The EuroPrevall birth cohort study on food allergy: baseline characteristics of 12,000 newborns and their families from nine European countries

Extensively hydrolyzed casein formula containing Lactobacillus rhamnosus GG reduces the occurrence of other allergic manifestations in children with cow's milk allergy: 3-year randomized controlled trial

BACKGROUND

Children with cow's milk allergy (CMA) have an increased risk of other allergic manifestations (AMs).

OBJECTIVE

We performed a parallel-arm randomized controlled trial to test whether administration of an extensively hydrolyzed casein formula (EHCF) containing the probiotic Lactobacillus rhamnosus GG (LGG) can reduce the occurrence of other AMs in children with CMA.

METHODS

Children with IgE-mediated CMA were randomly allocated to the EHCF or EHCF+LGG groups and followed for 36 months. The main outcome was occurrence of at least 1 AM (eczema, urticaria, asthma, and rhinoconjunctivitis). The secondary outcome was tolerance acquisition, which was defined as the negativization of a double-blind food challenge results at 12, 24, and 36 months. AMs were diagnosed according to standardized criteria. Tolerance acquisition was evaluated every 12 months.

RESULTS

A total of 220 children (147 boys [67%]) with a median age of 5.0 months (interquartile range, 3.0-8.0 months) were randomized; 110 children were placed in the EHCF group, and 110 children were placed in the EHCF+LGG group. In the complete case analysis the absolute risk difference for the occurrence of at least 1 AM over 36 months was -0.23 (95% CI, -0.36 to -0.10; P < .001), and the absolute risk difference for the acquisition of cow's milk tolerance was 0.20 (95% CI, 0.05-0.35; P < .01) at 12 months, 0.24 (95% CI, 0.08-0.41; P < .01) at 24 months, and 0.27 (95% CI, 0.11-0.43; P < .001) at 36 months. In the sensitivity analysis the effect size of the main outcome was virtually unchanged when the occurrence of AMs was assigned to all 27 missing children.

CONCLUSIONS

EHCF+LGG reduces the incidence of other AMs and hastens the development of oral tolerance in children with IgE-mediated CMA.

Self-Reported Food Hypersensitivity: Prevalence, Characteristics, and Comorbidities in the Norwegian Women and Cancer Study

BACKGROUND

This study aims to investigate the prevalence of self-reported food hypersensitivity, (SFH), the characteristics of women with SFH, and whether SFH is associated with multiple health complaints among the participants of the Norwegian Women and Cancer study (NOWAC).

METHODS

We conducted a cross-sectional study among 64,316 women aged 41-76 years. The women were randomly selected from the Norwegian Central Person Register. Information on SFH and all covariates except age and place of residence was collected by questionnaires in 2002-2005.

RESULTS

The prevalence of SFH in our study sample was 6.8% (95% confidence interval: 6.7-7.0). Logistic regression analysis showed a negative association between SFH and age (odds ratio [OR] 0.97). The odds of SFH increased among women living in or near urban centers, women with more than 9 years of education, women who did not have full-time work, women who had experienced poor economic conditions in childhood, those living without a partner, and those who did not consume alcohol or smoke (OR varied from 1.10 to 1.70). Women with a low body mass index had higher odds of SFH (OR 1.37) than those with a moderate body mass index. SFH was positively associated with poor self-perceived health (OR 2.56). The odds of SFH increased with the number of concurrent health complaints, with an OR for 5-6 comorbidities of 4.93.

CONCLUSION

We found an association between SFH, poor health, and different socio demographic and lifestyle characteristics. Women with SFH had increased odds of reporting multiple health complaints.

Usefulness of component resolved analysis of cat allergy in routine clinical practice

BACKGROUND

Cat allergy is of great importance, and its prevalence is increasing worldwide. Cat allergens and house dust mite allergens represent the major indoor allergens; however, they are ubiquitous. Cat sensitization and allergy are known risk factors for rhinitis, bronchial hyperreactivity and asthma. Thus, the diagnosis of sensitization to cats is important for any allergist.

METHODS

70 patients with positive skin prick tests for cats were retrospectively compared regarding their skin prick test results, as well as their specific immunoglobulin E antibody profiles with regard to their responses to the native cat extract, rFel d 1, nFel d 2 and rFel d 4. 35 patients were allergic to cats, as determined by positive anamnesis and/or nasal provocation with cat allergens, and 35 patients exhibited clinically non-relevant sensitization, as indicated by negative anamnesis and/or a negative nasal allergen challenge.

RESULTS

Native cat extract serology testing detected 100% of patients who were allergic to cats but missed eight patients who showed sensitization in the skin prick test and did not have allergic symptoms. The median values of the skin prick test, as well as those of the specific immunoglobulin E antibodies against the native cat extract, were significantly higher for allergic patients than for patients with clinically non-relevant sensitization. Component based diagnostic testing to rFel d 1 was not as reliable. Sensitization to nFel d 2 and rFel d 4 was seen only in individual patients.

CONCLUSION

Extract based diagnostic methods for identifying cat allergy and sensitization, such as the skin prick test and native cat extract serology, remain crucial in routine clinical practice. In our study, component based diagnostic testing could not replace these methods with regard to the detection of sensitization to cats and differentiation between allergy and sensitization without clinical relevance. However, component resolved allergy diagnostic tools have individual implications, and future studies may facilitate a better understanding of its use and subsequently may improve the clinical management of allergic patients.

Usefulness of component resolved analysis of cat allergy in routine clinical practice

Background

Cat allergy is of great importance, and its prevalence is increasing worldwide. Cat allergens and house dust mite allergens represent the major indoor allergens; however, they are ubiquitous. Cat sensitization and allergy are known risk factors for rhinitis, bronchial hyperreactivity and asthma. Thus, the diagnosis of sensitization to cats is important for any allergist.

Methods

70 patients with positive skin prick tests for cats were retrospectively compared regarding their skin prick test results, as well as their specific immunoglobulin E antibody profiles with regard to their responses to the native cat extract, rFel d 1, nFel d 2 and rFel d 4. 35 patients were allergic to cats, as determined by positive anamnesis and/or nasal provocation with cat allergens, and 35 patients exhibited clinically non-relevant sensitization, as indicated by negative anamnesis and/or a negative nasal allergen challenge.

Results

Native cat extract serology testing detected 100% of patients who were allergic to cats but missed eight patients who showed sensitization in the skin prick test and did not have allergic symptoms. The median values of the skin prick test, as well as those of the specific immunoglobulin E antibodies against the native cat extract, were significantly higher for allergic patients than for patients with clinically non-relevant sensitization. Component based diagnostic testing to rFel d 1 was not as reliable. Sensitization to nFel d 2 and rFel d 4 was seen only in individual patients.

