Highlights and recent developments in allergic diseases in EAACI journals (2019)

The European Academy of Allergy and Clinical Immunology (EAACI) owns three journals: Allergy, Pediatric Allergy and Immunology and Clinical and Translational Allergy. One of the major goals of EAACI is to support health promotion in which prevention of allergy and asthma plays a critical role and to disseminate the knowledge of allergy to all stakeholders including the EAACI junior members. There was substantial progress in 2019 in the identification of basic mechanisms of allergic and respiratory disease and the translation of these mechanisms into clinics. Better understanding of molecular and cellular mechanisms, efforts for the development of biomarkers for disease prediction, novel prevention and intervention studies, elucidation of mechanisms of multimorbidities, entrance of new drugs in the clinics as well as recently completed phase three clinical studies and publication of a large number of allergen immunotherapy studies and meta-analyses have been the highlights of the last year.

Highlights and recent developments in skin allergy and related diseases in EAACI journals (2018)

The European Academy of Allergy and Clinical Immunology (EAACI) supports three journals: Allergy, Paediatric Allergy and Immunology as well as Clinical and Translational Allergy. The major goals of EAACI include (i) supporting health promotion in which the prevention of allergy and asthma plays a critical role and (ii) disseminating the knowledge of allergy to all stakeholders including the EAACI junior members. Substantial progress was made in 2018 in the identification of basic mechanisms of atopic dermatitis and urticaria and the translation of these mechanisms into clinics. Many large epidemiologic studies and meta-analyses have been the highlights of the last year.

Highlights and recent developments in airway diseases in EAACI journals (2017)

The European Academy of Allergy and Clinical Immunology (EAACI) owns three journals: Allergy, Pediatric Allergy and Immunology and Clinical and Translational Allergy. One of the major goals of EAACI is to support health promotion in which prevention of allergy and asthma plays a critical role and to disseminate the knowledge of allergy to all stakeholders including the EAACI junior members. There was substantial progress in 2017 in the identification of basic mechanisms of allergic and respiratory disease and the translation of these mechanisms into clinics. Better understanding of molecular and cellular mechanisms, efforts for the development of biomarkers for disease prediction, novel prevention and intervention studies, elucidation of mechanisms of multimorbidies, entrance of new drugs in the clinics as well as recently completed phase three clinical studies and publication of a large number of allergen immunotherapy studies and metaanalyses have been the highlights of the last year.

The urgent need for a harmonized severity scoring system for acute allergic reactions

The accurate assessment and communication of the severity of acute allergic reactions are important to patients, clinicians, researchers, the food industry, and public health and regulatory authorities. Severity has different meanings to different stakeholders with patients and clinicians rating the significance of particular symptoms very differently. Many severity scoring systems have been generated, most focusing on the severity of reactions following exposure to a limited group of allergens. They are heterogeneous in format, none has used an accepted developmental approach, and none has been validated. Their wide range of outcome formats has led to difficulties with interpretation and application. Therefore, there is a persisting need for an appropriately developed and validated severity scoring system for allergic reactions that work across the range of allergenic triggers and address the needs of different stakeholder groups. We propose a novel approach to develop and then validate a harmonized scoring system for acute allergic reactions, based on a data-driven method that is informed by clinical and patient experience and other stakeholders' perspectives. We envisage two formats: (i) a numerical score giving a continuum from mild to severe reactions that are clinically meaningful and are useful for allergy healthcare professionals and researchers, and (ii) a three-grade-based ordinal format that is simple enough to be used and understood by other professionals and patients. Testing of reliability and validity of the new approach in a range of settings and populations will allow eventual implementation of a standardized scoring system in clinical studies and routine practice.

A new framework for the interpretation of IgE sensitization tests

IgE sensitization tests, such as skin prick testing and serum-specific IgE, have been used to diagnose IgE-mediated clinical allergy for many years. Their prime drawback is that they detect sensitization which is only loosely related to clinical allergy. Many patients therefore require provocation tests to make a definitive diagnosis; these are often expensive and potentially associated with severe reactions. The likelihood of clinical allergy can be semi-quantified from an IgE sensitization test results. This relationship varies though according to the patients' age, ethnicity, nature of the putative allergic reaction and coexisting clinical diseases such as eczema. The likelihood of clinical allergy can be more precisely estimated from an IgE sensitization test result, by taking into account the patient's presenting features (pretest probability). The presence of each of these patient-specific factors may mean that a patient is more or less likely to have clinical allergy with a given test result (post-test probability). We present two approaches to include pretest probabilities in the interpretation of results. These approaches are currently limited by a lack of data to allow us to derive pretest probabilities for diverse setting, regions and allergens. Also, cofactors, such as exercise, may be necessary for exposure to an allergen to result in an allergic reaction in specific IgE-positive patients. The diagnosis of IgE-mediated allergy is now being aided by the introduction of allergen component testing which may identify clinically relevant sensitization. Other approaches are in development with basophil activation testing being closest to clinical application.

