Genetic differences in omega-gliadins involved in two different immediate food hypersensitivities to wheat

Responders and nonresponders to pharmacotherapy and allergen immunotherapy

Allergen immunotherapy (AIT) is a very useful therapy for allergic rhinitis. However, some patients do not achieve the expected results. The aim of the study was to investigate the potential factors that could affect the result, either good or poor, from AIT.Methods: A retrospective analysis of 1624 patients with allergic rhinitis who underwent AIT and 1519 matched patients who underwent only symptomatic therapy (without AIT) was performed. Symptoms, medications scores and quality of life related to allergic diseases before and after therapy were recorded. Cluster analysis on all of the patients was performed to find any associations between responsiveness to therapy and the analyzed parameters. Responsiveness to therapy was assessed by the Mailing criteria.Results: A total of 1266 (77.8%) patients from the AIT group met the criterion of 30% or greater improvement, and 1061 (65.2%) of these patients met the threshold of 60% or greater improvement according to the Mailing criteria. Patients who had a frequently better response to AIT were highly represented in the two clusters. There were subjects with a short history of allergic rhinitis and concomitant allergy to grass pollen or house dust mites. Patients with a prolonged duration of allergic rhinitis before therapy and with polysensitization were more frequently worse responders to AIT.Conclusion: Responsiveness to therapy, including that to AIT, is difficult to assess. However, there were associations suggesting that short-term allergic rhinitis and monovalent allergies to grass pollen or mites could correspond to a better response to AIT.

Allergic reactions to hydrolysed wheat proteins: clinical aspects and molecular structures of the allergens involved

Wheat gluten can be chemically or enzymatically hydrolysed to produce functional ingredients useful in food and cosmetics. However severe allergies to hydrolysed wheat proteins (HWP) have been described in Europe and Japan since the early 2000's. Triggering proteins and IgE epitopes were described both for French and Japanese cohorts and appeared remarkably similar leading to define a new wheat allergic entity. Deamidation induced by functionalisation generate neo-allergens responsible for this particular allergy. This article aims to review the processes leading to deamidation and the clinical features of the patients suffering from this allergy. Then the molecular determinants involved in HWP-allergy were exhaustively described and hypothesis regarding the sensitizing mechanism of HWP-allergy are discussed. Finally, current regulation and tools aiming at managing this risk associated with HWP are presented.

Prolonged effect of allergen sublingual immunotherapy to grass pollen

Background: The prolonged effect of allergen immunotherapy is unknown, especially in older patients. Objective: The three-year effect of sublingual allergen-specific immunotherapy (AIT) to grass pollen on elderly patients with allergic rhinitis was analyzed. Methods: Thirty-eight elderly patients (63.18 ± 3.12 yrs.) underwent AIT to grass pollen, were monitored for three years and were compared to a placebo group. AIT was performed with the use of an oral Staloral 300 SR grass extract (Stallergens Greer, London, UK) or a placebo. Symptoms and medication scores, represented by the average adjusted symptom score (AAdSS), the serum level of IgG4 to Phl p5 and the quality of life were assessed immediately after AIT and three years later. Results: After AIT, the AAdSS was significantly decreased and remained lower than in the placebo group during the three years after AIT. Serum-specific IgG4 against Phl p5 increased during the AIT trial in the study group. For the three years of observation after AIT, there were no significant changes in specific IgG4 levels against the analyzed allergens in comparison to the results immediately after AIT. The quality of life, based on the Rhinoconjunctivitis Quality of Life Questionnaire, was significantly decreased in patients who received AIT, from 1.83 (95%CI: 1.45-1.96) to 0.74 (95%CI: 0.39-1.92) (p < 0.05) to 0.82 (95%CI: 0.45- 1.04) three years after AIT. Conclusion: A prolonged positive effect after AIT to grass pollen was observed in elderly patients with allergic rhinitis. Further trials are needed to confirm this effect.

Effects of water stress on the composition and immunoreactive properties of gliadins from two wheat cultivars: Nawra and Tonacja

BACKGROUND

Water shortage during wheat vegetation causes changes in the composition of gliadins in grains, which can lead to changes in their immunoreactive properties.

RESULTS

The investigated wheat cultivars exposed to water stress accumulated significantly lower amounts (P < 0.05) of gliadins and glutenins in grains. The composition of proteins accumulated in grains was also modified. Water shortage results in a decreased share of αβ and γ fractions in total gliadins. Grains of wheat cultivated under water stress contain significantly higher (P < 0.05) levels of ω-gliadins by 4.5% and 43.3% for Nawra and Tonacja cultivars, respectively. Water stress promotes an increase in the share of P and Q/E residues in gliadins. In protein samples R5 antibodies recognized increased amounts of gliadins matching the QQPFP sequence. Wheat proteins also reacted with IgE antibodies isolated from subjects allergic to gluten.

