Glucose/Ribitol Dehydrogenase and 16.9 kDa Class I Heat Shock Protein 1 as Novel Wheat Allergens in Baker’s Respiratory Allergy

Wheat allergens are responsible for symptoms in 60–70% of bakers with work-related allergy, and knowledge, at the molecular level, of this disorder is progressively accumulating. The aim of the present study is to investigate the panel of wheat IgE positivity in allergic Italian bakers, evaluating a possible contribution of novel wheat allergens included in the water/salt soluble fraction. The water/salt-soluble wheat flour proteins from the Italian wheat cultivar Bolero were separated by using 1-DE and 2-DE gel electrophoresis. IgE-binding proteins were detected using the pooled sera of 26 wheat allergic bakers by immunoblotting and directly recognized in Coomassie stained gel. After a preparative electrophoretic step, two enriched fractions were furtherly separated in 2-DE allowing for detection, by Coomassie, of three different proteins in the range of 21–27 kDa that were recognized by the pooled baker’s IgE. Recovered spots were analyzed by nanoHPLC Chip tandem mass spectrometry (MS/MS). The immunodetected spots in 2D were subjected to mass spectrometry (MS) analysis identifying two new allergenic proteins: a glucose/ribitol dehydrogenase and a 16.9 kDa class I heat shock protein 1. Mass spectrometer testing of flour proteins of the wheat cultivars utilized by allergic bakers improves the identification of until now unknown occupational wheat allergens.

Non-Celiac Gluten/Wheat Sensitivity: Clinical Characteristics and Microbiota and Mycobiota Composition by Response to the Gluten Challenge Test

The aims of this observational “proof-of-concept” study were to analyze the clinical/psychological characteristics and gut microbiota/mycobiota composition of individuals with suspected non-celiac gluten/wheat sensitivity (NCGS/WS) according to responses to the double-blind-placebo-controlled (DBPC) crossover gluten challenge test. Fifty individuals with suspected NCGS/WS were subjected to the DBPC challenge test; anthropometric measurements, psychometric questionnaires, and fecal samples were collected. Twenty-seven (54%) participants were gluten responsive (NCGS), and 23 were placebo responsive, with an order effect. NCGS individuals displayed a significantly lower risk of eating disorders and a higher mental health score when compared to placebo-responsive participants, confirmed by multiple logistic regression analyses (OR = 0.87; 95% CI 0.76–0.98, p = 0.021, and OR = 1.30; 95% CI 1.06–1.59, p = 0.009, respectively). Principal coordinate analyses based on microbiota composition showed a separation by the DBPC response (p = 0.039). For Bacteroides (p = 0.05) and Parabacteroides (p = 0.007), the frequency of amplicon sequence variants was lower, and that for Blautia (p = 0.009) and Streptococcus (p = 0.004) was higher in NCGS individuals at multiple regression analyses. No difference in the mycobiota composition was detected between the groups. In conclusion, almost half of the individuals with suspected gluten sensitivity reported symptoms with placebo; they showed lower mental health scores, increased risk for eating disorders, and a different gut microbiota composition.

Profiling serum antibodies with a pan allergen phage library identifies key wheat allergy epitopes

Allergic reactions occur when IgE molecules become crosslinked by antigens such as food proteins. Here we create the 'AllerScan' programmable phage display system to characterize the binding specificities of anti-allergen IgG and IgE antibodies in serum against thousands of allergenic proteins from hundreds of organisms at peptide resolution. Using AllerScan, we identify robust anti-wheat IgE reactivities in wheat allergic individuals but not in wheat-sensitized individuals. Meanwhile, a key wheat epitope in alpha purothionin elicits dominant IgE responses among allergic patients, and frequent IgG responses among sensitized and non-allergic patients. A double-blind, placebo-controlled trial shows that alpha purothionin reactivity, among others, is strongly modulated by oral immunotherapy in tolerized individuals. AllerScan may thus serve as a high-throughput platform for unbiased analysis of anti-allergen antibody specificities.

Minimal Lesions of the Small Intestinal Mucosa: More than Morphology

Minimal lesions of the small bowel are mucosal changes characterized by an increased number of intraepithelial lymphocytes (with or without crypt hyperplasia) and normal villous architecture. Such changes are associated with a wide spectrum of conditions, ranging from food intolerances to infections, and from drugs to immune diseases, with different clinical profiles and manifestations, which complicates the formulation of a differential diagnosis. Patient history, symptom evaluation, and histopathology are the diagnostic features needed to establish a correct diagnosis. Physicians should assist pathologists in formulating a precise morphological evaluation by taking well-oriented small intestinal biopsies and collecting informative clinical findings that inform histopathology. In this current clinical controversy, the authors provide the reader with an appraisal of the small intestine minimal lesions through a careful analysis of the major conditions (e.g., celiac disease and other non-celiac disorders) responsible for such changes and their differential diagnosis. Also, we acknowledge that some of the diseases detailed in this article may progress from an early minimal lesion to overt mucosal atrophy. Thus, the timing of the diagnosis is of paramount importance.

TNF-α, IL-17, and IL-22 production in the rectal mucosa of nonceliac wheat sensitivity patients: role of adaptive immunity

In recent years, a new gluten- or wheat-related disease has emerged, a condition labeled "nonceliac gluten sensitivity" (NCGS) or "nonceliac wheat sensitivity" (NCWS). NCWS pathogenesis is still uncertain and attributed to very different mechanisms. We aimed to study the different T-lymphocyte subsets in the rectal mucosa of NCWS patients to demonstrate the possible contribution of adaptative immune response. Twelve patients (11 women, 1 man, age range 23-61 yr, median 32 yr) with a definitive diagnosis of NCWS were recruited at random for the present study. They underwent rectal endoscopy with multiple mucosal biopsies at the end of a double-blind placebo-controlled (DBPC) wheat challenge when they reported the reappearance of the symptoms. As controls we included 11 "healthy patients", sex- and age-matched with the patients who underwent colonoscopy evaluation for rectal bleeding due to hemorrhoids. Cells freshly obtained from rectal tissue were stained to detect anti-CD45, anti-CD3, anti-CD4, and anti-CD8. Furthermore, intracellular staining was performed with anti-tumor necrosis factor (TNF)-α, anti-interleukin (IL)-17, and anti-IL-22. Production of TNF-α by CD45+, CD3+, CD4+, and CD8+ cells, as well as of IL-17 by CD4+ cells, was higher in the rectal tissue of NCWS patients than in controls. On the contrary, IL-22 production by CD8+ cells was lower in NCWS patients than in the controls. In NCWS patients diagnosed by DBPC wheat challenge, there is a complex immunological activation, with a significant role for the adaptive response.NEW & NOTEWORTHY Nonceliac wheat sensitivity (NCWS) is a syndrome characterized by symptoms triggered by gluten intake. The pathogenesis is still uncertain. Studies have shown a role for innate immunity. We demonstrated that production of TNF-α by CD45+, CD3+, CD4+, and CD8+ cells and of IL-17 by CD4+ cells is higher in the rectal tissue of NCWS patients than in controls. We clearly demonstrated that in patients with NCWS there is a significant role for the adaptive response.