Gut T cell receptor-γδ(+) intraepithelial lymphocytes are activated selectively by cholera toxin to break oral tolerance in mice

The gut immune system is usually tolerant to harmless foreign antigens such as food proteins. However, tolerance breakdown may occur and lead to food allergy. To study mechanisms underlying food allergy, animal models have been developed in mice by using cholera toxin (CT) to break tolerance. In this study, we identify T cell receptor (TCR)-γδ(+)  intraepithelial lymphocytes (IELs) as major targets of CT to break tolerance to food allergens. TCR-γδ(+)  IEL-enriched cell populations isolated from mice fed with CT and transferred to naive mice hamper tolerization to the food allergen β-lactoglobulin (BLG) in recipient mice which produce anti-BLG immunoglobulin (Ig)G1 antibodies. Furthermore, adoptive transfer of TCR-γδ(+)  cells from CT-fed mice triggers the production of anti-CT IgG1 antibodies in recipient mice that were never exposed to CT, suggesting antigen-presenting cell (APC)-like functions of TCR-γδ(+)  IELs. In contrast to TCR-αβ(+)  cells, TCR-γδ(+)  IELs bind and internalize CT both in vitro and in vivo. CT-activated TCR-γδ(+)  IELs express major histocompatibility complex (MHC) class II molecules, CD80 and CD86 demonstrating an APC phenotype. CT-activated TCR-γδ(+)  IELs migrate to the lamina propria, where they produce interleukin (IL)-10 and IL-17. These results provide in-vivo evidence for a major role of TCR-γδ(+)  IELs in the modulation of oral tolerance in the pathogenesis of food allergy.

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.

Paediatric oral peanut challenges: a comparison of practice in London and western Switzerland

BACKGROUND

There are guidelines on how to develop a food challenge protocol, but at present there is no gold standard guidance on method, and separate units produce differing protocols.

METHODS

We performed a retrospective analysis of 200 patients' data from the paediatric allergy units in Lausanne and Geneva, Western Switzerland, and St Thomas' Hospital (STH), UK.

RESULTS

St Thomas' Hospital has a younger cohort with a lower overall mean spIgE (2.36 kU/l vs. 8.00 kU/l, P = 0.004). The target peanut protein volumes differed: Switzerland 4.4 g vs. STH 8.4 g. Despite this, the dose actually achieved in positive challenges was not significantly different (2.33 g vs. 1.49 g, P = 0.16). 26% of challenges reacted at 4 g or more of peanut protein.

CONCLUSIONS

The differences in results highlight how the variation in reasoning behind food challenge alters the outcome. Standardization of food challenges would allow easy comparison between hospitals and geographical areas for research purposes.

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.

Perspectives on allergen-specific immunotherapy in childhood: an EAACI position statement

This article is the result of consensus reached by a working group of clinical experts in paediatric allergology as well as representatives from an ethical committee and the European Medicine Agency (EMA). The manuscript covers clinical, scientific, regulatory and ethical perspectives on allergen-specific immunotherapy in childhood. Unmet needs are identified. To fill the gaps and to bridge the different points of view, recommendations are made to researchers, to scientific and patient organizations and to regulators and ethical committees. Working together for the benefit of the community is essential. The European Academy of Allergy and Clinical Immunology (EAACI) serves as the platform of such cooperation.

[Skin barrier defects in atopic dermatitis: new treatments?]

Atopic dermatitis (AD) is a chronic inflammatory skin disorder and the most frequent skin disease in children. Skin barrier defects play a crucial role in its pathogenesis. 50% of patients suffering from AD present mutations in the filaggrin gene, coding for a key protein of the upper layer of the skin. However these mutations alone are not sufficient for disease development, suggesting that environmental factors are also of great importance in the genesis of AD. In particular skin infections frequently provoke clinical exacerbations in patients suffering from AD. New insights into skin barrier dysfunctions have facilitated the development of drugs targeting the sustainable restitution of the skin's physiologic function. These agents could modify the pharmacological approach of AD treatments in the future.