CONCLUSION

Cultivation of wheat under conditions of water stress results in the qualitative and quantitative changes of gliadins by increasing their immunoreactivity. © 2016 Society of Chemical Industry.

Characterization of a hypoallergenic wheat line lacking ω-5 gliadin

BACKGROUND

There is no curative treatment for wheat-dependent exercise-induced anaphylaxis (WDEIA). ω-5 Gliadin is one of the dominant allergens affecting WDEIA patients. The use of ω-5 gliadin-free wheat flour in the regular diet is considered one of the prophylactic approaches against the elicitation of allergic symptoms and sensitization to ω-5 gliadin. We sought to find hypoallergenic bread wheat (or common wheat) that lacked the genes encoding ω-5 gliadin and to evaluate its in vitro allergenicity. We also aimed to evaluate the sensitization ability of one of the selected hypoallergenic wheat lines by using a possible animal model of wheat allergy.

METHODS

We screened the deletion lines of bread wheat by western blotting to ascertain common wheat lines lacking the ω-5 gliadin locus. The deletion lines we used have partial deficiency of chromosome 1B (Endo and Gill, 1996). To assess sensitization ability of gluten from the selected deletion line, guinea pigs were fed with either the gluten from the selected deletion line or commercially available gluten, and allergic score was evaluated after challenging the same gluten preparations.

RESULTS

We found that a deletion line 1BS-18 had the least deficiency of chromosome 1B among the deletion stocks lacking the ω-5 gliadin locus. The challenge test using the guinea pigs revealed that the symptoms induced by application of the 1BS-18 gluten were much less than that of commercially available gluten.

CONCLUSIONS

The deletion line 1BS-18, which lacked the ω-5 gliadin locus, is likely to have a low sensitization capacity in the guinea pig. The use of the wheat products of the 1BS-18 line in daily life may provide a feasible solution for the onset of wheat allergy.

MK-8237: a house dust mite vaccine for treating allergic rhinitis, asthma and atopic dermatitis

INTRODUCTION

Since its introduction in clinical practice one century ago for the treatment of respiratory allergic diseases, allergen-specific immunotherapy (AIT) has exhibited a relevant clinical efficacy that was subsequently confirmed in controlled trials. Thus, AIT has been accepted worldwide, as testified by guidelines and international documents. AIT is considered pivotal in the management of allergic rhinitis with or without conjunctivitis and with or without asthma. These conditions, in addition to hymenoptera venom allergy, currently are the accepted indications. The use of AIT in house-dust mite allergy still remains debated, especially due to the methodological problems in assessing this form of respiratory allergy. The more recent experimental data on MK-8237 sublingual tablets provided evidence that AIT, in the sublingual form, is effective in dust mite allergy.

AREAS COVERED

At present, the evidence of the efficacy of AIT in conditions other than respiratory allergy are not conclusive, but encouraging results have been obtained in food allergy and atopic dermatitis. Herein, the authors discuss the data for these indications.

EXPERT OPINION

Not all patients respond to AIT in the same way. Accordingly, AIT represents a promising path to precision medicine and hopefully will be able to reduce this burden of non-responding patients.

The Effect of Wheat Allergy on the Course of Atopic Eczema in Patients over 14 Years of Age

Few studies concerning the importance of wheat allergy affecting the course of atopic eczema in adolescents and adult patients exist. Aim: The evaluation if wheat allergy can deteriorate the course of atopic eczema. Follow-up of patients with confirmed food allergy to wheat. Method: Altogether 179 persons suffering from atopic eczema were included in the study: 51 men and 128 women entered the study with an average age of 26.2 (s.d. 9.5 years) Dermatological and allergological examinations were performed, including skin prick tests, atopy patch tests, and specific serum IgE for wheat, open exposure test and double-blind, placebo-controlled food challenge test with wheat flour. Results: Wheat allergy affecting the coures of atopic eczema was confirmed in eight patients (4.5%) out of 179 patients enrolled in this study by double-blind, placebo controlled food challenge test. The course of atopic eczema showed a positive trend in patients with confirmed food allergy at 3, 6, 9, 12 month follow-up (statistical evaluation with paired t-test) after the elimination of wheat flour. Conclusion: Wheat allergy may play an important role in the worsening of atopic eczema (acting as a triggering exacerbating factor) only in a minority of adolescents and adult patients (4.5% in our study). The diagnostic methods (skin prick test, specific IgE, atopy patch test, history) cannot be used as separated tests for the determination of food allergy to wheat in patients with atopic eczema.Open exposure tests and double-blind, placebo-controlled food challenge should be used for the confirmation of wheat allergy affecting the course of atopic eczema.