Comparative Characterization of Gluten and Hydrolyzed Wheat Proteins

Hydrolyzed wheat proteins (HWPs) are widely used as functional ingredients in foods and cosmetics, because of their emulsifying and foaming properties. However, in individuals suffering from celiac disease or wheat allergy, HWPs may have a modified immunoreactivity compared to native gluten due to changes in molecular structures. Although a variety of HWPs are commercially available, there are no in-depth comparative studies that characterize the relative molecular mass (M_r) distribution, solubility, and hydrophilicity/hydrophobicity of HWPs compared to native gluten. Therefore, we aimed to fill this gap by studying the above characteristics of different commercial HWP and gluten samples. Up to 100% of the peptides/proteins in the HWP were soluble in aqueous solution, compared to about 3% in native gluten. Analysis of the M_r distribution indicated that HWPs contained high percentages of low-molecular-weight peptides/proteins and also deamidated glutamine residues. We also found considerable differences between the seven HWPs studied, so that each HWP needs to be studied in detail to help explain its potential immunoreactivity.

Mechanisms of Wheat Allergenicity in Mice: Comparison of Adjuvant-Free vs. Alum-Adjuvant Models

Wheat protein is considered a major type of food allergen in many countries including the USA. The mechanisms of allergenicity of wheat proteins are not well understood at present. Both adjuvant-based and adjuvant-free mouse models are reported for this food allergy. However, it is unclear whether the mechanisms underlying wheat allergenicity in these two types of models are similar or different. Therefore, we compared the molecular mechanisms in a novel adjuvant-free (AF) model vs. a conventional alum-adjuvant (AA) model of wheat allergy using salt-soluble wheat protein (SSWP). In the AF model, Balb/cJ mice were sensitized with SSWP via skin exposure. In the AA model, mice were sensitized by an intraperitoneal injection of SSWP with alum. In both models, allergic reactions were elicited using an identical protocol. Robust IgE as well as mucosal mast cell protein-1 responses were elicited similarly in both models. However, an analysis of the spleen immune markers identified strikingly different molecular activation patterns in these two models. Furthermore, a number of immune markers associated with intrinsic allergenicity were also identified in both models. Since the AF model uses skin exposure without an adjuvant, the mechanisms in the AF model may more closely simulate the human wheat allergenicity mechanisms from skin exposure in occupational settings such as in the baking industry.

Wheat Consumption Leads to Immune Activation and Symptom Worsening in Patients with Familial Mediterranean Fever: A Pilot Randomized Trial

We have identified a clinical association between self-reported non-celiac wheat sensitivity (NCWS) and Familial Mediterranean Fever (FMF). Objectives: A) To determine whether a 2-week double-blind placebo-controlled (DBPC) cross-over wheat vs. rice challenge exacerbates the clinical manifestations of FMF; B) to evaluate innate immune responses in NCWS/FMF patients challenged with wheat vs. rice. The study was conducted at the Department of Internal Medicine of the University Hospital of Palermo and the Hospital of Sciacca, Italy. Six female volunteers with FMF/NCWS (mean age 36 ± 6 years) were enrolled, 12 age-matched non-FMF, NCWS females, and 8 sex- and age-matched healthy subjects served as controls. We evaluated: 1. clinical symptoms by the FMF-specific AIDAI (Auto-Inflammatory Diseases Activity Index) score; 2. serum soluble CD14 (sCD14), C-reactive protein (CRP), and serum amyloid A (SSA); 3. circulating CD14+ monocytes expressing interleukin (IL)-1β and tumor necrosis factor (TNF)-α. The AIDAI score significantly increased in FMF patients during DBPC with wheat, but not with rice (19 ± 6.3 vs. 7 ± 1.6; p = 0.028). sCD14 values did not differ in FMF patients before and after the challenge, but were higher in FMF patients than in healthy controls (median values 11357 vs. 8710 pg/ml; p = 0.002). The percentage of circulating CD14+/IL-1β+ and of CD14+/TNF-α+ monocytes increased significantly after DBPC with wheat vs. baseline or rice challenge. Self-reported NCWS can hide an FMF diagnosis. Wheat ingestion exacerbated clinical and immunological features of FMF. Future studies performed on consecutive FMF patients recruited in centers for auto-inflammatory diseases will determine the real frequency and relevance of this association.

Deamidation and Enzymatic Hydrolysis of Gliadins Alter Their Processing by Dendritic Cells in Vitro

Gliadins are major wheat allergens. Their treatment by acid or enzymatic hydrolysis has been shown to modify their allergenic potential. As the interaction of food proteins with dendritic cells (DCs) is a key event in allergic sensitization, we wished to investigate whether deamidation and enzymatic hydrolysis influence gliadin processing by DC and to examine the capacity of gliadins to activate DCs. We compared the uptake and degradation of native and modified gliadins by DCs using mouse bone marrow-derived DCs. We also analyzed the effects of these interactions on the phenotypes of DCs and T helper (Th) lymphocytes. Modifying gliadins induced a change in physicochemical properties (molecular weight, hydrophobicity, and sequence) and also in the peptide size. These alterations in turn led to increased uptake and intracellular degradation of the proteins by DCs. Native gliadins (NGs) (100 μg/mL), but not modified gliadins, increased the frequency of DC expressing CD80 (15.41 ± 2.36% vs 6.81 ± 1.10%, p < 0.001), CCR7 (28.53 ± 8.17% vs 17.88 ± 2.53%, p < 0.001), CXCR4 (70.14 ± 4.63% vs 42.82 ± 1.96%, p < 0.001), and CCR7-dependent migration (2.46 ± 1.45 vs 1.00 ± 0.22, p < 0.01) compared with NGs. This was accompanied by Th lymphocyte activation (30.37 ± 3.87% vs 21.53 ± 3.14%, p < 0.1) and proliferation (16.39 ± 3.97% vs 9.31 ± 2.80%, p > 0.1). Moreover, hydrolysis decreases the peptide size and induces an increase in gliadin uptake and degradation. Deamidation and extensive enzymatic hydrolysis of gliadins modify their interaction with DCs, leading to alteration of their immunostimulatory capacity. These findings demonstrate the strong relationship between the biochemical characteristics of proteins and immune cell interactions.

The Role of Gluten in Autism

Autism spectrum disorder (ASD) is an inherited neurodevelopmental disorder of social communication and restricted, repetitive behaviors. Much remains unknown about their mechanisms of action and physiological effects. In recent years, there has been a growing interest in nutritional diets, which can be used as a form of therapeutic intervention for ASD with a recent increase in the research being carried out in this field. Selective nutrition therapy for ASD and brain function shows improvement in behavioral changes and reduction in malnutrition seemingly associated with the allergies or food intolerances to gluten. Therefore, a gluten-free diet has yielded positive outcomes giving hope in developing therapy for ASD.

