A pathogenic role for cystic fibrosis transmembrane conductance regulator in celiac disease.

Intestinal handling of dietary proteins usually prevents local inflammatory and immune responses and promotes oral tolerance. However, in ~ 1% of the world population, gluten proteins from wheat and related cereals trigger an HLA DQ2/8-restricted TH1 immune and antibody response leading to celiac disease. Prior epithelial stress and innate immune activation are essential for breaking oral tolerance to the gluten component gliadin. How gliadin subverts host intestinal mucosal defenses remains elusive. Here, we show that the α-gliadin-derived LGQQQPFPPQQPY peptide (P31-43) inhibits the function of cystic fibrosis transmembrane conductance regulator (CFTR), an anion channel pivotal for epithelial adaptation to cell-autonomous or environmental stress. P31-43 binds to, and reduces ATPase activity of, the nucleotide-binding domain-1 (NBD1) of CFTR, thus impairing CFTR function. This generates epithelial stress, tissue transglutaminase and inflammasome activation, NF-κB nuclear translocation and IL-15 production, that all can be prevented by potentiators of CFTR channel gating. The CFTR potentiator VX-770 attenuates gliadin-induced inflammation and promotes a tolerogenic response in gluten-sensitive mice and cells from celiac patients. Our results unveil a primordial role for CFTR as a central hub orchestrating gliadin activities and identify a novel therapeutic option for celiac disease.

Bromelain and ficin proteolytic effects on gliadin cytotoxicity and expression of genes involved in cell-tight junctions in Caco-2 cells.

Enzyme therapy for celiac disease (CeD), which digests gliadin into non-immunogenic and non-toxic peptides, can be an appropriate treatment option for CeD. Here, we have investigated the effectiveness of bromelain and ficin on gliadin digestion using in vitro, such as SDS-PAGE, HPLC, and circular dichroism (CD). Furthermore, the cytotoxicity of gliadin and 19-mer peptide before and after digestion with these enzymes was evaluated using the MTT assay in the Caco-2 cell line. Finally, we examined the effect of these treatments along with Larazotide Acetate on the expression of genes involved in cell-tight junctions, such as Occludin, Claudin 3, tight junction protein-1, and Zonulin in the Caco-2 cell line. Our study demonstrated bromelain and ficin digestion effects on the commercial and wheat-extracted gliadin by SDS-PAGE, HPLC, and CD. Also, the cytotoxicity results on Caco-2 showed that toxicity of the gliadin and synthetic 19-mer peptide was decreased by adding bromelain and ficin. Furthermore, the proteolytic effects of bromelain and ficin on gliadin indicated the expression of genes involved in cell-tight junctions was improved. This study confirms that bromelain and ficin mixture could be effective in improving the symptoms of CeD.

Celiac disease-associated Neisseria flavescens decreases mitochondrial respiration in CaCo-2 epithelial cells: Impact of Lactobacillus paracasei CBA L74 on bacterial-induced cellular imbalance.

We previously identified a Neisseria flavescens strain in the duodenum of celiac disease (CD) patients that induced immune inflammation in ex vivo duodenal mucosal explants and in CaCo-2 cells. We also found that vesicular trafficking was delayed after the CD-immunogenic P31-43 gliadin peptide-entered CaCo-2 cells and that Lactobacillus paracasei CBA L74 (L. paracasei-CBA) supernatant reduced peptide entry. In this study, we evaluated if metabolism and trafficking was altered in CD-N. flavescens-infected CaCo-2 cells and if any alteration could be mitigated by pretreating cells with L. paracasei-CBA supernatant, despite the presence of P31-43. We measured CaCo-2 bioenergetics by an extracellular flux analyser, N. flavescens and P31-43 intracellular trafficking by immunofluorescence, cellular stress by TBARS assay, and ATP by bioluminescence. We found that CD-N. flavescens colocalised more than control N. flavescens with early endocytic vesicles and more escaped autophagy thereby surviving longer in infected cells. P31-43 increased colocalisation of N. flavescens with early vesicles. Mitochondrial respiration was lower (P < .05) in CD-N. flavescens-infected cells versus not-treated CaCo-2 cells, whereas pretreatment with L. paracasei-CBA reduced CD-N. flavescens viability and improved cell bioenergetics and trafficking. In conclusion, CD-N. flavescens induces metabolic imbalance in CaCo-2 cells, and the L. paracasei-CBA probiotic could be used to correct CD-associated dysbiosis.