ProPepper: a curated database for identification and analysis of peptide and immune-responsive epitope composition of cereal grain protein families

ProPepper is a database that contains prolamin proteins identified from true grasses (Poaceae), their peptides obtained with single- and multi-enzyme in silico digestions as well as linear T- and B-cell-specific epitopes that are responsible for wheat-related food disorders. The integrated database and analysis platform contains datasets that are collected from multiple public databases (UniprotKB, IEDB, NCBI GenBank), manually curated and annotated, and interpreted in three main data tables: Protein-, Peptide- and Epitope list views that are cross-connected by unique identifications. Altogether 21 genera and 80 different species are represented. Currently, the database contains 2146 unique and complete protein sequences related to 2618 GenBank entries and 35 657 unique peptide sequences that are a result of 575 110 unique digestion events obtained by in silico digestion methods involving six proteolytic enzymes and their combinations. The interface allows advanced global and parametric search functions along with a download option, with direct connections to the relevant public databases.

Database URL:https://propepper.net

Epidemiological link between wheat allergy and exposure to hydrolyzed wheat protein in facial soap

BACKGROUND

Recent studies have highlighted the importance of extra-intestinal routes of sensitization to food-related allergens as the cause of epidemics of food allergy. Instances of Japanese women developing food allergy to wheat after exposure to hydrolyzed wheat protein (HWP) present in facial soap have been reported. However, the epidemiologic impact of these ingredients as a cause of food allergy has not been well studied.

METHODS

To clarify the epidemiological relationship between food allergy to wheat and contact exposure to HWP, a case-control study of Japanese women aged 20-54 years with self-reported wheat allergy (WA) (cases, n = 157) and age-matched control subjects without WA (controls, n = 449) was performed using a large-scale Web-based research panel. Subjects answered a Web-based questionnaire regarding the use of skin and hair care products, as well as other possible risk factors.

RESULTS

Current use of an HWP-containing facial soap (Cha no Shizuku; Yuka) was significantly associated with an increased risk of WA (adjusted odds ratio, 2.6; 95% confidence interval, 1.2-5.7; frequencies of current use in cases and controls; 11% and 6%, respectively). Use of Cha no Shizuku was more common in subjects with more recent-onset WA, implying that this soap may have contributed to the recent epidemic of WA.

CONCLUSIONS

An epidemiological relationship between WA and contact exposure to HWP has been documented. This study implicates a possible role of contact exposure to food-derived protein hydrolysates as a risk factor for the development of food allergy manifesting itself as anaphylaxis.

Acid hydrolysis of wheat gluten induces formation of new epitopes but does not enhance sensitizing capacity by the oral route: a study in "gluten free" Brown Norway rats

Background

Acid hydrolyzed wheat proteins (HWPs) are used in the food and cosmetic industry as emulsifiers. Cases of severe food allergic reactions caused by HWPs have been reported. Recent data suggest that these reactions are caused by HWPs produced by acid hydrolysis.

Objectives

To examine the sensitizing capacity of gluten proteins per se when altered by acid or enzymatic hydrolysis relative to unmodified gluten in rats naïve to gluten.

Methods

High IgE-responder Brown Norway (BN) rats bred on a gluten-free diet were sensitized without the use of adjuvant to three different gluten products (unmodified, acid hydrolyzed and enzymatic hydrolyzed). Rats were sensitized by intraperitoneal (i.p.) immunization three times with 200 µg gluten protein/rat or by oral dosing for 35 days with 0.2, 2 or 20 mg gluten protein/rat/day. Sera were analyzed for specific IgG and IgE and IgG-binding capacity by ELISA. IgE functionality was measured by rat basophilic leukemia (RBL) assay.

Results

Regardless of the route of dosing, all products had sensitizing capacity. When sensitized i.p., all three gluten products induced a strong IgG1 response in all animals. Acid hydrolyzed gluten induced the highest level of specific IgE but with a low functionality. Orally all three gluten products induced specific IgG1 and IgE but with different dose-response relations. Sensitizing rats i.p. or orally with unmodified or enzymatic hydrolyzed gluten induced specific IgG1 responses with similar binding capacity which was different from that of acid hydrolyzed gluten indicating that acid hydrolysis of gluten proteins induces formation of ‘new’ epitopes.