State of the art and new horizons in the diagnosis and management of egg allergy

Egg allergy is one of the most frequent food allergies in children below the age of three. Common symptoms of egg allergy involve frequently the skin as well as the gut and in more severe cases result in anaphylaxis. Non-IgE-mediated symptoms such as in eosinophilic diseases of the gut or egg-induced enterocolitis might also be observed. Sensitization to egg white proteins can be found in young children in absence of clinical symptoms. The diagnosis of egg allergy is based on the history, IgE tests as well as standardized food challenges. Ovomucoid is the major allergen of egg, and recent advances in technology have improved the diagnosis and follow-up of patients with egg allergy by using single allergens or allergens with modified allergenic properties. Today, the management of egg allergy is strict avoidance. However, oral tolerance induction protocols, in particular with egg proteins with reduced allergenic properties, are promising tools for inducing an increased level of tolerance in specific patients.

Intestinal lamina propria TcRgammadelta+ lymphocytes selectively express IL-10 and IL-17

BACKGROUND

The characteristics and roles of gut lymphocytes have been only partly elucidated, in particular with regard to activation patterns.

OBJECTIVES

To characterize lymphocytes from various parts of the gut and examine their activation pattern as a network.

METHODS

Lymphocytes were isolated from the epithelium, the lamina propria, Peyer's patches, mesenteric lymph nodes, the spleen, and peripheral blood of naive mice. They were then characterized for T cell phenotype, T cell receptors (TcRs), activation markers, and cytokine production.

RESULTS

The results showed a gradient of cells with an increasing proportion of TcRgammadelta+, CD8alphaalpha+ cells towards the gut lumen, with the highest number found in intraepithelial lymphocytes. These cells, together with lamina propria lymphocytes (LPLs) were also characterized by a memory-like phenotype (CD25- CD45RB(low) and CD44(high)) and CD69 expression. CD8+ TcRgammadelta+ LPLs produced IL-10 and IL-17, while TcRalphabeta+ LPLs were FoxP3 positive.

CONCLUSIONS

Gut lymphocytes express various receptors and cytokines according to their location. These specific features suggest a differential function for gut lymphocytes depending on their location.

[Allergic reactions and vaccines: distinguishing true and false reactions]

Similarly to other medications, vaccines may be responsible of allergic reactions. However, IgE-mediated allergies are extremely rare. The diagnosis of allergies to a vaccine is complex and these allergies are often over-diagnosis due to fear of severe anaphylaxis. Indeed, most of the patients labelled as allergic to a vaccine may tolerate a subsequent injection of the vaccine without clinical reaction. The economic impact and the impact on health, both from an individual point of view but also in terms of public health, are very important. Before this diagnosis can accurately be made, a complete work up is essential. If an allergy workup is necessary, it will be primarily based on skin tests.

Diagnosis and treatment of asthma in childhood: a PRACTALL consensus report

Asthma is the leading chronic disease among children in most industrialized countries. However, the evidence base on specific aspects of pediatric asthma, including therapeutic strategies, is limited and no recent international guidelines have focused exclusively on pediatric asthma. As a result, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology nominated expert teams to find a consensus to serve as a guideline for clinical practice in Europe as well as in North America. This consensus report recommends strategies that include pharmacological treatment, allergen and trigger avoidance and asthma education. The report is part of the PRACTALL initiative, which is endorsed by both academies.

Avirulant Salmonella typhimurium strains prevent food allergy in mice

Oral tolerance to foods can be regulated by microorganisms in the gut lumen. We hypothesized that pretreatment with avirulent Salmonella typhimurium strains could prevent food allergy in mice. Mice were administered S. typhimurium PhoPc (STPhoPc) or S. typhimurium AroA prior to oral sensitization to beta-lactoglobulin in the presence of cholera toxin. An oral antigen challenge after sensitization assessed antigen-induced anaphylaxis. Antigen-specific antibody titres were measured by enzyme-linked immunosorbent assay in the serum and enzyme-linked immunospot (ELISPOT) in the spleen, and cytokine-secreting cells were measured by ELISPOT in the Peyer's patches, lamina propria and epithelium cells. We showed first that S. typhimurium could up-regulate interleukin (IL)-12 and IL-10 secretion by gut T cells. Mice pretreated with STPhoPc had decreased anaphylaxis upon challenge, along with decreased immumoglobulin G1 (IgG1) and IgE antibody titres. Mice having received S. typhimurium AroA had partly decreased anaphylaxis as well as decreased serum IgG1 antibody titres in the serum, and increased serum IgA antibody titres. Antibody titres could be correlated with increased numbers of spleen and Peyer's patches antibody-producing cells. STPhoPc-treated mice showed significantly decreased anaphylaxis when compared with the control mice, while S. typhimurium AroA-pretreated mice had a similar immune response together with increased secretory IgA titres. Our experiments have proved a potential immunomodulatory protective effect by two avirulent S. typhimurium strains.