An explorative study identifies miRNA signatures for the diagnosis of non-celiac wheat sensitivity

Non-celiac wheat sensitivity (NCWS), also referred to as non-celiac gluten sensitivity, is a recently described disorder triggered by wheat/gluten ingestion. NCWS elicits a wide range of symptoms including diarrhoea, intestinal discomfort, and fatigue in analogy with other wheat/gluten-related disorders and celiac disease in particular. From the pathological standpoint, NCWS patients only have a slight increase of intraepithelial lymphocytes, while antibodies to tissue transglutaminase (tTG) and villous atrophy, otherwise diagnostic features of celiac disease, are absent. To date, the diagnosis of NCWS relies on symptoms and exclusion of confounding diseases, since biomarkers are not yet available. Here, the expression levels of selected miRNAs were examined in duodenal biopsies and peripheral blood leukocytes collected from newly diagnosed patients with NCWS and, as controls, from patients with celiac disease and gluten-independent gastrointestinal problems. We identified a few miRNAs whose expression is higher in the intestinal mucosa of patients affected by NCWS in comparison to control patients affect by gluten-independent dyspeptic symptoms (Helicobacter pylori-negative) and celiac disease. The present study provided the first evidence that NCWS patients have a characteristic miRNA expression patterns, such peculiarity could be exploited as a biomarker to the diagnosis of this disease.

In vitro selection of anti-gliadin single-domain antibodies from a naïve library for cDNA-display mediated immuno-PCR

Gluten intolerance, or adverse intestinal reactions to gluten, is a fairly common problem among certain groups of people. Celiac disease is the most severe form of gluten intolerance, which can lead to permanent damage in the digestive system. Since lifelong avoidance of gluten is the only available treatment, development of reliable techniques to identify gluten contamination in food is important. Gliadin, a component of gluten, is known to play a major role in gluten toxicity. In this study, cDNA display method was used to select specific single-domain antibodies against toxic gliadin from an alpaca-derived naïve VHH library. The cDNA display method is a promising in vitro display technique, which uniquely converts an unstable mRNA-protein fusion molecule to a stable mRNA/cDNA-protein fusion molecule using a well-designed puromycin linker. Three candidate VHHs were selected and the affinities of the VHHs were observed by pulldown assay and indirect ELISA method. In addition, a novel cDNA display mediated immuno-PCR method (cD-IPCR) was successfully applied to detect gliadin in food. We believe this work demonstrates the potential application of the cDNA display method in selecting binders against toxic and heterogeneous targets such as gliadin with an immunization-free preparation manner.

A Comprehensive Peptidomic Approach to Characterize the Protein Profile of Selected Durum Wheat Genotypes: Implication for Coeliac Disease and Wheat Allergy

The wheat varietal selection undertaken by breeders in recent decades has been tailored mainly to improve technological and productivity-related traits; however, the latter has resulted in a considerable impoverishment of the genetic diversity of wheat-based products available on the market. This pitfall has encouraged researchers to revalue the natural diversity of cultivated and non-cultivated wheat genotypes in light of their different toxic/immunogenic potential for celiac disease and wheat-allergic patients. In the present investigation, an advanced proteomic approach was designed for the global characterization of the protein profile of selected tetraploid wheat genotypes (Triticum turgidum). The approach combined proteins/peptides sequence information retrieved by specific enzymatic digestions (single and dual proteolytic enzymes) with protein digestibility information disclosed by means of in-vitro simulated human gastroduodenal digestion experiments. In both cases, the peptide pools were characterized by discovery analysis with liquid chromatography high-resolution tandem mass spectrometry, and specific amino acid sequences were identified via commercial software. The peptide list was screened for in silico toxicity/immunogenicity risk assessment, with the aid of various open-source bioinformatics tools for epitopes matching. Given the global information provided by the designed proteomic approach, the in silico risk assessment not only tackled toxicity implication for celiac disease patients, but also scouted for immunogenic sequences relevant for wheat allergic patients, achieving a comprehensive characterization of the protein profile of the selected genotypes. These latter were assessed to encrypt a variable number of toxic/immunogenic epitopes for celiac disease and wheat allergy, and as such they could represent convenient bases for breeding practices and for the development of new detoxification strategies.

Going Against the Grains: Gluten-Free Diets in Patients Without Celiac Disease-Worthwhile or Not?

While the gluten-free diet (GFD) is the only known effective therapy for celiac disease, in recent years it has become increasingly popular in the USA and worldwide, with many believing it to be more "healthful" and others claiming that it has beneficial effects for health conditions, many extraintestinal, other than celiac disease. This review examines the evidence for use of the GFD in patients without celiac disease who self-report intestinal and/or extraintestinal symptoms (non-celiac gluten sensitivity), as well as for enhancement of athletic performance and treatment of autism, rheumatoid arthritis, and psychiatric disorders. Overall, the evidence for use of GFDs in conditions other than celiac disease is poor. Though non-celiac gluten sensitivity may ultimately emerge as a biomarker-defined condition, a large proportion of patients with apparent non-celiac gluten sensitivity have, after careful investigation, an alternative diagnosis. In light of this, and coupled with the potential physical and psychological harms associated with the avoidance of gluten, initiating a GFD should not be encouraged for people who have these other conditions or are seeking physical/athletic enhancement.

Phosphorylation and Enzymatic Hydrolysis with Alcalase and Papain Effectively Reduce Allergic Reactions to Gliadins in Normal Mice

Gliadins are major allergens responsible for wheat allergies. Food processing is an effective strategy to reduce the allergenicity of gluten. In the present study, we determined the secondary and tertiary structures of gluten and gliadins treated by chemical, physical, and enzymatic means through FTIR, surface hydrophobicity, intrinsic fluorescence spectra, and UV absorption spectra. The results showed that the three treatments of phosphorylation and alcalase and papain hydrolyses significantly changed the conformational structures of gliadins, especially the secondary structure. Then, the potential allergenicity of the phosphorylated and alcalase and papain hydrolyzed gliadins were further characterized, and we observed a significant decrease in the allergenicity through the results of the index of spleen, serum total IgE, gliadin-specific IgE, histamine, and serum cytokine concentrations. An elevation of Th17 cells, the absence of Treg cells, and an imbalance in Treg/Th17 are associated with allergy. On the basis of the expression levels of related cytokines and key transcription factors, we also confirmed that phosphorylation and alcalase and papain hydrolysis could effectively reduce the allergenicity of gliadins by improving the imbalance of both Th1/Th2 and Treg/Th17 in the spleens of sensitized mice. This study suggested that the changes in conformational structure contribute to gliadin hyposensitization and that phosphorylation and alcalase and papain hydrolysis may be promising strategies for the production of wheat products with low allergenicity.

