Diagnosis and resolution of olmesartan-associated sprue-like enteropathy confirmed by capsule endoscopy: a case report and literature review.

Herein, we describe a case of olmesartan-associated sprue-like enteropathy, in which improvement in villous atrophy was confirmed using small bowel capsule endoscopy. The patient was a 69-year-old woman who had persistent watery diarrhea (20 bowel movements/day) for 1 year and experienced a weight loss of 10 kg in the same period. Abdominal computed tomography revealed no abnormalities, and blood test results revealed no inflammatory reactions. Upper endoscopy and colonoscopy revealed villous atrophy in the duodenum and terminal ileum. As the patient was administered olmesartan for a long time and capsule endoscopy showed villous atrophy throughout the small bowel, she was diagnosed with olmesartan-associated sprue-like disease. Following the discontinuation of the medication, symptoms of diarrhea soon improved, and repeat capsule endoscopy indicated improvement in small intestinal villous atrophy. Olmesartan-associated sprue-like enteropathy should be considered a differential diagnosis in patients with severe chronic watery diarrhea. Our report is the first in which capsule endoscopy was performed multiple times over a long period for follow-up observation of improvements in the small intestine. In addition, our literature review regarding capsule endoscopy for olmesartan-associated enteritis might aid clinicians in the early diagnosis of the condition and the assessment of treatment efficacy.

Iron, vitamins and minerals status in pediatric patients with celiac diseaseand non celiac gluten sensitivity prior to diagnosis and three months later.

AIM: Pathologies associated with gluten intake are increasingly prevalent. Diagnosis of celiac disease (CD) or non-celiac gluten sensitivity (NCGS) is based on compatible clinical alterations and in case of CD on compatible serology or intestinal biopsy. The aim was to determine the values of iron, vitamins and minerals prior to diagnosis and to verify whether a gluten-free diet treatment can cause the normalization of these parameters both in patients diagnosed with celiac disease and gluten sensitivity. METHODS: Retrospective observational study from November 2016 to November 2021. 101 celiac patients and 26 with NCGS were included, all under 18 years of age. Levels of Fe, Na+ , K+ , Cl-, Ferritin, Ca2 + , P, Vitamin B12, Vitamin D and Transferrin were determined, following the quality standards of the Hospital Clínico San Carlos laboratory. Statistical software IBM SPSS Statistics v.26 was used. RESULTS: Calcium levels in celiac patients follow a positive trend after 3 months of gluten-free diet. Ferritin levels in patients with NCGS increased in a statistically significant way (p < 0.017). CONCLUSION: Calcium in the CD group increases its values after the establishment of a gluten-free diet as treatment, as well as ferritin in patients with NCGS. No significant changes were found in the rest of the analyzed parameters. This could be due to the precocity of the diagnosis thanks to a rapid clinical suspicion that determines few analytical alterations.

Subclinical Celiac Disease Unmasked by Immune Checkpoint Inhibitor Therapy.

Immune checkpoint inhibitors (ICI) are antibodies that block immune checkpoint proteins from binding with their partner proteins on cancer cells, subsequently allowing cytotoxic T-cell-associated enhancement of antitumor responses. Although ICIs have become the standard of care for various malignancies, their use is often limited by unique immune-related adverse events, including dermatologic, endocrine, inflammatory, hepatic, and gastrointestinal events. Diarrhea and colitis are common lower gastrointestinal tract immune-related adverse events, however, only a few cases have reported the association between celiac disease (CD) and ICIs. We report here a case of a 75-year-old man with new onset CD after exposure to the cytotoxic T-lymphocyte-associated antigen-4 ICI, ipilimumab. Although ICI-induced CD is relatively rare, it is essential to consider it in a genetically susceptible patient undergoing treatment with ICI. Patients with known high susceptibility to CD, such as a family history of CD, or with the ancestry of high celiac penetrance (eg, Northern Europe, North Africa, etc), dermatitis herpetiformis, or chronic bowel symptoms, we feel should have celiac panel testing before initiating ICI therapy.

Nanoparticles in the Food Industry and Their Impact on Human Gut Microbiome and Diseases.