Conclusion

Extract based diagnostic methods for identifying cat allergy and sensitization, such as the skin prick test and native cat extract serology, remain crucial in routine clinical practice. In our study, component based diagnostic testing could not replace these methods with regard to the detection of sensitization to cats and differentiation between allergy and sensitization without clinical relevance. However, component resolved allergy diagnostic tools have individual implications, and future studies may facilitate a better understanding of its use and subsequently may improve the clinical management of allergic patients.

Epidemiology of food allergy and food-induced anaphylaxis: is there really a Western world epidemic?

PURPOSE OF REVIEW

Food-induced anaphylaxis continues to be an important cause of hospital admissions, particularly in children. This review outlines recent advances in understanding the epidemiology of IgE-mediated food allergy and potential mechanisms for its rise in prevalence.

RECENT FINDINGS

The rise in food allergy prevalence in Western countries has happened more quickly than changes to the genome can occur; thus, environmental changes are likely to be important. Recent studies, however, suggest that genetic risk determines responses to environmental risk factors. Environmental peanut exposure has been associated with increased peanut allergy risk in individuals with filaggrin null mutations, consistently with sensitization occurring through a damaged skin barrier. Reduced microbial and vitamin D exposure is also leading candidates for risk factors for food allergy in the context of genetic susceptibility. In addition, HLA-DR and HLA-DQ gene region variants appear to play a role in peanut allergy, although no studies have yet assessed their susceptibility to environmental cues. Finally, findings from observational cohorts and the first large-scale intervention trials for food allergy prevention support early oral allergen exposure to reduce the prevalence of specific food allergies, which is informing changes in public health guidelines at the population level. Further research will be required to assess the impact of these guideline changes on the population prevalence of food allergy.

SUMMARY

New studies are providing important insights into the prevalence, causes, and mechanisms of food allergy. Recent findings are informing changes to population health guidelines in developed countries, which have the potential to halt or reverse the increase in food allergy prevalence. By contrast, food allergy in the developing world remains understudied.

Cow's milk allergy in Dutch children: an epigenetic pilot survey

Background

Cow’s milk allergy (CMA) is a common disease in infancy. Early environmental factors are likely to contribute to CMA. It is known that epigenetic gene regulation can be altered by environmental factors. We have set up a proof of concept study, aiming to detect epigenetic associations specific with CMA.

Methods

We studied children from the Dutch EuroPrevall birth cohort study (N = 20 CMA, N = 23 controls, N = 10 tolerant boys), age and gender matched. CMA was challenge proven. Bisulfite converted DNA (blood) was analyzed using the 450K infinium DNA-methylation array. Four groups (combined, girls, boys and tolerant boys) were analysed between CMA and controls. Statistical analysis and pathway-analysis were performed in “R” using IMA, Minfi and the global-test package. Differentially methylated regions in DHX58, ZNF281, EIF42A and HTRA2 genes were validated by quantitative amplicon sequencing (ROCHE 454^®).

Results

General hypermethylation was found in the CMA group compared to control children, while this effect was absent in the tolerant group. Methylation differences were, among others, found in regions of DHX58, ZNF281, EIF42A and HTRA2 genes. Several of these genes are known to be involved in immunological pathways and associated with other allergies.

Conclusion

We show that epigenetic associations are involved in CMA. Although, the statistical power of our study is limited and our sample was based on whole blood, we were still able to detect feasible loci and pathways. Therefore our findings might contribute to future diagnostic or therapeutic interventions for specific CMA. Further studies have to confirm the findings of our study.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-016-0105-z) contains supplementary material, which is available to authorized users.

Understanding the feasibility and implications of implementing early peanut introduction for prevention of peanut allergy

BACKGROUND

A recent randomized trial (the Learning Early About Peanut Allergy [LEAP] study) provided evidence that earlier dietary peanut introduction reduces peanut allergy prevalence in high-risk infants. However, questions remain as to how to identify and target the "at-risk" population to facilitate timely introduction of peanut.

OBJECTIVE

We sought to use population-based infant peanut allergy data to understand feasibility and implications of implementing the LEAP trial intervention.

METHODS

Using the HealthNuts study cohort (n = 5276) of 1-year-old infants, we explored the impact of using various criteria to identify infants at high risk of developing peanut allergy, and the implications of skin prick test (SPT) screening before peanut introduction.

RESULTS

Screening all infants with early onset eczema and/or egg allergy could require testing 16% of the population and would still miss 23% of peanut allergy cases; 29% of screened infants would require clinical follow-up because of being SPT-positive. Around 11% of high-risk infants were excluded from the LEAP study because of an SPT wheal size of more than 4 mm to peanut at baseline; data from the HealthNuts study suggest that 80% of these would be peanut allergic on food challenge. There were no life-threatening events among either low- or high-risk infants whose parents chose to introduce peanut at home in the first year of life, or in 150 peanut-allergic infants during hospital-based challenges.

CONCLUSIONS

Based on this large epidemiological study, a population program aiming to identify and screen all infants at risk of peanut allergy would pose major cost and logistic challenges that need to be carefully considered. Further research might be required to provide data for low-risk infants.

Clinical Features of Food Allergy during the 1st Year of Life: The ADAPAR Birth Cohort Study

BACKGROUND

Although food allergies (FAs) occur most commonly during the 1st year of life, there is limited information available regarding the epidemiology of FAs. In this study, we investigated the incidence of FA and the associated risk factors during the 1st year of life in southeast Turkey.

METHODS

This study is a prospective evaluation of 1,377 infants born at the Balcalı Hospital (Çukurova University) and includes four routine follow-up assessments until the age of 1 year. At birth, a physical examination was performed, cord blood samples were taken, and parents completed a baseline questionnaire. Follow-up visits were scheduled at 3, 6 and 12 months and included the infants' physical examination and a follow-up questionnaire. A skin prick test (SPT) was performed and food-specific IgE levels were measured at 6 and 12 months. Telephone interviews were conducted when the infants were 9 months of age, and the questionnaire was administered. The diagnosis of FA was based on food-specific IgE levels, positive SPT results, associated clinical findings and an oral food challenge (OFC) test.

RESULTS

Patient histories, physical examinations and laboratory results indicated a possible FA in 90 infants (6.5%) during the 1st year of life. All of them underwent OFC testing with the suspected foods, and FA was confirmed in 33 cases (2.4%). Cow's milk allergy was the major cause of FA. Skin reactions were major clinical findings in FA. A family history of atopy was identified as the major risk factor for FA.

CONCLUSIONS

The prevalence and risk factors of FA in our region are consistent with those reported in the literature.

Vitamin D deficiency in Europe: pandemic?

BACKGROUND

Vitamin D deficiency has been described as being pandemic, but serum 25-hydroxyvitamin D [25(OH)D] distribution data for the European Union are of very variable quality. The NIH-led international Vitamin D Standardization Program (VDSP) has developed protocols for standardizing existing 25(OH)D values from national health/nutrition surveys.