Body Mass Index and Associated Clinical Variables in Patients with Non-Celiac Wheat Sensitivity

Background: Non-Celiac Wheat Sensitivity (NCWS) is still a largely undefined condition, due to the lack of a diagnostic marker. Few data are available about the nutritional characteristics of NCWS patients at diagnosis. Aims: To evaluate the proportion of NCWS patients who were underweight, normal weight, overweight, or obese at diagnosis, and to search for possible correlations between their Body Mass Index (BMI) and other NCWS-related disease characteristics. Patients and Methods: The clinical charts of 145 NCWS patients (125 F, 20 M, mean age 37.1 ± 11.4 years), diagnosed between January 2012 and March 2018, were reviewed. As a comparison, 84 celiac disease (CD) patients (73 F, 11 M, mean age 39.8 ± 13.9 years) were evaluated. All NCWS diagnoses were based on a double-blind placebo-controlled wheat challenge (DBPCWC) method. Results: BMI distribution was similar in the NCWS (6.2% underweight and 15.2% obese subjects) and CD patients (6% underweight and 7.1% obese subjects). Underweight NCWS subjects were significantly younger and had a shorter clinical history than the overweight or obese ones. Unlike the other NCWS patients, none of them had a DQ2 and/or DQ8 haplotype. Overweight and obese NCWS patients were more frequently suffering from associated autoimmune diseases than the other BMI categories (P = 0.05). Compared to the CD controls, NCWS patients showed a higher frequency of Irritable Bowel Syndrome (IBS)-like (P = 0.01) and extraintestinal symptoms (P = 0.03) and a longer clinical history (P = 0.04), whereas weight loss was more frequent in CD (P = 0.02). Conclusions: NCWS patients showed a BMI distribution similar to CD patients. However, NCWS was found to be a heterogenous condition that regards BMI, and clinical characteristics differed between the underweight and overweight/obese patients.

Targeted LC-MS/MS Reveals Similar Contents of α-Amylase/Trypsin-Inhibitors as Putative Triggers of Nonceliac Gluten Sensitivity in All Wheat Species except Einkorn

Amylase/trypsin-inhibitors (ATIs) are putative triggers of nonceliac gluten sensitivity, but contents of ATIs in different wheat species were not available. Therefore, the predominant ATIs 0.19 + 0.53, 0.28, CM2, CM3, and CM16 in eight cultivars each of common wheat, durum wheat, spelt, emmer, and einkorn grown under the same environmental conditions were quantitated by targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) and stable isotope dilution assays using specific marker peptides as internal standards. The results were compared to a label-free untargeted LC-MS/MS analysis, in which protein concentrations were determined by intensity based absolute quantitation. Both approaches yielded similar results. Spelt and emmer had higher ATI contents than common wheat, with durum wheat in between. Only three of eight einkorn cultivars contained ATIs in very low concentrations. The distribution of ATI types was characteristic for hexaploid, tetraploid, and diploid wheat species and suitable as species-specific fingerprint. The results point to a better tolerability of einkorn for NCGS patients, because of very low total ATI contents.

Towards reducing the immunogenic potential of wheat flour: omega gliadins encoded by the D genome of hexaploid wheat may also harbor epitopes for the serious food allergy WDEIA

BACKGROUND

Omega-5 gliadins are a group of highly repetitive gluten proteins in wheat flour encoded on the 1B chromosome of hexaploid wheat. These proteins are the major sensitizing allergens in a severe form of food allergy called wheat-dependent exercise-induced anaphylaxis (WDEIA). The elimination of omega-5 gliadins from wheat flour through biotechnology or breeding approaches could reduce the immunogenic potential and adverse health effects of the flour.

RESULTS

A mutant line missing low-molecular weight glutenin subunits encoded at the Glu-B3 locus was selected previously from a doubled haploid population generated from two Korean wheat cultivars. Analysis of flour from the mutant line by 2-dimensional gel electrophoresis coupled with tandem mass spectrometry revealed that the omega-5 gliadins and several gamma gliadins encoded by the closely linked Gli-B1 locus were also missing as a result of a deletion of at least 5.8 Mb of chromosome 1B. Two-dimensional immunoblot analysis of flour proteins using sera from WDEIA patients showed reduced IgE reactivity in the mutant relative to the parental lines due to the absence of the major omega-5 gliadins. However, two minor proteins showed strong reactivity to patient sera in both the parental and the mutant lines and also reacted with a monoclonal antibody against omega-5 gliadin. Analysis of the two minor reactive proteins by mass spectrometry revealed that both proteins correspond to omega-5 gliadin genes encoded on chromosome 1D that were thought previously to be pseudogenes.

CONCLUSIONS

While breeding approaches can be used to reduce the levels of the highly immunogenic omega-5 gliadins in wheat flour, these approaches are complicated by the genetic linkage of different classes of gluten protein genes and the finding that omega-5 gliadins may be encoded on more than one chromosome. The work illustrates the importance of detailed knowledge about the genomic regions harboring the major gluten protein genes in individual wheat cultivars for future efforts aimed at reducing the immunogenic potential of wheat flour.

Multicenter, randomized, double-blind, placebo-controlled clinical trial of vital wheat gluten oral immunotherapy

BACKGROUND

Wheat is a common food allergen that can cause anaphylaxis.

OBJECTIVE

We sought to determine the efficacy and safety of vital wheat gluten (VWG) oral immunotherapy (OIT).

METHODS

After baseline double-blind, placebo-controlled food challenge (DBPCFC), 46 patients with wheat allergy (median age, 8.7 years; range, 4.2-22.3 years) were randomized 1:1 to low-dose VWG OIT or placebo, with biweekly escalation to 1445 mg of wheat protein (WP). After a year 1 DBPCFC, active subjects continued low-dose VWG OIT for another year and underwent a year 2 DBPCFC and, if passed, a subsequent off-therapy DBPCFC. Placebo-treated subjects crossed over to high-dose VWG OIT (maximum, 2748 mg of WP).

RESULTS

The median baseline successfully consumed dose (SCD) was 43 mg of WP in both groups. At year 1, 12 (52.2%) of 23 low-dose VWG OIT-treated and 0 (0%) of 23 placebo-treated subjects achieved the primary end point of an SCD of 4443 mg of WP or greater (P < .0001); median SCDs were 4443 and 143 mg, respectively. At year 2, 7 (30.4%) of 23 low-dose VWG OIT-treated subjects were desensitized to an SCD of 7443 mg of WP; 3 (13%) achieved sustained unresponsiveness 8 to 10 weeks off therapy. Among placebo-treated subjects who crossed over to high-dose VWG OIT, 12 (57.1%) of 21 were desensitized after 1 year (median SCD, 7443 mg of WP; nonsignificant vs low-dose VWG OIT). At year 1, skin prick test responses and wheat- and omega-5 gliadin-specific IgE levels did not differ between groups; the low-dose VWG OIT median specific IgG₄ level was greater than placebo (wheat, P = .0005; omega-5 gliadin, P = .0001). Year 1 SCDs correlated with wheat-specific (rho = 0.55, P = .0003) and omega-5 gliadin-specific (rho = 0.51, P = .001) IgG₄ levels in all subjects. Among 7822 low-dose VWG OIT doses in year 1, 15.4% were associated with adverse reactions: 0.04% were severe, and 0.08% subjects received epinephrine. Among 7921 placebo doses, 5.8% were associated with adverse reactions; none were severe.

CONCLUSIONS

Low- and high-dose VWG OIT induced desensitization in about one half of the subjects after 1 year of treatment. Two years of low-dose VWG OIT resulted in 30% desensitization, and 13% had sustained unresponsiveness.