The use of inorganic nanoparticles (NPs) has expanded into various industries including food manufacturing, agriculture, cosmetics, and construction. This has allowed NPs access to the human gastrointestinal tract, yet little is known about how they may impact human health. As the gut microbiome continues to be increasingly implicated in various diseases of unknown etiology, researchers have begun studying the potentially toxic effects of these NPs on the gut microbiome. Unfortunately, conflicting results have limited researcher's ability to evaluate the true impact of NPs on the gut microbiome in relation to health. This review focuses on the impact of five inorganic NPs (silver, iron oxide, zinc oxide, titanium dioxide, and silicon dioxide) on the gut microbiome and gastrointestinal tract with consideration for various methodological differences within the literature. This is important as NP-induced changes to the gut could lead to various gut-related diseases. These include irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), celiac disease, and colorectal cancer. Research in this area is necessary as the use of NPs in various industries continues to grow along with the number of people suffering from chronic gastrointestinal diseases.

Celiac Disease After Administration of Immune Checkpoint Inhibitors: A Case Report.

Immune checkpoint inhibitors (ICI) reinvigorate the immune system to recognize and destroy tumor cells. Because of this biological mechanism, patients might develop autoimmune toxicities, notably in the digestive tract (most frequently, hepatitis or colitis). A 70-year-old man with relapsed mesothelioma was treated with nivolumab in 3rd line. He was hospitalized for watery and foul-smelling diarrhea. He underwent gastrointestinal endoscopy, showing duodenitis and villous atrophy and measurement of serum IgA antibodies to tissue transglutaminase (tTG-IgA+), leading to the diagnosis of ICI-induced celiac disease. He was treated with steroids, proton pump inhibitors, and a gluten-free diet. If ICI-induced celiac disease is rare in the literature, increasing reports suggest that celiac disease might represent an underestimated ICI toxicity. This case highlights the necessity of complementary investigation (including tTG-IgA and endoscopic biopsies) in patients with atypical digestive symptoms during immunotherapy.

Immune checkpoint inhibitor-associated celiac disease.

BACKGROUND: Rare cases of immune checkpoint inhibitor (ICI)-associated celiac disease (ICI-CeD) have been reported, suggesting that disruption of tolerance mechanisms by ICIs can unmask celiac disease (CeD). This study aims to characterize the clinicopathological and immunophenotypic features of ICI-CeD in comparison to ICI-associated duodenitis (ICI-Duo) and usual CeD. METHODS: A medical and pathological records search between 2015 and 2019 identified eight cases of ICI-CeD, confirmed by tTG-IgA. Nine cases of ICI-Duo, 28 cases of moderate CeD, as well as 5 normal controls were used as comparison groups. Clinical information was collected from the electronic medical records. Immunohistochemistry for CD3, CD8, T-cell receptor gamma/delta (γδ), programmed death ligand 1 (PD-L1), and programmed death 1 (PD-1) were performed, with quantification of intraepithelial lymphocyte (IEL) subsets in three well-oriented villi. CD68, PD-L1, and PD-1 were assessed as a percentage of lamina propria surface area infiltrated by positive cells. Statistical significance was calculated by the Student's t-test and Fisher's exact test. RESULTS: The eight patients with ICI-CeD (F:M=1:3) and nine patients with ICI-Duo (F:M=5:4) presented similarly with diarrhea (13/17) and abdominal pain (11/17) after a median of 1.6 months on ICI therapy. In patients with ICI-CeD, tTG-IgA ranged from 104 to >300 IU/mL. Histological findings in ICI-CeD and ICI-Duo were similar and included expansion of the lamina propria, active neutrophilic duodenitis, variably increased IELs, and villous blunting. Immunohistochemistry showed that the average number of IELs per 100 enterocytes is comparable between ICI-CeD and ICI-Duo, with increased CD3+ CD8+ T cells compared with normal duodenum but decreased γδ T cells compared with CeD. Average PD-L1 percentage was 9% in ICI-CeD and 18% in ICI-Duo, in comparison to <1% in CeD and normal duodenum; average PD-1 percentage was very low to absent in all cases (<3%). On follow-up, five patients with ICI-CeD improved on a gluten-free diet (GFD) as the sole therapeutic intervention (with down-trending tTG-IgA) while the other three required immunosuppression. All patients who developed ICI-Duo received immunosuppression with variable improvement in symptoms. CONCLUSIONS: ICI-CeD resembles ICI-Duo clinically and histologically but shares the serological features and response to gluten withdrawal with classic CeD. Immunophenotyping of IELs in ICI-CeD and ICI-Duo also shows similar CD3, CD8, γδ T cell subsets, and PD-L1 populations, all of which differed quantitatively from usual CeD. We conclude that ICI-CeD is biologically similar to ICI-Duo and is likely a variant of ICI-Duo, but treatment strategies differ, with ICI-CeD often improving with GFD alone, whereas ICI-Duo requires systemic immunosuppression.

Persistent organic pollutant exposure and celiac disease: A pilot study.