Pro-Inflammatory Effect of Gliadins and Glutenins Extracted from Different Wheat Cultivars on an In Vitro 3D Intestinal Epithelium Model.

There is a need to assess the relationship between improved rheological properties and the immunogenic potential of wheat proteins. The present study aimed to investigate the in vitro effects of total protein extracts from three modern and two landrace Triticum aestivum commercial flour mixes, with significant differences in gluten strength (GS), on cell lines. Cytotoxicity and innate immune responses induced by wheat proteins were investigated using Caco-2 monocultures, two dimensional (2D) Caco-2/U937 co-cultures, and three dimensional (3D) co-cultures simulating the intestinal mucosa with Caco-2 epithelial cells situated above an extra-cellular matrix containing U937 monocytes and L929 fibroblasts. Modern wheat proteins, with increased GS, significantly reduced Caco-2 cell proliferation and vitality in monoculture and 2D co-cultures than landrace proteins. Modern wheat proteins also augmented Caco-2 monolayer disruption and tight junction protein, occludin, redistribution in 3D co-cultures. Release of interleukin-8 into the cell medium and increased U937 monocyte migration in both 2D and 3D co-cultures were similarly apparent. Immuno-activation of migrating U937 cells was evidenced from cluster of differentiation 14 (CD14) staining and CD11b-related differentiation into macrophages. The modern wheat proteins, with gluten polymorphism relatedness and increased GS, were shown to be more cytotoxic and immunogenic than the landrace wheat proteins.

Development of wheat genotypes expressing a glutamine-specific endoprotease from barley and a prolyl endopeptidase from Flavobacterium meningosepticum or Pyrococcus furiosus as a potential remedy to celiac disease.

Ubiquitous nature of prolamin proteins dubbed gluten from wheat and allied cereals imposes a major challenge in the treatment of celiac disease, an autoimmune disorder with no known treatment other than abstinence diet. Administration of hydrolytic glutenases as food supplement is an alternative to deliver the therapeutic agents directly to the small intestine, where sensitization of immune system and downstream reactions take place. The aim of the present research was to evaluate the capacity of wheat grain to express and store hydrolytic enzymes capable of gluten detoxification. For this purpose, wheat scutellar calli were biolistically transformed to generate plants expressing a combination of glutenase genes for prolamin detoxification. Digestion of prolamins with barley endoprotease B2 (EP-HvB2) combined with Flavobacterium meningosepticum prolyl endopeptidase (PE-FmPep) or Pyrococcus furiosus prolyl endopeptidase (PE-PfuPep) significantly reduced (up to 67%) the amount of the indigestible gluten peptides of all prolamin families tested. Seven of the 168 generated lines showed inheritance of transgene to the T2 generation. Reversed phase high-performance liquid chromatography of gluten extracts under simulated gastrointestinal conditions allowed the identification of five T2 lines that contained significantly reduced amounts of immunogenic, celiac disease-provoking gliadin peptides. These findings were complemented by the R5 ELISA test results where up to 72% reduction was observed in the content of immunogenic peptides. The developed wheat genotypes open new horizons for treating celiac disease by an intraluminal enzyme therapy without compromising their agronomical performance.

Structural insights on P31-43, a gliadin peptide able to promote an innate but not an adaptive response in celiac disease.

