes, and total and allergen-specific IgE are recommended as supplemental measures. Measurement of sputum polymorphonuclear leukocytes and other analytes, cortisol measures, airway imaging, breath markers, and system-wide studies (eg, genomics, proteomics) are considered as emerging outcome measures.

CONCLUSION

The working group participants propose the use of multiallergen screening in all asthma clinical trials to characterize study populations with respect to atopic status. Blood, sputum, and urine specimens should be stored in biobanks, and standard procedures should be developed to harmonize sample collection for clinical trial biorepositories.

Severe episodic viral wheeze in preschool children: High risk of asthma at age 5-10 years

In population studies, most children with episodic viral wheeze (EVW) become symptom free by 6 years. We studied the outcome of children with severe EVW, treated and followed up in hospital. We followed up 78 children <4 years, managed by paediatricians for severe EVW, to the age of 5-10 years. We recorded respiratory symptoms, spirometry and exhaled nitric oxide (FeNO). At follow-up, 42 children (54%) had current wheeze or dyspnoea, and 52 (67%) had current asthma. There was no significant difference between children with and without current asthma in FEV1 (p = 0.420), but FeNO was higher in children with current asthma (median (interquartile range) 14.5 (11.25-21.50) ppb) than in those without (12.0 (10.0-13.8) ppb, p = 0.020). Positive family history of asthma was the only factor associated with current asthma (odds ratio 8.77, 95% CI 2.88-26.69, p < 0.001). This remained significant after adjustment for duration of follow-up, gender and parental smoking. Conclusion. Severe EVW at preschool age has a high risk of asthma at age 5-10 years, and this is reinforced by a positive family history of asthma and to elevated FeNO levels.

Natural course and comorbidities of allergic and nonallergic rhinitis in children

BACKGROUND

Not much data are available from large, unselected, birth cohort studies on the natural course and comorbidities of rhinitis in children.

OBJECTIVE

To study phenotypes of rhinitis in relation to the natural course and comorbidities of allergic diseases in preschool-age and early school-age children.

METHODS

We analyzed data from a birth cohort of 2024 children, for whom information on IgEs against 8 common inhaled allergens was available, collected at age 4 and 8 years. The children were assigned to groups of allergic rhinitis (rhinitis with sensitization to allergens), nonallergic rhinitis (rhinitis without sensitization), allergic sensitization but no rhinitis, or neither rhinitis nor sensitization.

RESULTS

The proportion of children with allergic rhinitis increased from 5% to 14% from age 4 to 8 years, whereas the proportion of children with nonallergic rhinitis decreased slightly over the same period of development, from 8% to 6%. Of the children with allergic rhinitis when they were 4 years old, 12% underwent remission by the time they were 8 years old; of the children with nonallergic rhinitis, 73% underwent remission during this period of development. Among 4-year-olds without rhinitis who were sensitized to allergen, 56% had allergic rhinitis when they were 8 years old. Among 4- and 8-year-olds, allergic rhinitis and nonallergic rhinitis were associated with asthma, eczema, and food hypersensitivity. Twenty-five percent of 8-year-olds with allergic rhinitis also had oral allergy syndrome.

CONCLUSIONS

Fewer preschool-age children with allergic rhinitis undergo remission than do those with nonallergic rhinitis. Sensitization to inhaled allergens at an early age (4 years) precedes the development of allergic rhinitis, whereas symptoms of rhinitis do not. Oral allergy syndrome is common among 8-year-olds with allergic rhinitis.

Ciclesonide in wheezy preschool children with a positive asthma predictive index or atopy

BACKGROUND

Few large-scale studies have examined inhaled corticosteroid treatment in preschool children with recurrent wheeze. We assessed the effects of ciclesonide in preschool children with recurrent wheeze.

METHODS

We included children 2-6 yrs with recurrent wheeze and a positive asthma predictive index or aeroallergen sensitization to, excluding patients with episodic viral wheezing. After a 2-4-week baseline period, patients with ongoing symptoms or rescue medication use were randomised to once-daily ciclesonide 40, 80, 160 μg or placebo for 24 weeks.

