The association between early sensitization patterns and subsequent allergic disease. The DARC birth cohort study

Rhinitis Disease Burden and the Impact of Social Determinants of Health

Social determinants of health (SDHs) have a substantial impact on patient care and outcomes globally, both in low- to middle-income countries and in high-income countries. In the clinic, lack of availability of diagnostic tools, inequities in access to care, and challenges obtaining and adhering to prescribed treatment plans may further compound these issues. This article addresses a case of rhinitis in the context of SDHs and inequities in care that may affect various communities and populations around the world. SDHs may include various aspects of one's financial means, education, access to medical care, environment and living situation, and community factors, each of which could play a role in the rhinitis disease manifestations, diagnosis, and management. Allergic and nonallergic rhinitis are considered from this perspective. Rhinitis epidemiology, disease burden, and risk factors are broadly addressed. Patient evaluation, diagnostic tests, and management options are also reviewed, and issues related to SDHs are noted. Finally, inequities in care, knowledge gaps, and unmet needs are highlighted. It is critical to consider SDHs and care inequities when evaluating and treating patients for rhinitis and other allergic conditions.

25 Years of translational research in the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC)

The Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) mother-child cohorts have provided a foundation of 25 years of research on the origins, prevention, and natural history of childhood asthma and related disorders. COPSAC's approach is characterized by clinical translational research with longitudinal deep phenotyping and exposure assessments from pregnancy, in combination with multi-omic data layers and embedded randomized controlled trials. One trial showed that fish oil supplementation during pregnancy prevented childhood asthma and identified pregnant women with the highest benefits from supplementation, thereby creating the potential for personalized prevention. COPSAC revealed that airway colonization with pathogenic bacteria in early life is associated with an increased risk of asthma. Further, airway bacteria were shown to be a trigger of acute asthma-like symptoms, with benefit from antibiotic treatment. COPSAC identified an immature gut microbiome in early life as a risk factor for asthma and allergy and further demonstrated that asthma can be predicted by infant lung function. At a molecular level, COPSAC has identified novel susceptibility genes, early immune deviations, and metabolomic alterations associated with childhood asthma. Thus, the COPSAC research program has enhanced our understanding of the processes causing childhood asthma and has suggested means of personalized prevention and treatment.

Effect of early atopic sensitization in children aged 0-2 years on the development of asthma symptoms at 9-11 years of age

BACKGROUND

Personal genetic predisposition and early life environmental factors are important for the development of childhood asthma. We aimed to search whether egg, milk and mite sensitizations at 0-2 years old are risk factors for asthma symptoms at 9-11 years old.

METHODS

A total of 210 wheezer children who had specific immunoglobulin (Ig) E in 2010-2012 were included in the study (followed by pediatric allergy). Patients were divided into non-atopic (group 1, n = 157) and atopic patients [groups 2-7, n = 53 (5 patients were in both group 4 and group 5)] based on sensitizations. Using the International Study of Asthma and Allergy in Childhood questionnaire, current wheeze (CW, 2nd question), exercise wheezing (EW, 7th question), and dry cough (DC, 8th question) were surveyed. Also, parental allergies, eczema at 0-2 years, current eosinophil percentage and total IgE were recorded.

RESULTS

Eczema was observed as an important risk factor [CW: odds ratio (OR) = 2.83, 95% confidence interval (CI) = 1.54-5.23, P ≤ 0.001; EW: OR = 2.71, 95% CI = 1.33-5.54, P = 0.006; DC: OR = 3.03, 95% CI = 1.47-6.25, P = 0.003], whereas having no atopic sensitization at 0-2-year-old (group 1) was found as a significant protective factor for asthma at 9-11 years old (CW: OR = 0.32, 95% CI = 0.15-0.70, P = 0.004; EW: OR = 0.21, 95% CI 0.10-0.44, P ≤ 0.001; DC: OR = 0.25, 95% CI = 0.10-0.59, P = 0.002).

CONCLUSION

Early personal eczema is a significant risk factor for the development of asthma symptoms at 9-11 years old, whereas not having an allergic sensitization at 0-2 years old (group 1) is an important protective factor.

Allergic sensitization trajectories to age 8 years in the Singapore GUSTO cohort

Background

Allergic sensitization is linked to allergy development, with early sensitization often associated with worse outcomes. We aimed to identify if distinct allergic sensitization trajectories existed within a diverse and multi-ethnic Asian cohort.

Methods

We administered modified ISAAC questionnaires in the first 8 years and conducted skin prick testing at ages 18 months, 3, 5 and 8 years in the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. We used latent class analysis to derive allergic sensitization trajectories, and adjusted odds ratios (AOR) to evaluate predictive risk factors and associations with allergic comorbidities.

Results

Among 997 children, three trajectories were identified: early food and mite sensitization (16.2%), late mite sensitization (24.2%) and no/low sensitization (59.6%). Early food and mite sensitization was associated with early eczema by 6 months [AOR (95%CI) 4.67 (1.78-12.28)], increased risk of wheeze by 3-8 years (ARR 1.72-1.99) and eczema in the first 8 years of life (ARR 1.87-2.41). Late mite sensitization was associated with female sex [AOR 0.58 (0.35-0.96)], cesarean section [AOR 0.54 (0.30-0.98)], early eczema by 6 months [AOR 3.40 (1.38-8.42)], and increased risk of eczema by 18 months [ARR 1.47 (1.03-2.08)] and 8 years [ARR 1.35 (1.05-1.73)].

Conclusion

Early onset of eczema and early allergic sensitization were strongly associated. Early sensitization, especially to house dust mites, was associated with increased risks of developing wheeze and eczema, pointing to the importance of developing preventive perinatal interventions and effective therapeutics for sensitized toddlers.

Impaired skin barrier and allergic sensitization in early infancy

BACKGROUND

Factors predicting allergic sensitization in the first 6 months of life are poorly understood. We aimed to determine whether eczema, dry skin, and high transepidermal water loss (TEWL) at 3 months were associated with allergic sensitization at 6 months of age and, secondarily, to establish whether these characteristics predicted sensitization from 3 to 6 months of age.

METHODS

At 3 months of age, 1,994 infants from the population-based PreventADALL birth cohort in Norway and Sweden were assessed for eczema and dry skin on the cheeks and/or extensors; impaired skin barrier function, defined as TEWL in the upper quartile (>9.4 g/m² /h), and allergen-specific IgE levels <0.1 kU_A /L, available in 830. At 6 months, we assessed allergic sensitization to any food (egg, cow's milk, peanut, wheat, soy) or inhalant (birch, timothy grass, dog, and cat) allergen by a skin prick test wheal diameter ≥2 mm larger than negative control.

RESULTS

Any sensitization was found in 198 of the 1,994 infants (9.9%), the majority to food allergens (n = 177, 8.9%). Eczema, dry skin, and high TEWL at 3 months increased the risk of sensitization at 6 months; adjusted odds ratios 4.20 (95% CI 2.93-6.04), 2.09 (95% CI 1.51-2.90) and 3.67 (95% CI 2.58-5.22), respectively. Eczema predicted sensitization with 55.6% sensitivity and 68.1% specificity; dry skin with 65.3% sensitivity and 57.3% specificity; and high TEWL with 61.7% sensitivity and 78.1% specificity.