OBJECTIVE

This study applied VDSP protocols to serum 25(OH)D data from representative childhood/teenage and adult/older adult European populations, representing a sizable geographical footprint, to better quantify the prevalence of vitamin D deficiency in Europe.

DESIGN

The VDSP protocols were applied in 14 population studies [reanalysis of subsets of serum 25(OH)D in 11 studies and complete analysis of all samples from 3 studies that had not previously measured it] by using certified liquid chromatography-tandem mass spectrometry on biobanked sera. These data were combined with standardized serum 25(OH)D data from 4 previously standardized studies (for a total n= 55,844). Prevalence estimates of vitamin D deficiency [using various serum 25(OH)D thresholds] were generated on the basis of standardized 25(OH)D data.

RESULTS

An overall pooled estimate, irrespective of age group, ethnic mix, and latitude of study populations, showed that 13.0% of the 55,844 European individuals had serum 25(OH)D concentrations <30 nmol/L on average in the year, with 17.7% and 8.3% in those sampled during the extended winter (October-March) and summer (April-November) periods, respectively. According to an alternate suggested definition of vitamin D deficiency (<50 nmol/L), the prevalence was 40.4%. Dark-skinned ethnic subgroups had much higher (3- to 71-fold) prevalence of serum 25(OH)D <30 nmol/L than did white populations.

CONCLUSIONS

Vitamin D deficiency is evident throughout the European population at prevalence rates that are concerning and that require action from a public health perspective. What direction these strategies take will depend on European policy but should aim to ensure vitamin D intakes that are protective against vitamin D deficiency in the majority of the European population.

[Food allergies in paediatrics: Current concepts]

The concept of allergic reaction currently includes all those where an immunological reaction depends on a reaction mediated by IgE, as well as those that involve other immune mechanisms, such as T-cell regulators. There are many different clinical situations, like the classic immediate reactions (IgE mediated) such as urticaria, angioedema, immediate vomiting, abdominal pain, both upper respiratory (aphonia or rhinitis) and lower (wheezing or dyspnoea) symptom, and cardiovascular symptoms. The reactions that involve more than one organ, such as anaphylaxis, which could be an anaphylactic shock if there is cardiovascular involvement. The clinical signs and symptoms produced by non-IgE mediated reactions are usually more insidious in how they start, such as vomiting hours after the ingestion of food in enterocolitis, diarrhoea after days or weeks from starting food, dermatitis sometime after starting food. In these cases it is more difficult to associate these clinical symptoms directly with food. In this article, we attempt to clarify some concepts such as sensitisation/allergy, allergen/allergenic source, or the relationship of different clinical situations with food allergy, in order to help the paediatrician on the one hand, to prescribe strict diets in case of a suspicion based on the cause/effect relationship with the food, and on the other hand not to introduce unnecessary diets that very often have to last an excessively long time, and could lead to nutritional deficiencies in the children.

Incidence and natural history of hen's egg allergy in the first 2 years of life-the EuroPrevall birth cohort study

BACKGROUND

Parents and health staff perceive hen's egg allergy (HEA) as a common food allergy in early childhood, but the true incidence is unclear because population-based studies with gold-standard diagnostic criteria are lacking.

OBJECTIVE

To establish the incidence and course of challenge-confirmed HEA in children, from birth until the age of 24 months, in different European regions.

METHODS

In the EuroPrevall birth cohort study, children with a suspected HEA and their age-matched controls were evaluated in 9 countries, using a standardized protocol including measurement of HE-specific immunoglobulin E-antibodies in serum, skin prick tests, and double-blind, placebo-controlled food challenges (DBPCFC).

RESULTS

Across Europe, 12 049 newborns were enrolled, and 9336 (77.5%) were followed up to 2 years of age. In 298 children, HEA was suspected and DBPCFC was offered. HEA by age two was confirmed in 86 of 172 challenged children (mean raw incidence 0.84%, 95% confidence interval (95% CI) 0.67-1.03). Adjusted mean incidence of HEA was 1.23% (95% CI 0.98-1.51) considering possible cases among eligible children who were not challenged. Centre-specific incidence ranged from United Kingdom (2.18%, 95% CI 1.27-3.47) to Greece (0.07%). Half of the HE-allergic children became tolerant to HE within 1 year after the initial diagnosis.

CONCLUSIONS

The largest multinational European birth cohort study on food allergy with gold-standard diagnostic methods showed that the mean adjusted incidence of HEA was considerably lower than previously documented, although differences in incidence rates among countries were noted. Half of the children with documented HEA gained tolerance within 1 year postdiagnosis.

Spring season birth is associated with higher emergency department admission for acute allergic reactions

BACKGROUND

Acute allergic reactions are important causes of emergency department (ED) admission, imposing a significant clinical and organizational burden. Since the season of birth is linked with early exposure to allergens, this study was aimed to establish whether an association exists between season of birth and incidence and severity of acute allergic reactions in the ED.

METHODS

The electronic hospital database was searched to identify all consecutive adult patients who were admitted to the ED for acute allergic reactions (acute urticaria, acute angioedema, urticaria-angioedema and anaphylaxis) during a 1-year period.

RESULTS

The final study population consisted in 588 patients (328 women and 260 men; mean age 43 ± 18 years, range 16-96 years). Increased frequency of ED admission was observed for patients born in spring, whereas the lowest frequency was found for those born in autumn. Patients born in spring exhibited 1.19 and 1.12 higher risk of ED admission for acute allergic reactions compared to those born in autumn and in all other seasons, respectively. This difference remained significant in patients with allergic reaction attributable to drugs and in those with unknown triggers, whereas no pattern of seasonality was observed in patients with allergic reactions attributable to aliments, hymenoptera, chemicals or inhalants. Patients born in spring also exhibited 1.86 and 1.52 higher risk of being admitted to the ED for severe acute allergic reactions compared to those born in autumn and in all other seasons, respectively.

CONCLUSIONS

Patients born in spring appear particularly vulnerable to allergic reactions requiring ED visit.

Incidence and risk factors for food hypersensitivity in UK infants: results from a birth cohort study

BACKGROUND

The prevalence of food hypersensitivity in the UK is still largely open to debate. Additionally its pathogenesis is also unclear although it is known that there are differing phenotypes. Determining its prevalence, along with identifying those factors associated with its development will help to assess its clinical importance within the national setting and also add to the debate on appropriate prevention strategies.

METHODS

A population based birth cohort study conducted in Hampshire, UK as part of the EuroPrevall birth cohort study. 1140 infants were recruited with 823 being followed up until 2 years of age. Infants with suspected food reactions were assessed including specific IgE measurement and skin prick testing. Diagnosis of food hypersensitivity was by positive double-blind, placebo-controlled food challenge (DBPCFC) where symptoms up to 48 h after the end of the food challenge were considered indicative of a food hypersensitivity. Factors associated with food hypersensitivity and its two phenotypes of IgE-mediated and non-IgE-mediated disease were modelled in a multivariable logistic regression analysis.

