Scientific criteria and the selection of allergenic foods for product labelling

The Role of Exposomes in the Pathophysiology of Autoimmune Diseases I: Toxic Chemicals and Food

Autoimmune diseases affect 5–9% of the world’s population. It is now known that genetics play a relatively small part in the pathophysiology of autoimmune disorders in general, and that environmental factors have a greater role. In this review, we examine the role of the exposome, an individual’s lifetime exposure to external and internal factors, in the pathophysiology of autoimmune diseases. The most common of these environmental factors are toxic chemicals, food/diet, and infections. Toxic chemicals are in our food, drink, common products, the air, and even the land we walk on. Toxic chemicals can directly damage self-tissue and cause the release of autoantigens, or can bind to human tissue antigens and form neoantigens, which can provoke autoimmune response leading to autoimmunity. Other types of autoimmune responses can also be induced by toxic chemicals through various effects at the cellular and biochemical levels. The food we eat every day commonly has colorants, preservatives, or packaging-related chemical contamination. The food itself may be antigenic for susceptible individuals. The most common mechanism for food-related autoimmunity is molecular mimicry, in which the food’s molecular structure bears a similarity with the structure of one or more self-tissues. The solution is to detect the trigger, remove it from the environment or diet, then repair the damage to the individual’s body and health.

Immunotherapy of mold allergy: A review

Mold allergies are common, mainly target the respiratory tract and present as allergic rhinitis and/or bronchial asthma. Molds include a large group of different allergens that induce all types of allergic reactions. Allergen specific immunotherapies (AITs) to molds are common; however, at the present time, they are limited to Alternaria. This review presents not only the benefits but also the problems with such types of AIT based on the literature and our experience.

Knowledge, perspectives and attitudes about allergen-specific immunotherapy for respiratory allergic disease among paediatricians in Turkey

BACKGROUND

Allergen-specific immunotherapy (ASI) is the only effective treatment for allergic respiratory diseases which has the potential to change the natural course of the disease. In this present study we aimed to evaluate the paediatricians' knowledge, perspectives and attitudes about ASI for allergic respiratory diseases.

MATERIALS AND METHODS

The study was conducted between September 2014 - January 2015. A survey of 25 questions assessing paediatricians' knowledge, perceptions and attitudes about ASI was developed by an expert panel and applied by physicians in hospitals in Izmir, Turkey, where the paediatricians work. Data were recorded in SPSS for Windows v.16. Descriptive statistics, chi square analysis was used. P<0.05 was considered as significant.

RESULTS

Fully completed surveys from 180 paediatricians were analysed. The respondent paediatricians had an age of 37±8.2 years, and 56 of them were male. The majority of the respondents (n: 146) were working fewer than five years as a paediatric specialist. 93.9% of the paediatricians believed that ASI was effective for the treatment of allergic respiratory diseases. There was satisfactory knowledge of the characteristics, aims, effects and limits of ASI.

CONCLUSION

ASI is generally well-known and accepted among paediatricians. A better synergy between paediatricians and paediatric allergy specialists can provide more use of this treatment method for allergic respiratory diseases in childhood.

Allergic diseases in the elderly: biological characteristics and main immunological and non-immunological mechanisms

Life expectancy and the number of elderly people are progressively increasing around the world. Together with other pathologies, allergic diseases also show an increasing incidence in geriatric age. This is partly due to the growing emphasis on a more accurate and careful diagnosis of the molecular mechanisms that do not allow to ignore the real pathogenesis of many symptoms until now unknown, and partly to the fact that the allergic people from 20 years ago represent the elderly population now. Moreover, environmental pollution predisposes to the onset of allergic asthma and dermatitis which are the result of internal pathologies more than the expression of allergic manifestations. At the same time the food contamination permits the onset of allergic diseases related to food allergy. In this review we provide the state of the art on the physiological changes in the elderly responsible for allergic diseases, their biological characteristics and the major immunological and extra immunological mechanisms. Much emphasis is given to the management of several diseases in the elderly, including anaphylactic reactions. Moreover, some new features are discussed, such as management of asthma with the support of physical activity and the use of the AIT as prevention of respiratory diseases and for the purpose of a real and long lasting benefit. The mechanisms of adverse reactions to drugs are also discussed, due to their frequency in this age, especially in polytherapy regimens. Study of the modifications of the immune system is also of great importance, as regards to the distribution of the lymphocytes and also the presence of a chronic inflammatory disease related to the production of cytokines, especially in prevision of all the possible therapies to be adopted to allow an active and healthy aging.

Mouse models of food allergy: how well do they simulate the human disorder?