RESULTS

The number of wheeze exacerbations requiring systemic corticosteroids was unexpectedly low in all groups: 25 (10.2%) in placebo group, as compared to 11 (4.4%), 18 (7.3%), and 17 (6.7%) in ciclesonide 40, 80, and 160 μg, respectively. The difference in time to first exacerbation was not significantly different between groups (p = 0.786), but the difference in exacerbation rates between placebo and the pooled ciclesonide groups was (p = 0.03). Large and significant (p < 0.0001) improvements in symptom scores and rescue medication use occurred in all groups, including placebo. Improvements in FEV(1) and FEF(25-75) (measured in 284 4-6 yr olds) were larger in the ciclesonide than in the placebo group. No differences in safety parameters (adverse events, height growth, serum and urinary cortisol levels) between ciclesonide and placebo were observed.

CONCLUSIONS

In preschool children with recurrent wheeze and a positive asthma predictive index, ciclesonide modestly reduces wheeze exacerbation rates and improves lung function. A large placebo response and unexpected selection of patients with mild disease may have affected outcomes, highlighting the heterogeneity of preschool wheezing disorders.

Serum IgE reactivity profiling in an asthma affected cohort

BACKGROUND

Epidemiological evidence indicates that atopic asthma correlates with high serum IgE levels though the contribution of allergen specific IgE to the pathogenesis and the severity of the disease is still unclear.

METHODS

We developed a microarray immunoassay containing 103 allergens to study the IgE reactivity profiles of 485 asthmatic and 342 non-asthmatic individuals belonging to families whose members have a documented history of asthma and atopy. We employed k-means clustering, to investigate whether a particular IgE reactivity profile correlated with asthma and other atopic conditions such as rhinitis, conjunctivitis and eczema.

RESULTS

Both case-control and parent-to-siblings analyses demonstrated that while the presence of specific IgE against individual allergens correlated poorly with pathological conditions, particular reactivity profiles were significantly associated with asthma (p<10E-09). An artificial neural network (ANN)-based algorithm, calibrated with the profile reactivity data, correctly classified as asthmatic or non-asthmatic 78% of the individual examined. Multivariate statistical analysis demonstrated that the familiar relationships of the study population did not affect the observed correlations.

CONCLUSIONS

These findings indicate that asthma is a higher-order phenomenon related to patterns of IgE reactivity rather than to single antibody reactions. This notion sheds new light on the pathogenesis of the disease and can be readily employed to distinguish asthmatic and non-asthmatic individuals on the basis of their serum reactivity profile.

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.

Atopic predisposition of recipients in allergic transfusion reactions to apheresis platelets

BACKGROUND

The biologic mechanisms of allergic transfusion reactions (ATRs) are largely unknown. We sought to compare the atopic predisposition of platelet (PLT) recipients who experienced an ATR to nonreactive control recipients.

STUDY DESIGN AND METHODS

We identified 37 consecutive apheresis PLT recipients who experienced an ATR and 26 matched controls. Total immunoglobulin (Ig)E and aero- and food allergen-specific IgE were quantified in plasma by a blood test for allergies (ImmunoCAP: Phadiatop and Fx5). IgE testing of apheresis PLT supernatants was also performed.

RESULTS

Pruritus and urticaria were manifest in 91.9 and 83.8% of all ATRs, with more severe respiratory symptoms and angioedema occurring in less than 15% of cases. No subject had anaphylaxis. Sex, age, and primary diagnosis were balanced between the two groups. Total and aeroallergen-specific IgE was higher among subjects experiencing an ATR in comparison to control subjects (median total IgE, 55.5 kU/L vs. 8.3 kU/L, p = 0.002; and median aeroallergen-specific IgE, 0.57 kUa/L vs. 0.36 kUa/L, p = 0.046). IgE antibody levels in apheresis products associated with ATRs were similar to control products (p > 0.1 for all IgE tests).

CONCLUSION

Recipient atopic predisposition, as defined by IgE sensitization, is a risk factor associated with ATRs.