RESULTS

Cumulative incidence of food hypersensitivity by 2 years of age was 5.0 %. The cumulative incidence for individual food allergens were hens' egg 2.7 % (1.6-3.8); cows' milk 2.4 % (1.4-3.5); peanut 0.7 % (0.1-1.3); soy 0.4 % (0.0-0.8); wheat 0.2 % (0.0-0.5) and 0.1 % (0.0-0.32) for fish. The cumulative incidence of IgE-mediated food allergy was 2.6 % with 2.1 % reacting to hens' egg. For non-IgE-mediated food allergy the cumulative incidence was 2.4 % (cows' milk 1.7 %). Predictors for any food hypersensitivity were wheeze, maternal atopy, increasing gestational age, age at first solid food introduction and mean healthy dietary pattern score. Predictors for IgE mediated allergy were eczema, rhinitis and healthy dietary pattern score whereas for non-IgE-mediated food allergy the predictors were dog in the home, healthy dietary pattern score, maternal consumption of probiotics during breastfeeding and age at first solid food introduction.

CONCLUSIONS

Just under half the infants with confirmed food hypersensitivity had no demonstrable IgE. In an exploratory analysis, risk factors for this phenotype of food hypersensitivity differed from those for IgE-mediated food allergy except for a healthy infant diet which was associated with less risk for both phenotypes.

Prevalence of Self-Reported Food Allergy in Lebanon: A Middle-Eastern Taste

Background. Food allergy (FA) is an important health problem in Western countries but there is limited data on the prevalence of food allergy in the Middle East. The main objective of our study is to assess the prevalence of self-reported food allergy in Lebanon. Methods. The survey was conducted by Telephone Calls questionnaire through random selection of landline phone numbers from the white pages all over Lebanon. A study questionnaire addressing the main objectives of the study was filled during the telephone call conversation. Results. Food allergy prevalence is estimated to be 4.1% in infants and children and 3.2% in adults. 65% of patients suffering from food allergy are females and 35% are males. Skin reactions are the most common symptoms among food allergy sufferers, reported in 86% of the cases. Signs of anaphylaxis appeared in 10.8% of cases. Fruits were the most common allergens at 35%, followed by eggs (19%) and nuts (16%). Cow's milk and spices ranked fourth (14%). Only half of food allergy sufferers sought medical advice. Allergists, dermatologists, gastroenterologists, or GPs (general practitioners) were consulted. Blood testing for specific IgE was the main diagnostic tool used by physicians. Conclusion. This is a pilot study of self-reported food allergy prevalence in Lebanon based on telephone survey. General prevalence is estimated to be 4.1% in infants and children and 3.2% in adults. Our study may improve awareness for proper diagnosis, food elimination, and acquisition of epinephrine autoinjectors in this part of the world.

What have studies of non-industrialized countries told us about the cause of allergic disease?

The increase in allergic diseases that was observed in countries that had experienced rapid economic growth since the mid-20th century initiated a search for environmental exposures that may explain these phenomena that continues to the present day. Societies that are in the earlier stages of the process of industrialization provide an opportunity to compare the initial stages of economic development and the lifestyle changes that may accompany this, with other communities whose way of life may not have changed appreciably for centuries. These studies have consistently demonstrated higher levels of allergic disease in the relatively affluent populations compared with those who maintain a more traditional lifestyle. Environmental changes that have emerged from these studies that may modify the risk of allergic disease include microbial exposures including parasite infection, pollution, diet and obesity. In addition, food and drug allergies represent a neglected area of research in these countries that may be causing a relatively high burden of disease.

Dietary habits and supplement use in relation to national pregnancy recommendations: data from the EuroPrevall birth cohort

Assessing maternal dietary habits across Europe during pregnancy in relation to their national pregnancy recommendations. A collaborative, multi-centre, birth cohort study in nine European countries was conducted as part of European Union funded EuroPrevall project. Standardised baseline questionnaire data included details of food intake, nutritional supplement use, exposure to cigarette smoke during pregnancy and socio-demographic data. Pregnancy recommendations were collected from all nine countries from the appropriate national organisations. The most commonly taken supplement in pregnancy was folic acid (55.6 % Lithuania-97.8 % Spain) and was favoured by older, well-educated mothers. Vitamin D supplementation across the cohort was very poor (0.3 % Spain-5.1 % Lithuania). There were significant differences in foods consumed in different countries during pregnancy e.g. only 2.7 % Dutch mothers avoided eating peanut, while 44.4 % of British mothers avoided it. Some countries have minimal pregnancy recommendations i.e. Lithuania, Poland and Spain while others have similar, very specific recommendations i.e. UK, the Netherlands, Iceland, Greece. Allergy specific recommendations were associated with food avoidance during pregnancy [relative rate (RR) 1.18 95 % CI 0.02-1.37]. Nutritional supplement recommendations were also associated with avoidance (RR 1.08, 1.00-1.16). Maternal dietary habits and the use of dietary supplements during pregnancy vary significantly across Europe and in some instances may be influenced by national recommendations.

Incidence and natural history of challenge-proven cow's milk allergy in European children--EuroPrevall birth cohort

BACKGROUND

Cow's milk allergy (CMA) is one of the most commonly reported childhood food problems. Community-based incidence and prevalence estimates vary widely, due to possible misinterpretations of presumed reactions to milk and differences in study design, particularly diagnostic criteria.

METHODS

Children from the EuroPrevall birth cohort in 9 European countries with symptoms possibly related to CMA were invited for clinical evaluation including cows' milk-specific IgE antibodies (IgE), skin prick test (SPT) reactivity and double-blind, placebo-controlled food challenge.

RESULTS

Across Europe, 12 049 children were enrolled, and 9336 (77.5%) were followed up to 2 years of age. CMA was suspected in 358 children and confirmed in 55 resulting in an overall incidence of challenge-proven CMA of 0.54% (95% CI 0.41-0.70). National incidences ranged from 1% (in the Netherlands and UK) to <0.3% (in Lithuania, Germany and Greece). Of all children with CMA, 23.6% had no cow's milk-specific IgE in serum, especially those from UK, the Netherlands, Poland and Italy. Of children with CMA who were re-evaluated one year after diagnosis, 69% (22/32) tolerated cow's milk, including all children with non-IgE-associated CMA and 57% of those children with IgE-associated CMA.

CONCLUSIONS

This unique pan-European birth cohort study using the gold standard diagnostic procedure for food allergies confirmed challenge-proven CMA in <1% of children up to age 2. Affected infants without detectable specific antibodies to cow's milk were very likely to tolerate cow's milk one year after diagnosis, whereas only half of those with specific antibodies in serum 'outgrew' their disease so soon.