CONCLUSION

Eczema, dry skin, and high TEWL at 3 months predicted allergic sensitization at 6 months of age.

Extract and molecular-based early infant sensitization and associated factors-A PreventADALL study

BACKGROUND

More knowledge about sensitization patterns in early infancy, including impact of molecular allergology, is needed to help predict future allergy development more accurately.

OBJECTIVE

We aimed to determine the prevalence and patterns of allergic sensitization at 3 months of age, and explore possible associated factors.

METHODS

From the Scandinavian antenatally recruited PreventADALL mother-child cohort, we included 1110 3-month infants with available serum. Sensitization was defined as s-IgE of ≥0.1 kU_A /L by Phadiatop Infant^® (ThermoFisher Scientific) including birch, cat, grass, dog, milk, egg, peanut and wheat. Further ImmunoCAP analyses to ovomucoid, casein, Ara h 1-3, omega-5-gliadin were performed in food extract s-IgE-positive children. Maternal sensitization was defined as s-IgE ≥ 0.35 kU_A /L to Phadiatop^® (inhalant allergen mix) and/or Fx5 (food allergen mix) at 18-week pregnancy.

RESULTS

Overall 79 (7.3%) infants had specific sensitization, many with low s-IgE-levels (IQR 0.16-0.81 kU_A /L), with 78 being sensitized to food extract allergens; 41 to egg, 27 to milk, 10 to peanut, and 25 to wheat. A total of 62/78 were further analysed, 18 (29%) had s-IgE to ovomucoid, casein, Ara h 1-3 and/or omega-5-gliadin. Eight infants (0.7%) were sensitized to inhalant allergens. Maternal sensitization to food allergens was associated with infant sensitization, odds ratio 3.64 (95% CI 1.53-8.68).

CONCLUSION

Already at 3 months of age, 7% were sensitized to food, mostly without detectable s-IgE to food allergen molecules, and <1% to inhalant allergens. Maternal food sensitization was associated with infants' sensitization.

Allergy-Related Symptoms Are Poorly Predicted by IgE and Skin Prick Testing in Early Life

INTRODUCTION

In childhood, the so-called allergic march involves progression from IgE sensitization to allergy-related symptoms. Both IgE sensitization and relevant clinical symptoms are required for the diagnosis of allergy, but concordance between test results and clinical symptoms varies greatly, creating challenges for the diagnostics and for the prediction of outcomes. We assessed the prevalence of IgE sensitization and allergy symptoms, concordance between 2 IgE sensitization testing methods, and predictive value of these tests in relation to clinical symptoms in young Finnish children.

METHODS

The current study included 2 series of children: a birth cohort, in which the participants were followed prospectively from birth up to 3 years, and a young children cohort observed from 3 to 5 years of age. They were regularly monitored for sensitization by measuring serum allergen-specific IgEs (sIgEs) and performing skin prick tests (SPTs). The emergence of atopic dermatitis, wheezing, and symptoms associated with food allergies was recorded.

RESULTS

Over the first 5 years of life, the prevalence of sIgE sensitization was 46%, while it was 36% for positive SPTs. Disease prevalence was 26% for atopic dermatitis, 25% for wheezing, and 19% for symptoms associated with food allergies. Concordance between sIgE and SPT results was good for aeroallergens, but poor for dietary allergens. The association between clinical symptoms and sensitization was stronger at 5 years than at 3 years of age. The proportion of children with concordant combinations of allergy symptoms and sensitization markers in contrast to those with discordant combinations increased from 3 to 5 years.

CONCLUSION

In early childhood, testing for IgE sensitization predicts allergy-related symptoms in an age-dependent manner, but not particularly well. Tests predict symptoms caused by aeroallergens clearly better than those caused by dietary allergens. The clinical relevance of sensitization testing in early life is therefore limited in the prediction of true allergy.

Consensus statement on the epidemiology, diagnosis, prevention, and management of cow's milk protein allergy in the Middle East: a modified Delphi-based study

BACKGROUND

This study aimed to develop an expert consensus regarding the epidemiology, diagnosis, and management of cow's milk protein allergy (CMPA) in the Middle East.

METHODS

A three-step modified Delphi method was utilized to develop the consensus. Fifteen specialized pediatricians participated in the development of this consensus. Each statement was considered a consensus if it achieved an agreement level of ≥ 80%.

RESULTS

The experts agreed that the double-blind placebo-controlled oral challenge test (OCT) should be performed for 2-4 weeks using an amino acid formula (AAF) in formula-fed infants or children with suspected CMPA. Formula-fed infants with confirmed CMPA should be offered a therapeutic formula. The panel stated that an extensively hydrolyzed formula (eHF) is indicated in the absence of red flag signs. At the same time, the AAF is offered for infants with red flag signs, such as severe anaphylactic reactions. The panel agreed that infants on an eHF with resolved symptoms within 2-4 weeks should continue the eHF with particular attention to the growth and nutritional status. On the other hand, an AAF should be considered for infants with persistent symptoms; the AAF should be continued if the symptoms resolve within 2-4 weeks, with particular attention to the growth and nutritional status. In cases with no symptomatic improvements after the introduction of an AAF, other measures should be followed. The panel developed a management algorithm, which achieved an agreement level of 90.9%.

CONCLUSION

This consensus document combined the best available evidence and clinical experience to optimize the management of CMPA in the Middle East.

Correlation of skin prick testing to environmental allergens

BACKGROUND

To diagnose and adequately treat allergies, identification of sensitizing allergens is crucial. Skin prick or serum immunoglobulin E testing determines sensitization to potential allergens. Consensus varies regarding degree of cross-reactivity between aeroallergens.

OBJECTIVE

To quantify correlations between aeroallergen skin prick test results.

METHODS

A total of 11,832 patients' quantitative skin prick test results and basic characteristics were obtained from a tertiary academic center's electronic medical record and deidentified. Data were analyzed using Spearman's rank correlation coefficients to detect nonlinear associations between wheal sizes of skin prick test results.

RESULTS

The highest correlation among grasses was 0.903 (fescue and red top). Of note, 13 more grass pairs had correlation more than 0.8, and 19 had correlation between 0.7 and 0.8. The Northern grass comparative results are from a satellite clinic that tested more grasses than the main clinic, in which only Kentucky blue and Bermuda were tested (correlation 0.768; n = 9348). Highest correlation among weeds was 0.74 (lambs quarter and pigweed). In addition, 6 more weed pairs had correlation more than 0.7. Highest correlation among trees was 0.724 (palm and alder) and 6 more tree pairs had correlation more than 0.7. Highest correlation among molds was 0.711 (Helminthosporium and Epicoccum). Dust mite correlation between Dermatophagoides farinae and Dermatophagoides pteronyssinus was 0.848 (n = 10,022).