Questionnaire predictors of atopy in a US population sample: findings from the National Health and Nutrition Examination Survey, 2005-2006

Allergic conditions and biochemical measures are both used to characterize atopy. To assess questionnaires' ability to predict biochemical measures of atopy, the authors used data on 5 allergic conditions (allergy, hay fever, eczema, rhinitis, and itchy rash) and serum-specific immunoglobulin E (IgE) levels from the 2005-2006 National Health and Nutrition Examination Survey. Atopy was defined as 1 or more positive specific IgEs (≥0.35 kU/L). Questionnaire responses were assessed for sensitivity, specificity, and positive and negative predictive values for atopy. In this population-based US sample, 44% of participants were specific IgE-positive and 53% reported at least 1 allergic condition. Discordance between atopy and allergic conditions was considerable; 37% of persons with atopy reported no allergic condition, and 48% of persons who reported an allergic condition were not atopic. Thus, no combination of self-reported allergic conditions achieved both high sensitivity and high specificity for IgE. The positive predictive value of reported allergic conditions for atopy ranged from 50% for eczema to 72% for hay fever, while the negative predictive value ranged from 57% for eczema to 65% for any condition. Given the high proportion of asymptomatic participants who were specific IgE-positive and persons who reported allergic conditions but were specific IgE-negative, it is unlikely that questionnaires will ever capture the same participants as those found to be atopic by biochemical measures.

Inflammatory markers in childhood asthma

The major characteristic of asthma is persistent airway inflammation that fails to resolve spontaneously. Dysregulation of pro- and anti-inflammatory mechanisms is responsible for the development of chronic inflammation. The inflammatory reaction is mediated by numerous cells and their mediators. Detection and quantification of airway inflammation in children are subject to many requirements, e.g., use of biologic samples obtained in a non-invasive way; use of standardized analytical methods to determine biomarkers that can identify inflammation processes (inflammation itself, oxidative stress, apoptosis and remodelling); determining the role of systemic inflammation; assessment of correlation of various biomarkers of inflammation with clinical parameters and their diagnostic efficacy; providing a tool(s) to monitor diseases, and to evaluate adequacy of therapy; and predicting the clinical course of inflammation and prognosis of asthma. Using standardized analyses, it is now possible to determine direct markers of local inflammation, i.e., fractional nitric oxide (marker of oxidative stress) in exhaled breath, pH (marker of acid stress) in breath condensate, and indirect markers in blood/serum, i.e., eosinophil granulocytes (indicating migration), eosinophil cationic protein (marker of activated eosinophil granulocytes) and C-reactive protein (marker of systemic inflammation). However, none of these biomarkers are specific for asthma. Further standardization of the known pulmonary biomarkers of local inflammation and identification of new ones will allow for longitudinal follow-up of inflammation in children with asthma.

National prevalence and risk factors for food allergy and relationship to asthma: results from the National Health and Nutrition Examination Survey 2005-2006

BACKGROUND

The national prevalence and patterns of food allergy (FA) in the United States are not well understood.

OBJECTIVE

We developed nationally representative estimates of the prevalence of and demographic risk factors for FA and investigated associations of FA with asthma, hay fever, and eczema.

METHODS

A total of 8203 participants in the National Health and Nutrition Examination Survey 2005-2006 had food-specific serum IgE measured to peanut, cow's milk, egg white, and shrimp. Food-specific IgE and age-based criteria were used to define likely FA (LFA), possible FA, and unlikely FA and to develop estimates of clinical FA. Self-reported data were used to evaluate demographic risk factors and associations with asthma and related conditions.

RESULTS

In the United States, the estimated prevalence of clinical FA was 2.5% (peanut, 1.3%; milk, 0.4%; egg, 0.2%; shrimp, 1.0%; not mutually exclusive). Risk of possible FA/LFA was increased in non-Hispanic blacks (odds ratio, 3.06; 95% CI, 2.14-4.36), males (1.87; 1.32-2.66), and children (2.04; 1.42-2.93). Study participants with doctor-diagnosed asthma (vs no asthma) exhibited increased risk of all measures of food sensitization. Moreover, in those with LFA, the adjusted odds ratio for current asthma (3.8; 1.5-10.7) and an emergency department visit for asthma in the past year (6.9; 2.4-19.7) were both notably increased.