Autoantibodies in the Extraintestinal Manifestations of Celiac Disease

Increased antibody reactivity towards self-antigens is often indicative of a disruption of homeostatic immune pathways in the body. In celiac disease, an autoimmune enteropathy triggered by the ingestion of gluten from wheat and related cereals in genetically predisposed individuals, autoantibody reactivity to transglutaminase 2 is reflective of the pathogenic role of the enzyme in driving the associated inflammatory immune response. Autoantibody reactivity to transglutaminase 2 closely corresponds with the gluten intake and clinical presentation in affected patients, serving as a highly useful biomarker in the diagnosis of celiac disease. In addition to gastrointestinal symptoms, celiac disease is associated with a number of extraintestinal manifestations, including those affecting skin, bones, and the nervous system. Investigations of these manifestations in celiac disease have identified a number of associated immune abnormalities, including B cell reactivity towards various autoantigens, such as transglutaminase 3, transglutaminase 6, synapsin I, gangliosides, and collagen. Clinical relevance, pathogenic potential, mechanism of development, and diagnostic and prognostic value of the various identified autoantibody reactivities continue to be subjects of investigation and will be reviewed here.

Genome mapping of seed-borne allergens and immunoresponsive proteins in wheat

Wheat is an important staple grain for humankind globally because of its end-use quality and nutritional properties and its adaptability to diverse climates. For a small proportion of the population, specific wheat proteins can trigger adverse immune responses and clinical manifestations such as celiac disease, wheat allergy, baker's asthma, and wheat-dependent exercise-induced anaphylaxis (WDEIA). Establishing the content and distribution of the immunostimulatory regions in wheat has been hampered by the complexity of the wheat genome and the lack of complete genome sequence information. We provide novel insights into the wheat grain proteins based on a comprehensive analysis and annotation of the wheat prolamin Pfam clan grain proteins and other non-prolamin allergens implicated in these disorders using the new International Wheat Genome Sequencing Consortium bread wheat reference genome sequence, RefSeq v1.0. Celiac disease and WDEIA genes are primarily expressed in the starchy endosperm and show wide variation in protein- and transcript-level expression in response to temperature stress. Nonspecific lipid transfer proteins and α-amylase trypsin inhibitor gene families, implicated in baker's asthma, are primarily expressed in the aleurone layer and transfer cells of grains and are more sensitive to cold temperature. The study establishes a new reference map for immunostimulatory wheat proteins and provides a fresh basis for selecting wheat lines and developing diagnostics for products with more favorable consumer attributes.

Oral Immunotherapy to Wheat in Allergic Asthmatic Female: A Case Report

Wheat is the most commonly grown cereal. Immunological reaction to wheat may be IgE or T-cell- mediated. Asthma could be induced by inhaled flour or by exposure to allergens present in bakery products. In patients with IgE-mediated allergy to wheat proteins there is no specific therapy, except oral immunotherapy (OIT). There are few data regarding OIT with wheat protein in allergic patients. We present a case of a 32-yearold female patient, who worked for 5 years in wheat and bakery products industry, who developed an occupational asthma and chronic urticaria after flour inhalation or ingestion of foods that containit. The patient underwent wheat  OIT, that  was well-tolerated with no severe reaction during treatment. We may conclude that wheat OIT is a safe therapy and may induce symptoms improvement in allergic asthma and urticaria in patients with wheat allergy. Wheat OIT may induce tolerance to allergic patients.

Celiac Disease and Wheat Allergy: A Growing Association?

INTRODUCTION

Celiac disease and wheat allergy (WA) are infrequent diseases in the general population, and a combination of the 2 is particularly rare. Celiac disease occurs in around 1% of the general population and WA in around 1% of all children.

CASE REPORT

We report 2 patients with celiac disease and a gluten-free diet who developed WA consistent in anaphylaxis and an eyelid angioedema, respectively, through accidental wheat exposure. A serum study and an intestinal biopsy confirmed celiac disease. Both patients were studied with a skin prick test and serum-specific IgE, with a diagnosis of WA.

DISCUSSION

In patients with celiac disease, the trace amounts of cereals present in gluten-free food could act as a sensitization factor, and probably patients with persistent symptoms (despite a gluten-free diet) are experiencing WA symptoms rather than celiac disease symptoms. The number of patients diagnosed with celiac disease has increased in the recent decades: the association between celiac disease and WA, exceedingly rare to date, could increase as well, prompting special attention to the possibility of inadvertent intake of cereals.

A chimeric IgE that mimics IgE from patients allergic to acid-hydrolyzed wheat proteins is a novel tool for in vitro allergenicity assessment of functionalized glutens

Background

Acid-hydrolyzed wheat proteins (acid-HWPs) have been shown to provoke severe allergic reactions in Europe and Japan that are distinct from classical wheat allergies. Acid-HWPs were shown to contain neo-epitopes induced by the deamidation of gluten proteins. However, products with variable rates of deamidation can be found.

Objectives

In this work, we studied the effect of the extent of wheat proteins deamidation on its allergenicity. A recombinant chimeric IgE was produced and compared to patients’ IgE for its capacity to assess the IgE-mediated triggering potential of acid-HWPs.

Methods

Sera from acid-HWP allergic patients were analyzed via ELISA and a functional basophil assay for their IgE reactivity to wheat proteins with different deamidation levels. A chimeric mouse/human IgE (chIgE-DG1) specific for the main neo-epitope, QPEEPFPE, involved in allergy to acid-HWPs was characterized with respect to its functionality and its reactivity compared to that of patients’ IgE.

Results

Acid-HWPs with medium (30%) and high (50–60%) deamidation levels displayed a markedly stronger IgE binding and capacity to activate basophils than those of samples with weak (15%) deamidation levels. The monoclonal chIgE-DG1 allowed basophil degranulation in the presence of deamidated wheat proteins. ChIgE-DG1 was found to mimic patients’ IgE reactivity and displayed the same ability to rank acid-HWP products in a degranulation assay.

Conclusion

Increasing the deamidation level of products from 15% to 60% resulted in an approximately 2-fold increase in their antigenicity and a 100-fold increase in their eliciting potential. The chimeric ChIgE-DG1 may be a useful tool to evaluate functionalized glutens for their allergenic potential. By mimicking patient sera reactivity, chIgE-DG1 also provided data on the patients' IgE repertoire and on the functionality of certain repeated epitopes in gluten proteins.

A New Proposal for the Pathogenic Mechanism of Non-Coeliac/Non-Allergic Gluten/Wheat Sensitivity: Piecing Together the Puzzle of Recent Scientific Evidence

Non-coeliac/non-allergic gluten/wheat sensitivity (NCG/WS) is a gluten-related disorder, the pathogenesis of which remains unclear. Recently, the involvement of an increased intestinal permeability has been recognized in the onset of this clinical condition. However, mechanisms through which it takes place are still unclear. In this review, we attempt to uncover these mechanisms by providing, for the first time, an integrated vision of recent scientific literature, resulting in a new hypothesis about the pathogenic mechanisms involved in NCG/WS. According to this, the root cause of NCG/WS is a particular dysbiotic profile characterized by decreased butyrate-producing-Firmicutes and/or Bifidobacteria, leading to low levels of intestinal butyrate. Beyond a critical threshold of the latter, a chain reaction of events and vicious circles occurs, involving other protagonists such as microbial lipopolysaccharide (LPS), intestinal alkaline phosphatase (IAP) and wheat α-amylase trypsin inhibitors (ATIs). NCG/WS is likely to be a multi-factor-onset disorder, probably transient and preventable, related to quality and balance of the diet, and not to the presence of gluten in itself. If future studies confirm our proposal, this would have important implications both for the definition of the disease, as well as for the prevention and therapeutic-nutritional management of individuals with NCG/WS.