Inflammation of intestinal tissue in patients affected by celiac disease (CD) originates from the adaptive and innate immune responses elicited by the undigested gliadin fragments through molecular mechanisms not yet completely described. Undigested A-gliadin peptide P31-43 is central to CD pathogenesis, entering enterocytes in vesicular compartments by endocytosis and inducing an innate immune response in CD intestinal mucosa. This study focused on the reasons why P31-43 does not behave as adaptive immunogenic agent. Once obtained by NMR analysis, the three-dimensional model of P31-43 was used to implement a series of in silico experiments aimed to explore the ability of the peptide to interact with HLA-DQ2 and the corresponding receptor onto T cells. Our results show that P31-43 is a poor ligand for DQ2 and/or T-cell receptor. This study was also aimed to investigate, from a structural point of view, the previous experimental findings by which P31-43 is able to enhance the phosphorylation level of the protein ERK2, while some P31-43 Ala-mutants decrease or totally inhibit that process. The molecular models of P31-43, P31-43 P36A, and F37A mutants were used for in silico docking experiments onto the ERK2 structure. The experiments support the hypothesis that P31-43 F37A works as an ERK2 phosphorylation inhibitor because it binds to the ERK2 phosphorylation site. This study reports on the structural properties of so far never NMR characterized gliadin peptides relevant in CD and explores details about their mechanisms of action.

Similar Responses of Intestinal T Cells From Untreated Children and Adults With Celiac Disease to Deamidated Gluten Epitopes.

BACKGROUND & AIMS: Celiac disease is a chronic small intestinal inflammatory disorder mediated by an immune response to gluten peptides in genetically susceptible individuals. Celiac disease is often diagnosed in early childhood, but some patients receive a diagnosis late in life. It is uncertain whether pediatric celiac disease is distinct from adult celiac disease. It has been proposed that gluten-reactive T cells in children recognize deamidated and native gluten epitopes, whereas T cells from adults only recognize deamidated gluten peptides. We studied the repertoire of gluten epitopes recognized by T cells from children and adults. METHODS: We examined T-cell responses against gluten by generating T-cell lines and T-cell clones from intestinal biopsies of adults and children and tested proliferative response to various gluten peptides. We analyzed T cells from 14 children (2-5 years old) at high risk for celiac disease who were followed for celiac disease development. We also analyzed T cells from 6 adults (26-55 years old) with untreated celiac disease. All children and adults were positive for HLA-DQ2.5. Biopsies were incubated with gluten digested with chymotrypsin (modified or unmodified by the enzyme transglutaminase 2) or the peptic-tryptic digest of gliadin (in native and deamidated forms) before T-cell collection. RESULTS: Levels of T-cell responses were higher to deamidated gluten than to native gluten in children and adults. T cells from children and adults each reacted to multiple gluten epitopes. Several T-cell clones were cross-reactive, especially clones that recognized epitopes from γ-and ω-gliadin. About half of the generated T-cell clones from children and adults reacted to unknown epitopes. CONCLUSIONS: T-cell responses to different gluten peptides appear to be similar between adults and children at the time of diagnosis of celiac disease.

Gliadin intake induces oxidative-stress responses in Caenorhabditis elegans.

Clinical attention to gluten-related disorders, such as celiac disease and nonceliac gluten sensitivity, is on the rise. However, identifying the pathophysiological mechanisms of gluten-related disorders remains elusive. Gliadin, a component of gluten, is known to play a major role in gluten toxicity. Caenorhabditis elegans has been widely used as the predominant experimental animal model to study toxicity and stress response in biomedical research. We investigated the stress response induced by gliadin intake in C. elegans to evaluate its toxicity and found brood size, body bending, and pumping rates to be significantly altered in response to gliadin. Notably, reactive oxygen species (ROS) production and Pgst-4::GFP transgene expression, an indicator of the oxidative-stress response, were significantly increased after gliadin intake. Reduced pumping rates were most likely caused by gliadin-induced oxidative stress, since pumping rates in oxidative stress-sensitive mev-1 mutants were more severely reduced than in oxidative stress-resistant daf-2 mutants following gliadin intake. Our results indicated that gluten/gliadin intake in C. elegans triggered ROS production and induced an oxidative stress response that reduced pumping rates and decreased brood size. We suggest C. elegans to be a useful model system for studying gluten/gliadin toxicity.