Conclusions

In rats not tolerant to gluten acid hydrolysis of gluten enhances the sensitizing capacity by the i.p. but not by the oral route. In addition, acid hydrolysis induces formation of new epitopes. This is in contrast to the enzymatic hydrolyzed gluten having an epitope pattern similar to unmodified gluten.

Characterization of causative allergens for wheat-dependent exercise-induced anaphylaxis sensitized with hydrolyzed wheat proteins in facial soap

BACKGROUND

In Japan, hydrolyzed wheat proteins (HWP) have been reported to cause wheat-dependent exercise-induced anaphylaxis (WDEIA) by transcutaneous sensitization using HWP-containing soap. Patients develop allergic reactions not only with soap use, but also with exercise after the intake of wheat protein (WP). ω5-Gliadin and HMW-glutenin were identified as major allergens in conventional WP-WDEIA patients. However, the allergens in HWP-WDEIA have yet to be elucidated.

METHODS

Sera were obtained from 22 patients with HWP-sensitized WDEIA. The allergenic activities of HWP and six recombinant wheat gluten proteins, including α/β-, γ-, ω1,2- and ω5-gliadin and low- and high molecular weight (HMW)-glutenins, were characterized by immunoblot analysis and histamine releasing test. IgE-binding epitopes were identified using arrays of overlapping peptides synthesized on SPOTs membrane.

RESULTS

Immunoblot analysis showed that IgE antibodies (Abs) from HWP-WDEIA bound to α/β-, γ- and ω1,2-gliadin. Recombinant γ-gliadin induced significant histamine release from basophils in eight of 11 patients with HWP-WDEIA. An IgE-binding epitope "QPQQPFPQ" was identified within the primary sequence of γ-gliadin, and the deamidated peptide containing the "PEEPFP" sequence bound with IgE Abs more strongly compared to the native epitope-peptide. The epitope-peptide inhibited IgE-binding to HWP, indicating that the specific IgE to HWP cross-reacts with γ-gliadin.

CONCLUSIONS

HWP-WDEIA patients could be sensitized to HWP containing a PEEPFP sequence, and WDEIA symptoms after WP ingestion could partly be induced by γ-gliadin. These findings could be useful to help develop tools for diagnosis and desensitization therapy for HWP-WDEIA.

The sensitivity and clinical course of patients with wheat-dependent exercise-induced anaphylaxis sensitized to hydrolyzed wheat protein in facial soap - secondary publication

BACKGROUND

Recently, an increasing number of patients with wheat-dependent exercise-induced anaphylaxis (WDEIA) have been reported in Japan. Most of them had developed this condition during or after using hydrolyzed wheat protein (HWP)-containing soap (HWP-WDEIA).

METHODS

To clarify the relation between WDEIA and HWP-containing soap and their prognosis, we retrospectively studied the patients who visited Hiroshima University Hospital and were diagnosed as WDEIA from January 2010 to June 2011. We took detailed clinical histories, performed skin prick tests, serum immunoassays for antigen-specific IgE and basophil histamine release test, and followed up their clinical courses after the diagnosis.

RESULTS

Among 36 patients with WDEIA, 30 patients had used only one type of HWP-soap. The patients with HWP-WDEIA were mainly women and had developed facial symptoms and angioedema. They suffered from blood pressure reductions less frequently than patients with conventional WDEIA. The levels of gluten-specific IgE were higher than those of omega-5 gliadin in patients with HWP-WDEIA (P < 0.05, One-way ANOVA). All patients with HWP-WDEIA were positive against HWP in histamine release test. Among the conventional wheat antigens, glutenins induced the highest histamine release from basophils of patients with HWP-WDEIA. The sensitivities of patients against glutens and glutenins were reduced over months along with the discontinuance of HWP-soap.

CONCLUSIONS

The development of HWP-WDEIA is associated with the use of HWP-soap. The sensitivity to HWP that cross reacts with non-processed wheat may be reduced or possibly cured after the discontinuation of HWP-soap.

Sensitization to acid-hydrolyzed wheat protein by transdermal administration to BALB/c mice, and comparison with gluten

BACKGROUND

An increasing number of studies have shown that hydrolyzed wheat protein (HWP) can induce IgE-mediated hypersensitivity by skin contact and/or food ingestion. However, there has been no study of the sensitizing potential of HWP. In this study, the possibility of transdermal pathway for sensitization to acid-HWP (HWP1) was investigated using BALB/c mice, and compared with that of gluten.