Diagnosis and treatment of asthma in childhood: a PRACTALL consensus report

Asthma is the leading chronic disease among children in most industrialized countries. However, the evidence base on specific aspects of pediatric asthma, including therapeutic strategies, is limited and no recent international guidelines have focused exclusively on pediatric asthma. As a result, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology nominated expert teams to find a consensus to serve as a guideline for clinical practice in Europe as well as in North America. This consensus report recommends strategies that include pharmacological treatment, allergen and trigger avoidance and asthma education. The report is part of the PRACTALL initiative, which is endorsed by both academies.

The management of anaphylaxis in childhood: position paper of the European academy of allergology and clinical immunology

Anaphylaxis is a growing paediatric clinical emergency that is difficult to diagnose because a consensus definition was lacking until recently. Many European countries have no specific guidelines for anaphylaxis. This position paper prepared by the EAACI Taskforce on Anaphylaxis in Children aims to provide practical guidelines for managing anaphylaxis in childhood based on the limited evidence available. Intramuscular adrenaline is the acknowledged first-line therapy for anaphylaxis, in hospital and in the community, and should be given as soon as the condition is recognized. Additional therapies such as volume support, nebulized bronchodilators, antihistamines or corticosteroids are supplementary to adrenaline. There are no absolute contraindications to administering adrenaline in children. Allergy assessment is mandatory in all children with a history of anaphylaxis because it is essential to identify and avoid the allergen to prevent its recurrence. A tailored anaphylaxis management plan is needed, based on an individual risk assessment, which is influenced by the child's previous allergic reactions, other medical conditions and social circumstances. Collaborative partnerships should be established, involving school staff, healthcare professionals and patients' organizations. Absolute indications for prescribing self-injectable adrenaline are prior cardiorespiratory reactions, exercise-induced anaphylaxis, idiopathic anaphylaxis and persistent asthma with food allergy. Relative indications include peanut or tree nut allergy, reactions to small quantities of a given food, food allergy in teenagers and living far away from a medical facility. The creation of national and European databases is expected to generate better-quality data and help develop a stepwise approach for a better management of paediatric anaphylaxis.

Eczematous reactions to food in atopic eczema: position paper of the EAACI and GA2LEN

Food allergy and atopic eczema (AE) may occur in the same patient. Besides typical immediate types of allergic reactions (i.e. noneczematous reactions) which are observed in patients suffering from AE, it is clear that foods, such as cow's milk and hen's eggs, can directly provoke flares of AE, particularly in sensitized infants. In general, inhaled allergens and pollen-related foods are of greater importance in older children, adolescents and adults. Clinical studies have revealed that more than 50% of affected children with AE that can be exacerbated by certain foods will react with a worsening of skin eczema either alone or in addition to immediate symptoms. Adolescents and adults may also react to foods, but reactions to 'classical' food allergens, such as hen's eggs and cow's milk, are not as common as in childhood. Some patients with AE do react to pollen-associated foods. Food-induced eczema should not be neglected by the allergologist: On the one hand, food can be a relevant trigger factor of persistent moderate-to-severe AE; on the other hand, unnecessary diets which are not based on a proper diagnosis may lead to malnutrition and additional psychological stress on patients suffering from AE. Eczematous reactions to food can only be diagnosed by a thorough diagnostic procedure, taking into account the patient's history, the degree of sensitization and the clinical relevance of the sensitization. The latter has often to be proven by oral food challenges. Upon oral food challenge it is most important to evaluate the status of the skin with an established score (e.g. SCORAD, EASI) after 24 h and later because otherwise worsening of eczema will be missed.

[Atopic dermatitis and food allergies]

Around 13% of children in Switzerland are affected by atopic dermatitis. Cutaneous defects with increased water loss and allergens permeability are hallmark of the disease. The prevalence of food allergy in children with moderate-to-severe atopic dermatitis is estimated to be 34%, mostly to eggs, milk and peanuts. Food allergy can cause immediate reactions with urticaria and anaphylaxis or delayed flares of eczema. In older patients and adults, exposition to respiratory allergens (dust mites, pollen) can also cause an exacerbation of the eczema. Allergy testing identifies patients with atopy, who are at greater risk of rhinitis and asthma. Skin prick tests, in vitro tests and food challenges can identify a concomitant allergy, leading to specific allergen avoidance mea-sures potentially improving skin symptoms.

Trends in prevalence of asthma, allergic rhinitis and atopic dermatitis in 5-7-year old Swiss children from 1992 to 2001

BACKGROUND

Changing occurrence rates of asthma, allergic rhinitis and atopic dermatitis are of public health concern and require surveillance. Changes in prevalence rates of these atopic diseases were monitored during 10 years and their trend with time was determined taking into account the influence of personal and environmental risk factors.