Non-celiac gluten sensitivity: All wheat attack is not celiac

Currently, 1% of the United States population holds a diagnosis for celiac disease (CD), however, a more recently recognized and possibly related condition, "non-celiac gluten sensitivity" (NCGS) has been suggested to affect up to 6% of the United States public. While reliable clinical tests for CD exist, diagnosing individuals affected by NCGS is still complicated by the lack of reliable biomarkers and reliance upon a broad set of intestinal and extra intestinal symptoms possibly provoked by gluten. NCGS has been proposed to exhibit an innate immune response activated by gluten and several other wheat proteins. At present, an enormous food industry has developed to supply gluten-free products (GFP) with GFP sales in 2014 approaching $1 billion, with estimations projecting sales to reach $2 billion in the year 2020. The enormous demand for GFP also reflects a popular misconception among consumers that gluten avoidance is part of a healthy lifestyle choice. Features of NCGS and other gluten related disorders (e.g., irritable bowel syndrome) call for a review of current distinctive diagnostic criteria that distinguish each, and identification of biomarkers selective or specific for NCGS. The aim of this paper is to review our current understanding of NCGS, highlighting the remaining challenges and questions which may improve its diagnosis and treatment.

Polyphenol Interactions Mitigate the Immunogenicity and Allergenicity of Gliadins

Wheat allergy is an IgE-mediated disorder. Polyphenols, which are known to interact with certain proteins, could be used to reduce allergic reactions. This study screened several polyphenol sources for their ability to interact with gliadins, mask epitopes, and affect basophil degranulation. Polyphenol extracts from artichoke leaves, cranberries, apples, and green tea leaves were examined. Of these extracts, the first three formed insoluble complexes with gliadins. Only the cranberry and apple extracts masked epitopes in dot blot assays using anti-gliadin IgG and IgE antibodies from patients with wheat allergies. The cranberry and artichoke extracts limited cellular degranulation by reducing mouse anti-gliadin IgE recognition. In conclusion, the cranberry extract is the most effective polyphenol source at reducing the immunogenicity and allergenicity of wheat gliadins.

Antibody reactivity in patients with IgE-mediated wheat allergy to various subunits and fractions of gluten and non-gluten proteins from ω-gliadin-free wheat genotypes

[b]Abstract Introduction and objective[/b]. Gluten proteins (gliadins and glutenins) are polymorphic wheat storage proteins of allergenic properties. Significant differences in chemical composition between both protein groups allow to expect highly specific immunological response of individual subunits and fractions in reactions with IgE sera of people allergic to wheat. The aim of these studies was to identify and characterize the most allergenic gluten proteins (GP) and nongluten proteins (NGP) occurred in two closely related wheat hybrid genotypes. [b]Materials and method.[/b] 3xC and 3xN wheat hybrids, which differ strongly in regard of gliadin composition, were analyzed. Seven people manifesting different symptoms of wheat allergy donated sera for the experiment. The technique of immunoblotting after SDS-PAGE was used for identification of allergenic subunits and fractions among GP and NGP. Immunologically active protein bands were visualized by chemiluminescence. [b]Results[/b]. Great variation of immunodetection spectra was observed. Results of immunoblotting showed LMW glutenins to be of highest, gliadins of medium, while NGP of lowest allergenicity for selected patients. The 43-kDa and 47-kDa LMW glutenin subunits, 40-kDa and 43-kDa γ-gliadin fractions and 49-kDa NGP can be considered as the most immunoreactive among all protein bands [b]separated by SDS-PAGE.

CONCLUSION

[/b] The observed differentiation of immunodetection spectra allows to model highly specific IgE-binding profiles of allergenic wheat proteins attributed to individual patients with symptoms of gluten intolerance. Highly immunoreactive subunits and fractions among GP and NGP were identified. The observed immunoreactivity of 49 kDa NGP is worth to emphasize, as it has never been reported as wheat allergenic protein before.

[Food-dependent exercise-induced anaphylaxis : a stepwise diagnosis]

Food-dependent exercise-induced anaphylaxis (FDEIA) is a potentially severe food allergy. Physical exercise, NSAID, alcohol, infectious diseases and estrogens are recognized cofactors, able to reduce the amount of allergen needed to achieve a threshold for the induction of anaphylaxis. Various kinds of causative food but only a few responsible proteins have been identified. The best known is wheat ω5-gliadine. An oral food challenge remains the gold standard to prove the diagnosis. Its clinical application remains difficult and includes an allergen challenge, a cofactor challenge and a third step which integrates both of them in a single test. Gluten flour and NSAID + alcohol combination seem more efficient than respectively wheat flour and physical exercise in a provocation test condition.

Usefulness of antigen-specific IgE probability curves derived from the 3gAllergy assay in diagnosing egg, cow's milk, and wheat allergies

BACKGROUND

Specific IgE (sIgE) antibody detection using the Siemens IMMULITE^® 3gAllergy™ (3gAllergy) assay have not been sufficiently examined for the diagnosis of food allergy. The aim of this study was to evaluate the utility of measuring sIgE levels using the 3gAllergy assay to diagnose allergic reactions to egg, milk, and wheat.

METHODS

This retrospective study was conducted on patients with diagnosed or suspected allergies to egg, milk and wheat. Patients were divided into two groups according to their clinical reactivity to these allergens based on oral food challenge outcomes and/or convincing histories of immediate reaction to causative food(s). The sIgE levels were measured using 3gAllergy and ImmunoCAP. Predicted probability curves were estimated using logistic regression analysis.

RESULTS

We analyzed 1561 patients, ages 0-19 y (egg = 436, milk = 499, wheat = 626). The sIgE levels determined using 3gAllergy correlated with those of ImmunoCAP, classifying 355 patients as symptomatic: egg = 149, milk = 123, wheat = 83. 3gAllergy sIgE levels were significantly higher in symptomatic than in asymptomatic patients (P < 0.0001). Predictive probability for positive food allergy was significantly increased and correlated with increased sIgE levels. The cut-offs for allergic reaction with 95% predictive probability as determined by the 3gAllergy probability curves were different from those of ImmunoCAP.

CONCLUSIONS

Measurements of sIgE against egg, milk, and wheat as determined by 3gAllergy may be used as a tool to facilitate the diagnosis of food allergy in subjects with suspected food allergies. However, these probability curves should not be applied interchangeably between different assays.

What Do We Know Now about IgE-Mediated Wheat Allergy in Children?

IgE-mediated wheat allergy is a gluten-related disorder. Wheat is one of the five most common food allergens in children. However, the natural history of IgE-mediated wheat allergy has seldom been described in the research literature. This study presents the current state of knowledge about the IgE-mediated wheat allergy in children.

[INSOLUBILITY AND ALTERATION OF ALLERGENIC ACTIVITY OF WHEAT PROTEINS IN PROCESSED FOODS]

BACKGROUND

Food processing causes decomposition, denaturation or polymerization of protein, which may alter an allergic reaction. This study aimed to investigate the insolubility and alteration of wheat allergens in processed foods and the reactivity to patient sera.