CONCLUSION

This study confirmed the expected high degrees of correlation not only between skin prick test results of related environmental allergens but also between less closely related Northern grasses and Bermuda grass. This has implications for simplification of testing and immunotherapy protocols in the future.

Single and multiple time-point allergic sensitization during childhood and risk of asthma by age 13

BACKGROUND

The relationship between allergic sensitization during childhood and risk of developing asthma remains unclear.

OBJECTIVE

To analyze single time-point and temporal patterns of sensitization in childhood in relation to asthma at age 13.

METHODS

Specific IgE (sIgE) level and skin prick test (SPT) toward 22 food allergens and aeroallergens were assessed at 6, 18 months, 4, 6, and 13 years in children from the high-risk Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ (COPSAC₂₀₀₀ ) mother-child cohort. We analyzed the association between single time-point monosensitization, polysensitization, and quantitative assessment of sensitization, that is, sum of all sIgE levels and SPT wheal sizes, against asthma at age 13. In addition, we analyzed the association between three temporal patterns of sensitization: (a) early-transient, (b) late-onset, and (c) persistent sensitization and asthma.

RESULTS

Polysensitization status measured by SPT or sIgE was at all single time-points associated with increased risk of asthma at age 13: OR range, SPT = 3.0-15.7, and sIgE = 2.6-15.7, respectively, whereas monosensitization status was inconsistently associated with asthma. Quantitative assessment of both sIgE and SPT results was associated with asthma at all single time-points: OR range, SPT = 1.3-3.6, and sIgE = 1.1-1.7. Persistent sensitization, but not early-transient or late-onset sensitization was associated with asthma by age 13: OR [95% CI], SPT = 8.9 [2.8-28.23], and sIgE = 2.9 [1.1-7.6], respectively.

CONCLUSION

Sensitization to multiple allergens at single time-points, increasing sIgE levels and SPT wheal sizes, and persistent sensitization during childhood were associated with increased risk of asthma at age 13, suggesting the use of quantitative and repetitive sensitization measurements when assessing risk of developing asthma.

Asthma and Food Allergy: Which Risks?

Over the past few decades, an increase in the prevalence of asthma and food allergy has been observed in the pediatric population. In infants, food sensitization, particularly to egg, has increased the risk of developing allergic asthma. This is even more likely if sensitization to food allergens occurs early within the first few years of life. It is indeed known that both diseases may be present simultaneously in the pediatric population, but coexistence may negatively influence the severity of both conditions by increasing the risk of life-threatening asthmatic episodes as well as food-related anaphylaxis. Therefore, an accurate clinical and phenotype characterization of this high-risk group of children with both asthma and food allergy and a more aggressive management might lead to reducing related morbidity and mortality. The aim of this review is to provide an updated overview on the close link between food allergy and asthma and their negative mutual influence.

Identification of two early life eczema and non-eczema phenotypes with high risk for asthma development

BACKGROUND

The "atopic march" has been considered a linear progression starting with eczema and culminating with development of asthma. Not all asthma cases, however, are preceded by eczema, and not all children with eczema go on to develop asthma.

OBJECTIVE

The aim of this study was to explore the impact of allergic sensitization patterns on the association between early eczema and later childhood asthma. Given the numerous reported associations of the ciliary gene KIF3A with the atopic march, we also examined the impact of KIF3A risk allele rs12186803 on our analyses.

METHODS

We studied 505 participants in the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS), a prospective birth cohort, with longitudinal eczema and asthma outcomes as well as prospective data regarding timing of sensitization to foods and aeroallergens. KIF3A genotypes were available on all children.

RESULTS

Two high-risk groups were identified: one with and one without early eczema. The high-risk group with early eczema was more likely to be sensitized to food allergens, while the group without early eczema was more likely to be polysensitized to aeroallergens. The KIF3A rs12186803 risk allele interacted with food sensitization to increase asthma risk in children with eczema (P = 0.02). In children without eczema, asthma was associated with the interaction between rs12186803 and aeroallergen sensitization (P = 0.007).

CONCLUSIONS & CLINICAL RELEVANCE

KIF3A interacted differentially with sensitization pattern to increase the risk of asthma in two high-risk groups of children with and without early eczema. Given the reported role of KIF3A in epithelial cell functioning, the results add evidence to the hypothesis that an impaired epithelial barrier is a key aspect in the development of allergic disease.

Diverse age-incidence patterns of atopic sensitization in an unselected Finnish population up to 12 years

BACKGROUND

The temporal sequence in which allergic sensitization to different allergens emerges is not well characterized at the level of general population.

OBJECTIVE

We describe the incidence patterns of atopic sensitization to different allergens from birth up to 12 years of age in an unselected Finnish population.

METHODS

The study population comprised all children born between 2001 and 2006 identified from the nationwide population register as residents of the province of South Karelia, Finland (n = 5564). The results of allergy tests (22,380 results from skin prick tests, immunoglobulin E [IgE] antibodies, and open food challenges [OFCs], performed in 1827 children) were collected from patient records of all the health care units in the area.

RESULTS

The incidence rates of positive results for food and animal allergens as well as positive OFCs for cow's milk showed prominent peaks at 5 months of age. Positive results for pollen allergens started to emerge after 1.5 years of age. The 12-year cumulative incidence of sensitization to food, animal, pollen, and any allergens was 12%, 8%, 10%, and 18%, respectively. The cumulative incidence of sensitization to house dust mites was 1% and to molds or latex less than 1%. Firstborn boys had the highest, and those who were not firstborn girls and children born in rural municipalities had the lowest early incidence of sensitization to inhalation allergens.

CONCLUSION

In the unselected population, the atopic sensitization against food and animal allergens began before 6 months of age and was followed by sensitization to pollen allergens before 2 years of age. Primary prevention of sensitization to food and inhalation allergens should therefore occur in early infancy.

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.

Protocol for Pertussis Immunisation and Food Allergy (PIFA): a case-control study of the association between pertussis vaccination in infancy and the risk of IgE-mediated food allergy among Australian children

INTRODUCTION

Atopic diseases, including food allergy, have become a predominant cause of chronic illness among children in developed countries. In Australia, a rise in hospitalisations among infants coded as anaphylaxis to foods coincided with the replacement of whole-cell pertussis (wP) vaccine with subunit acellular pertussis (aP) vaccine on the national immunisation schedule in the late 1990s. Atopy is characterised by a tendency to mount T helper type 2 (Th2) responses to otherwise innocuous environmental antigens. Compared with infants who receive aP as their first pertussis vaccine, those who receive wP appear less likely to mount Th2 immune responses to either vaccine or extraneous antigens. We therefore speculate that removal of wP from the vaccine schedule contributed to the observed rise in IgE-mediated food allergy among Australian infants.

METHODS AND ANALYSIS

This is a retrospective individually matched case-control study among a cohort of Australian children born from 1997 to 1999, the period of transition from wP to aP vaccines; we include in the cohort children listed on Australia's comprehensive population-based immunisation register as having received a first dose of either pertussis vaccine by 16 weeks old. 500 cohort children diagnosed as having IgE-mediated food allergy at specialist allergy clinics will be included as cases. Controls matched to each case by date and jurisdiction of birth and regional socioeconomic index will be sampled from the immunisation register. Conditional logistic regression will be used to estimate OR (±95% CI) of receipt of wP (vs aP) as the first vaccine dose among cases compared with controls.