Protective Effect of 1,25-Dihydroxy Vitamin D3 on Pepsin-Trypsin-Resistant Gliadin-Induced Tight Junction Injuries.

BACKGROUND: Tight junction (TJ) injuries induced by pepsin-trypsin-resistant gliadin (PT-G) play an important role in the pathogenesis of celiac disease. Previously, 1,25-dihydroxy vitamin D3 (VD3) was reported to be a TJ regulator that attenuates lipopolysaccharide- and alcohol-induced TJ injuries. However, whether VD3 can attenuate PT-G-induced TJ injuries is unknown. AIM: The aim of this study was to evaluate the effects of VD3 on PT-G-induced TJ injuries. METHODS: Caco-2 monolayers were used as in vitro models. After being cultured for 21 days, the monolayers were treated with PT-G plus different concentrations of VD3. Then, the changes in trans-epithelial electrical resistance and FITC-dextran 4000 (FD-4) flux were determined to evaluate the monolayer barrier function. TJ protein levels were measured to assess TJ injury severity, and myeloid differentiation factor 88 (MyD88) expression and zonulin release levels were determined to estimate zonulin release signaling pathway activity. Additionally, a gluten-sensitized mouse model was established as an in vivo model. After the mice were treated with VD3 for 7 days, we measured serum FD-4 concentrations, TJ protein levels, MyD88 expression, and zonulin release levels to confirm the effect of VD3. RESULTS: Both in vitro and in vivo, VD3 significantly attenuated the TJ injury-related increase in intestinal mucosa barrier permeability. Moreover, VD3 treatment up-regulated TJ protein expression levels and significantly decreased MyD88 expression and zonulin release levels. CONCLUSIONS: VD3 has protective effects against PT-G-induced TJ injuries both in vitro and in vivo, which may correlate with the disturbance of the MyD88-dependent zonulin release signaling pathway.

The In Vitro Effects of Enzymatic Digested Gliadin on the Functionality of the Autophagy Process.

Gliadin, the alcohol-soluble protein fraction of wheat, contains the factor toxic for celiac disease (CD), and its toxicity is not reduced by digestion with gastro-pancreatic enzymes. Importantly, it is proved that an innate immunity to gliadin plays a key role in the development of CD. The immune response induces epithelial stress and reprograms intraepithelial lymphocytes into natural killer (NK)-like cells, leading to enterocyte apoptosis and an increase in epithelium permeability. In this contribution, we have reported that in Caco-2 cells the administration of enzymatically digested gliadin (PT-gliadin) reduced significantly the expression of the autophagy-related marker LC3-II. Furthermore, electron and fluorescent microscope analysis suggested a compromised functionality of the autophagosome apparatus. The rescue of the dysregulated autophagy process, along with a reduction of PT-gliadin toxicity, was obtained with a starvation induction protocol and by 3-methyladenine administration, while rapamycin, a well-known autophagy inducer, did not produce a significant improvement in the clearance of extra- and intra-cellular fluorescent PT-gliadin amount. Altogether, our results highlighted the possible contribution of the autophagy process in the degradation and in the reduction of extra-cellular release of gliadin peptides and suggest novel molecular targets to counteract gliadin-induced toxicity in CD.

Celiac anti-type 2 transglutaminase antibodies induce differential effects in fibroblasts from celiac disease patients and from healthy subjects.