Remaining symptoms in half the children treated for milk allergy

The aim of this study was to investigate the cumulative incidence and predictive variables of treatment failure with a whey-based extensively hydrolyzed formula (w-eHF) in children with cow's milk allergy (CMA). All children were diagnosed with CMA, using double-blind placebo-controlled food challenge (DBPCFC) with amino acid-based formula as placebo, and receive w-eHF treatment after diagnosis. Forty-nine children with CMA were included. w-eHF treatment failure was defined as incomplete resolution of original CMA symptoms upon w-eHF treatment and disappearance of these symptoms upon replacement of w-eHF with amino acid-based formula. A multiple logistic regression model was used to investigate which variables could predict treatment failure. Twenty-five (51%; 95% confidence interval (CI) 38-64%) of the children with CMA failed on w-eHF. Only "gastrointestinal discomfort" was found to contribute independently to the probability of failing w-eHF, odds ratio (95% CI) 8.994 (1.007-79.457).

CONCLUSIONS

In half of the children with proven CMA, there is incomplete resolution of symptoms upon w-eHF treatment. This study needs to be repeated including DBPCFC with w-eHF to provide more definitive diagnosis, especially since gastrointestinal discomfort seems to be the sole predictive variable for treatment failure. In the meantime, a change in formula should be considered in children with incomplete symptom resolution upon w-eHF treatment.

IgE recognition patterns in peanut allergy are age dependent: perspectives of the EuroPrevall study

BACKGROUND

We tested the hypothesis that specific molecular sensitization patterns correlate with the clinical data/manifestation in a European peanut-allergic population characterized under a common protocol.

METHODS

Sixty-eight peanut-allergic subjects and 82 tolerant controls from 11 European countries were included. Allergy to peanut and lowest symptom-eliciting dose was established by double-blind placebo-controlled food challenge in all but anaphylactic subjects. Information of early or late (before or after 14 years of age) onset of peanut allergy was obtained from standardized questionnaires. IgE to peanut allergens rAra h 1-3, 6, 8-9, profilin and CCD was determined using ImmunoCAP.

RESULTS

Seventy-eight percent of peanut allergics were sensitized to peanut extract and 90% to at least one peanut component. rAra h 2 was the sole major allergen for the peanut-allergic population. Geographical differences were observed for rAra h 8 and rAra h 9, which were major allergens for central/western and southern Europeans, respectively. Sensitization to rAra h 1 and 2 was exclusively observed in early-onset peanut allergy. Peanut-tolerant subjects were frequently sensitized to rAra h 8 or 9 but not to storage proteins. Sensitization to Ara h 2 ≥ 1.0 kUA /l conferred a 97% probability for a systemic reaction (P = 0.0002). Logistic regression revealed a significant influence of peanut extract sensitization and region on the occurrence of systemic reactions (P = 0.0185 and P = 0.0436, respectively).

CONCLUSION

Sensitization to Ara h 1, 2 and 3 is usually acquired in childhood. IgE to Ara h 2 ≥ 1.0 kUA /l is significantly associated with the development of systemic reactions to peanut.

Genetic susceptibility for cow's milk allergy in Dutch children: the start of the allergic march?

BACKGROUND

Cow's milk allergy (CMA) is the most common allergic disease in infancy. It is not clear, whether infants with CMA have an increased risk of developing other allergic diseases later in life, the so-called "allergic march". We aimed to detect genetic associations of CMA using reported single nucleotide polymorphisms (SNP) in other allergic diseases and genetic mutations within the filaggrin (FLG) gene. Both to investigate possible causes of CMA, which also suggests an "allergic march".

METHODS

Thirty children from the Dutch EuroPrevall birth cohort study with CMA in infancy and twenty-three healthy controls were studied. Six candidate SNPs were selected (minor allele frequency 10-50 % combined with a large effect) based on the literature. Thirteen FLG candidate mutations were selected spread over repeats 1, 3, 4, 5, 6, 7, 9 and 10 respectively.

RESULTS

We found two SNP's, rs17616434 (P = 0.002) and rs2069772 (P = 0.038), significantly associated with CMA. One is located near the toll like receptor 6 (TLR6) gene, which functionally interacts with toll-like receptor 2, and is associated with an increased risk of other allergic diseases. One is located at the Interleukin 2 (IL2) locus. Twelve FLG amplicons were analyzed, but showed no significant enrichment. Nevertheless, we did observe more FLG mutations in the CMA-group compared to controls.

CONCLUSION

We significantly associated two SNPs with CMA, suggesting that variation in the TLR6 and IL2 genes contribute to the expression of CMA. In addition, since TLR6 and IL2 were earlier associated with other later onset allergies, this also favours the "allergic march" hypothesis. We observed more FLG mutations in the CMA-group, albeit we found no statistical significant enrichment of FLG mutations. Further studies are necessary to investigate the role of common variants and FLG or other skin barrier gene mutations in CMA.

Allergy to furry animals: New insights, diagnostic approaches, and challenges

The prevalence of allergy to furry animals has been increasing, and allergy to cats, dogs, or both is considered a major risk factor for the development of asthma and rhinitis. An important step forward in the diagnosis of allergy to furry animals has been made with the introduction of molecular-based allergy diagnostics. A workshop on furry animals was convened to provide an up-to-date assessment of our understanding of (1) the exposure and immune response to the major mammalian allergens, (2) the relationship of these responses (particularly those to specific proteins or components) to symptoms, and (3) the relevance of these specific antibody responses to current or future investigation of patients presenting with allergic diseases. In this review research results discussed at the workshop are presented, including the effect of concomitant exposures from other allergens or microorganisms, the significance of the community prevalence of furry animals, molecular-based allergy diagnostics, and a detailed discussion of cat and dog components.

Geographic and temporal variations in pollen exposure across Europe

BACKGROUND

The EC-funded EuroPrevall project examined the prevalence of food allergy across Europe. A well-established factor in the occurrence of food allergy is primary sensitization to pollen.

OBJECTIVE

To analyse geographic and temporal variations in pollen exposure, allowing the investigation of how these variations influence the prevalence and incidence of food allergies across Europe.

METHODS

Airborne pollen data for two decades (1990-2009) were obtained from 13 monitoring sites located as close as possible to the EuroPrevall survey centres. Start dates, intensity and duration of Betulaceae, Oleaceae, Poaceae and Asteraceae pollen seasons were examined. Mean, slope of the regression, probability level (P) and dominant taxa (%) were calculated. Trends were considered significant at P < 0.05.

RESULTS

On a European scale, Betulaceae, in particular Betula, is the most dominant pollen exposure, two folds higher than to Poaceae, and greater than five folds higher than to Oleaceae and Asteraceae. Only in Reykjavik, Madrid and Derby was Poaceae the dominant pollen, as was Oleaceae in Thessaloniki. Weed pollen (Asteraceae) was never dominant, exposure accounted for >10% of total pollen exposure only in Siauliai (Artemisia) and Legnano (Ambrosia). Consistent trends towards changing intensity or duration of exposure were not observed, possibly with the exception of (not significant) decreased exposure to Artemisia and increased exposure to Ambrosia.