Celiac disease affects approximately 1% of the population worldwide. Little is known about environmental factors that may modulate risk in genetically susceptible populations. Persistent organic pollutants (POPs) are known endocrine disruptors and, given the interplay between the endocrine and immune systems, are plausible contributors to celiac disease. The current study aims to elucidate the association between POPs and celiac disease. We conducted a single-site pilot study of 88 patients recruited from NYU Langone's Hassenfeld Children's Hospital outpatient clinic, 30 of which were subsequently diagnosed with celiac disease using standard serology and duodenal biopsy examination. Polybrominated diphenyl ether (PBDEs), perfluoroalkyl substances (PFASs), and p,p'-dichlorodiphenyldichloroethylene (DDE) and HLA-DQ genotype category were measured in blood serum and whole blood, respectively. Multivariable logistic regressions were used to obtain odds ratios for celiac disease associated with serum POP concentrations. Controlling for sex, race, age, BMI, and genetic susceptibility score, patients with higher serum DDE concentrations had 2-fold higher odds of celiac disease (95% CI: 1.08, 3.84). After stratifying by sex, we found higher odds of celiac disease in females with serum concentrations of DDE (OR = 13.0, 95% CI = 1.54, 110), PFOS (OR = 12.8, 95% CI = 1.17, 141), perfluorooctanoic acid (OR = 20.6, 95% CI = 1.13, 375) and in males with serum BDE153, a PBDE congener (OR = 2.28, 95% CI = 1.01, 5.18). This is the first study to report on celiac disease with POP exposure in children. These findings raise further questions of how environmental chemicals may affect autoimmunity in genetically susceptible individuals.

Smoking in pregnancy, cord blood cotinine and risk of celiac disease diagnosis in offspring.

Ecological observations suggest an inverse relationship between smoking in pregnancy and celiac disease (CD) in offspring. While individual-level analyses have been inconsistent, they have mostly lacked statistical power or refined assessments of exposure. To examine the association between pregnancy-related smoking and CD in the offspring, as well as its consistency across data sets, we analyzed: (1) The Norwegian Mother and Child Cohort (MoBa) of 94,019 children, followed from birth (2000-2009) through 2016, with 1035 developing CD; (2) a subsample from MoBa (381 with CD and 529 controls) with biomarkers; and (3) a register-based cohort of 536,861 Norwegian children, followed from birth (2004-2012) through 2014, with 1919 developing CD. Smoking behaviors were obtained from pregnancy questionnaires and antenatal visits, or, in the MoBa-subsample, defined by measurement of cord blood cotinine. CD and potential confounders were identified through nationwide registers and comprehensive parental questionnaires. Sustained smoking during pregnancy, both self-reported and cotinine-determined, was inversely associated with CD in MoBa (multivariable-adjusted [a] OR = 0.61 [95%CI, 0.46-0.82] and aOR = 0.55 [95%CI, 0.31-0.98], respectively); an inverse association was also found with the intensity of smoking. These findings differed from those of our register-based cohort, which revealed no association with sustained smoking during pregnancy (aOR = 0.97 [95%CI, 0.80-1.18]). In MoBa, neither maternal smoking before or after pregnancy, nor maternal or paternal smoking in only early pregnancy predicted CD. In a carefully followed pregnancy cohort, a more-detailed smoking assessment than oft-used register-based data, revealed that sustained smoking during pregnancy, rather than any smoking exposure, predicts decreased likelihood of childhood-diagnosed CD.

Clinical, laboratory, serological, and histological profile of sprue-like enteropathy associated with olmesartan use.

Olmesartan is one of the various angiotensin II antagonists currently used for the management of high blood pressure. A sprue-like enteropathy was first described in 2012 in association with this antihypertensive drug. An observational, descriptive study was carried out on a series of 12 patients who met the clinical, histopathological, and outcome criteria for olmesartan-related sprue-like enteropathy from May 2013 to December 2015. All patients had watery diarrhea, weight loss, and negative celiac serology. They all were admitted with severe illness including dehydration with prerenal kidney failure, metabolic acidosis, water-electrolyte imbalance, and malnutrition parameters. Most common laboratory abnormalities included anemia and hypoalbuminemia. Duodenal biopsy histology revealed villous atrophy in all 12 patients. They all responded well to drug discontinuation, and 100% of individuals with follow-up biopsy showed histological recovery. Olmesartan should therefore be considered a potential cause of severe diarrhea, particularly in patients with duodenal villous atrophy and negative celiac serology.

Sprue-like enteropathy linked to olmesartan.

