The serum bank of EuroPrevall - the prevalence, cost and basis of food allergy across Europe

A survey on prevalence and parents' perceptions of food allergy in 3- to 16-year-old children in Wuhan, China

Background

The prevalence of food allergy (FA) has risen in recent decades, yet there is limited data on the cognition and beliefs of FA among the parents of FA children.

Objective

To investigate the prevalence of FA and assess the knowledge and perception of FA among parents of FA children in Wuhan, China.

Methods

Online questionnaires were conducted for the parents of 3- to 16-year-old children. They reported symptoms of suspected FA in the screening questionnaire were interviewed for further diagnostic evaluation. All the parents of the suspected FA children completed the subsequent assessments of the knowledge and perception on FA as well as their attitude towards the current online platforms.

Results

A total of 1963 children were recruited. The prevalence of self-reported FA was 10.2% (95% CI: 8.1-12.4%) and the physician-diagnosed FA was 6.2% (95% CI: 5.1-7.2%) in 3- to 16-year-olds in Wuhan. And the children with family history (57.9%) were predisposed to developing FA (P＜0.001). The total Brief Illness Perception Questionnaire (B-IPQ) score was 41.3 ± 10.0 among the parents. The B-IPQ scores correlated with symptom onset, but not with family history or other atopic comorbidities. The parents who never sought treatments obtained lower B-IPQ scores on most items compared to those who received treatments. The accuracy rate of the FA knowledge questionnaire was 56.7%. 11.6% of participants reported that children's FA had an impact on their lives. 67.2% of participants had searched information of FA online, among whom 80% expected to obtain professional suggestions on management and prevention strategies of FA from online platform.

Conclusion

In 3- to 16-year-old children in Wuhan, the prevalence of self-reported and physician-diagnosed FA was 10.2% and 6.2% respectively. Parents' knowledge of FA was insufficient and only a small proportion of parents perceived that their lives and careers have been affected considerably by FA of their children. Patient education and current online platforms should be improved among parents of FA children.

Food Allergens: When Friends Become Foes-Caveats and Opportunities for Oral Immunotherapy Based on Deactivation Methods

Food allergies represent a serious health concern and, since the 1990s, they have risen gradually in high-income countries. Unfortunately, the problem is complex because genetic, epigenetic, and environmental factors may be collectively involved. Prevention and diagnoses have not yet evolved into efficacious therapies. Identification and control of allergens present in edible substances hold promise for multi-purpose biomedical approaches, including oral immunotherapy. This review highlights recent studies and methods to modify the otherwise innocuous native proteins in most subjects, and how oral treatments targeting immune responses could help cancel out the potential risks in hypersensitive individuals, especially children. We have focused on some physical methods that can easily be conducted, along with chemo-enzymatic modifications of allergens by means of peptides and phytochemicals in particular. The latter, accessible from naturally-occurring substances, provide an added value to hypoallergenic matrices employing vegetal wastes, a point where food chemistry meets sustainable goals as well.

The Israel National Sera Bank: Methods, Representativeness, and Challenges

The Israel National Sera Bank (INSB) was established in 1997 in the Israel Center for Disease Control. The purpose of the INSB was to provide policymakers with data on the immunity status of the Israeli population against vaccine-preventable diseases, and on the extent and characteristics of exposure to emerging and re-emerging infectious diseases. The aim of this paper is to describe the methods, representativeness, and challenges in maintaining the INSB. The INSB comprises residual sera collected in six laboratories. By the end of 2019, 138,898 samples had been deposited in the INSB. These include samples from four community laboratories: 30.7% from the National Blood Service, 22.2% from Haifa and the Western Galilee, 21.7% from Soroka, and 0.7% from Jerusalem; and from two medical center laboratories: 18.6% from Schneider and 6.1% from Mayanei Hayeshua. The demographic characteristics of the sample at the end of 2019 closely resembled those of the general population. The main challenges addressed in maintaining the INSB relate to its representativeness, the possibility of repeated donors, costs, stability of antibody levels after long-term storage, ethical aspects, and the data available for each sample. The INSB is a unique, powerful, and necessary tool for assessing population immunity levels, based on serum samples collected over a long period of time.