CONCLUSIONS

This is the first comprehensive study quantifying exposure to the major allergenic pollen families Betulaceae, Oleaceae, Poaceae and Asteraceae across Europe. These data can now be used for studies into patterns of sensitization and allergy to pollen and foods.

Food allergy and anaphylaxis in infants and preschool-age children

Food allergy (FA) prevalence data in infants and preschool-age children are sparse, and proposed risk factors lack confirmation. In this study, 19 children's day care centers (DCC) from 2 main Portuguese cities were selected after stratification and cluster analysis. An ISAAC's (International Study of Asthma and Allergies in Childhood) derived health questionnaire was applied to a sample of children attending DCCs. Outcomes were FA parental report and anaphylaxis. Logistic regression was used to explore potential risk factors for reported FA. From the 2228 distributed questionnaires, 1217 were included in the analysis (54.6%). Children's median age was 3.5 years, and 10.8% were described as ever having had FA. Current FA was reported in 5.7%. Three (0.2%) reports compatible with anaphylaxis were identified. Reported parental history of FA, personal history of atopic dermatitis, and preterm birth increased the odds for reported current FA. A high prevalence of parental-perceived FA in preschool-age children was identified. Risk factor identification may enhance better prevention.

Recent advances on diagnosis and management of childhood asthma and food allergies

The epidemic of childhood allergic disorders has been associated to the decline of infectious disease. However, exposure to many triggers (airborne viruses, tobacco smoke, pollution, indoor allergens, etc.) contribute to the disease. Breast feeding practices, nutrition, dietary and obesity also play a multifaceted role in shaping the observed worldwide trends of childhood allergies. Guidelines for treatment are available, but their implementation is suboptimal. Then developed countries are slowing learning integrating the development of suitable guidelines with implementation plans. Awareness, psychosocial and family factors strongly influence asthma and food allergy control. Moreover, monitoring tools are necessary to facilitate self-management. By taking into consideration these and many other pragmatic aspects, national public health programs to control the allergic epidemic have been successful in reducing its impact and trace the need for future research in the area.

The potential link between gut microbiota and IgE-mediated food allergy in early life

There has been a dramatic rise in the prevalence of IgE-mediated food allergy over recent decades, particularly among infants and young children. The cause of this increase is unknown but one putative factor is a change in the composition, richness and balance of the microbiota that colonize the human gut during early infancy. The coevolution of the human gastrointestinal tract and commensal microbiota has resulted in a symbiotic relationship in which gut microbiota play a vital role in early life immune development and function, as well as maintenance of gut wall epithelial integrity. Since IgE mediated food allergy is associated with immune dysregulation and impaired gut epithelial integrity there is substantial interest in the potential link between gut microbiota and food allergy. Although the exact link between gut microbiota and food allergy is yet to be established in humans, recent experimental evidence suggests that specific patterns of gut microbiota colonization may influence the risk and manifestations of food allergy. An understanding of the relationship between gut microbiota and food allergy has the potential to inform both the prevention and treatment of food allergy. In this paper we review the theory and evidence linking gut microbiota and IgE-mediated food allergy in early life. We then consider the implications and challenges for future research, including the techniques of measuring and analyzing gut microbiota, and the types of studies required to advance knowledge in the field.

A global survey of changing patterns of food allergy burden in children

While food allergies and eczema are among the most common chronic non-communicable diseases in children in many countries worldwide, quality data on the burden of these diseases is lacking, particularly in developing countries. This 2012 survey was performed to collect information on existing data on the global patterns and prevalence of food allergy by surveying all the national member societies of the World Allergy Organization, and some of their neighbouring countries. Data were collected from 89 countries, including published data, and changes in the health care burden of food allergy. More than half of the countries surveyed (52/89) did not have any data on food allergy prevalence. Only 10% (9/89) of countries had accurate food allergy prevalence data, based on oral food challenges (OFC). The remaining countries (23/89) had data largely based on parent-reporting of a food allergy diagnosis or symptoms, which is recognised to overestimate the prevalence of food allergy. Based on more accurate measures, the prevalence of clinical (OFC proven) food allergy in preschool children in developed countries is now as high as 10%. In large and rapidly emerging societies of Asia, such as China, where there are documented increases in food allergy, the prevalence of OFC-proven food allergy is now around 7% in pre-schoolers, comparable to the reported prevalence in European regions. While food allergy appears to be increasing in both developed and developing countries in the last 10-15 years, there is a lack of quality comparative data. This survey also highlights inequities in paediatric allergy services, availability of adrenaline auto-injectors and standardised National Anaphylaxis Action plans. In conclusion, there remains a need to gather more accurate data on the prevalence of food allergy in many developed and developing countries to better anticipate and address the rising community and health service burden of food allergy.

Introduction of complementary foods and the relationship to food allergy

OBJECTIVES

To address questions regarding breastfeeding, complementary feeding, allergy development, and current infant-feeding recommendations.

METHODS

This was a nested, case-control within a cohort study in which mothers of 41 infants diagnosed with food allergy by the age of 2 years (according to double-blind, placebo-controlled food challenge) and their 82 age-matched controls kept prospective food diaries of how their infants were fed in the first year of life.

RESULTS

Infants who were diagnosed with food allergy by the time they were 2 years of age were introduced to solids earlier (≤16 weeks of age) and were less likely to be receiving breast milk when cow's milk protein was first introduced into their diet.

CONCLUSIONS

This study supports the current American Academy of Pediatrics' allergy prevention recommendations and the European Society of Pediatric Gastroenterology, Hepatology and Nutrition recommendations on complementary feeding to not introduce solids before 4 to 6 months of age. It also supports the American Academy of Pediatrics' breastfeeding recommendations that breastfeeding should continue while solids are introduced into the diet and that breastfeeding should continue for 1 year, or longer, as mutually desired by mother and infant.

Adverse reactions to foods and food allergy: development and reproducibility of a questionnaire for clinical diagnosis

Objective. To develop a questionnaire as a screening tool for adverse reactions to foods in children and to assess the technical reproducibility by test-retest. Methods. Reproducibility of the questionnaire was performed by the literature review, preparing the preliminary questionnaire, peer review, pretest, and retest analysis. The study of the test-retest reproducibility was cross-sectional and descriptive. Kappa coefficient was used to study the reproducibility of the questionnaire. The sample consisted of 125 2–4 year-old children from 15 daycare centers in Recife, Brazil, and interviews with parents or caregivers were used to collect data. Results. From the total children, sixty-three were boys (50.4%), forty-six were two years old (36.8%), forty-seven were three years old (37.6%), and thirty-two were four years old (25.6%). Forty caregivers reported that their child had health problems with food. Most frequently reported offending foods were milk, peanuts, shrimp, and chocolate. Nine questions showed a good Kappa index (≥0,6). Conclusions. The questionnaire used needs to be resized and reshaped on the basis of the issues with good internal consistency and reproducibility. The use of a validated and reproducible questionnaire in the children represents an important contribution towards assessing an eventual rise in overt food allergy.