Olmesartan is a therapy used for the management of hypertension available since 2002. A sprue like enteropathy associated with olmesartan has been first described in 2012. Endoscopic and histopathological findings are partial or total villous atrophy, mimicking a Celiac Disease. We explain two cases diagnosed in our hospital. Both patients took more than one year of treatment with olmesartan. In both cases, the biopsy showed duodenal villous atrophy, negative serology for celiac disease and they improved after stopping treatment with olmesartan. Olmesartan associate sprue-like enteropathy should be included in the differential diagnosis of seronegative villous atrophy. After the discontinuation of olmesartan, clinical remission usually occurs in every patients.

Extraintestinal manifestations of celiac disease: 33-mer gliadin binding to glutamate receptor GRINA as a new explanation.

We propose a biochemical mechanism for celiac disease and non-celiac gluten sensitivity that may rationalize many of the extradigestive disorders not explained by the current immunogenetic model. Our hypothesis is based on the homology between the 33-mer gliadin peptide and a component of the NMDA glutamate receptor ion channel - the human GRINA protein - using BLASTP software. Based on this homology the 33-mer may act as a natural antagonist interfering with the normal interactions of GRINA and its partners. The theory is supported by numerous independent data from the literature, and provides a mechanistic link with otherwise unrelated disorders, such as cleft lip and palate, thyroid dysfunction, restless legs syndrome, depression, ataxia, hearing loss, fibromyalgia, dermatitis herpetiformis, schizophrenia, toxoplasmosis, anemia, osteopenia, Fabry disease, Barret's adenocarcinoma, neuroblastoma, urinary incontinence, recurrent miscarriage, cardiac anomalies, reduced risk of breast cancer, stiff person syndrome, etc. The hypothesis also anticipates better animal models, and has the potential to open new avenues of research.

Responsive population dynamics and wide seeding into the duodenal lamina propria of transglutaminase-2-specific plasma cells in celiac disease.

A hallmark of celiac disease is autoantibodies to transglutaminase 2 (TG2). By visualizing TG2-specific antibodies by antigen staining of affected gut tissue, we identified TG2-specific plasma cells in the lamina propria as well as antibodies in the subepithelial layer, inside the epithelium, and at the brush border. The frequency of TG2-specific plasma cells were found not to correlate with serum antibody titers, suggesting that antibody production at other sites may contribute to serum antibody levels. Upon commencement of a gluten-free diet, the frequency of TG2-specific plasma cells in the lesion dropped dramatically within 6 months, yet some cells remained. The frequency of TG2-specific plasma cells in the celiac lesion is thus dynamically regulated in response to gluten exposure. Laser microdissection of plasma cell patches, followed by antibody gene sequencing, demonstrated that clonal cells were seeded in distinct areas of the mucosa. This was confirmed by immunoglobulin heavy chain repertoire analysis of plasma cells isolated from individual biopsies of two untreated patients, both for TG2-specific and non-TG2-specific cells. Our results shed new light on the processes underlying the B-cell response in celiac disease, and the approach of staining for antigen-specific antibodies should be applicable to other antibody-mediated diseases.

Effects of Gluten Intake on Risk of Celiac Disease: A Case-Control Study on a Swedish Birth Cohort.

BACKGROUND & AIMS: Early nutrition may affect the risk of celiac disease. We investigated whether amount of gluten in diet until 2 years of age increases risk for celiac disease. METHODS: We performed a 1-to-3 nested case-control study of 146 cases, resulting in 436 case-control pairs matched for sex, birth year, and HLA genotype generated from Swedish children at genetic risk for celiac disease. Newborns were annually screened for tissue transglutaminase autoantibodies (tTGA). If tested tTGA positive, time point of seroconversion was determined from frozen serum samples taken every 3 months. Celiac disease was confirmed by intestinal biopsies. Gluten intake was calculated from 3-day food records collected at ages 9, 12, 18 and 24 months. Odds ratios (OR) were calculated through conditional logistic regression. RESULTS: Breastfeeding duration (median, 32 wk) and age at first introduction to gluten (median, 22 wk) did not differ between cases and tTGA-negative controls. At the visit before tTGA seroconversion, cases reported a larger intake of gluten than controls (OR, 1.28; 95% confidence interval [CI], 1.13-1.46; P = .0002). More cases than controls were found in the upper third tertile (ie, >5.0 g/d) before they tested positive for tTGA seroconversion than controls (OR, 2.65; 95% CI, 1.70-4.13; P < .0001). This finding was similar in children homozygous for DR3-DQ2 (OR, 3.19; 95% CI, 1.61-6.30; P = .001), heterozygous for DR3-DQ2 (OR, 2.24; 95% CI, 1.08-4.62; P = .030), and for children not carrying DR3-DQ2 (OR, 2.43; 95% CI, 0.90-6.54; P = .079). CONCLUSIONS: The amount of gluten consumed until 2 years of age increases the risk of celiac disease at least 2-fold in genetically susceptible children. These findings may be taken into account for future infant feeding recommendations.