Food allergy is a growing health problem with serious concerns due to high potential for fatality. Rapid advances in the knowledge on causes and mechanisms as well as in developing effective prevention/therapeutic strategies are needed. To meet these goals, mouse models that simulate the human disorder are highly desirable. During the past decade, several mouse models of food allergies have been reported. Here, we briefly reviewed the human disorder and then critically evaluated these models seeking answers to the following important questions: To what extent do they simulate the human disorder? What are the strengths and limitations of these models? What are the challenges facing this scientific area? Our analysis suggest that: (i) the mouse models, with inherent strengths and limitations, are available for many major food allergies; there is scope for additional model development and validation; (ii) models mostly simulate the severe forms of human disorder with similar immune and clinical features; (iii) the approaches used to develop some of the mouse models may be questionable; and (iv) the specific mechanisms of sensitization as wells as oral elicitation of fatal reactions in both humans and mice remains incompletely understood and therefore warrants further research.

The prevalence of antibodies against wheat and milk proteins in blood donors and their contribution to neuroimmune reactivities

The aim of this study was to look for the presence of IgG, IgM, and IgA antibodies against two widely consumed foods, wheat and milk, in a relatively large number of specimens. As wheat, milk, and their antigens have been found to be involved in neuroimmune disorders, we measured the co-occurrence of their antibodies against various neural antigens. We assessed the reactivity of sera from 400 donors to wheat and milk proteins, GAD-65, cerebellar, MBP, and MOG. Statistical analysis showed significant clustering when certain wheat and milk protein antibodies were cross-referenced with neural antibodies. Approximately half of the sera with antibody elevation against gliadin reacted significantly with GAD-65 and cerebellar peptides; about half of the sera with elevated antibodies against α + β-casein and milk butyrophilin also showed antibody elevation against MBP and MOG. Inhibition studies showed that only two out of four of the samples with elevated cerebellar or MOG antibodies could be inhibited by gliadin or α + β-casein, confirming individual variation in epitope recognition. We conclude that a subgroup of blood donors, due to a breakdown in immunological tolerance, may react and produce significant levels of antibodies (p-values less than 0.05) against wheat and milk antigens that cross-react with different neural antigens, which may have broader implications in the induction of neuroimmune reactivities.

False positive detection of peanut residue in liquid caramel coloring using commercial ELISA kits

Initial food industry testing in our laboratory using enzyme-linked immunosorbent assay (ELISA) methods indicated that the darkest caramel color (class IV) unexpectedly contained traces of peanut protein, a potential undeclared allergen issue. Caramel production centers on the heating of sugars, often glucose, under controlled heat and chemical processing conditions with other ingredients including ammonia, sulfite, and/or alkali salts. These ingredients should not contain any traces of peanut residue. We sought to determine the reliability of commercially available peanut allergen ELISA methods for detection of apparent peanut residue in caramel coloring. Caramel color samples of classes I, II, III, and IV were obtained from 2 commercial suppliers and tested using 6 commercially available quantitative and qualitative peanut ELISA kits. Five lots of class IV caramel color were spiked with a known concentration of peanut protein from light roasted peanut flour to assess recovery of peanut residue using a spike and recovery protocol with either 15 ppm or 100 ppm peanut protein on a kit-specific basis. A false positive detection of peanut protein was found in class IV caramel colors with a range of 1.2 to 17.6 parts per million recovered in both spiked and unspiked liquid caramel color samples. ELISA kit spike/recovery results indicate that false negative results might also be obtained if peanut contamination were ever to actually exist in class IV caramel color. Manufacturers of peanut-free products often test all ingredients for peanut allergen residues using commercial ELISA kits. ELISA methods are not reliable for the detection of peanut in class IV caramel ingredients and their use is not recommended with this matrix.

Oral food desensitization in children with IgE-mediated hen's egg allergy: a new protocol with raw hen's egg

BACKGROUND

Hen's egg allergy affects young children and can cause severe allergic reactions. Avoidance results in dietary limitations and can affect the quality of life, especially in cases where potentially life-threatening reactions exist. Our objective was to desensitize children with moderate-severe IgE-mediated hen's egg allergy over a 6-month period, by introducing increasing and very gradual daily doses of raw hen's egg in order to enable the children to assume 25ml of this food, or to induce tolerance to the highest possible dose. The protocol foresaw the egg reintroduction in the home setting.

METHODS

In this randomized, controlled open study, 20 hen's egg allergic children (10 in the active group) were admitted. A convincing history or a positive double-blind placebo-controlled food challenge confirmed the diagnosis. Oral desensitization was performed with increasing doses starting from 0.27 mg of hen's egg proteins (1 drop of raw hen's egg diluted 1:100). We adopted an original, mathematically calculated protocol in order to ensure a constant, daily increment of doses.