METHODS

HWP1 or gluten (500 μg/mouse) was transdermally administered using patches. After three or four cycles of sensitization for 3 days/week, active systemic anaphylaxis (ASA) was induced by intraperitoneal injection of the antigen, and rectal temperatures, scores of anaphylactic responses, and plasma histamine levels were determined. Because HWP1 was included in facial soap in Japan, the effect of detergent on the sensitizing potential was also investigated.

RESULTS

Transdermal administration of HWP1 induced dose-dependent production of IgE and IgG1. After sensitization for 3 or 4 weeks, intraperitoneal injection of HWP1 caused ASA, leading to decreased rectal temperatures, increased anaphylaxis scores, and increased plasma histamine levels. In addition, splenocytes harvested after ASA produced IL-4, IL-5, and IL-10 by re-stimulation with HWP1. Transdermal exposure to gluten also induced IgE and IgG1 production, and intraperitoneal injection of gluten also induced ASA only in mice sensitized in the presence of sodium dodecyl sulfate.

CONCLUSIONS

Transdermal exposure to HWP1 is sufficient to activate key immune pathways necessary for sensitizing mice for immediate hypersensitivity reactions. This study shows that HWP has a sensitizing potential as well as gluten, whereas its allergenicity may be different from that of gluten.

Evaluation of allergenicity of acid-hydrolyzed wheat protein using an in vitro elicitation test

BACKGROUND

We performed an in vitro elicitation test to determine the ability of different types of wheat-allergic patients' IgE to induce humanized mast cell activation after the addition of various time-treated acid-hydrolyzed wheat proteins (HWPs).

METHODS

The reactivity of heat- and various time-treated acid-hydrolyzed glutens (acid-HGs) and commercial acid-HWP (HWP1), using serum IgE from wheat allergy accompanied by skin and rhinoconjunctival sensitization to HWP1 in the facial soap, pediatric subjects with food allergy to native wheat, adult wheat-dependent exercise-induced anaphylaxis subjects, and nonatopic healthy subjects, was elucidated by dot blot and a luciferase assay-based in vitro elicitation test (EXiLE test).

RESULTS

Serum from subjects sensitized with HWP1 reacted only to acid-HGs (acid-HGs treated for 0.5-3 or 6 h), but not native gluten, in the results of the dot blot. In contrast, sera from pediatric subjects sensitized with native wheat reacted to native gluten more strongly and showed only slight reactions to 0.5- to 1-hour-treated acid-HGs. The results of the in vitro elicitation test showed that acid hydrolyzation of the gluten attenuated antigen-induced luciferase expression in a time-dependent manner for sera from native-wheat-sensitized pediatric subjects. On the other hand, in the sera from HWP1-sensitized subjects, acid hydrolyzation of the gluten for 0.5 h dramatically increased luciferase expression.

CONCLUSIONS

Even after prolonged hydrolyzation, acid-HGs still retained the ability to activate mast cells in the case of HWP1-sensitized subjects.

Brachypodium distachyon as a model for defining the allergen potential of non-prolamin proteins

Epitope databases and the protein sequences of published plant genomes are suitable to identify some of the proteins causing food allergies and sensitivities. Brachypodium distachyon, a diploid wild grass with a sequenced genome and low prolamin content, is the closest relative of the allergen cereals, such as wheat or barley. Using the Brachypodium genome sequence, a workflow has been developed to identify potentially harmful proteins which may cause either celiac disease or wheat allergy-related symptoms. Seed tissue-specific expression of the potential allergens has been determined, and intact epitopes following an in silico digestion with several endopeptidases have been identified. Molecular function of allergen proteins has been evaluated using Gene Ontology terms. Biologically overrepresented proteins and potentially allergen protein families have been identified.