ETHICS AND DISSEMINATION

The study is approved by all relevant human research ethics committees: Western Australia Child and Adolescent Health Services (2015052EP), Women's and Children's Hospital (HREC/15/WCHN/162), Royal Children's Hospital (35230A) and Sydney Children's Hospital Network (HREC/15/SCHN/405). Outcomes will be disseminated through publication and scientific presentation.

TRIAL REGISTRATION NUMBER

NCT02490007.

Neonatal BCG has no effect on allergic sensitization and suspected food allergy until 13 months

BACKGROUND

Vaccination with Bacillus Calmette-Guérin (BCG) is used in many countries as protection against tuberculosis. Studies have suggested that BCG may also have non-specific effects, reducing non-tuberculosis mortality, morbidity, and atopic manifestations. In this study, we evaluated the effect of neonatal BCG vaccination on allergic sensitization and suspected food allergy at 13 months of age.

METHODS

The Danish Calmette Study was conducted from 2012 to 2015 at three Danish hospitals. Within 7 days of birth, the 4262 newborns of 4184 included mothers were randomized 1:1 to BCG or to a no-intervention control group. Exclusion criteria were gestational age <32 weeks, birth weight <1000 g, known immunodeficiency, or no Danish-speaking parent. Follow-up information was collected through telephone interviews at 3 and 13 months of age. Subgroups of participants were offered blood sampling at 13 months of age.

RESULTS

By 13 months of age, the parents and/or general practitioners of 5.6% (117/2089) of the children in the BCG group and 6.1% (126/2061) of the control group suspected food allergy, resulting in a risk ratio comparing BCG-vaccinated children with control children of 0.91 (95% CI 0.71-1.16). Among 1370 blood samples, sensitization (Phadiatop Infant >0.35 kUA/L) was found in 55 of 743 (7.4%) children in the BCG group and 50 of 627 (8.0%) of the control group (risk ratio 0.94 [0.65-1.36]).

CONCLUSION

In this randomized clinical trial, neonatal BCG had no significant effect on suspected food allergy or on sensitization at 13 months of age.

A cross-sectional observational study on allergen-specific IgE positivity in a southeast coastal versus a southwest inland region of China

Few studies addressed trans-regional differences in allergen sensitization between areas within a similar latitudinal range but with distinct geomorphological features. We investigated specific IgE (sIgE) positivity to common allergens in populations from two southern China provinces. Using a uniformed protocol, serum samples were collected from 2778 subjects with suspected atopy in coastal Guangdong and inland Yunnan. The overall prevalence of sIgE positivity were 57.8% (95% CI: 56.0%, 59.6%) from Guangdong vs 60.9% (95% CI: 59.1%, 62.7%) from Yunnan. House dust mite (d1) was the most common allergen in both regions. Among d1-sensitized subjects, only 35.7% (208/583) in Guangdong and 22.9% (147/642) in Yunnan tested positive for d1 alone. Among those poly-sensitized d1-positive subjects, cockroach was the most common co-sensitizing aeroallergen. 41.9% of the d1-sensitized Guangdong subjects showed high-class sIgE reactivity (≥class 4), in contrast to a very low percentage of such reactivity in Yunnan. However, 36.3% of d1-sensitized subjects in Yunnan were concomitantly positive for tree pollen mix. Surprisingly, Yunnan subjects showed high prevalence of sIgE positivity for crabs and shrimps, either by overall or by age-group analysis, compared with their Guangdong counterparts (both P < 0.05). These findings may add to data about local allergies in China and worldwide.

Windows of opportunity for tolerance induction for allergy by studying the evolution of allergic sensitization in birth cohorts

Allergic sensitization is a risk factor for developing IgE-mediated allergic diseases, which are a major cause of chronic illness world-wide. The introduction of allergen molecules to the field of allergy diagnostics has allowed dissecting the IgE response on a molecular level to pinpoint the specific disease-causing allergens. Studying birth cohorts is an essential tool for understanding the development and life course of allergy, enabling the possibility to design preventive strategies. Here we review the evolution of sensitization using data from some of the large European birth cohort studies. Differences and similarities between sensitization to food and various sources of inhalant allergens are discussed and allergen molecules of importance in early childhood predicting disease in adolescence are highlighted. Finally, we discuss windows of opportunity where intervention could be considered and address possible preventive strategies.

Pediatric Asthma and Food Allergy

OBJECTIVE

To quantitatively summarize the evidence from observational studies on the relation between pediatric asthma and food allergy.

METHODS

A literature search was conducted in Medline and EMBASE (August 2016). Two independent reviewers appraised the studies and extracted the estimates of interest. Methodological quality of the included studies was assessed using National Heart Lung and Blood Institute (NHLBI) Quality Assessment Tools. Data were pooled using random-effects meta-analysis.

RESULTS

A total of 32 relevant studies were identified but only 8 studies met the inclusion criteria. Using random-effect model, food allergy showed strong association with asthma in children (OR = 2.87 [95% CI: 2.05-4.00]; P < 0.0001).

CONCLUSIONS

This study suggested that food allergy is associated with an increased risk of asthma in children.

Prevalence and risk factors for wheezing and allergic diseases in preschool children: A perspective from the Mediterranean coast of Turkey

OBJECTIVES

The aim of the present study was to determine the prevalence and risk factors of allergic diseases in preschool children from one of the biggest cities in the Mediterranean Region of Turkey.

METHODS

The study population included 396 preschool children attending to urban daycare centres in Mersin. In the first stage, a comprehensive standardised questionnaire modified from the International Study of Asthma and Allergies in Childhood (ISAAC) was employed. In the second stage, serum food and inhalant specific IgE, and skin tests were performed in 45 children with frequent wheezing and 28 children with no wheezing.

RESULTS

The prevalence of ever wheezing, current wheezing, physician-diagnosed asthma, allergic rhinitis and eczema were 53% (210), 33.3% (132), 27.3% (108), 13.4% (53) and 8.3% (33), respectively. A family history of atopy (OR=2.5, 95% CI: 1.3-4.7, p=0.004), dampness at home (OR=2.4, 95% CI: 1.2-4.8, p=0.008), a history of intestinal parasites (OR=4.3, 95% CI: 1.7-10.9, p=0.002), previous history of pneumonia (OR=6.9, 95% CI: 1.9-25.9, p=0.004), initiation of complementary foods before the age of three months (OR=6.1, 95%CI: 1.4-26.9, p=0.02) and presence of food allergy (OR=3.1, 95% CI: 1.1-9.2, p=0.03) were found to be significant risk factors for physician-diagnosed asthma. The risk factors for frequent wheezing were maternal smoking during pregnancy (OR=5.2, 95% CI: 0.9-28.7, p=0.05) and high serum IgE levels (OR=2.9, 95% CI: 0.9-9.0, p=0.05) at borderline significance.