RESULTS

8/10 children (80%) in the active group achieved the daily intake of 25ml over a 6-month period. One child (10%) could tolerate up to 2ml/day while another child (10%) failed the desensitization. Six months after enrolment only 2 children in the control group (20%) could tolerate hen's egg.

CONCLUSIONS

We successfully desensitized 8/10 children with IgE-mediated hen's egg allergy in a 6-month period. The partial outcome in the child who could tolerate 2ml/day reduced the risk of severe reactions after unnoticed introduction of egg. A regular protocol that ensures a daily constant increase of doses helps to reduce possible adverse events, thus improving safety and effectiveness.

Emerging drugs for perennial allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is a high-prevalence disease, sustained by an IgE-triggered reaction with histamine release, followed by an inflammatory response which involves cells, mediators, cytokines and adhesion molecules. According to its duration, AR can be either intermittent or persistent. In the persistent form, the inflammatory component usually predominates.

AREAS COVERED

The current therapeutic strategy is based on antihistamines, antileukotrienes and on corticosteroids (which broadly act on inflammation). Allergen-specific immunotherapy is a biological response modifier that affects the immune response to allergens in a broad sense. The available pharmacotherapy is overall effective in controlling symptoms and inflammation, but safety concerns may be present (especially for prolonged treatments), and a proportion of patients remain uncontrolled. The available therapeutic innovations, as derived from the most recent literature are reviewed herein.

EXPERT OPINION

In the last years there have been very few innovative approaches to optimize the management of AR. These include new histamine receptor antagonists, combination therapy and strategies to selectively block relevant signaling pathways of the allergic reaction. Some more promising advances have been shown for allergen immunotherapy, where a number of new strategies are currently under development.

Specific detection by the polymerase chain reaction of potentially allergenic salmonid fish residues in processed foods

Salmonid fish is one of the allergenic items that are recommended to be labeled in the Japanese allergen-labeling system. This study develops a salmonid-specific polymerase chain reaction (PCR) method. A new primer pair, SKE-F/SKE-R, was designed to specifically detect the salmonid fish gene encoding mitochondrial DNA cytochrome b. Genomic DNAs extracted from 58 kinds of seafood and 11 kinds of processed food were individually subjected to PCR by using the primer pair, and a salmonid-specific fragment of 212 bp was only amplified in the salmonid samples and salmonid-containing processed foods. The detection limit of the PCR method was as low as 0.02 fg/µL of salmonid fish DNA (corresponding to 10 copies). There is no ELISA method for salmonid fish, making our PCR method the only reliable measure for detecting salmonid fish in processed foods.

Specific immunotherapy in children: the evidence

Specific immunotherapy (SIT) is the only treatment able to not only act on the symptoms of allergy but also act on the causes. At present, SIT may be administered in two forms: subcutaneous (SCIT) and sublingual immunotherapy (SLIT). SCIT represents the standard modality of treatment while SLIT has recently been introduced into clinical practice and today represents an accepted alternative to SCIT. The main advantages of SIT that are lacking with drug treatment are long-lasting clinical effects and alteration of the natural course of the disease. This prevents the new onset of asthma in patients with allergic rhinitis and the onset of new sensitizations. The mechanism of action of both routes is similar; they modify peripheral and mucosal Th2-responses into a prevalent Th1-polarization with subsequent reduction of the allergic inflammatory reaction. Both have long-term effects for years after they have been discontinued, although for SLIT these evidences are insufficient. To date several guidelines have defined indications, controindications, side-effects, and clinical aspect for SCIT and SLIT. New forms of immunotherapy, allergen products and approaches to food allergy and atopic eczema represents the future of SIT.

Reliable enzyme-linked immunosorbent assay for the determination of coconut milk proteins in processed foods

This study was designed to develop a novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of coconut milk proteins in processed foods. The developed sandwich ELISA was able to detect coconut milk proteins from various coconut milk products and did not show any cross-reactivity with 41 of 42 kinds of popularly used food ingredients, thus reflecting great specificity for coconut milk proteins. In addition, the established ELISA is highly sensitive and allowed the detection of 0.31 μg/g of coconut milk protein in complex food matrices. This proposed assay could serve as a useful tool for the detection of the presence of hidden coconut milk proteins in processed foods.

Which allergen extract for grass pollen immunotherapy? An in vitro study

BACKGROUND

Grass pollen is a major cause of allergy throughout the world. The only treatment targeting the causes and not only the symptoms of allergy is specific immunotherapy (IT). A number of controlled trials demonstrated the efficacy of IT in grass pollen allergic subjects, most using extracts of multiple grasses but some using extracts of a single grass. The optimal grass extract for IT has not yet been established.