Quality of life in patients with food allergy

Food allergy has increased in developed countries and can have a dramatic effect on quality of life, so as to provoke fatal reactions. We aimed to outline the socioeconomic impact that food allergy exerts in this kind of patients by performing a complete review of the literature and also describing the factors that may influence, to a greater extent, the quality of life of patients with food allergy and analyzing the different questionnaires available. Hitherto, strict avoidance of the culprit food(s) and use of emergency medications are the pillars to manage this condition. Promising approaches such as specific oral or epicutaneous immunotherapy and the use of monoclonal antibodies are progressively being investigated worldwide. However, even that an increasing number of centers fulfill those approaches, they are not fully implemented enough in clinical practice. The mean annual cost of health care has been estimated in international dollars (I$) 2016 for food-allergic adults and I$1089 for controls, a difference of I$927 (95 % confidence interval I$324–I$1530). A similar result was found for adults in each country, and for children, and interestingly, it was not sensitive to baseline demographic differences. Cost was significantly related to severity of illness in cases in nine countries. The constant threat of exposure, need for vigilance and expectation of outcome can have a tremendous impact on quality of life. Several studies have analyzed the impact of food allergy on health-related quality of life (HRQL) in adults and children in different countries. There have been described different factors that could modify HRQL in food allergic patients, the most important of them are perceived disease severity, age of the patient, peanut or soy allergy, country of origin and having allergy to two or more foods. Over the last few years, several different specific Quality of Life questionnaires for food allergic patients have been developed and translated to different languages and cultures. It is important to perform lingual and cultural translations of existent questionnaires in order to ensure its suitability in a specific region or country with its own socioeconomic reality and culture. Tools aimed at assessing the impact of food allergy on HRQL should be always part of the diagnostic work up, in order to provide a complete basal assessment, to highlight target of intervention as well as to evaluate the effectiveness of interventions designed to cure food allergy. HRQL may be the only meaningful outcome measure available for food allergy measuring this continuous burden.

The EuroPrevall outpatient clinic study on food allergy: background and methodology

BACKGROUND

The EuroPrevall project aimed to develop effective management strategies in food allergy through a suite of interconnected studies and a multidisciplinary integrated approach. To address some of the gaps in food allergy diagnosis, allergen risk management and socio-economic impact and to complement the EuroPrevall population-based surveys, a cross-sectional study in 12 outpatient clinics across Europe was conducted. We describe the study protocol.

METHODS

Patients referred for immediate food adverse reactions underwent a consistent and standardized allergy work-up that comprised collection of medical history; assessment of sensitization to 24 foods, 14 inhalant allergens and 55 allergenic molecules; and confirmation of clinical reactivity and food thresholds by standardized double-blind placebo-controlled food challenges (DBPCFCs) to milk, egg, fish, shrimp, peanut, hazelnut, celeriac, apple and peach.

RESULTS

A standardized methodology for a comprehensive evaluation of food allergy was developed and implemented in 12 outpatient clinics across Europe. A total of 2121 patients (22.6% <14 years) reporting 8257 reactions to foods were studied, and 516 DBPCFCs were performed.

CONCLUSIONS

This is the largest multicentre European case series in food allergy, in which subjects underwent a comprehensive, uniform and standardized evaluation including DBPCFC, by a methodology which is made available for further studies in food allergy. The analysis of this population will provide information on the different phenotypes of food allergy across Europe, will allow to validate novel in vitro diagnostic tests, to establish threshold values for major allergenic foods and to analyse the socio-economic impact of food allergy.

Oil body-associated hazelnut allergens including oleosins are underrepresented in diagnostic extracts but associated with severe symptoms

BACKGROUND

Oil body-associated allergens such as oleosins have been reported for important allergenic foods such as peanut, sesame and hazelnut. Here we investigate whether oil body associated proteins (OAPs) are linked with specific clinical phenotypes and whether they are represented in skin prick test (SPT) reagents.

METHODS

A hazelnut OAP fraction was characterized by mass-spectrometry (MS) to identify its major constituents. Polyclonal rabbit antibodies were generated against hazelnut OAPs. The presence of OAPs in commercially available hazelnut SPTs was studied by immunoblot and spiking experiments. OAP-specific IgE antibodies were measured in sera from patients with a convincing history of hazelnut allergy by RAST (n = 91), immunoblot (n = 22) and basophil histamine release (BHR; n = 14).