METHODS

Four cross-sectional surveys in 5-7-year old children were performed in seven different communities in Switzerland between 1992 and 2001. Prevalence of respiratory and allergic symptoms and of affecting risk factors including parental environmental concern were assessed using a standardized parental questionnaire.

RESULTS

A total of 988 (74.1%), 1778 (79.0%), 1406 (82.6%) and 1274 (78.9%) children participated, respectively, in the 1992, 1995, 1998 and 2001 surveys. Prevalence rates of asthma and hay fever symptoms remained quite stable over time (wheeze/past year: 8.8%, 7.8%, 6.4% and 7.4%, sneezing attack during pollen season: 5.0%, 5.6%, 5.4% and 4.6%). Rates of reported atopic dermatitis symptoms (specific skin rash/past year: 4.6%, 6.5%,7.4% and 7.6%) showed an increase over time, but those of diagnosis of eczema did not show a clear pattern (18.4%, 15.7%, 14.0% and 15.2%). Stratified analysis by parental environmental concern and by parental atopy showed similar trends. Rates of atopic dermatitis symptoms showed significant increase in girls but stayed stable in boys.

CONCLUSION

Results of these four consecutive surveys suggest that the increase in prevalence of asthma and hay fever in 5-7-year old children living in Switzerland may have ceased. However, symptoms of atopic dermatitis may still be on the rise, especially among girls.

Diagnosis of allergy syndromes: do symptoms always mean allergy?

Allergic disease has become a major burden in westernized societies because of a recent rise in its prevalence. Approximately one-third of children suffer from an allergic disease, with the prevalence varying from 15 to 20% for atopic dermatitis, 7 to 10% for asthma and 15 to 20% for allergic rhinitis and conjunctivitis. Despite the increase, it is important not to assume a diagnosis of allergy on the basis of symptoms alone, because allergic and nonallergic conditions may present with similar symptoms. An accurate allergy diagnosis is important in order to treat the patient most appropriately and to potentially prevent or delay the development of allergic disease. A good clinical history is the starting point for accurate allergy diagnosis but is not unequivocal. The European Academy of Allergy and Clinical Immunology has recognized the importance of allergy testing and therefore developed evidence-based recommendations on allergy testing in children. Widespread adherence to these recommendations should improve the quality of care for allergy patients. Cooperation between all healthcare professionals involved in the treatment of allergy patients is also a key to improve our response to the allergy epidemic.

[Treatment of atopic dermatitis: practical approach]

Atopic dermatitis (AD) is a chronic disease frequent in childhood. The treatment is based on regular moisturizing of the skin, information to the parents on the chronic course with recurrent flares, topical anti-infectious therapy for superinfections and colonization of the skin by staphylococcus aureus, and topical steroids. The immuno-modulatory macrolides (tacrolimus and pimecrolimus) represent a new alternative to topical steroids. These molecules are well tolerated, but theirs effects on the long-term are unknown. A food allergy may be responsible for a AD flare in up to a third of the cases, but the presence of an allergy should be demonstrated before the prescription of an elimination diet. AD is often the first manifestation of atopy: the physician should be aware of the future occurence of respiratory symptoms.

Breast-feeding and atopic eczema dermatitis syndrome: protective or harmful?

Numerous studies have addressed the potential of breast-feeding to protect for the development of allergic diseases, and in particular of atopic eczema dermatitis syndrome (AEDS). Although the majority of studies, as well as several meta-analyses, are strongly in favour of breast-feeding, there are some conflicting results and open issues. Furthermore, breast-feeding might be detrimental in a subgroup of young infants with severe early manifestations of AEDS and immunoglobulin E sensitizations to common foods. The aim of this review is not to analyse systematically the current literature, but to suggest a scientifically and clinically based analysis of the benefits of breast-feeding in atopic infants.

A consensus protocol for the determination of the threshold doses for allergenic foods: how much is too much?

BACKGROUND

While the ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies, little information is known regarding these threshold doses for specific allergenic foods. While low-dose challenge trials have been conducted on an appreciable number of allergic individuals, a variety of different clinical protocols were used making the estimation of the threshold dose very difficult.

OBJECTIVE

A roundtable conference was convened to develop a consensus clinical protocol for low-dose challenge trials for the estimation of threshold doses for specific allergenic foods.

METHODS

In May 2002, 20 clinical allergists and other interested parties were invited to participate in a roundtable conference to develop consensus of the key elements of a clinical protocol for low-dose challenge trials.