METHODS

This study is aimed at investigating the IgE-binding pattern in sera from IT-naïve patients from central Italy with allergic rhinitis and/or asthma caused by grass pollen. A 5-grass extract was used (containing Dactylis glomerata, Poa pratensis, Lolium perenne, Antoxanthum odoratum and Phleum pratense) and compared to Phleum pratense alone, which is the most frequently used single grass extract, by the RAST-inhibition technique.

RESULTS

The 5-grass extract showed, by RAST-inhibition, a significantly higher binding compared to the Phleum pratense extract for Antoxanthum odoratum and Poa pratensis, while the two extracts for immunotherapy showed similar binding affinity for Phleum pratense and the non-Pooideae grass, Cynodon dactylon.

CONCLUSIONS

The use of a mixed-grass pollen extract seems to be the optimal choice when applying specific IT in grass pollen-allergic subjects from the Mediterranean area.

Multiplexed identification of different fish species by detection of parvalbumin, a common fish allergen gene: a DNA application of multi-analyte profiling (xMAP) technology

Fish are a common cause of allergic reactions associated with food consumption, with parvalbumin being the major allergenic protein. Some fish-hypersensitive patients tolerate some fish species while being allergic to others. Reliable detection methods for allergenic fish species in foods are necessary to ensure compliance with food allergen labeling guidelines to protect fish-allergic consumers. The objective of this project was to develop a multi-analyte detection method for the presence of fish in food. Therefore, conserved parvalbumin exon sequences were utilized for the design of universal PCR primers amplifying intron DNA and small regions of exons flanking the enclosed intron from even very distantly related fish species. An assay for the identification of eight fish species was developed using xMAP technology with probes targeting species-specific parvalbumin intron regions. Additionally, a universal fish probe was designed targeting a highly conserved exon region located between the intron and the reverse primer region. The universal fish assay showed no cross-reactivity with other species, such as beef, pork, lamb, chicken, turkey, and shrimp. Importantly, with the exception of one notable case with fish in the same subfamily, species-specific detection showed no cross-reactivity with other fish species. Limits of detection for these eight species were experimentally estimated to range from 0.01% to 0.04%, with potential to increase the detection sensitivity. This report introduces a newly developed method for the multiplex identification of at least eight allergenic fish species in food, which could conceivably be extended to detect up to 100 species simultaneously in one sample.

Biosensor immunoassay for traces of hazelnut protein in olive oil

The fraudulent addition of hazelnut oil to more expensive olive oil not only causes economical loss but may also result in problems for allergic individuals as they may inadvertently be exposed to potentially allergenic hazelnut proteins. To improve consumer safety, a rapid and sensitive direct biosensor immunoassay, based on a highly specific monoclonal antibody, was developed to detect the presence of hazelnut proteins in olive oils. The sample preparation was easy (extraction with buffer); the assay time was fast (4.5 min only) and the limit of detection was low (0.08 microg/g of hazelnut proteins in olive oil). Recoveries obtained with an olive oil mixed with different amounts of a hazelnut protein containing hazelnut oil varied between 93% and 109%.

A reliable enzyme linked immunosorbent assay for the determination of bovine and porcine gelatin in processed foods

Since gelatin-containing foods pose a risk for eliciting allergic reactions in sensitized individuals, a novel sandwich enzyme linked-immunosorbent assay (ELISA) for the detection and quantification of bovine and porcine gelatin in processed foods was developed. Rabbits and goats were immunized with bovine gelatin, and three antisera (pAb1 and pAb2 from rabbits, and pAb3 from goats) were obtained. We established a sandwich ELISA method based on a combination of these antibodies. In this study, two sandwich ELISA methods, rabbit pAb2-pAb1 and goat pAb3-pAb3, were evaluated for sensitivity, specificity, cross-reactivity, and applicability. Both ELISA methods were highly specific for bovine and porcine gelatin but had little reactivity with fish gelatin. The detection and quantification limits for porcine gelatin were found to be 0.78 ng/mL and 1.56 ng/mL, respectively. The established sandwich ELISA methods produced no false-positives, except for heated meat products or false negatives when various commercial foods were analyzed for their gelatin content. The rabbit pAb2-pAb1 ELISA cross-reacted with boiled squid, while the goat pAb3-pAb3 ELISA did not. Thus, the proposed goat pAb3-pAb3 ELISA method is a reliable tool for the detection of gelatin contaminants present in processed foods.