CONCLUSION

Population-based serologic data on 4 foods indicate an estimated 2.5% of the US population has FA, and increased risk was found for black subjects, male subjects, and children. In addition, FA could be an under-recognized risk factor for problematic asthma.

Asthma, allergy, and IgE levels in NYC head start children

BACKGROUND

Among preschool-age children in New York City neighborhoods with high asthma hospitalization rates, we analyzed the associations of total immunoglobulin E (IgE), specific IgE to common indoor allergens, and allergy symptoms with asthma.

METHODS

Parents of children in New York City Head Start programs were asked to complete a questionnaire covering demographic factors, health history (including respiratory conditions), lifestyle, and home environment. Children's serum samples were analyzed for total IgE and specific IgE antibodies to cockroach, dust mite, mouse, and cat allergens by immunoassay. Logistic regression was used to model the association between asthma and IgE, controlling for age, gender, ethnicity/national origin, BMI, parental asthma, smokers in the household, and allergy symptoms (e.g., runny nose, rash).

RESULTS

Among 453 participating children (mean age 4.0+/-0.5 years), 150 (33%) met our criteria for asthma. In our multivariable logistic regression models, children with asthma were more likely than other children to be sensitized to each allergen, to be sensitized to any of the four allergens (OR=1.6, 95% CI 1.0-2.6), or to be in the highest quartile of total IgE (OR=3.1, 95% CI 1.5-6.4). Allergy symptoms based on questionnaire responses were independently associated with asthma (OR=3.7, 95% CI 2.3-5.9).

CONCLUSIONS

Among preschool-aged urban children, asthma was associated with total IgE and sensitization to cat, mouse, cockroach, and dust mite allergens. However, allergy symptoms were more prevalent and more strongly associated with asthma than was any allergen-specific IgE; such symptoms may precede elevated specific IgE or represent a different pathway to asthma.

Dynamic evolution of serum immunoglobulin E to airborne allergens throughout childhood: results from the Multi-Centre Allergy Study birth cohort

BACKGROUND

Allergic rhinoconjunctivitis and asthma evolve dynamically throughout childhood. Yet, data on the evolution of serum levels of IgE antibodies against airborne allergens throughout the first decade of life are scarce.

OBJECTIVE

To describe the patterns of new and persistent sensitization against airborne allergens including remission from birth to 10 years of age and the long-term clinical outcomes up to the age of 13 years.

METHODS

In 273 children from the Multi-Centre Allergy Study, a German birth cohort, IgE levels were determined against airborne allergens (Dermatophagoides pteronyssinus, cat and dog dander, birch and grass species pollens) at 2, 5, 7, and 10 years of age (ImmunoCAP, Phadia); allergic rhino-conjunctivitis and asthma were ascertained at the 13 years of age through a standardized questionnaire (International Study of Asthma and Allergies in Childhood).

RESULTS

The prevalence of sensitization to each allergen increased steadily throughout childhood, and a hierarchy of sensitization prevalence (grass>birch>mites>cat>dog) was maintained from 5 years of age onwards. A mono-sensitization state was relatively short (measurable half-life=3 years) as additional sensitizations were acquired frequently, and relatively soon after the first one. Remission of weak sensitization (UNICAP classes 1-2) was also quite frequent, especially before 5 years of age. By contrast, stronger IgE responses (>3.5 kU/L) were invariably persistent. Early sensitization was associated with a higher tendency for poly-sensitization at 10 years of age and allergic rhino-conjunctivitis and/or asthma at 13 years of age.

CONCLUSIONS

IgE responses against airborne allergens undergo dynamic changes throughout childhood, with a high frequency of new sensitization or remission. The long-term persistence and the clinical impact of IgE responses are affected by the intensity of IgE sensitization and the age of its onset.

Prevalence of allergic rhinitis in 3-6-year-old children in Wuhan of China

BACKGROUND

Only a few prevalence studies of allergic rhinitis (AR) have been reported in China. This study aimed to evaluate the prevalence of AR in a population of 3-6-year-old children in Wuhan, China.