Type 2 transglutaminase (TG2) has an important pathogenic role in celiac disease (CD), an inflammatory intestinal disease that is caused by the ingestion of gluten-containing cereals. Indeed, TG2 deamidates specific gliadin peptides, thus enhancing their immunogenicity. Moreover, the transamidating activity seems to provoke an autoimmune response, where TG2 is the main autoantigen. Many studies have highlighted a possible pathogenetic role of anti-TG2 antibodies, because they modulate TG2 enzymatic activity and they can interact with cell-surface TG2, triggering a wide range of intracellular responses. Autoantibodies also alter the uptake of the alpha-gliadin peptide 31-43 (p31-43), responsible of the innate immune response in CD, thus partially protecting cells from p31-43 damaging effects in an intestinal cell line. Here, we investigated whether anti-TG2 antibodies protect cells from p31-43-induced damage in a CD model consisting of primary dermal fibroblasts. We found that the antibodies specifically reduced the uptake of p31-43 by fibroblasts derived from healthy subjects but not in those derived from CD patients. Analyses of TG2 expression and enzymatic activity did not reveal any significant difference between fibroblasts from healthy and celiac subjects, suggesting that other features related to TG2 may be responsible of such different behaviors, e.g., trafficking or subcellular distribution. Our findings are in line with the concept that a "celiac cellular phenotype" exists and that TG2 may contribute to this phenotype. Moreover, they suggest that the autoimmune response to TG2, which alone may damage the celiac mucosa, also fails in its protective role in celiac cells.

Involvement of cell surface TG2 in the aggregation of K562 cells triggered by gluten.

Gluten-induced aggregation of K562 cells represents an in vitro model reproducing the early steps occurring in the small bowel of celiac patients exposed to gliadin. Despite the clear involvement of TG2 in the activation of the antigen-presenting cells, it is not yet clear in which compartment it occurs. Herein we study the calcium-dependent aggregation of these cells, using either cell-permeable or cell-impermeable TG2 inhibitors. Gluten induces efficient aggregation when calcium is absent in the extracellular environment, while TG2 inhibitors do not restore the full aggregating potential of gluten in the presence of calcium. These findings suggest that TG2 activity is not essential in the cellular aggregation mechanism. We demonstrate that gluten contacts the cells and provokes their aggregation through a mechanism involving the A-gliadin peptide 31-43. This peptide also activates the cell surface associated extracellular TG2 in the absence of calcium. Using a bioinformatics approach, we identify the possible docking sites of this peptide on the open and closed TG2 structures. Peptide docks with the closed TG2 structure near to the GTP/GDP site, by establishing molecular interactions with the same amino acids involved in stabilization of GTP binding. We suggest that it may occur through the displacement of GTP, switching the TG2 structure from the closed to the active open conformation. Furthermore, docking analysis shows peptide binding with the ß-sandwich domain of the closed TG2 structure, suggesting that this region could be responsible for the different aggregating effects of gluten shown in the presence or absence of calcium. We deduce from these data a possible mechanism of action by which gluten makes contact with the cell surface, which could have possible implications in the celiac disease onset.

Development of gliadin-specific immune responses in children with HLA-associated genetic risk for celiac disease.

OBJECTIVE: The development of gliadin-specific antibody and T-cell responses were longitudinally monitored in young children with genetic risk for celiac disease (CD). MATERIAL AND METHODS: 291 newborn children positive for HLA-DQB1*02 and -DQA1*05 alleles were followed until 3-4 years of age by screening for tissue transglutaminase autoantibodies (tTGA) by using a commercial ELISA-based kit and antibodies to deamidated gliadin peptide (anti-DGP) by an immunofluorometric assay. Eighty-five of the children were also followed for peripheral blood gliadin-specific CD4(+) T-cell responses by using a carboxyfluorescein diacetate succinimidyl ester-based in vitro proliferation assay. RESULTS: The cumulative incidence of tTGA seropositivity during the follow-up was 6.5%. CD was diagnosed in nine of the tTGA-positive children (3.1%) by duodenal biopsy at a median 3.5 years of age. All of the children with confirmed CD were both IgA and IgG anti-DGP positive at the time of tTGA seroconversion and in over half of the cases IgG anti-DGP positivity even preceded tTGA seroconversion. Peripheral blood T-cell responses to deamidated and native gliadin were detected in 40.5% and 22.2% of the children at the age of 9 months and these frequencies decreased during the follow-up to the levels of 22.2% and 8.9%, respectively. CONCLUSIONS: Anti-DGP antibodies may precede tTGA seroconversion and thus frequent monitoring of both tTGA and anti-DGP antibodies may allow earlier detection of CD in genetically susceptible children. Peripheral blood gliadin-specific T-cell responses are relatively common in HLA-DQ2-positive children and are not directly associated with the development of CD.

microRNA profiles in coeliac patients distinguish different clinical phenotypes and are modulated by gliadin peptides in primary duodenal fibroblasts.