CONCLUSION

Our study was the first epidemiological study in preschool children in the Mediterranean region of Turkey and demonstrated a high prevalence of asthma and allergic diseases, probably related to humid climatic properties in addition to other environmental and genetic factors.

In-vitro diagnostic in atopic dermatitis: Options and limitations

Atopic dermatitis is a chronic inflammatory skin disease with a complex pathogenesis and different exogenous and endogenous trigger factors. One important factor is the sensitization to inhalant and/or food allergens. The detection of total IgE and specific IgE antibodies to inhalant and/or food allergens is one central aspect in diagnosing atopic dermatitis, especially if skin prick tests are not feasible. Many patients are polysensitized, but not all sensitizations are of clinical relevance. The challenge is to identify the sensitizations with clinical relevance and to initiate suitable therapeutic options. In this article we go into detail for the allergens house dust mite, pollen, food, and Malassezia sympodialis. Furthermore, the authors comment on the impact of the detection of specific IgG/IgG4 antibodies in the diagnosis of food allergy in atopic dermatitis. Moreover, new options in the in-vitro diagnostic will be explained briefly and their actual diagnostic significance in patients with atopic dermatitis will be highlighted. These options are the detection of specific IgE antibodies to recombinant allergens and the allergen chip.

The ADAPAR Birth Cohort Study: Food Allergy Results at Five Years and New Insights

BACKGROUND

Although food allergy (FA) is often a transient condition during childhood, when and in whom FA will resolve can be affected by many factors. In this study, we analyzed the data at 5 years on 33 children diagnosed with FA in the ADAPAR (Adana Pediatric Allergy Research) birth cohort study in southern Turkey.

METHODS

Thirty-three infants detected as having FA at the end of their first year in the ADAPAR study were assessed every 6 months until the age of 5 years. Each follow-up included a clinical examination, questionnaire, blood sampling and a skin-prick test.

RESULTS

Culprit allergens were cow's milk (n = 20), eggs (n = 17), chicken meat (n = 1) and bananas (n = 1). Of the 17 patients with egg allergy, 14 developed complete tolerance and 1 developed partial tolerance (i.e. tolerance to baked food). Of the 20 patients with milk allergy, complete tolerance was observed in 16 and partial tolerance in 1. The mean age of tolerance to egg was 22.4 ± 7.5 months and to cow's milk, it was 20.9 ± 1.1 months. Complete tolerance developed in 1 case allergic to chicken meat and in 1 case allergic to banana. Other allergic conditions were also determined: allergic rhinitis in 27.2%, atopic dermatitis in 21.2%, asthma in 9%, urticaria in 9% and drugs in 9%.

CONCLUSIONS

Our results confirm early and high tolerance rates before school age in children with food allergies that started in infancy. This will help pediatricians to give more informed advice to parents of infants with cow's milk or hen's egg allergy.

Differential factors associated with challenge-proven food allergy phenotypes in a population cohort of infants: a latent class analysis

BACKGROUND

Food allergy, eczema and wheeze are early manifestations of allergic disease and commonly co-occur in infancy although their interrelationship is not well understood. Data from population studies are essential to determine whether there are differential drivers of multi-allergy phenotypes. We aimed to define phenotypes and risk factors of allergic disease using latent class analysis (LCA).

METHODS

The HealthNuts study is a prospective, population-based cohort of 5276 12-month-old infants in Melbourne, Australia. LCA was performed using the following baseline data collected at age 12 months: food sensitization (skin prick test ≥ 2 mm) and allergy (oral food challenge) to egg, peanut and sesame; early (< 4 months) and late-onset eczema; and wheeze in the first year of life. Risk factors were modelled using multinomial logistic regression.

RESULTS

Five distinct phenotypes were identified: no allergic disease (70%), non-food-sensitized eczema (16%), single egg allergy (9%), multiple food allergies (predominantly peanut) (3%) and multiple food allergies (predominantly egg) (2%). Compared to the baseline group of no allergic disease, shared risk factors for all allergic phenotypes were parents born overseas (particularly Asia), delayed introduction of egg, male gender (except for single egg allergy) and family history of allergic disease, whilst exposure to pet dogs was protective for all phenotypes. Other factors including filaggrin mutations, vitamin D and the presence of older siblings differed by phenotype.

CONCLUSIONS AND CLINICAL RELEVANCE

Multiple outcomes in infancy can be used to determine five distinct allergy phenotypes at the population level, which have both shared and separate risk factors suggesting differential mechanisms of disease.

The march from early life food sensitization to allergic disease: a systematic review and meta-analyses of birth cohort studies

BACKGROUND

There is growing evidence for an increase in food allergies. The question of whether early life food sensitization, a primary step in food allergies, leads to other allergic disease is a controversial but important issue. Birth cohorts are an ideal design to answer this question.

OBJECTIVES

We aimed to systematically investigate and meta-analyse the evidence for associations between early food sensitization and allergic disease in birth cohorts.

METHODS

MEDLINE and SCOPUS databases were searched for birth cohorts that have investigated the association between food sensitization in the first 2 years and subsequent wheeze/asthma, eczema and/or allergic rhinitis. We performed meta-analyses using random-effects models to obtain pooled estimates, stratified by age group.

RESULTS

The search yielded fifteen original articles representing thirteen cohorts. Early life food sensitization was associated with an increased risk of infantile eczema, childhood wheeze/asthma, eczema and allergic rhinitis and young adult asthma. Meta-analyses demonstrated that early life food sensitization is related to an increased risk of wheeze/asthma (pooled OR 2.9; 95% CI 2.0-4.0), eczema (pooled OR 2.7; 95% CI 1.7-4.4) and allergic rhinitis (pooled OR 3.1; 95% CI 1.9-4.9) from 4 to 8 years.

CONCLUSION

Food sensitization in the first 2 years of life can identify children at high risk of subsequent allergic disease who may benefit from early life preventive strategies. However, due to potential residual confounding in the majority of studies combined with lack of follow-up into adolescence and adulthood, further research is needed.

Disagreement between skin prick test and specific IgE in young children

BACKGROUND

Skin prick test (SPT) and measurement of serum-specific IgE (sIgE) level are important tools for the clinician to diagnose allergic sensitization. However, little is known about the agreement between the two methods in young children.

METHODS

SPT and sIgE levels were assessed simultaneously for 16 common inhalant and food allergens at age ½, 1½, 4, and 6 years in 389 children from the Copenhagen Prospective Study on Asthma in Childhood2000 (COPSAC2000 ) at-risk birth cohort. Agreement between the two methods for diagnosing inhalant and food allergic sensitization at the four age points was analyzed using kappa statistics.