METHODS

Sixteen kindergartens in Wuhan City were randomly selected; for each kindergarten, there were three classes from three grades (top, middle and bottom grade, 3-6 years old, respectively). Questionnaires generated by the authors were distributed and filled out by parents of the selected children, with a telephone interview subsequently. Skin prick test (SPT) was carried out on the children after a written consent was signed by the parents.

RESULTS

A total of 1211 (89.5%) valid questionnaires were returned for evaluation. The adjusted current prevalence of AR in 3-6-year-old children was 10.8% with the diagnostic criterion of nasal symptoms(+) and SPTs(+). In the SPTs(+) children, the most common inhalant allergen was house dust mites (94.7%), followed by moulds (28.4%). The prevalence of AR was higher in males than that in females (13.0% vs. 7.7%, P < 0.05). 15.8% and 23.2% of AR children were sensitive to egg and milk, respectively. The percentage of children sensitive to both inhalant and food allergens was 27.4%.

CONCLUSIONS

We found an unexpectedly high prevalence of diagnosed AR in 3-6-year-old children within the investigated population. Dust mite was the most important allergen source for 3-6-year-old children in Wuhan.

Horse allergens: An underestimated risk for allergic sensitization in an urban atopic population without occupational exposure

BACKGROUND

Data on allergic sensitization to horse allergen in modern urban areas are scarce. The aim of this study was to investigate the characteristics of allergic sensitization and the modality of exposure to horse allergens in atopic patients living in an urban area and without occupational exposure to horse and/or horse-derived materials.

METHODS

From among 1822 consecutive outpatients, we selected all subjects who had an immediate skin reaction to horse dander. We recorded the patients' clinical history including a meticulous evaluation of the possibility and eventual modality of horse exposure, and the results of skin-prick tests (SPT) and total/specific IgE antibody analyses.

RESULTS

Of 1201 SPT-positive patients, 35 (3.43%) were sensitized to horse dander. No patient was mono-sensitized. Six individuals reported having direct horse contact, 10 subjects had occasional contact with horse owners (indirect exposure), and 19 denied direct or indirect exposure to horses or horse allergens. Twenty of the 35 horse-sensitized patients reported both nasal and bronchial symptoms, 14 had rhinitis without asthma and one had asthma without rhinitis.

CONCLUSIONS

Our results suggest that allergic sensitization to horse allergens is more frequent than expected in urban-dwelling subjects without direct or occupational exposure to horses. Highly atopic individuals or individuals who are sensitized to common pet dander should undergo SPT and evaluation of serum specific IgE before starting activities involving regular contact with horses such as riding, and before entering environments associated with horses.

Specific IgE serum concentration is associated with symptom severity in children with seasonal allergic rhinitis

BACKGROUND

The impact of allergen-specific and total IgE serum levels before and during the pollen season on symptom severity as well as efficacy of treatment with anti-IgE requires further delineation.

METHODS

Birch and grass pollen allergic patients aged 6-17 years with seasonal allergic rhinitis (SAR) were analyzed for the association of IgE serum concentration with symptom severity and rescue medication use (combination: symptom load, SL) during the grass pollen season. Reference group A (n = 53) received placebo, while group B (n = 54) received Omalizumab (anti-IgE) monotherapy before and during the grass pollen season.

RESULTS

Patients on placebo with high baseline specific grass pollen IgE (>50 kU/l) had a significantly higher SL compared with those with low IgE levels (< or =50 kU/l): SL 1.28 vs 0.61, P = 0.015. This association was nonexistent in patients treated with anti-IgE. In contrast, baseline total IgE levels did not correlate with SL in any group. Patients with anti-IgE treatment and high free total IgE levels (>16.7 ng/ml) had a significantly higher SL compared with those with low free total IgE levels (< or =16.7 ng/ml): SL 0.63 vs 0.23, P = 0.031.

CONCLUSIONS

Baseline specific IgE, but not total IgE, is associated with symptom severity during the pollen season in children with SAR. Likewise, the symptom load in SAR patients with anti-IgE correlates with free total IgE levels. Although further research in larger populations is needed to confirm our findings, our data suggest that specific IgE can be used as a parameter for patient selection for this kind of treatment.