METHODS

We extracted proteins from wheat flour, udon and bread using different extracts and conducted SDS-polyacrylamide gel electrophoresis. IgE-immunoblotting was also conducted using sera from children with wheat allergy.

RESULTS

Soluble protein was extracted from wheat flour, and gluten fractions were also extracted by adding SDS. However, no proteins were able to be extracted from udon or bread witout severing the disulfide bonds under reducing condition. Only trace amounts of protein were detected in the water after boiling udon noodles. The reactivity of IgE antibody to the extracted protein did not differ among the different processed food types.

CONCLUSIONS

Wheat allergens became strongly insolubilized after gluten formation and heating. However, the reactivity of IgE antibody to each allergen was not affected by food processing. Further studies are needed for the effects on clinical symptoms.

Allergenicity Assessment of Transgenic Wheat Lines In Silico

Agriculture biotechnology is a promising tool for developing varieties with enhanced quality and quantity. Transgenic proteins expressed by genetically modified (GM) food crops improve crop characteristics like nutritional value, taste, and texture, and endow plants with resistance against fungus, pests, and insects. Despite such potential benefits, there are concerns regarding possible adverse effects of GM crops on human health, animals and the environment. Among the proposed guidelines for GM food safety testing-the weight-of-evidence approach proposed by the Codex Alimentarius Commission (ALINORM 03/34A) is the most recent. Till date, several transgenic wheat lines have been developed and research is underway for further improvement. However, GM wheat is not being grown or consumed in any part of the world. In the present study, in silico tools were employed for safety testing of eight transgenes used for the development of transgenic wheat lines. Among the genes studied, none of them shared sequence homology with the reported allergens and may be safe for use in genetic engineering. In conclusion, gene selection for developing transgenic wheat lines should be done with utmost care to ensure its safety for feed and fodder.

A Safe and Effective Method for Wheat Oral Immunotherapy

At present the only available management for food allergy is avoidance; however, abstaining from allergic foods can affect the quality of life. Oral Immunotherapy (OIT) is an efficient method for increasing tolerance towards food allergens. The aim of this study was desensitizing patients above five years of age with wheat allergy and evaluating the safety and efficacy of OIT for children with IgE-mediated wheat allergy. The method of Rush Oral Immunotherapy (ROIT) was performed on 8 anaphylactic wheat allergic patients as well as outpatient method on 5 non-anaphylactic ones. In ROIT, build-up phase was performed during several days, but in outpatient, the amount of ingestion gradually increased to 5.2 g wheat protein within several weeks. After that, maintenance doses were prescribed daily for 3 months. Then, if the oral food challenge (OFC) was negative, the patients were considered to be in desensitized state, which meant they had to continue eating same doses without interruption. In ROIT, build-up phase continued for about 4.6 days during which, 21 from 71 doses, showed clinical symptoms (29.6%). On the contrary, outpatient method lasted approximately 72.4 days in which 356 doses were used and symptoms developed in only 9 doses (2.5%). In total -regardless of type of build-up phase- 12 patients could complete the maintenance phase with 1080 doses that 28 of them (2.6%) developed mild symptoms. Our OIT study proved to be safe and effective, although it is utterly evident that further investigation on more patients is necessary.

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.

[THE COMPARISON OF EFFECTIVENESS OF SLOW SPECIFIC ORAL IMMUNOTHERAPY FOR WHEAT ALLERGY USING TWO DIFFERENT INTAKE FREQUENCY]

OBJECTIVE

We performed a constructive study on the effectiveness of oral immunotherapy for wheat allergy using two different intake frequency, and evaluated the impact of intake frequency.

SUBJECTS

Of all the subjects who had a positive result in an oral food challenge test for udon (wheat noodles), informed consent was obtained from 49 subjects. Forty-one of the subjects successfully completed testing; data was tabulated for only the 16 in each group who complied with their assigned intake frequency.

METHOD

Oral immunotherapy was administered after randomly dividing the subjects into the following two groups according to intake frequency: the frequent group, whose intake was six times/week or more; and the intermittent group, whose intake was two times/week. The ability of these patients to ingest the noodles at the target dose was evaluated after 6 months.

RESULTS

After six months, the proportion of subjects who had a negative result on testing with the target dose (20g dried noodle weight for subjects ≤3 years of age, and 50g dried noodle weight for those ≥4 years of age) or who were capable of the target intake within six months was 75%, and there was no difference among the both groups.

CONCLUSION

The findings suggest that even when intake frequency is reduced to twice/week, no clear difference is seen with the target dose after six months of immunotherapy.

Selection of lactic acid bacteria strains for the hydrolysis of allergenic proteins of wheat flour

BACKGROUND

Wheat flour is one of the most common causative agents of food allergy. The study presents the selection and characterization of lactic acid bacteria (LAB) strains capable of hydrolyzing/modifying allergenic proteins of wheat flour. Hydrolysis of wheat proteins was determined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with sera from patients with food allergy to gluten.

RESULTS

The analysis of electrophoretic profiles of protein extracted from sourdough shows the capability of selected LAB strains for proteolytic degradation of wheat proteins that belong to two factions: albumin/globulin (hydrolysis of 13 polypeptides with a molecular weight between 103 and 22 kDa); and gliadin (seven polypeptides with a molecular weight between 39 and 24 kDa). All analyzed strains were capable of hydrolyzing some IgE-binding epitopes of wheat allergens. The lack of such changes in control samples indicates that they were induced rather by the proteolytic activity of bacterial strains than endogenous enzymes of wheat flour. The gluten proteins were susceptible to hydrolysis by sequential digestion with pepsin and trypsin.

CONCLUSION

The selected strains exhibit proteolytic activity, which leads to a reduction in allergenicity of wheat sourdoughs. These strains may be applied as specific starter cultures to prepare bakery products of special nutritional use. © 2015 Society of Chemical Industry.

Better management of wheat allergy using a very low-dose food challenge: A retrospective study

BACKGROUND

Low-dose reactive wheat-allergic children are at a high risk of a positive oral food challenge (OFC). The present study aimed to evaluate whether the results of a very low-dose (VL) OFC would contribute to better wheat allergy management in this population.

METHODS

We retrospectively reviewed wheat-allergic subjects who underwent a VL OFC with 2 g of udon noodles (equivalent to 53 mg of wheat protein) and had a previous allergic reaction to <15 g of udon noodles (equivalent to 400 mg of wheat protein) within 2 years before the OFC. Subjects who passed the OFC were defined as VL tolerant; those who failed were considered VL reactive. In VL tolerant subjects, the dose was increased to 15 g of udon noodles either during an OFC in our hospital or gradually at home.

RESULTS

Of the 57 included subjects (median age, 2.9 years; range, 1.0-11.8 years), 32 (56%) were VL tolerant and 25 (44%) were VL reactive. Most reactions during the OFC could be treated with an antihistamine and/or a nebulized β2 agonist. VL tolerant subjects consumed 2 g of udon noodles or a seasoning containing wheat. Within a year after the OFC, 18 VL tolerant subjects (56%), but no VL reactive subjects, were able to consume 15 g of udon noodles (p < 0.001).

CONCLUSIONS

A VL OFC can shift the management of some low-dose reactive wheat-allergic children from complete avoidance to partial wheat intake.