Identification of tropomyosins as major allergens in antarctic krill and mantis shrimp and their amino acid sequence characteristics

Tropomyosin represents a major allergen of decapod crustaceans such as shrimps and crabs, and its highly conserved amino acid sequence (>90% identity) is a molecular basis of the immunoglobulin E (IgE) cross-reactivity among decapods. At present, however, little information is available about allergens in edible crustaceans other than decapods. In this study, the major allergen in two species of edible crustaceans, Antarctic krill Euphausia superba and mantis shrimp Oratosquilla oratoria that are taxonomically distinct from decapods, was demonstrated to be tropomyosin by IgE-immunoblotting using patient sera. The cross-reactivity of the tropomyosins from both species with decapod tropomyosins was also confirmed by inhibition IgE immunoblotting. Sequences of the tropomyosins from both species were determined by complementary deoxyribonucleic acid cloning. The mantis shrimp tropomyosin has high sequence identity (>90% identity) with decapod tropomyosins, especially with fast-type tropomyosins. On the other hand, the Antarctic krill tropomyosin is characterized by diverse alterations in region 13-42, the amino acid sequence of which is highly conserved for decapod tropomyosins, and hence, it shares somewhat lower sequence identity (82.4-89.8% identity) with decapod tropomyosins than the mantis shrimp tropomyosin. Quantification by enzyme-linked immunosorbent assay revealed that Antarctic krill contains tropomyosin at almost the same level as decapods, suggesting that its allergenicity is equivalent to decapods. However, mantis shrimp was assumed to be substantially not allergenic because of the extremely low content of tropomyosin.

Reliable enzyme-linked immunosorbent assay for the determination of walnut proteins in processed foods

Among food allergens of tree nuts, walnuts are a frequent cause of adverse food reactions in allergic patients. A novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of walnut soluble proteins in processed foods was developed. The sandwich ELISA is highly specific for walnut soluble proteins. The recovery ranged from 83.4 to 123%, whereas the intra- and interassay coefficients of variation were less than 8.8 and 7.2%, respectively. This study showed that the proposed method is a reliable tool for detection in the presence of hidden walnut proteins in processed foods.

Reliable enzyme-linked immunosorbent assay for the determination of soybean proteins in processed foods

Among allergenic foods, soybean is known as a food causing adverse reactions in allergenic patients. To clarify the validity of labeling, the specific and sensitive detection method for the analysis of the soybean protein would be necessary. The p34 protein, originally characterized to be p34 as an oil-body associated protein in soybean, has been identified as one of the major allergenic proteins and named Gly m Bd 30K. A novel sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of the soybean protein in processed foods was developed using polyclonal antibodies raised against p34 as a soybean marker protein and the specific extraction buffer for extract. The developed sandwich ELISA method was highly specific for the soybean protein. The limit of detection (LOD) and the limit of quantification (LOQ) of the developed ELISA were 0.47 ng/mL (equivalent to 0.19 microg/g in foods) and 0.94 ng/mL (equivalent to 0.38 microg/g in foods), respectively. The recovery ranged from 87.7 to 98.7%, whereas the intra- and interassay coefficients of variation were less than 4.2 and 7.5%, respectively. This study showed that the developed ELISA method is a specific, precise, and reliable tool for the quantitative analysis of the soybean protein in processed foods.

Molluscan shellfish allergy

Food allergies affect approximately 3.5-4.0% of the worldwide population. Immediate-type food allergies are mediated by the production of IgE antibodies to specific proteins that occur naturally in allergenic foods. Symptoms are individually variable ranging from mild rashes and hives to life-threatening anaphylactic shock. Seafood allergies are among the most common types of food allergies on a worldwide basis. Allergies to fish and crustacean shellfish are very common. Molluscan shellfish allergies are well known but do not appear to occur as frequently. Molluscan shellfish allergies have been documented to all classes of mollusks including gastropods (e.g., limpet, abalone), bivalves (e.g., clams, oysters, mussels), and cephalopods (e.g., squid, octopus). Tropomyosin, a major muscle protein, is the only well-recognized allergen in molluscan shellfish. The allergens in oyster (Cra g 1), abalone (Hal m 1), and squid (Tod p 1) have been identified as tropomyosin. Cross-reactivity to tropomyosin from other molluscan shellfish species has been observed with sera from patients allergic to oysters, suggesting that individuals with allergies to molluscan shellfish should avoid eating all species of molluscan shellfish. Cross-reactions with the related tropomyosin allergens in crustacean shellfish may also occur but this is less clearly defined. Occupational allergies have also been described in workers exposed to molluscan shellfish products by the respiratory and/or cutaneous routes. With food allergies, one man's food may truly be another man's poison. Individuals with food allergies react adversely to the ingestion of foods and food ingredients that most consumers can safely ingest (Taylor and Hefle, 2001). The allergens that provoke adverse reactions in susceptible individuals are naturally occurring proteins in the specific foods (Bush and Hefle, 1996). Molluscan shellfish, like virtually all foods that contain protein, can provoke allergic reactions in some individuals.