Sensitization to inhalant allergens between 4 and 8 years of age is a dynamic process: results from the BAMSE birth cohort

BACKGROUND

There is limited knowledge of the development of IgE-antibody levels over time in childhood, with respect to persistency and co-sensitization to specific inhalant allergens.

METHODS

Data from 2033 children participating in the BAMSE birth cohort was used. Background factors and clinical parameters were obtained and IgE antibody (ab) levels to eight common airborne allergens were measured (>or=0.35 kU(A)/L) when the children were 4 and 8 years of age.

RESULTS

Between 4 and 8 years the proportion of children sensitized to any of the inhalant allergens tested increased from 15% to 25%. At 4 years IgE-ab to birch and cat dominated, whereas at the age of 8, there was a considerable increase in the proportion of sensitization to timothy and dog. Except for mites and moulds, IgE-ab levels to all aeroallergens increased significantly between 4 and 8 years among those already sensitized at 4. Transient sensitization to inhalant allergen was uncommon. Furthermore, sensitization to birch pollen at 4 years increased the risk for becoming sensitized to timothy, cat and dog later in life. Such an association was not observed among those sensitized primarily to animal dander.

CONCLUSIONS

There is a prominent process of sensitization at pre-school age to inhalant allergens, and in Northern Europe sensitization to birch pollen early in life seems to be important for this process. Such a process has a probable impact on the development of allergic disease in the growing child.

Potential, pitfalls, and prospects of food allergy diagnostics with recombinant allergens or synthetic sequential epitopes

This article aims to critically review developments in food allergy diagnostics with regard to the verification of specific IgE antibodies and the identification of the responsible allergens. Results of IgE-binding tests with food extracts are hampered by cross-reactive proteins, low-quality test agents, or both. Specificity can be increased by defining adequate cutoff values, whereas sensitivity can be improved by using high-quality test agents. IgE-binding tests with purified allergens enabled reliable quantification of allergen-specific IgE titers, with higher levels found in individuals with food allergy compared with individuals without food allergy. However, the overlap in individual test reactivity between allergic and nonallergic subjects complicates interpretation. Recombinant allergens and synthetic sequential epitopes enabled detection of sensitization profiles, with IgE specific to several allergens and substructures now being suggested as markers of severity, persistence, or both. However, high-power quantitative studies with larger numbers of patients are required to confirm these markers. IgE-binding tests merely indicate sensitization, whereas the final proof of clinical relevance still relies on family/case history, physical examinations, and provocation tests. Novel technologies promise superior diagnostics. Microarray technology permits simultaneous measurement of multiple IgE reactivities regarding specificity, abundance, reactivity, or interaction. Improved functional tests might enable reliable estimation of the clinical relevance of IgE sensitizations at justifiable expenses.

Patterns of quantitative food-specific IgE-antibodies and reported food hypersensitivity in 4-year-old children

BACKGROUND

Diagnosis of food hypersensitivity (FHS) is difficult and interpretation of food allergy tests is complicated.

OBJECTIVE

To investigate the probability of reported FHS in relation to levels of food-specific IgE-antibodies (AB) in a population-based setting of 4-year-old children (n = 2336).

METHODS

Information on FHS was obtained from a questionnaire and specific IgE-AB to milk, egg, fish, peanut, soy and wheat were analysed.

RESULTS

Thirty-one per cent of the children with reported FHS (n = 284) were sensitized (> or =0.35 kU(A)/l) to at least one of the tested foods compared with 11% of children without FHS (n = 2052). Furthermore, the probability of reported symptoms to milk, egg and fish increased with increasing levels of food-specific IgE-AB to the same food allergens. A similar trend was seen for peanut and wheat, but not for soy. Increasing levels of specific IgE-AB to milk or egg were also associated with an increasing risk of reported symptoms caused by other foods.