Monitoring immune modulation by nutrition in the general population: identifying and substantiating effects on human health

Optimal functioning of the immune system is crucial to human health, and nutrition is one of the major exogenous factors modulating different aspects of immune function. Currently, no single marker is available to predict the effect of a dietary intervention on different aspects of immune function. To provide further guidance on the assessment and interpretation of the modulation of immune functions due to nutrition in the general population, International Life Sciences Institute Europe commissioned a group of experts from academia, government and the food industry to prepare a guidance document. A draft of this paper was refined at a workshop involving additional experts. First, the expert group defined criteria to evaluate the usefulness of immune function markers. Over seventy-five markers were scored within the context of three distinct immune system functions: defence against pathogens; avoidance or mitigation of allergy; control of low-grade (metabolic) inflammation. The most useful markers were subsequently classified depending on whether they by themselves signify clinical relevance and/or involvement of immune function. Next, five theoretical scenarios were drafted describing potential changes in the values of markers compared with a relevant reference range. Finally, all elements were combined, providing a framework to aid the design and interpretation of studies assessing the effects of nutrition on immune function. This stepwise approach offers a clear rationale for selecting markers for future trials and provides a framework for the interpretation of outcomes. A similar stepwise approach may also be useful to rationalise the selection and interpretation of markers for other physiological processes critical to the maintenance of health and well-being.

The influence of early feeding practices on fruit and vegetable intake among preschool children in 4 European birth cohorts

BACKGROUND

Fruit and vegetable intake in children remains below recommendations in many countries. The long-term effects of early parental feeding practices on fruit and vegetable intake are not clearly established.

OBJECTIVE

The purpose of the current study was to examine whether early feeding practices influence later fruit and vegetable intake in preschool children.

DESIGN

The study used data from 4 European cohorts: the British Avon Longitudinal Study of Parents and Children (ALSPAC), the French Etude des Déterminants pre et postnatals de la santé et du développement de l'Enfant study, the Portuguese Generation XXI Birth Cohort, and the Greek EuroPrevall study. Fruit and vegetable intake was assessed in each cohort by food-frequency questionnaire. Associations between early feeding practices, such as breastfeeding and timing of complementary feeding, and fruit and/or vegetable intake in 2-4-y-old children were tested by using logistic regressions, separately in each cohort, after adjustment for infant's age and sex and maternal age, educational level, smoking during pregnancy, and maternal fruit and vegetable intake.

RESULTS

Large differences in early feeding practices were highlighted across the 4 European cohorts with longer breastfeeding duration in the Generation XXI Birth Cohort and earlier introduction to complementary foods in ALSPAC. Longer breastfeeding duration was consistently related to higher fruit and vegetable intake in young children, whereas the associations with age of introduction to fruit and vegetable intake were weaker and less consistent across the cohorts. Mothers' fruit and vegetable intake (available in 3 of the cohorts) did not substantially attenuate the relation with breastfeeding duration.

CONCLUSION

The concordant positive association between breastfeeding duration and fruit and vegetable intake in different cultural contexts favors an independent specific effect.

The prevalence and socio-demographic risk factors of clinical eczema in infancy: a population-based observational study

BACKGROUND

Socio-demographic predictors for the development of clinically observed, infantile eczema have not been formally examined in a large population-based study. Few studies of eczema risk factors have included current, objective eczema outcomes as well as parent-reported history.

OBJECTIVES

We aimed to measure the population prevalence of infantile eczema using novel sampling methodology, and identify socio-demographic risk factors for eczema in the first year of life.

METHODS

A population-based cross-sectional study of infantile allergy (the HealthNuts study, n = 4972, response rate 74.1%) was conducted from 2008-2011 in Melbourne, Australia. Infants were examined for current eczema at age 12 months (mean 12.7, SD 0.7). Parents provided information about the infants' history of eczema and demographic factors. Factors associated with eczema were modelled using multinomial logistic regression.

RESULTS

The population prevalence of observed eczema at 12 months was 20.3% (95% CI 19.0, 21.5), while cumulative prevalence for parent-reported eczema was 28.0% (95% CI 26.7, 29.4). The strongest predictors of eczema were maternal eczema and asthma (multinomial (M)-OR 1.7, P < 0.001, and M-OR 1.4, P = 0.007), male sex (M-OR 1.4, P < 0.001), and East Asian ethnicity (M-OR 1.6, P < 0.001) with over 80% of infants with all risk factors exhibiting eczema. East Asian parents, particularly recent migrants, reported fewer allergies than other parents.

CONCLUSIONS AND CLINICAL RELEVANCE

Approximately, one in three infants developed eczema by 12 months of age. East Asian infants are at increased risk of eczema despite their parents having lower rates of allergy than non-Asian parents. Gene-environment interactions may explain the differential effect seen in this minority group.

Oral immunotherapy for allergic diseases using transgenic rice seeds: current state and future prospects

Allergen-specific immunotherapy (IT) has been shown to provide clinical benefit for patients with allergic diseases. At present, subcutaneous and sublingual ITs are mainly authorized for clinical treatment. Oral administration of allergens seems to be the easiest way to achieve IT, though it has yet to be translated to the clinical setting, mainly due to the requirement of a large amount of allergens. Plants, especially rice seeds, have recently been recognized as superior allergen carriers for oral administration, because of their high productivity, stability and safety. Therefore, in order to establish clinically applicable oral IT, we have been developing transgenic rice seeds (Tg rice), in which major epitopes of cedar pollen allergens or house-dust mites (HDM) are expressed. The efficacy of this orally administered Tg rice was confirmed in murine models of allergic rhinitis and bronchial asthma. In the safety study of the Tg rice, no adverse effects on cynomolgus macaques were observed. In this review, we summarized the current state and future prospects of allergen-specific IT, focusing particularly on oral IT with allergen-expressing Tg rice.

Validation of the Paediatric Food Allergy Quality of Life Questionnaire (PFA-QL)

BACKGROUND

The Paediatric Food Allergy Quality of Life Questionnaire (PFA-QL) was the first tool to be developed for assessing health-related quality of life (QoL) in children with food allergy. It has been used in a number of published studies, but has not been validated.

OBJECTIVE

The aim of the current study was to validate child (PFA-QL) and parent-proxy (PFA-QL-PF) versions of the scale in a specialist allergy clinic and in parents of children with food allergy.

METHODS

For the clinic sample, a generic QoL scale (PedsQL) and the PFA-QL were completed by 103 children (age 6-16 yrs) with peanut or tree nut allergy; test-retest reliability of the PFA-QL was tested in 50 stable patients. For the non-clinical sample, 756 parents of food allergic children completed the PFA-QL-PF, the Child Health Questionnaire (CHQ-PF50), Food Allergy Quality of Life Parental Burden Scale (FAQL-PB) and a Food Allergy Impact Measure.