RESULTS

Hazelnut OAPs were analysed by MS and found to be dominated by oleosins at ~14 and ~17 kDa, and a 27 kDa band containing oleosin dimers and unidentified protein. In 36/91 sera specific IgE against hazelnut OAPs was detected, and confirmed to be biologically active by BHR (n = 14). The majority (21/22) recognized the oleosin bands at 17 kDa on immunoblot, of which 11 exclusively. These OAP-specific IgE responses dominated by oleosin were associated with systemic reactions to hazelnut (OR 4.24; p = 0.015) and negative SPT (χ2 6.3, p = 0.012). Immunoblot analysis using OAP-specific rabbit antiserum demonstrated that commercial SPT reagents are virtually devoid of OAPs, sometimes (3/9) resulting in false-negative SPT. Spiking of SPT reagents with OAP restored serum IgE binding of these false-negative patients on immunoblot at mainly 17 kDa.

CONCLUSION

Hazelnut allergens found in oil bodies dominated by oleosin are associated with more severe systemic reactions and negative SPT. Defatted diagnostic extracts are virtually devoid of these allergens, resulting in poor sensitivity for detection of IgE antibodies against these clinically relevant molecules.

[Current aspects in risk assessment of allergen traces in foodstuffs]

In contrast to usual ingredients in processed packaged foodstuffs, there are no suitable and binding regulations for the labeling of unintentional allergen traces in these foods as yet. This situation is unsatisfactory in regard to the fact that even traces of undeclared "hidden" allergens can constitute a considerable health risk for food allergic consumers. Furthermore, the unintentional cross-contact (cross-contamination) of allergens is also an issue in regard to food manufacturer product liability and due diligence. Therefore, stakeholders consider imperative need for the scientific determination of maximum tolerable levels of allergen traces in order to establish thresholds for legally binding food labeling. In addition to conventional toxicological risk assessments, the risk assessment of allergen traces that would be necessary in this context nowadays also incorporates modern approaches such as benchmark procedures and probabilistic modeling and methods. The scientific debate concerning the establishment of safe threshold levels continues, and a consensus must still be reached.

Isolation, cloning, and characterization of the 2S albumin: a new allergen from hazelnut

SCOPE

2S albumins are the major allergens involved in severe food allergy to nuts, seeds, and legumes. We aimed to isolate, clone, and express 2S albumin from hazelnut and determine its allergenicity.

METHODS

2S albumin from hazelnut extract was purified using size exclusion chromatography and RP-HPLC. After N-terminal sequencing, degenerated and poly-d(T) primers were used to clone the 2S albumin sequence from hazelnut cDNA. After expression in Escherichia coli and affinity purification, IgE reactivity was evaluated by Immunoblot/ImmunoCAP (inhibition) analyses using sera of nut-allergic patients.

RESULTS

N-terminal sequencing of a approximately 10 kDa peak from size exclusion chromatography/RP-HPLC gave two sequences highly homologous to pecan 2S albumin, an 11 amino acid (aa) N-terminal and a 10 aa internal peptide. The obtained clone (441 bp) encoded a 147 aa hazelnut 2S albumin consisting of a putative signal peptide (22 aa), a linker peptide (20 aa), and the mature protein sequence (105 aa). The latter was successfully expressed in E. coli. Both recombinant and natural 2S albumin demonstrated similar IgE reactivity in Immunoblot/ImmunoCAP (inhibition) analyses.

CONCLUSION

We confirmed the postulated role of hazelnut 2S albumin as an allergen. The availability of recombinant molecules will allow establishing the importance of hazelnut 2S albumin for hazelnut allergy.

Scientific advancement of novel protein allergenicity evaluation: an overview of work from the HESI Protein Allergenicity Technical Committee (2000-2008)

The safety assessment of genetically modified crops includes the evaluation for potential allergenicity. The current 'state-of-the-science' utilizes a weight of evidence approach, as outlined by the Codex Alimentarius commission (Alinorm 03/34 A), recognizing no single endpoint is predictive of the allergenic potential of a novel protein. This approach evaluates: whether the gene source is allergenic, sequence similarity to known allergens, and protein resistance to pepsin in vitro. If concerns are identified, serological studies may be necessary to determine if a protein has IgE binding similar to known allergens. Since there was a lack of standardized/validated methods to conduct the allergenicity assessment, a committee was assembled under the International Life Sciences Institute Health and Environmental Sciences Institute to address this issue. Over the last eight years, the Protein Allergenicity Technical Committee has convened workshops and symposia with allergy experts and government authorities to refine methods that underpin the assessment for potential protein allergenicity. This publication outlines this ongoing effort, summarizing workshops and formal meetings, referencing publications, and highlighting outreach activities. The purpose is to (1) outline 'the state-of-the-science' in predicting protein allergenicity in the context of current international recommendations for novel protein safety assessment, and (2) identify approaches that can be improved and future research needs.