CONCLUSIONS

Quantitative measurements of IgE-AB to milk, egg and fish are useful to evaluate IgE-associated FHS in preschool children also in a population based sample. Such measurements appear to be of limited value for soy bean and wheat, in particular as a screening method.

Reported symptoms of food hypersensitivity and sensitization to common foods in 4-year-old children

AIM

To characterize reported food hypersensitivity (FHS) among young children in a birth cohort.

METHODS

At 4 years of age a parental questionnaire on FHS and allergic symptoms was evaluated. Blood was collected for analyses of IgE-antibodies to egg, milk, fish, wheat, peanut and soy. Complete questionnaire data was available for 3694 children (90%), and blood samples were obtained from 2563 children (63%).

RESULTS

FHS was reported in 11% of the children (n=397). Eczema was the most commonly reported symptom and the only symptom in half of these children. Food-related reactions from the airways, facial oedema or urticaria were reported in 198 children, and the majority of these children (75%) reported multiple symptoms. Furthermore, a combination of airway symptoms, facial oedema or urticaria together with sensitization to food suggested a more severe form of FHS. This was found in 1.6% of all children. Symptoms caused by peanut were closely associated with sensitization to peanut (p<0.001).

CONCLUSIONS

FHS in 4-year-old children with any of asthma, rhino-conjunctivitis, facial oedema or urticaria in combination is in most cases associated to sensitization to food. This phenotype of FHS is likely to represent a more severe form of FHS.

The effect of infectious burden on the prevalence of atopy and respiratory allergies in Iceland, Estonia, and Sweden

BACKGROUND

Epidemiologic reports on the effect of microbe exposure on the development of atopy and allergic asthma are inconsistent.

OBJECTIVES

The study investigates the association between serologic markers of infections and occurrence of atopy, allergic asthma, and rhinitis among adults in Iceland, Sweden, and Estonia.

METHODS

Individuals (n = 1249; mean age, 42 years) from Iceland, Sweden, and Estonia underwent a structured interview and blood sampling. Specific IgE was measured against 4 allergens, and IgG antibodies were measured against Helicobacter pylori, Toxoplasmosis gondii, hepatitis A virus, herpes simplex virus 1, Chlamydia pneumoniae, EBV, and cytomegalovirus.

RESULTS

Nonatopic subjects more often had positive serology for Helicobacter pylori, herpes simplex virus 1, Chlamydia pneumoniae, and cytomegalovirus. Having a low number (</=3) of IgG antibodies against the various infectious agents was an independent risk factor for atopy (odds ratio [OR], 1.43; 95% CI, 1.06-1.93), allergic asthma (OR, 1.82; 95% CI, 1.12-2.98), and allergic rhinitis (OR, 1.69; 95% CI, 1.21-2.37). The proportion of atopy that can be explained by a lower number (</=3) of infections was 6.7% in Iceland, 9.2% in Estonia, and 16.4% in Sweden, and 6.7%, 48.2%, and 33.4% for allergic asthma, respectively.

CONCLUSION

Our data are consistent with cumulative protective effect of infections against atopy and respiratory allergies irrespective of route of infection.

CLINICAL IMPLICATIONS

The study indicates what microbes or combination of microbes play a role in the complex interplay between hygiene and allergy and may contribute toward the understanding of the allergy epidemic.

Sensitization to different pollens and allergic disease in 4-year-old Swedish children

BACKGROUND

Although the relationship between sensitization to different inhalant allergens in adolescents and adults has been intensively studied, information concerning sensitization in children is scarce in particular to pollens.

OBJECTIVES

In 4-year-old children to elucidate the pollen immunoglobulin (IgE) antibody profile (birch only, timothy only and combinations of three pollens (birch, timothy or mugwort) and to relate the results to other inhalant and food allergens, as well as the presence of allergic diseases.

METHODS

A total of 2551 4-year-old children belonging to a prospective birth cohort, which has been followed longitudinally (BAMSE), were investigated with respect to IgE antibodies to pollen and other inhalant and food allergens, and expression of allergic disease, based on questionnaire data.