A recombinant ω-gliadin-like D-type glutenin and an α-gliadin from wheat (Triticum aestivum): two immunoglobulin E binding proteins, useful for the diagnosis of wheat-dependent allergies

Among the wheat prolamins, D-type glutenins display a highly repetitive sequence similar to ω-gliadins, but they contain a cysteine, that allows them to be included in the gluten macropolymers. An ω-gliadin-like D-type glutenin, an α-gliadin, and an ω5-gliadin-like D-type glutenin were obtained as recombinant proteins and compared using synchrotron radiation circular dichroism. This technique evidenced the strong thermostability of the ω5-gliadin-like protein. The IgE reactivity of recombinant proteins was evaluated using 45 sera from wheat-allergic patients. The sera from patients diagnosed with cutaneous hypersensitivity to hydrolyzed wheat proteins often reacted with the ω-gliadin-like D-type glutenin and α-gliadin, whereas the IgE reaction was less frequent after dietary sensitization. So, these two proteins could be useful to diagnose these diseases. The sera from patients with exercise-induced anaphylaxis recognized the ω5-gliadin-like protein as a positive control and, less frequently, the other proteins tested. Only some sera from patients with baker's asthma reacted with the proteins tested.

Allergy to deamidated gluten in patients tolerant to wheat: specific epitopes linked to deamidation

BACKGROUND

Gluten proteins can be modified by deamidation to enhance their solubility and technological applications. However, severe allergic reactions have been reported after the consumption of food products containing deamidated gluten (DG) in subjects tolerant to wheat. This work aimed to characterize allergen profiles for these patients in comparison with those of patients allergic to wheat and to identify IgE-binding epitopes.

METHODS

Sera were obtained from 15 patients allergic to DG and from nine patients allergic to wheat proteins (WP). IgE-binding profiles were characterized both in ELISA and in a humanized rat basophilic leukaemia (RBL) cell model. Epitopes were mapped on γ- and ω2-gliadin sequences by Pepscan, and effect of glutamine/glutamic acid substitutions was studied.

RESULTS

Compared to the heterogeneous pattern of allergens detected by IgE from patients allergic to WP, responses of patients allergic to DG were homogeneous. In ELISA, all the sera displayed IgE binding to deamidated γ- and ω2-gliadins and deamidated total gliadins, frequently with high concentrations. These modified proteins induced RBL degranulation with most of the sera from DG-allergic patients. A consensus epitope was found on native γ- and ω2-gliadins (QPQQPFPQ); it was repeated several times in their sequences. The substitution of two or three glutamines of this epitope into glutamic acid at positions Q3 or Q4 and Q8 (QPEEPFPE) increased its recognition the best.

CONCLUSION

Allergy to DG is a separate entity from wheat allergy. It can be evidenced by strong IgE binding to deamidated gliadins or peptides of the type QPEEPFPE.

High molecular weight entities in industrial wheat protein hydrolysates are immunoreactive with IgE from allergic patients

Hydrolyzed wheat proteins (HWP) can induce immediate hypersensitivity through skin contact and/or food ingestion. Such patients develop IgE against unmodified wheat proteins without allergy to wheat. Our objective was to study the IgE-reacting content of HWP. We compared the reactivity of HWP and unmodified wheat proteins with IgE from patients suffering from immediate hypersensitivity to HWP. We studied the cross-reactivity between one HWP preparation and wheat proteins using immunoblot inhibition experiments. This showed that the tested HWP carried mainly unmodified epitopes originating from wheat proteins. The size distribution of polypeptides from two HWP preparations was analyzed by size-exclusion-high performance liquid chromatography (SE-HPLC), and their reactivity with IgE was studied. This showed that they contained highly IgE-reacting high molecular weight entities, likely resulting in a rearrangement of peptides issued from gluten processes. These multiepitopic entities could explain the high immunogenicity of HWP for sensitized people.

Wheat allergy

PURPOSE OF REVIEW

This review describes the diverse clinical manifestations of IgE-mediated allergy to ingested wheat and summarizes recent advances in characterization of clinically significant allergens and diagnostic workup.

RECENT FINDINGS

Recent population-based studies have shown the prevalence of wheat allergy and sensitization more precisely than past studies among small populations and in hospital settings. Intensive research has demonstrated the diverse profile of both water/salt-soluble and insoluble allergens involved in clinical types of wheat allergies determined depending on the patient age, the sensitization route, and the protein state during the exposure. Consequently, some new allergens, including nonspecific lipid transfer protein (Tri a 14), have been identified. For diagnosis, the role of water/salt-insoluble gliadins, particularly omega-5 gliadin, a major allergen of wheat-dependent, exercise-induced anaphylaxis, was assessed as compared with the results of oral challenges. The mechanisms of eliciting anaphylactic symptoms by exercise in wheat-dependent, exercise-induced anaphylaxis were speculated upon; one is the allergenicity strengthened by activated tissue transglutaminase and another is the increased absorption of allergens through the gastrointestinal tract.

SUMMARY

Findings of the recent studies show potential for more precise diagnosis in each clinical type of wheat allergies.