Is sublingual immunotherapy the final answer? Implications for the allergist

Sublingual immunotherapy (SLIT) is now accepted as a viable alternative to the traditional injection route based on more than 40 clinical trials and several meta-analyses of efficacy. In addition, the safety profile is very favorable, also in younger children. Although some aspects need to be further clarified (eg, optimal doses, patient selection, and mechanisms of action), SLIT can be currently regarded as an additional therapeutic option that allergists have available. The main distinctive feature of SLIT is certainly its tolerability, safety, and convenience for the patient. Nonetheless, as happens with injection immunotherapy, it is mandatory that the prescription of SLIT is made by a trained specialist, and that a detailed diagnosis is made before prescribing it.

Allergic rhinitis in women

Allergic rhinitis is a high-prevalence disease that significantly impairs the quality of life. Its pathogenesis is quite well understood, and involves numerous cells, cytokines and mediators, which result in an inflammatory process. The triggering IgE-mediated reaction does not differ between men and women, but in females some aspects, related mainly to the hormonal frame, must be taken into account. In fact, cyclic hormonal changes can affect the severity of rhinitis, as can pregnancy, which may result in a particular form of 'pregnancy rhinitis'. The most important and challenging aspect is the management of allergic rhinitis in pregnancy, which require a careful evaluation of the risk:benefit ratio. This review will examine the aforementioned aspects, with particular regard to the pharmacotherapy of rhinitis in pregnancy.

Novel therapeutic interventions for allergic rhinitis

Allergic rhinitis is a high-prevalence disease, affecting 10 - 20% of the general population. Allergic rhinitis is sustained by an IgE-mediated reaction and by a complex inflammatory network of cells, mediators and cytokines that becomes chronic when exposure to allergen persists. A T(H)2-biased immune response is the background of the allergic inflammation. The current therapeutic strategy is mainly based on drugs (antihistamines, nasal corticosteroids, cromones and decongestants) and allergen immunotherapy. Drugs are (overall) effective in controlling symptoms but do not modify the immune background that leads to allergic inflammation and safety concerns may be present, especially for prolonged treatments. Immunotherapy can modify the allergic response but there is still room for improvement. Nowadays, several approaches are under investigation to optimise the management of allergic rhinitis. On one hand, new drugs and antimediators are being developed. On the other hand, attempts are being made to selectively block relevant signal pathways of allergic reaction. Finally, one of the major goals is to modify the T(H)2-biased immune response by improving the characteristics and modes of action of allergen immunotherapy.

Specific detection of soybean residues in processed foods by the polymerase chain reaction

A sensitive qualitative detection method for soybeans in foods by using the polymerase chain reaction (PCR) was developed. For specific detection of soybeans with high specificity, the primer pair of Gym 81/Gym 82 was designed on the gene encoding the Glycine max repetitive sequence. The trace amount of soybeans in commercial food products could be qualitatively detected by this method.

Food allergy and the introduction of solid foods to infants: a consensus document. Adverse Reactions to Foods Committee, American College of Allergy, Asthma and Immunology

OBJECTIVE

To make recommendations based on a critical review of the evidence for the timing of the introduction of solid foods and its possible role in the development of food allergy.

DATA SOURCES

MEDLINE searches using the following search algorithm: [weaning AND infant AND allergy]/[food allergy AND sensitization]/[dietary prevention AND food allergy OR allergens]/[Jan 1980-Feb 2006].

STUDY SELECTION

Using the authors' clinical experience and research expertise, 52 studies were retrieved that satisfied the following conditions: English language, journal impact factor above 1 or scientific society, expert, or institutional publication, and appraisable using the World Health Organization categories of evidence.

RESULTS

Available information suggests that early introduction can increase the risk of food allergy, that avoidance of solids can prevent the development of specific food allergies, that some foods are more allergenic than others, and that some food allergies are more persistent than others.

CONCLUSIONS

Pediatricians and allergists should cautiously individualize the introduction of solids into the infants' diet. With assessed risk of allergy, the optimal age for the introduction of selected supplemental foods should be 6 months, dairy products 12 months, hen's egg 24 months, and peanut, tree nuts, fish, and seafood at least 36 months. For all infants, complementary feeding can be introduced from the sixth month, and egg, peanut, tree nuts, fish, and seafood introduction require caution. Foods should be introduced one at a time in small amounts. Mixed foods containing various food allergens should not be given unless tolerance to every ingredient has been assessed.