RESULTS

The prevalence of inhalant allergen sensitization increased during childhood diagnosed by both sIgE levels (0.6% to 4.2% to 18.1% to 24.8%, P < 0.0001) and SPT results (1.5% to 3.8% to 8.4% to 15.4%, P < 0.0001). In contrast, the prevalence of food sensitization increased during childhood when diagnosed from sIgE (7.8% to 12.1% to 15.0% to 18.9%, P < 0.0001), but decreased when diagnosed from SPT (5.3% to 5.1% to 3.7% to 3.0%, P = 0.05). Overall, the agreement between SPT and sIgE levels was poor to moderate (all κ-coefficients ≤ 0.60) and decreased from moderate to slight for food allergens by increasing age (κ-coefficients: 0.46 to 0.31 to 0.16 to 0.14).

CONCLUSION

There is a substantial disagreement between SPT and sIgE for diagnosing allergic sensitization in young children, which increases with age for food sensitization. Choice of assessment method therefore has major impact on results with wide implications for both clinical practice and research.

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.

Natural history of allergic sensitization in infants with early-onset atopic dermatitis: results from ORCA Study

BACKGROUND

Early-onset atopic dermatitis (AD) is a particular phenotype that may convey a risk of developing multiple sensitizations to allergens but little is known about the pathway of sensitization. The aims of this study were to describe the natural history of sensitization to allergens for this phenotype and to identify the most predictive marker associated with the risk of developing sensitization to inhaled allergens in a well-selected cohort of infants with AD.

METHODS

Infants with active AD were enrolled and prospectively explored for biological markers of atopy every year until the age of 6 yr. Allergic sensitization was defined as the presence of positive specific IgEs to allergens and multiple sensitizations as being sensitized to ≥2 allergens. Elevated blood eosinophilia was defined as an eosinophil blood count ≥470 eosinophils/mm(3) and elevated total IgE as a serum IgE level ≥45 kU/l.

RESULTS

Two hundred and twenty-nine infants were included. Elevated blood eosinophilia was observed at baseline in 60 children (26.2%) and elevated total IgE in 85 (37.1%). When elevated at baseline, eosinophilia and IgE levels remained significantly higher during the follow-up period. Sensitization to food allergens decreased from 58% to 34%, whereas sensitization to inhaled allergens increased over time from 17% to 67%. Initial multiple sensitizations to food allergens were the most predictive factor for the risk of developing sensitization to inhaled allergens at 6 yr (OR 3.72 [1.68-8.30] p < 0.001).

CONCLUSIONS

In the early-onset AD phenotype, multiple sensitization to food allergens conveys a higher risk of sensitization to inhaled allergens than single sensitization.

Exhaled nitric oxide during infancy as a risk factor for asthma and airway hyperreactivity

Childhood asthma is often characterised by elevated exhaled nitric oxide (eNO), decreased lung function, increased airway reactivity and atopy; however, our understanding of when these phenotypic airway characteristics develop remains unclear. This study evaluated whether eNO, lung function, airway reactivity and immune characteristics during infancy are risk factors of asthma at age 5 years. Infants with eczema, enrolled prior to wheezy illness (n=116), had eNO, spirometry, airway reactivity and allergen sensitisation assessed at entry to the study and repeated at age 5 years (n=90). Increasing eNO at entry was associated with an increased risk of asthma (p=0.037) and increasing airway reactivity (p=0.015) at age 5 years. Children with asthma at 5 years of age had a greater increase in eNO between infancy and age 5 years compared with those without asthma (p=0.002). Egg sensitisation at entry was also associated with an increased risk of asthma (p=0.020), increasing eNO (p = 0.002) and lower forced expiratory flows (p=0.029) as a 5 year-old. Our findings suggest that, among infants at high risk for developing asthma, eNO early in life may provide important insights into the subsequent risk of asthma and its airway characteristics.

Agreement between the skin prick test and specific serum IgE for egg white and cow's milk allergens in young infant with atopic dermatitis

BACKGROUND

The skin prick test (SPT) for detecting atopic sensitization is not preferred in young infants with atopic dermatitis (AD) because of concerns about poor skin reactivity. This study aimed to evaluate whether the results of SPT agreed well with those of specific serum immunoglobulin E (sIgE) antibody test in young infants with AD.

METHODS

This study included 2,077 eligible infants (age, <12 months) with AD who were tested by either SPT or sIgE between 2007 and 2011. Among them, 199 infants tested for egg white (EW) and 192 infants tested for cow's milk (CM), by both SPT and sIgE on the same day were identified and reviewed retrospectively. Kappa statistics and tests for equal kappa statistics were used to evaluate the agreement between the SPT and sIgE.

RESULTS

The mean wheal diameter and the allergen-to-histamine ratio of SPT showed substantial agreement with those of sIgE for EW (κ = 0.62, 0.69) and CM (κ = 0.34, 0.47). The agreement for EW was significantly higher <6-month-old than in ≥6-month-old infants (κ = 0.79 vs. 0.54, P = 0.02), and that for CM was similar (P = 0.60). The mean wheal diameters for EW and CM were evenly distributed, and did not show increasing trends regardless of age in months (Ptrend = 0.13 and 0.06, respectively).

CONCLUSIONS

The results of SPT agreed well with those of sIgE. This finding provides a rationale for using SPT, and suggests that SPT can be used along with sIgE to detect food sensitization in young infants with AD.

EAACI food allergy and anaphylaxis guidelines. Primary prevention of food allergy

Food allergy can have significant effects on morbidity and quality of life and can be costly in terms of medical visits and treatments. There is therefore considerable interest in generating efficient approaches that may reduce the risk of developing food allergy. This guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on Prevention and is part of the EAACI Guidelines for Food Allergy and Anaphylaxis. It aims to provide evidence-based recommendations for primary prevention of food allergy. A wide range of antenatal, perinatal, neonatal, and childhood strategies were identified and their effectiveness assessed and synthesized in a systematic review. Based on this evidence, families can be provided with evidence-based advice about preventing food allergy, particularly for infants at high risk for development of allergic disease. The advice for all mothers includes a normal diet without restrictions during pregnancy and lactation. For all infants, exclusive breastfeeding is recommended for at least first 4-6 months of life. If breastfeeding is insufficient or not possible, infants at high-risk can be recommended a hypoallergenic formula with a documented preventive effect for the first 4 months. There is no need to avoid introducing complementary foods beyond 4 months, and currently, the evidence does not justify recommendations about either withholding or encouraging exposure to potentially allergenic foods after 4 months once weaning has commenced, irrespective of atopic heredity. There is no evidence to support the use of prebiotics or probiotics for food allergy prevention.

Infectious pathogens and bronchiolitis outcomes

Bronchiolitis is a common early childhood illness and an important cause of morbidity, it is the number one cause of hospitalization among US infants. Bronchiolitis is also an active area of research, and recent studies have advanced our understanding of this illness. Although it has long been the conventional wisdom that the infectious etiology of bronchiolitis does not affect outcomes, a growing number of studies have linked specific pathogens of bronchiolitis (e.g., rhinovirus) to short- and long-term outcomes, such as future risk of developing asthma. The authors review the advent of molecular diagnostic techniques that have demonstrated diverse pathogens in bronchiolitis, and they review recent studies on the complex link between infectious pathogens of bronchiolitis and the development of childhood asthma.