CD (coeliac disease) is a frequent autoimmune disorder of the small bowel, which is characterized by an immunological reaction against gluten and transglutaminase in genetically predisposed subjects. However, the molecular determinants underpinning CD pathogenesis are yet to be fully elucidated and little data are available about the involvement of miRNAs (microRNAs) in CD. In the present study, the duodenal mucosa miRNA expression was profiled in adult untreated CD presenting with a classic phenotype or iron-deficiency anaemia, treated patients with or without duodenal normalization, and non-CD subjects as controls. Deregulation of seven miRNAs (miR-31-5p, miR-192-3p, miR-194-5p, miR-551a, miR-551b-5p, miR-638 and miR-1290) was determined in a larger series of CD patients with different clinical phenotypes compared with non-CD subjects. These seven microRNAs were then analysed in duodenal fibroblasts obtained from CD patients and incubated with gliadin peptides (13- and 33-mer). The miRNA cluster miR-192/194, involved in matrix remodelling, was deregulated in CD according to the different clinical presentations, and miR-192-3p levels were modulated by gliadin peptides in vitro. In conclusion, the analysis of miRNAs deserves further consideration for its potential use in the treatment and management of CD.

Wheat-dependent exercise-induced anaphylaxis: a retrospective case review from a tertiary hospital.

BACKGROUND: Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a specific form of wheat allergy caused by the combination of wheat ingestion and physical exercise and has been reported in other parts of Asia. At present, there are no published reports of WDEIA in Singapore. The objective of this study is to characterise the common local clinical and laboratory manifestations of WDEIA. METHODS: This was a retrospective descriptive study of all WDEIA who presented to a tertiary Singaporean Hospital over a 5-year-period from 1 January 2009 to 30 June 2013. RESULTS: Eight patients aged 9-41 years old were characterised. Six were males and the majority (5) was of Chinese ethnicity. An atopic history was found in four patients. The symptoms of anaphylaxis included cutaneous manifestations such as urticaria (n=7), angioedema (n=6), respiratory symptoms of dyspnoea and wheezing (n=5) and hypotension (n=5). The symptoms occurred 20-75 min after consumption of wheat-based products, often upon cessation of exercise [running (n=3), walking (n=4) and swimming (n=1)]. The WDEIA was recurrent in seven patients. The skin prick tests were positive to wheat in seven patients, and ω-5 gliadin test to wheat was positive in five patients. CONCLUSIONS: With the emergence of wheat allergy in East Asian countries, WDEIA has become an important condition for physicians and Singapore is no exception. Under-recognition combined with life-threatening symptoms warrants better public awareness measures. In addition, further studies are necessary to identify possible unique genetic and environmental exposures that could explain the inter-regional differences of WDEIA.

In Vitro Protective Effect of Pea-Derived Peptides (PPs) via the Keap1/Nrf2 Signaling Pathway on Alpha-Gliadin-Sensitizing Peptide Induced Cacao-2 Cells.

SCOPE: Celiac disease (CD) is an allergic intestinal disease caused mainly by gliadin in wheat, which is widespread in the population and currently lacks effective treatment. α-Gliadin peptides cause cellular damage by substantially increasing cellular reactive oxygen species (ROS) levels. METHODS AND RESULTS: This study investigates the protective effect of 11 pea-derived peptides (PPs) on ɑ-gliadin peptide (P31-43) treated Caco-2 cells. Results show that cells treated with PP2, PP5, and PP6 peptides significantly reduce the cell mortality caused by P31-43. Three PPs significantly reduce the P31-43-induced decrease in ROS levels to control levels, and there is no difference between them and the vitamin C (Vc) group. The results in terms of antioxidant-related enzymes show that PPs significantly decrease superoxide dismutase activity (SOD), glutathione reductases (GR), and glutathione (GSH)/oxidized glutathione (GSSG) levels, thus significantly enhancing the antioxidant level of cells. By studying the key proteins of the Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor 2 (Nrf2) pathway, it is found that PPs activate the Keap1/Nrf2 signaling pathway. CONCLUSION: The study finds that peptides from peas can effectively alleviate ɑ-gliadin peptide-induced cell damage. The discovery of these food-derived peptides provides novel potential solutions for the prevention and treatment of CD.