Emerging anti-inflammatory agents for allergic rhinitis

Allergic rhinitis (AR) is a high-prevalence disease, affecting 10-15% of the general population. AR is sustained by an IgE-mediated reaction, and by a complex inflammatory network of cells, mediators and cytokines that becomes chronic when exposure to allergen persists. A T helper 2 (TH2)-biased immune response is the basis for the allergic inflammation. The current therapeutic strategy is mainly based on drugs (antihistamines, nasal corticosteroids, cromones, decongestants) and allergen immunotherapy. Drugs are overall effective in controlling symptoms, but do not modify the immune background that leads to allergic inflammation, and safety concerns may be present especially for prolonged treatments. Immunotherapy can modify the allergic response, but there is still space for improvement. Nowadays, several approaches are under investigation to optimise the management of AR. On one hand, new drugs and antimediators are being developed; on the other hand, attempts are made to selectively block relevant signal pathways of allergic reaction. Finally, one of the major goals is to modify the TH2-biased immune response by improving the characteristics and modes of action of allergen immunotherapy.

A protocol for oral desensitization in children with IgE-mediated cow's milk allergy

OBJECTIVES

To desensitize children with severe immunoglobulin (Ig)E-mediated cow's milk allergy in a period of 6 months by introducing increasing daily doses of cow's milk (CM) in order to enable the child to assume 200 ml of CM daily, or to induce tolerance of the highest possible CM dose.

STUDY DESIGN

Twenty-one children at least 6 years old with severe IgE-mediated CM allergy were admitted to the study. A convincing history of IgE-mediated CM allergy or a positive double-blind placebo-controlled food challenge with CM confirmed the diagnosis. Oral desensitization was performed with increasing doses starting from 0.06 mg of CM proteins.

RESULTS

Overall, 15 of 21 children (71.4%) achieved the daily intake of 200 ml during a 6-month period; three of 21 children (14.3%) tolerated 40-80 ml/day of undiluted CM; three of 21 children (14.3%) failed the desensitization because they presented allergic symptoms after ingesting minimal amounts of diluted CM.

CONCLUSIONS

We successfully desensitized 15 of 21 children with severe IgE-mediated CM allergy in a period of 6 months. We stress the importance of the partial outcome in those three of 21 children who could not reach the maximum amount of 200 ml/day of whole CM, but were able to tolerate 40-80 ml/day of CM. In this way we dramatically reduced the risk of severe reactions after accidental or unnoticed introduction of low quantities of CM. We do not propose generalizing this method beyond trained staff.

Allergic cross-reactivity: from gene to the clinic

A large number of allergenic proteins have now their complete cDNA sequences determined and in some cases also the 3D structures. It turned out that most allergens could be grouped into a small number of structural protein families, regardless of their biological source. Structural similarity among proteins from diverse sources is the molecular basis of allergic cross-reactivity. The clinical relevance of immunoglobulin E (IgE) cross-reactivity seems to be influenced by a number of factors including the immune response against the allergen, exposure and the allergen. As individuals are exposed to a variable number of allergenic sources bearing homologous molecules, the exact nature of the antigenic structure inducing the primary IgE immune response cannot be easily defined. In general, the 'cross-reactivity' term should be limited to defined clinical manifestations showing reactivity to a source without previous exposure. 'Co-recognition', including by definition 'cross-reactivity', could be used to describe the large majority of the IgE reactivity where co-exposure to a number of sources bearing homologous molecules do not allow unequivocal identification of the sensitizing molecule. The analysis of reactivity clusters in diagnosis allows the interpretation of the patient's reactivity profile as a result of the sensitization process, which often begins with exposure to a single allergenic molecule.

Prevalence of adverse reactions to food in Germany - a population study

OBJECTIVE

A population study was performed to identify the prevalence of all kinds of adverse reactions to food.

METHODS

In a representative cross-sectional survey performed in 1999 and 2000 in Berlin, 13 300 inhabitants of all ages were addressed by questionnaire. This questionnaire was answered by 4093 persons. All respondents mentioning any sign of food intolerance or the existence of allergic diseases (n = 2298) were followed up by telephone and, in case food intolerance could not be ruled out by patient history, were invited to attend to the clinic for personal investigation including double-blind, placebo-controlled food challenge tests (DBPCFC).