Increased food diversity in the first year of life is inversely associated with allergic diseases

BACKGROUND

The role of dietary factors in the development of allergies is a topic of debate, especially the potential associations between infant feeding practices and allergic diseases. Previously, we reported that increased food diversity introduced during the first year of life reduced the risk of atopic dermatitis.

OBJECTIVE

In this study we investigated the association between the introduction of food during the first year of life and the development of asthma, allergic rhinitis, food allergy, or atopic sensitization, taking precautions to address reverse causality. We further analyzed the association between food diversity and gene expression of T-cell markers and of Cε germline transcript, reflecting antibody isotype switching to IgE, measured at 6 years of age.

METHODS

Eight hundred fifty-six children who participated in a birth cohort study, Protection Against Allergy Study in Rural Environments/EFRAIM, were included. Feeding practices were reported by parents in monthly diaries during the first year of life. Data on environmental factors and allergic diseases were collected from questionnaires administered from birth up to 6 years of age.

RESULTS

An increased diversity of complementary food introduced in the first year of life was inversely associated with asthma with a dose-response effect (adjusted odds ratio with each additional food item introduced, 0.74 [95% CI, 0.61-0.89]). A similar effect was observed for food allergy and food sensitization. Furthermore, increased food diversity was significantly associated with an increased expression of forkhead box protein 3 and a decreased expression of Cε germline transcript.

CONCLUSION

An increased diversity of food within the first year of life might have a protective effect on asthma, food allergy, and food sensitization and is associated with increased expression of a marker for regulatory T cells.

Atopy, cytokine production, and airway reactivity as predictors of pre-school asthma and airway responsiveness

BACKGROUND

Childhood asthma is often characterized by recurrent wheezing, airway hyper-reactivity, atopy, and altered immune characteristics; however, our understanding of the development of these relationships from early in life remains unclear. The aim of our study was to evaluate whether atopy, cytokine production by peripheral blood mononuclear cells (PBMCs), and airway responsiveness, assessed in infants and toddlers, are associated with asthma and airway responsiveness at 4-years of age.

METHODS

Infants with eczema (N = 116), enrolled prior to wheezing, were assessed at entry (mean age of 10.7 months), at 1-year follow-up (N = 112), and at 4-years of age (N = 94). Total serum IgE, specific IgE to allergens, and cytokines produced by stimulated PBMCs, were assessed at entry and 1-year follow-up. Spirometry was obtained at all 3-visits, while airway reactivity to methacholine was assessed at entry and 1-year follow-up, and bronchodilator (BD) responsiveness, as well as current asthma was assessed at 4-years of age.

RESULTS

We found that pre-school children with asthma had lower spirometry and a greater BD-response. Serum IgE, particularly to egg and/or milk, and altered cytokine production by PBMCs at entry to the study were associated with asthma, lower spirometry, and greater airway responsiveness at 4-years of age. In addition, we found that airway responsiveness, as well as spirometry, tracked from infancy to 4-years of age.

CONCLUSIONS

While spirometry and airway responsiveness track longitudinally from early in life, atopy and cytokine production by PBMCs are associated not only with an increased risk of pre-school asthma, but also lower spirometry and increased airway responsiveness.

Caesarean section and allergic manifestations: insufficient evidence of association found in population-based study of children aged 1 to 4 years

AIM

To provide evidence on the association between caesarean section and allergic manifestations in an unselected child population.

METHODS

Research focused on all children aged from one to 4 years (N = 4779), born between April 2001 and March 2005 and living in the province of South Karelia, Finland. They were identified from the nationwide population register. Questionnaire data on 3181 participants were individually merged with allergy test results (skin prick tests, IgE antibodies and open food challenges) from all patient records.

RESULTS

Compared with vaginal delivery, the adjusted relative incidence of positive allergy tests (with 95% confidence intervals, CI) in children born by caesarean section was 1.14 (0.79, 1.65) for food, 1.16 (0.66, 2.05) for animals, 0.94 (0.46, 1.92) for pollen and 1.19 (0.87, 1.63) for any allergens. The corresponding adjusted prevalence odds ratios (with 95% CI) of physician-diagnosed allergic manifestations were 1.15 (0.80, 1.63) for food allergy, 0.90 (0.47, 1.59) for pollen allergy or hay fever, 1.00 (0.75, 1.31) for atopic eczema, 0.96 (0.53, 1.65) for asthma and 1.08 (0.85, 1.38) for any allergic manifestation.

CONCLUSION

Insufficient evidence was found in our population for any association between birth by caesarean section and allergic manifestations. Further evidence from unselected populations, with longer follow-up periods, is needed.

Patterns of sensitization to inhalant and food allergens - findings from the German Health Interview and Examination Survey for Children and Adolescents

BACKGROUND

To assess the prevalence of allergic sensitization and to analyze patterns of sensitization to common inhalant and food allergens in a nationwide representative sample of children and adolescents in Germany.

METHODS

Data were collected from 2003 to 2006 within the KiGGS, the national Health Interview and Examination Survey covering a representative sample of 17,641 children and adolescents in Germany. Immunoglobulin E (IgE) antibodies to 20 specific allergens (11 inhalant and 9 food allergens) were quantitatively measured in a subsample of 12,988 KiGGS participants aged 3-17 years using the ImmunoCAP system. Serum concentrations ≥0.35 kU/l indicate sensitized participants. An exploratory factor analysis was performed in order to identify sensitization patterns.

RESULTS

Sensitization to at least 1 of the 20 tested allergens was detected in 40.2% [95% confidence interval (CI) 39.0-41.4] of the participants. The highest sensitization prevalences were found for pollen from Timothy grass (22.7%; 21.5-23.9) and rye (21.2%; 20.0-22.4). Sensitization was more prevalent in boys than in girls and prevalence increased generally with increasing age. We identified seven sensitization groups, namely (in descending order of magnitude) 'Timothy grass/rye', 'house-dust mites', 'food/mugwort', 'birch/apple', 'animals', 'cow's milk/egg white' and 'moulds'.

CONCLUSIONS

Allergic sensitization is common in German children and adolescents. The fact that sensitization potentially leads to clinically relevant allergic diseases stresses the public health relevance of this topic. Whether the grouping reflects the propensity for persons to be sensitized to multiple allergens within a group, or whether it is due to IgE cross-reactivity between different allergens of similar structure is still being discussed.

Skin prick test to foods in childhood atopic eczema: pros and cons

Skin prick tests are the first investigation in allergy diagnostics and their use is described in all the guidelines on atopic eczema. However, the clinical usefulness of skin prick tests is the subject of great debate. On the one hand, skin prick tests allow the identification both of individuals at risk for food allergy and of the allergen inducing the eczematous flare. On the other hand, when performed by a non-specific specialist, positive skin prick tests to foods may wrongly lead to prolonged elimination diets, which may induce nutritional deficiencies and perhaps loss of tolerance to the avoided foods. Furthermore, skin prick tests increase health costs. A consensus on this topic has not yet been reached. Considering the diversity of clinical stages in which it occurs, atopic eczema presentation should be the starting point to determine whether or not skin prick tests should be carried out.