RESULTS

The PFA-QL and PFA-QL-PF had good internal consistency (α's of 0.77-0.82), and there was moderate-to-good agreement between the generic- and disease-specific questionnaires. The PFA-QL was stable over time in the clinic sample, and in both samples, girls were reported to have poorer QoL than boys.

CONCLUSIONS

The PFA-QL and PFA-QL-PF are reliable and valid scales for use in both clinical and non-clinical populations. Unlike other available tools, they were developed and validated in the UK and thus provide a culture-specific choice for research, clinical trials and clinical practice in the UK. Validation in other countries is now needed.

Sensitization to Malassezia in children with atopic dermatitis combined with food allergy

BACKGROUND

The yeast Malassezia belongs to our normal cutaneous flora, but is capable of sensitizing individuals with atopic dermatitis (AD). Our objective was to investigate the prevalence of sensitization to Malassezia with a 10-yr follow-up among children suffering from AD combined with food allergy (FA) in relation to the extent of AD in infancy.

METHODS

One hundred and eighty seven infants diagnosed with AD and milk/wheat allergy before 1 yr of age were included in the study. The area of AD was estimated from patient records of the first visit and measured with SCORAD at the 10-yr follow-up. Specific IgE against Malassezia was determined with ImmunoCAP™ at 11 yr of age.

RESULTS

In infancy, 24 children (13%) were allergic to milk, 71 (38%) to wheat, and 92 (49%) to both milk and wheat, and 94 (50%) children had mild, 57 (30%) moderate and 36 (19%) severe AD. At the 10-yr follow-up visit, 19 (10%) of the children had ongoing milk and/or wheat allergy; 147 children (79%) had mild AD and 30 (16%) had SCORAD index of 0. Specific IgE against Malassezia mix was positive (≥0.35 kU/l) in 27% and specific IgE against M. sympodialis in 20% of the 187 children. The area of AD in infancy was associated with a greater risk of having allergen-specific IgE to Malassezia at the 10-yr follow-up. The risk ratio for FA was 3.11 (95% CI: 2.05-4.72; p < 0.001) if specific IgE to Malassezia was positive.

CONCLUSIONS

Infants with severe AD and FA seem to have a greater risk of becoming sensitized to Malassezia during a 10-yr follow-up.

Dehydrated egg white: an allergen source for improving efficacy and safety in the diagnosis and treatment for egg allergy

BACKGROUND

Raw and cooked eggs are used as allergens in oral food challenge (OFC). Raw egg is the best option, as it keeps proteins intact and retains their allergenicity, albeit microbiologically safe manipulation is difficult. Therefore, the use of dehydrated egg white (DEW) could improve the efficacy and safety profile of OFC. The aim of the study was to compare the allergenicity of DEW, a product that undergoes a double heat treatment (pasteurization and drying), with that of raw egg white (REW) and determine the efficacy of DEW in the diagnosis of egg allergy.

METHODS

We conducted a prospective study of 40 egg-allergic patients who visited our outpatient clinic. Each patient underwent OFC with DEW and REW to determine the correlation between the tests. DEW and REW extracts were analyzed using SDS-PAGE. We compared the allergenicity of both extracts using IgE immunoblotting with a serum pool from patients with positive OFC results.

RESULTS

Ten patients (25%) had positive OFC results with both DEW and REW, and the doses that triggered an allergic reaction in each patient were similar (p > 0.05). All 30 patients (75%) with a negative OFC result with DEW also had negative OFC results with REW. SDS-PAGE and IgE immunoblotting revealed that the protein composition and IgE-binding capacity of both extracts were virtually identical.

CONCLUSIONS

This is the first time that it is shown that the allergenicity of commercially available DEW is equivalent to raw egg whites. In vivo and in vitro tests showed that processing of DEW does not affect the allergenicity of egg proteins. DEW is an effective and microbiologically safer source of allergen for the diagnosis of egg allergy. Furthermore, DEW can be used in egg oral immunotherapy.

Pooling birth cohorts in allergy and asthma: European Union-funded initiatives - a MeDALL, CHICOS, ENRIECO, and GA²LEN joint paper

Long-term birth cohort studies are essential to understanding the life course and childhood predictors of allergy and the complex interplay between genes and the environment (including lifestyle and socioeconomic determinants). Over 100 cohorts focusing on asthma and allergy have been initiated in the world over the past 30 years. Since 2004, several research initiatives funded under the EU Framework Program for Research and Technological Development FP6-FP7 have attempted to identify, compare, and evaluate pooling data from existing European birth cohorts (GA(2)LEN: Global Allergy and European Network, FP6; ENRIECO: Environmental Health Risks in European Birth Cohorts, FP7; CHICOS: Developing a Child Cohort Research Strategy for Europe, FP7; MeDALL: Mechanisms of the Development of ALLergy, FP7). However, there is a general lack of knowledge about these initiatives and their potentials. The aim of this paper is to review current and past EU-funded projects in order to make a summary of their goals and achievements and to suggest future research needs of these European birth cohort networks.

High prevalence of food sensitisation in young children with liver disease: a clue to food allergy pathogenesis?

BACKGROUND

The pathogenesis of food allergy is not completely understood - animal models suggest hepatic mechanisms may be important for immune tolerance to orally ingested antigens, but there is little direct evidence for this in humans.

OBJECTIVES

We investigated whether there is an association between liver dysfunction or transplantation in young children and IgE sensitisation to food.

METHODS

We evaluated paired pre- and post- liver transplant sera from children aged 0-36 months treated at a single centre during 2001-2008. Sera were assayed for total IgE and cow's milk, egg and peanut-specific IgE. We quantified hepatic dysfunction pre-transplant using the Paediatric End-stage Liver Disease (PELD) score. We also assessed 70 children after renal transplant to establish whether any association between liver transplant and food sensitisation was organ specific.

RESULTS

Paired sera were available from 50 of 94 children who had a liver transplant during the study period. 35 of 50 (70%) had IgE sensitisation (≥ 0.35 kUa/l) to ≥ 1 food pre-transplant and 18 (36%) post-transplant (p = 0.001). Ten (20%) children had food-specific IgE levels that carry high probability of challenge-confirmed food allergy pre-transplant. Food sensitisation pre-transplant was associated with severity of liver dysfunction [mean (s.d.) pre-transplant PELD score 1.52 (0.13) in food sensitised, 0.77 (0.22) in non-sensitised children p = 0.004]. Total IgE level was raised in 34/42 (81%) pre-transplant and fell significantly post-transplant. Interview assessment of the parents of 40 children revealed that 13 (33%) had a history consistent with food allergy. These findings were not replicated in the renal transplant group.

CONCLUSIONS

Young children with severe liver dysfunction appear to have a high prevalence of food sensitisation. Hepatic mechanisms may therefore be important for establishing immune tolerance to dietary antigens in humans.