RESULTS

A consensus protocol was developed. Patients with convincing histories of food allergies and supporting diagnostic evidence including past challenge trials or high CAP-RAST scores can be enrolled in low-dose challenge trials. Care must be taken with younger patients to assure that they have not outgrown their food allergy. An approach was developed for the medication status of patients entering such trials. Challenge materials must be standardized, for example, partially defatted peanut flour composed of equal amounts of the three major varieties of peanuts (Florunner, Virginia, Spanish). Challenge materials must be appropriately blinded with sensory evaluation used to confirm the adequacy of blinding. A double-blind, placebo-controlled design should be used for low-dose challenge trials. Low-dose challenge trials would begin at doses of 10 microg of the allergenic food and would continue with doses of 100 microg and 1 mg followed by specific higher doses up to 100 mg depending upon the expert judgement of the physician; even higher doses might be applied to assure that the patient is indeed reactive to the particular food. A 30-min time interval would be used between doses, and reactive doses would be expressed as both discrete and cumulative doses. The goal of each challenge would be to develop objective symptoms; trials should not be discontinued on the basis of subjective symptoms only. Statistically, a minimum of 29 patients would be enrolled in low-dose challenge trials for each allergenic food because 0 reactors out of 29 patients at a particular dose allow the conclusion that there is 95% certainty that 90% of allergic individuals will not react to that dose.

CONCLUSION

A consensus protocol was developed. Using this protocol, it will be possible to estimate threshold doses for allergenic foods, the lowest amount that elicits mild, objective symptoms in highly sensitive individuals.

Future therapeutic options in food allergy

Up to 5% of young children and 2% of adults suffer from food allergy. Among them many have immunoglobulin E (IgE)-mediated food allergy, a condition with potentially fatal allergic reactions. Several studies have addressed possible definite treatment options for food allergy. Immunotherapy, by the oral route or by systemic injections shows promising preliminary results, but current interpretation of these therapeutic options are mostly handicapped by studies with insufficient scientific support, or by severe side-effects. Currently, no studies can support pharmacotherapy. Finally, most promising results were recently published with anti-IgE antibodies in a human trial, or various approaches in a mouse model of food allergy (chinese herbal medicine, specific modulation of the T cell response). Rapidly evolving findings might provide hope for a cure of food allergy in the near future.

An internet-based survey on the circumstances of food-induced reactions following the diagnosis of IgE-mediated food allergy

BACKGROUND

Despite careful avoidance measures, food allergic patients have a significant risk of anaphylactic episodes. Risk situations need to be identified for more efficient preventive measures.

METHODS

Responders to an internet-based survey on the awareness of food anaphylaxis were invited to relate the circumstances of their most severe reaction following the diagnosis of IgE-mediated food allergy. Items of the questionnaire included the circumstances of the reaction and the treatment, as well as questions related to reactions occurring at specific categories of sites (i.e. home, schools, or restaurants).

RESULTS

Fifty-one of the returned questionnaires (34.1%) corresponded to the study criteria. The median age of the subjects was 7 years (range 0.5-61), with 33/51 (64.7%) being less than 16 years of age. Reactions were reported to peanuts (24/51; 47.1%), milk (12/51; 23.5%), tree nuts (6/51; 11.8%), fish and shellfish (5/51; 9.8%), and others (3/51; 5.8%). Reactions occurred at home (13/51; 25.5%), in restaurants (9/51; 17.6%), at school or daycare or kindergarten (8/51; 15.7%), at a relative or friend's home (7/51; 13.7%), at sites of leisure activities (6/51; 11.8%), at work (3/51; 5.9%), in church or a hospital ward (2/51; 3.9% each), or in a food store (1/51; 2.0%). In severe reactions (37/51; 72.5%) epinephrine was administered in 28/37 (75.7%) of the responders. Finally, while most reactions happened after ingestion of the food (40/51; 78.4%), others were reported after skin contact exclusively (8/51; 16%), or after inhalation (3/51; 5.9%).

CONCLUSION

Food induced-anaphylaxis in patients aware of their allergy happens most often at sites considered as safe (i.e. home, schools, workplace, hospitals). Better strategies to avoid accidental reactions include clear labelling of forbidden foods and increased information at all levels. These might dramatically reduce the risk of food-induced anaphylaxis in food allergy sufferers.

An Internet-based survey of anaphylactic reactions to foods

BACKGROUND

A favorable outcome of anaphylaxis depends on the rapidity of adequate initial management and epinephrine injection. However, few data on the management of anaphylactic reactions are available. The aim of this study was to investigate the management and awareness of anaphylaxis to foods by mean of an Internet-based survey.