IgE cross-linking critically impairs human monocyte function by blocking phagocytosis

BACKGROUND

IgE cross-linking triggers many cellular processes that drive allergic disease. While the role of IgE in mediating allergic responses is best described on basophils and mast cells, expression of the high-affinity IgE receptor on other innate immune cells, including monocytes, suggests that it may affect the function of these cells in allergic environments.

OBJECTIVE

To determine the effect of IgE cross-linking on the function of human monocytes.

METHODS

Monocytes purified from healthy donor blood samples were cultured for 4 to 96 hours with media alone, a cross-linking anti-IgE antibody or control IgG. Surface CD14 and CD64 expression and secreted cytokine concentrations were determined. Monocyte function was determined by assessing (1) phagocytosis of Escherichia coli or apoptotic HEp2 cells and (2) killing of intracellular E coli. Select experiments were performed on monocytes obtained from participants with elevated versus normal serum IgE concentrations.

RESULTS

IgE cross-linking on monocytes increased CD14 expression and induced secretion of TNF-α, IL-6, and autoregulatory IL-10. These effects were greatest in individuals with elevated serum IgE concentrations. In contrast, IgE cross-linking reduced CD64 expression and significantly impaired phagocytic function without disrupting the capacity of monocytes to kill bacteria.

CONCLUSIONS

IgE cross-linking drives monocyte proinflammatory processes and autoregulatory IL-10 in a serum IgE-dependent manner. In contrast, monocyte phagocytic function is critically impaired by IgE cross-linking. Our findings suggest that IgE cross-linking on monocytes may contribute to allergic disease by both enhancing detrimental inflammatory responses and concomitantly crippling phagocytosis, a primary mechanism used by these cells to resolve inflammation.

The development of TH2 responses from infancy to 4 years of age and atopic sensitization in areas endemic for helminth infections

Background

Helminth infections and allergies are associated with TH₂ responses. Whereas the development of TH₂ responses and allergic disorders in pediatric populations has been examined in affluent countries, no or little data exist from low income regions of the world.

The aim of this study is to examine factors influencing the development of TH₂ responses of children born in areas endemic for helminth infections and to relate these factors to atopic sensitization at 4 years of age.

Methods

Data were collected from pregnant mothers on helminth infections, education and socioeconomic status (SES). Total IgE, IL-5 in response to mitogen, and helminth antigens were measured in children at 2, 5, 12, 24 and 48 months of age. Skin prick testing (SPT) and allergen-specific IgE were determined at 4 years of age.

Results

Strong TH₂ responses were seen at 5 months of age and increased with time. Although maternal filarial infection was associated with helminth-antigen specific TH₂ responses, it was low maternal education or SES but not helminth infection, which was associated with the development of high total IgE and PHA-induced IL-5. At 4 years of age when allergen reactivity was assessed by SPT, the high general TH₂ responses did not translate into higher prevalence of SPT. The risk factor for SPT reactivity was low maternal education which decreased the risk of SPT positivity to allergens (adjusted OR, 0.32; 95% CI, 0.12 – 0.87) independently of maternal filarial infection which tended to reduce the child’s risk for being SPT positive (adjusted OR, 0.35; 95% CI, 0.07 – 1.70).

Conclusions

In areas endemic for helminths, potent TH₂ responses were seen early in life, but did not translate into a higher SPT reactivity to allergens. Therefore, in many parts of the world TH₂ responses in general and IgE in particular cannot be used for diagnosis of allergic diseases.

Testing children for allergies: why, how, who and when: an updated statement of the European Academy of Allergy and Clinical Immunology (EAACI) Section on Pediatrics and the EAACI-Clemens von Pirquet Foundation

Allergic diseases are common in childhood and can cause a significant morbidity and impaired quality-of-life of the children and their families. Adequate allergy testing is the prerequisite for optimal care, including allergen avoidance, pharmacotherapy and immunotherapy. Children with persisting or recurrent or severe symptoms suggestive for allergy should undergo an appropriate diagnostic work-up, irrespective of their age. Adequate allergy testing may also allow defining allergic trigger in common symptoms. We provide here evidence-based guidance on when and how to test for allergy in children based on common presenting symptoms suggestive of allergic diseases.

Atopic sensitization in the first year of life

BACKGROUND

There is conflicting evidence on whether allergen-specific memory is primed prenatally, whether this priming affects persistent immunologic effects, and whether it is modulated by the first environmental exposures in infancy.

OBJECTIVE

We sought to explore the course of atopic sensitization between birth and 12 months of age.

METHODS

Specific IgE levels for 6 food and 13 common inhalant allergens were assessed in cord blood and 1-year blood samples in the Protection against Allergy-Study in Rural Environments (PASTURE) birth cohort including 793 children from rural regions of 5 European countries. Detailed information on children's health, nutrition, and farm-related exposures was gathered by using a pregnancy questionnaire, 2 questionnaires at 2 and 12 months of age, and a diary covering the time in between.

RESULTS

Sensitization was more common at 12 months of age than at birth for almost all specificities. On an individual level, persistent sensitization to the same allergens was rare (1%), whereas transient (only at birth, 11%) and incident (only at 12 months, 34%) sensitization was seen in substantial proportions of children. Associations of transient sensitization with maternal sensitization differed with the allergen specificities, with the strongest associations for food allergens (odds ratio [OR], 10.6; 95% CI, 6.0-18.6) and the weakest associations for seasonal allergens (OR, 1.64; 95% CI, 0.94-2.86). Associations of maternal sensitization with incident sensitization were also seen. Incident sensitization was related to distinct prenatal and postnatal environmental exposures of mother and child, such as consumption of cereals for incident sensitization to seasonal allergens (OR, 0.66; 95% CI, 0.50-0.88).

CONCLUSION

IgE sensitization patterns change between birth and 12 months and are related to maternal and environmental influences.

IgE, mast cells, and eosinophils in atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with specific immune and inflammatory mechanisms. Atopy is among the major features of the diagnosis criteria for AD but is not an essential feature. Thus, patients diagnosed with AD can be atopic or non-atopic. This review focuses on the role of IgE, mast cells, and eosinophils in the pathogenesis of AD. The known functions of IgE in allergic inflammation suggest that IgE and IgE-mediated mast cell and eosinophil activation contribute to AD, but direct evidence supporting this is scarce. The level of IgE (thus the degree of allergic sensitization) is associated with severity of AD and contributed by abnormality of skin barrier, a key feature of AD. The function of IgE in development of AD is supported by the beneficial effect of anti-IgE therapy in a number of clinical studies. The role of mast cells in AD is suggested by the increase in the mast cell number and mast cell activation in AD lesions and the association between mast cell activation and AD. It is further suggested by their role in mouse models of AD as well as by the effect of therapeutic agents for AD that can affect mast cells. The role of eosinophils in AD is suggested by the presence of eosinophilia in AD patients and eosinophil infiltrates in AD lesions. It is further supported by information that links AD to cytokines and chemokines associated with production, recruitment, and activation of eosinophils.