RESULTS

The self-reported lifetime prevalence of any adverse reaction to food in the Berlin population (mean age 41 years) was 34.9%. Eight hundred and fourteen individuals were personally investigated according to the guidelines. The point prevalence of adverse reactions to food confirmed by DBPCFC tests in the Berlin population as a mean of all age groups was 3.6% (95% confidence interval [3.0-4.2%]) and 3.7% in the adult population (18-79 years, 95% confidence interval [3.1-4.4.%]). Two and a half percent were IgE-mediated and 1.1% non-IgE-mediated, females were more frequently affected (60.6%). Based on a statistical comparison with available data of adults from the nationwide German Health Survey from 1998, adverse reactions to food in the adult population of Germany (age 18-79) were calculated with 2.6% [2.1-3.2%]).

CONCLUSIONS

The study gives for the first time information about the point prevalence of both immunological and nonimmunological adverse reactions to food and underlines the relevance of this issue in public health. The data also show that an individualized stepwise approach including provocation tests is mandatory to confirm the diagnosis.

Prospective study of mustard allergy: first study with double-blind placebo-controlled food challenge trials (24 cases)

BACKGROUND

Mustard allergy accounts for 1.1% of food allergies in children. However, double-blind placebo-controlled food challenge trials (DB PCFCs) have not yet been proposed.

OBJECTIVE

To carry out DB PCFCs to determine the real frequency of mustard allergy in patients sensitized to mustard.

METHODS

A prospective study was conducted in 30 subjects aged 3-20 years presenting positive prick tests to ground mustard seeds (Brassica nigra), mustard flour (B. juncea), metabisulfite-free strong mustard seasoning (B. juncea) and a commercialized allergenic extract (B. nigra). Twenty-seven subjects were screened for mustard-specific immunoglobulin E (IgE). PCFCs were carried out either DB or single blind (SB) with up to 1340 mg of metabisulfite-free seasoning.

RESULTS

The mean diameter of the wheal induced by prick tests with the allergenic extract was lower (n.s.) than that induced by the native mustard products: 5.8 mm (1.5-15) vs 6.9 mm (0.5-18) for B. nigra ground seeds, 7.8 mm (1-20) for B. juncea flour and 9.7 mm (3-20) for the strong mustard seasoning. The diameter of the wheal induced by the allergenic extract was significantly different from that induced by the mustard seasoning (P < 0.005). The mean of mustard specific-IgE values was 8.7 KU/l (0.35-72.4). Seven of 30 food challenges were considered positive. Mean prick test results in the positive and negative PCFC subgroups were 5.5 mm vs 5.9 mm for the commercialized extract, 10.9 mm vs 5.8 mm for B. nigra ground seeds (P < 0.01), 9.9 mm vs 7.1 mm for B. juncea flour (n.s. P > 0.25) and 11.5 mm vs 9.1 mm for the metabisulfite-free mustard seasoning (n.s. P > 0.1). Mean specific IgE values determined by CAP system radioallergosorbent test (Phadebas Pharmacia) were higher but not significantly so (P > 0.25) in the subgroup with mustard allergy (12.3 K/l vs 7.6 KU/l).

CONCLUSIONS

About 23.3% of the sensitized subjects were allergic to a routine dose of mustard. Positive prick tests and the presence of specific IgE were not predictive. SB PCFC or DB PCFC is required before recommending avoidance diets.

The distribution of individual threshold doses eliciting allergic reactions in a population with peanut allergy

BACKGROUND

Hidden peanut in consumer products can endanger patients with peanut allergy. Individual threshold doses for eliciting allergic reactions need to be elucidated to assess the risks for development of allergic reactions after accidental ingestion of peanut in a population with peanut allergy.

OBJECTIVE

We sought to determine the distribution of individual threshold doses in a population with peanut allergy and to correlate these thresholds to the severity of peanut-induced symptoms.

METHODS

Twenty-six adult patients with a convincing history of peanut-related symptoms, a specific IgE level of 0.7 kU/L or greater, or a positive skin prick test response of 2+ or greater to peanut were included. These patients underwent double-blind, placebo-controlled food challenges with increasing doses of peanut. A threshold dose could be established when objective or repetitive subjective reactions occurred after active doses.

RESULTS

All patients had subjective oral symptoms (n = 26), prior subjective gastrointestinal symptoms (n = 14), or objective symptoms (n = 5). Reactions started within 30 minutes after ingestion of peanut, but in 2 patients additional symptoms were delayed by 1 to 2 hours. Threshold doses for allergic reactions ranged from a dose as low as 100 microg up to 1 g of peanut protein. Fifty percent of the study population (95% CI, 30%-70%) already had an allergic reaction after ingestion of 3 mg of peanut protein. Patients with severe symptoms had lower threshold doses compared with those of patients with mild symptoms (P =.027).

CONCLUSIONS

A substantial part of a population with peanut allergy will react to very low amounts of peanut, requiring accurate declaration of peanut content in consumer products. This is even more important because patients with severe reactions react to lower doses than patients with mild symptoms.