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.

Ex vivo gliadin stimulation of intestinal cells.

Celiac disease is an autoimmune response to gluten proteins. While causes for celiac disease have been identified, there is no effective treatment other than diet control. In vitro models for celiac disease are important for quickly gaining understanding of the disease mechanism and testing potential treatments. Here we describe an ex vivo stimulation of intestinal epithelial cells with gliadin peptides as a method to induce celiac disease features in vitro.

Tolerance to ingested deamidated gliadin in mice is maintained by splenic, type 1 regulatory T cells.

BACKGROUND & AIMS: Patients with celiac disease have permanent intolerance to gluten. Because of the high frequency of this disorder (approximately 1 in 100 individuals), we investigated whether oral tolerance to gluten differs from that to other food proteins. METHODS: Using transgenic mice that express human HLA-DQ2 and a gliadin-specific, humanized T-cell receptor, we compared gluten-specific T-cell responses with tolerogenic mucosal T-cell responses to the model food protein ovalbumin. RESULTS: Consistent with previous findings, the ovalbumin-specific response occurred in the mesenteric lymph nodes and induced Foxp3(+) regulatory T cells. In contrast, ingestion of deamidated gliadin induced T-cell proliferation predominantly in the spleen but little in mesenteric lymph nodes. The gliadin-reactive T cells had an effector-like phenotype and secreted large amounts of interferon gamma but also secreted interleukin-10. Despite their effector-like phenotype, gliadin-reactive T cells had regulatory functions, because transfer of the cells suppressed a gliadin-induced, delayed-type hypersensitivity response. CONCLUSIONS: Ingestion of deamidated gliadin induces differentiation of tolerogenic, type 1 regulatory T cells in spleens of HLA-DQ2 transgenic mice. These data indicate that under homeostatic conditions, the T-cell response to deamidated gliadin is tolerance, which is not conditioned by the mucosal immune system but instead requires interleukin-10 induction by antigen presentation in the spleen.

In vitro gliadin challenge: diagnostic accuracy and utility for the difficult diagnosis of celiac disease.

OBJECTIVES: Diagnosis of celiac disease is difficult when treatment with gluten-free diet (GFD) is started before diagnosis and/or when the results of tests are inconsistent. The objective of this study was to evaluate the in vitro gliadin challenge. METHODS: The study cohort included patients without celiac disease (negative controls, n=57), patients with celiac disease (positive controls, n=166 untreated and n=55 on GFD), and patients with difficult diagnosis (n=59). All patients underwent endoscopy for collection of duodenal samples, which served for the diagnosis of celiac disease and for the in vitro evaluation of the gliadin-induced mucosal expression of seven inflammatory markers: PY99, ICAM-1 (intercellular cell adhesion molecule), HLA-DR, CD3, CD25, CD69, and transglutaminase 2 IgA. Diagnostic work-up for celiac disease included the search of specific serum antibodies. Patients of the difficult diagnosis group were asked to stop GFD for repeated search of these antibodies under untreated conditions. The area under the receptor-operated curve (ROC) was used for statistical analyses on accuracy. RESULTS: HLA-DR had the highest accuracy for celiac disease diagnosis in analyses on negative controls and positive controls also excluding patients on GFD (area under ROC=0.99). Accuracy of test did not increase combining data of HLA-DR with data of other markers. Findings were similar in the 39 patients of the difficult diagnosis group undergoing the search celiac disease-specific antibodies under untreated conditions. CONCLUSIONS: The in vitro response of mucosal HLA-DR to gliadin is an accurate tool for the diagnosis of celiac disease also in patients with difficult diagnosis.