METHODS

Visitors to a website with information on food allergy were invited to join the survey. Items in the survey included the management of anaphylactic reactions, investigations done by the diagnosing physician, and information given to the responder in anticipation of a new anaphylactic reaction.

RESULTS

Almost all of the 264 responders were from North America, Europe, Australia, or New Zealand (263/264). The most recent reaction was treated by epinephrine injection in 68.7% (180/262) of cases, or by antihistamines in 14.1% (37/262). Epinephrine was the first treatment for the most severe reaction in only 43.9% (101/230), while antihistamines were given first in 43.5% (100/230). One-third (62/210 = 29.5%) of the responders diagnosed by a physician received neither a diagnostic blood test nor a skin test. Responders diagnosed by an allergist were more often investigated (91/105 = 86.7%) than those diagnosed by a pediatrician or an internist (29/44 = 65.9%), a general practitioner (22/45 = 48.9%), or another physician (6/16 = 37.5%) (P < 0.001). Most responders had received instructions on how to deal with a new episode of anaphylaxis (244/263 = 92.8%). Responders instructed by an allergist were most frequently satisfied with the instructions (115/131 = 87.8%).

CONCLUSION

A large number of responders did not receive epinephrine for treatment of their most severe, or most recent anaphylactic reaction, and did not undergo allergy tests. The conventional management of anaphylaxis might still be improved.

Oral carrageenan induces antigen-dependent oral tolerance: prevention of anaphylaxis and induction of lymphocyte anergy in a murine model of food allergy

Immunosuppressive effects of carrageenan, a high-molecular-weight polysaccharide, on antibody and T cell responses have been previously demonstrated. However, its effect on anaphylaxis is unknown. Our objectives were to test carrageenan-mediated oral tolerance induction in young mice subsequently sensitized to a common cow's milk antigen. C3H/HeJ mice were fed or not lambda-carrageenan (0.5 g/L) and/or 0.01 mg/mL beta-lactoglobulin (BLG) for 5 d before oral sensitization with BLG and cholera toxin. Subsequently, the mice were challenged with BLG and symptom scores of anaphylaxis were recorded. Mesenteric lymph node cells, spleen cells, Peyer's patches cells, intraepithelial lymphocytes, and lamina propria lymphocytes were isolated and stimulated in vitro with BLG, IL-2, or left unstimulated. BLG-specific IgG, IgG(1), and IgG(2a) antibodies were measured. Pretreatment with carrageenan and BLG, but not pretreatment with either carrageenan or BLG alone or omission of pretreatment, diminished significantly the number of anaphylactic mice after BLG challenge (6.3 % versus 53 % in mice without pretreatment, p = 0.006). Mesenteric lymph nodes and spleen cells from pretreated mice proliferated less in presence of BLG or IL-2 than cells from sensitized control mice. Antigen-specific antibody production and passive cutaneous anaphylaxis was not suppressed by carrageenan and BLG pretreatment. In conclusion, carrageenan administered to young mice in conjunction with low doses of allergen before sensitization efficiently prevents anaphylaxis.

Ethanol-induced urticaria: elevated tryptase levels after double-blind, placebo-controlled challenge

We present a 48-year-old patient who complained for 1 year about urticarial reactions which appeared always when he ingested alcoholic beverages. Skin prick tests with ethanol were negative but positive with 10% acetic acid in the patient. Normal controls tested negative with acetic acid. Skin prick tests to common immediate-type allergens were negative. The patient underwent a double-blind, placebo-controlled challenge test. A few minutes after challenge with ethanol but not with placebo, the patient developed erythema and wheals on the chest and the upper arms. The tryptase serum level rose from undetectable (0.1 U/ml) before challenge to 3.8 U/ml after skin lesions had appeared. This case demonstrates that increased tryptase serum levels can help in the diagnosis of ethanol-induced urticaria.

Diagnosis of IgE-mediated food allergy among Swiss children with atopic dermatitis