Assessment of the Allergenic Potential of Transgenic Wheat (Triticum aestivum) with Reduced Levels of ω5-Gliadins, the Major Sensitizing Allergen in Wheat-Dependent Exercise-Induced Anaphylaxis

The ω5-gliadins are the major sensitizing allergens in wheat-dependent exercise-induced anaphylaxis (WDEIA). In this study, two-dimensional immunoblot analysis was used to assess the allergenic potential of two transgenic wheat lines in which ω5-gliadin genes were silenced by RNA interference. Sera from 7 of 11 WDEIA patients showed greatly reduced levels of immunoglobulin E (IgE) reactivity to ω5-gliadins in both transgenic lines. However, these sera also showed low levels of reactivity to other gluten proteins. Sera from three patients showed the greatest reactivity to proteins other than ω5-gliadins, either high-molecular-weight glutenin subunits (HMW-GSs), α-gliadins, or non-gluten proteins. The complexity of immunological responses among these patients suggests that flour from the transgenic lines would not be suitable for individuals already diagnosed with WDEIA. However, the introduction of wheat lacking ω5-gliadins could reduce the number of people sensitized to these proteins and thereby decrease the overall incidence of this serious food allergy.

Study on the Immunoreactivity of Triticum monococcum (Einkorn) Wheat in Patients with Wheat-Dependent Exercise-Induced Anaphylaxis for the Production of Hypoallergenic Foods

Wheat [Triticum aestivum (T.a.)] ingestion can cause a specific allergic reaction, which is called wheat-dependent exercise-induced anaphylaxis (WDEIA). The major allergen involved is ω-5 gliadin, a gluten protein coded by genes located on the B genome. Our aim was to study the immunoreactivity of proteins in Triticum monococcum (einkorn, T.m.), a diploid ancestral wheat lacking B chromosomes, for possible use in the production of hypoallergenic foods. A total of 14 patients with a clear history of WDEIA and specific immunoglobulin E (IgE) to ω-5 gliadin were enrolled. Skin prick test (SPT) with a commercial wheat extract and an in-house T.a. gluten diagnostic solution tested positive for 43 and 100% of the cases, respectively. No reactivity in patients tested with solutions prepared from four T.m. accessions was observed. The immunoblotting of T.m. gluten proteins performed with the sera of patients showed different IgE-binding profiles with respect to T.a., confirming the absence of ω-5 gliadin. A general lower immunoreactivity of T.m. gluten proteins with scarce cross-reactivity to ω-5 gliadin epitopes was assessed by an enzyme-linked immunosorbent assay (ELISA). Given the absence of reactivity by SPT and the limited cross-reactivity with ω-5 gliadin, T.m. might represent a potential candidate in the production of hypoallergenic bakery products for patients sensitized to ω-5 gliadin. Further analyses need to be carried out regarding its safety.

Cutaneous Manifestations of Non-Celiac Gluten Sensitivity: Clinical Histological and Immunopathological Features

BACKGROUND

The dermatological manifestations associated with intestinal diseases are becoming more frequent, especially now when new clinical entities, such as Non-Celiac Gluten Sensitivity (NCGS), are identified. The existence of this new entity is still debated. However, many patients with diagnosed NCGS that present intestinal manifestations have skin lesions that need appropriate characterization.

METHODS

We involved 17 patients affected by NCGS with non-specific cutaneous manifestations who got much better after a gluten free diet. For a histopathological and immunopathological evaluation, two skin samples from each patient and their clinical data were collected.

RESULTS

The median age of the 17 enrolled patients affected by NCGS was 36 years and 76% of them were females. On the extensor surfaces of upper and lower limbs in particular, they all presented very itchy dermatological manifestations morphologically similar to eczema, psoriasis or dermatitis herpetiformis. This similarity was also confirmed histologically, but the immunopathological analysis showed the prevalence of deposits of C3 along the dermo-epidermal junction with a microgranular/granular pattern (82%).

CONCLUSIONS

The exact characterization of new clinical entities such as Cutaneous Gluten Sensitivity and NCGS is an important objective both for diagnostic and therapeutic purposes, since these are patients who actually benefit from a GFD (Gluten Free Diet) and who do not adopt it only for fashion.

Structural Basis of IgE Binding to α- and γ-Gliadins: Contribution of Disulfide Bonds and Repetitive and Nonrepetitive Domains

Wheat products cause IgE-mediated allergies. The present study aimed to decipher the molecular basis of α- and γ-gliadin allergenicity. Gliadins and their domains, the repetitive N-terminal and the nonrepetitive C-terminal domains, were cloned and expressed in Escherichia coli. Their secondary structures and their IgE binding capacity were compared with those of natural proteins before and after reduction/alkylation. Allergenicity was evaluated with sera from patients who had a wheat food allergy or baker's asthma. The secondary structures of natural and recombinant proteins were slightly different. Compared with natural gliadins, recombinant proteins retained IgE binding but with reduced reactivity. Reduction/alkylation decreased IgE binding for both natural and recombinant gliadins. Although more continuous epitopes were identified in the N-terminal domains of α- and γ-gliadins, both the N-terminal and C-terminal domains contributed to IgE binding. As for other members of the prolamin superfamily, disulfide bonds appear to be of high importance for IgE binding.

Assessment of Allergy to Milk, Egg, Cod, and Wheat in Swedish Schoolchildren: A Population Based Cohort Study

Objectives

Knowledge about the prevalence of allergies to foods in childhood and adolescence is incomplete. The purpose of this study was to investigate the prevalence of allergies to milk, egg, cod, and wheat using reported data, clinical examinations, and double-blind placebo-controlled food challenges, and to describe the phenotypes of reported food hypersensitivity in a cohort of Swedish schoolchildren.

Methods

In a population-based cohort of 12-year-old children, the parents of 2612 (96% of invited) completed a questionnaire. Specific IgE antibodies to foods were analyzed in a random sample (n=695). Children reporting complete avoidance of milk, egg, cod, or wheat due to perceived hypersensitivity and without physician-diagnosed celiac disease were invited to undergo clinical examination that included specific IgE testing, a celiac screening test, and categorization into phenotypes of food hypersensitivity according to preset criteria. Children with possible food allergy were further evaluated with double-blind challenges.

Results

In this cohort, the prevalence of reported food allergy to milk, egg, cod, or wheat was 4.8%. Food allergy was diagnosed in 1.4% of the children after clinical evaluation and in 0.6% following double-blind placebo-controlled food challenge. After clinical examination, children who completely avoided one or more essential foods due to perceived food hypersensitivity were categorized with the following phenotypes: allergy (29%), outgrown allergy (19%), lactose intolerance (40%), and unclear (12%).

Conclusions

There was a high discrepancy in the prevalence of allergy to milk, egg, cod and wheat as assessed by reported data, clinical evaluation, and double-blind food challenges. Food hypersensitivity phenotyping according to preset criteria was helpful for identifying children with food allergy.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: “food”, “diet”, “food allergy”, “food hypersensitivity”, “food intolerance”, “IBS”, “epidemiology”, “pathogenesis”, “pathophysiology”, “diagnosis”, “treatment”. We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.