RESULTS

Eleven percent (n=285) of the children were sensitized to pollen. Birch was the dominating cause of pollen sensitization (birch sensitization only, n=133); followed by timothy grass pollen (n=56) and a combination of two (n=64) or three (n=30) pollens. A remarkably high proportion of the children sensitized only to birch was also sensitized to other inhalant allergens. This was not seen for children sensitized only to timothy. The highest frequencies of IgE reactivity to food were found in the group of children sensitized to the combination of birch, timothy and mugwort pollen. Children sensitized to timothy only, exhibited symptoms of allergic disease significantly less frequently compared with children sensitized to birch only. Sensitization to birch pollen was found to be closely associated with rhinitis and eczema compared with asthma. The highest frequency of asthma and/or rhinitis and/or eczema was reported in children sensitized to at least two pollens.

CONCLUSION

Our results demonstrate that birch is the dominating source of pollen sensitization at the age of four in Sweden. This might associate with the pattern of sensitization to other inhalant and food allergens as well as influence on the expression of allergic disease in this particular age group.

Fish consumption during the first year of life and development of allergic diseases during childhood

BACKGROUND

Fish consumption during infancy has been regarded as a risk factor for allergic disease but later evidence suggests a protective role. However, methodological limitations in the studies make conclusions uncertain. The aim of this study was to assess the association between fish consumption during the first year of life and development of allergic diseases by age 4.

METHODS

A prospective birth cohort of 4089 new-born infants was followed for 4 years using parental questionnaires at ages 2 months, 1, 2 and 4 years to collect information on exposure and health effects. The response rate at 4 years was 90%. A clinical investigation was performed at age 4 years, which included blood sampling for analysis of specific IgE to common food and airborne allergens.

RESULTS

Parental allergic disease and onset of eczema or wheeze during the first year of life delayed introduction of fish in the child's diet. After exclusion of such children to avoid disease-related modification of exposure, regular fish consumption during the first year of life was associated with a reduced risk for allergic disease by age 4, OR(adj) 0.76 (95% CI 0.61-0.94) and sensitization, OR(adj) 0.76 (0.58-1.0). The reduced risk appeared most pronounced for multiple disease, OR(adj) 0.56 (0.35-0.89). IgE-sensitization to fish was only present among 18 of the 2614 children.

CONCLUSION

Regular fish consumption before age 1 appears to be associated with a reduced risk of allergic disease and sensitization to food and inhalant allergens during the first 4 years of life.

IgE sensitisation in relation to flow-independent nitric oxide exchange parameters

BACKGROUND

A positive association between IgE sensitisation and exhaled NO levels has been found in several studies, but there are no reports on the compartment of the lung that is responsible for the increase in exhaled NO levels seen in IgE-sensitised subjects.

METHODS

The present study comprised 288 adult subjects from the European Community Respiratory Health Survey II who were investigated in terms of lung function, IgE sensitisation (sum of specific IgE), smoking history and presence of rhinitis and asthma. Mean airway tissue concentration of NO (CawNO), airway transfer factor for NO (DawNO), mean alveolar concentration of NO (CalvNO) and fractional exhaled concentration of NO at a flow rate of 50 mL s(-1) (FENO 0.05) were determined using the extended NO analysis.

RESULTS

IgE-sensitised subjects had higher levels (geometric mean) of FENO 0.05 (24.9 vs. 17.3 ppb) (p < 0.001), DawNO (10.5 vs. 8 mL s(-1)) (p = 0.02) and CawNO (124 vs. 107 ppb) (p < 0.001) and positive correlations were found between the sum of specific IgE and FENO 0.05, CawNO and DawNO levels (p < 0.001 for all correlations). Sensitisation to cat allergen was the major determinant of exhaled NO when adjusting for type of sensitisation. Rhinitis and asthma were not associated with the increase in exhaled NO variables after adjusting for the degree of IgE sensitisation.

CONCLUSION

The presence of IgE sensitisation and the degree of allergic sensitisation were related to the increase in airway NO transfer factor and the increase in NO concentration in the airway wall. Sensitisation to cat allergen was related to the highest increases in exhaled NO parameters. Our data suggest that exhaled NO is more a specific marker of allergic inflammation than a marker of asthma or rhinitis.