Diagnosis of food allergy in children with atopic dermatitis (AD) relies on a good knowledge of the prevalence of the disease and of the foods most frequently involved. Our objective was to define these characteristics in a population-of Swiss children with AD. Patients referred to a pediatric allergist or a dermatologist for AD were routinely tested by skin-prick test (SPT) to seven common food allergens (milk, egg, peanut, wheat, soy, fish, and nuts), and to all other foods suspected by history. Patients with positive SPTs were further evaluated for specific serum immunoglobulin E (IgE) antibodies (by using the CAP System FEIA ). CAP values were interpreted following previously published predictive values for clinical reactivity. Patients with inconclusive results (between the 95% negative predictive value [NPV] and the 95% positive predictive value [PPV]) were challenged with the suspected food. A total of 74 children with AD were screened for food allergies. Negative SPTs excluded the diagnosis in 30 subjects. Nineteen patients were diagnosed by histories suggestive of recent anaphylactic reactions to foods and/or CAP values above the 95% PPV. Forty-three food challenges (35 open challenges and eight double-blind, placebo-controlled in children with persistent lesions of AD despite aggressive topical skin treatment) were performed in patients with positive SPTs but with inconclusive CAP values. Six patients were diagnosed as positive to 15 foods. Challenges were not performed to high-allergenic foods in young children (under 12 months of age for egg and fish, and under 3 years of age for peanuts and nuts). Altogether, 33.8% (25 of 74) of the AD patients were diagnosed with food allergy. The prevalence of food allergy was 27% (seven of 25) in the group referred to the dermatologist for primary care of AD. The foods most frequently incriminated were egg, milk, and peanuts. The prevalence of food allergy in our population was comparable to that in other westernized countries, suggesting an incidence of food allergy in approximately one-third of children with persistent lesions of AD. Together with milk and eggs, peanuts were most frequently involved in allergic reactions.

Allergenicity of major cow's milk and peanut proteins determined by IgE and IgG immunoblotting

BACKGROUND

Specific IgG antibodies are frequently observed in food-allergic patients. However, the allergen-fraction specificity of IgG antibodies in relation to IgE antibodies is not well defined. Our aim was to determine the IgE and IgG antibody profile to major cow's milk and peanut-antigen fractions in food-allergic patients and tolerant individuals.

METHODS

Sera were collected from 10 patients allergic to cow's milk and 10 patients allergic to peanuts, as well as from 20 control subjects. Cow's milk and peanut proteins were migrated on SDS-PAGE and immunoblotted for IgE, IgG, and IgG4 antibodies. Food-specific IgE concentrations were measured by CAP System FEIA, and IgG and IgG4 concentrations by ELISA.

RESULTS

In food-allergic children, similar fraction-specific IgE, IgG, and IgG4 antibody-binding profiles to the major cow's milk or peanut antigens were found. In nonallergics, the presence of fraction-specific IgG antibodies was mostly dependent on regular ingestion of the food. The presence of specific antibody on immunoblots correlated with their quantitative measurement. The mean value for specific IgE in cow's milk-allergic patients was 450 +/- 1,326 IU/ml, and 337 +/- 423 IU/ml in peanut-allergic patients. Specific IgG antibody values in milk-allergic patients were not different (median OD 1.5, range 0.3-2.3) from controls (median OD 1, range 0.2-1.8). However, in peanut-allergic patients, IgG concentrations were significantly higher than in controls (OD 1.2 [0.5-1.3] vs 0.5 [0.3-0.7]; P< 0.01).

CONCLUSIONS

Similar fraction-specific IgE and IgG antibody profiles in allergic individuals suggest a common switching trigger involving both isotypes. Intrinsic allergenicity might explain identical IgG antibody fraction specificity in nonallergics and in allergics. The presence of IgG antibodies in nonallergics was related to regular ingestion of the food.

The mucosal adhesion receptor alpha4beta7 integrin is selectively increased in lymphocytes stimulated with beta-lactoglobulin in children allergic to cow's milk

BACKGROUND

It has been shown in mice that the integrin alpha4beta7 directs the migration of memory T cells into the gut-associated lymphoid tissue. However, little is known about T-cell homing mechanisms in children with food allergies.

OBJECTIVE

We investigated the expression of this and other integrins in children with different manifestations of cow's milk allergy (urticaria, atopic dermatitis, and wheezing).

METHODS

PBMCs were stimulated with beta-lactoglobulin, 1 of the major allergenic proteins in cow's milk, and tetanus toxoid. Integrin expression was studied by flow cytometric analysis after 1 week of culture.

RESULTS

We found significantly higher expression of the alpha4beta7 integrin in cells from patients compared with control subjects with no allergies (P =. 005) when beta-lactoglobulin was used to stimulate the cells. alpha4beta7 integrin was also expressed at significantly higher levels in beta-lactoglobulin-stimulated cells than in tetanus toxoid-stimulated cells (P =.005). The alphaEbeta7 and the alpha4beta1 integrins were not upregulated by allergen stimulation. Most alpha4beta7 integrin-expressing cells were identified as CD4(+) T cells.

CONCLUSION

These results show that alpha4beta7 integrin expression after stimulation with beta-lactoglobulin correlates with the presumptive site of cow's milk sensitization (ie, the gut-associated lymphoid tissue but not with the site of symptoms of cow's milk allergy).