Sprue-like histology in patients with abdominal pain taking olmesartan compared with other angiotensin receptor blockers.

AIMS: A severe syndrome characterised by life-threatening diarrhoea and severe sprue-like histology has been described in patients taking the angiotensin receptor blocker (ARB) olmesartan. It is unknown whether there are any histopathological changes in patients without severe diarrhoea exposed to this medication. It is also unknown whether other ARBs cause sprue-like histology. METHODS: Retrospective cohort study of patients with abdominal pain undergoing upper gastrointestinal endoscopy with duodenal biopsy who were taking ARBs. Patients taking olmesartan (n=20) and a non-olmesartan ARB (n=20) were compared with age and sex-matched controls. Histological features (classic sprue-like and other inflammatory changes) were analysed. RESULTS: No single histopathological finding was significantly more common in olmesartan-using patients than controls. However, 10 of 20 olmesartan patients had one or more sprue-like histological features compared with 4 of 20 age-matched and sex-matched controls not taking ARBs (p=0.10). Patients taking ARBs other than olmesartan were not more likely than controls to have one or more of these sprue-like histological features (9/20 vs. 12/20, p=0.34). CONCLUSIONS: There were no statistically significant differences between olmesartan users with abdominal pain and controls for any single histopathological abnormality. However, there were trends towards significance for individual abnormalities as well as for a composite outcome of sprue-like changes. This raises the possibility that there is a spectrum of histological changes associated with olmesartan use.

[A new spruelike disease as a cause of severe diarrhea]. / Eine neue Sprue-ähnliche Erkrankung als Ursache schwerer Diarrhoe.

UNLABELLED: History and presentation at admission: A 77-years old woman presented with an 8-week history of pronounced diarrhea and weight loss of 10 kg. INVESTIGATIONS: Infectious enteritis and chronic inflammatory bowel disease were excluded. Duodenal biopsies showed villous atrophy and 50 intraepithelial lymphocytes per 100 enterocytes, but antibody testing for celiac disease was negative. TREATMENT AND COURSE: The diarrhea resolved within 2 weeks after withdrawing olmesartan, which she had received for hypertension for 5 years, without a gluten-free diet. 6 months later the histological abnormalities in the duodenum regressed markedly. A diagnosis of sprue-like enteropathy associated with olmesartan was made. CONCLUSION: The syndrome is probably rare and was first described in 2012. It should be suspected in patients on olmesartan treatment who have clinical and histological findings, but not serological markers of celiac disease.

Tolerogenic effect of mesenchymal stromal cells on gliadin-specific T lymphocytes in celiac disease.

BACKGROUND AIMS: Celiac disease is caused by a dysregulated immune response toward dietary gluten, whose only treatment is a lifelong gluten-free diet. We investigated the effects of mesenchymal stromal cells (MSCs) on gliadin-specific T cells, which are known to induce intestinal lesions, in view of a possible use as new therapy. METHODS: Bone marrow-derived MSCs and gliadin-specific T-cell lines were obtained from allogeneic donors and mucosal specimens of celiac patients, respectively. The immunosuppressant effect of MSCs was evaluated in terms of proliferative response and interferon (IFN)-γ production upon gliadin stimulation of long-term T-cell lines; the immunomodulant effect was assessed in terms of apoptotic rate, immunophenotype and cytokine profile of short-term T-cell lines generated in the presence of MSCs. Different MSC:T-cell ratios were applied, and statistics were performed as appropriate. RESULTS: MSCs inhibited both proliferative response and IFN-γ production of long-term T-cell lines in a dose-dependent manner while limiting the expansion of short-term T-cell lines by increasing the apoptotic rate. Moreover, a reduction of the CD4(+) population and expansion of the regulatory FoxP3+ subset were found in T-cell lines cultured with MSCs, in which a significant decrease of interleukin (IL)-21, IFN-γ and IL-10 paralleled by an upregulation of transforming growth factor-ß1, IL-6 and IL-8 were observed. Finally, an increase of the indoleamine 2,3-dioxygenase activity was found, possibly playing a key role in mediating these effects. CONCLUSIONS: MSCs exert potent immunomodulant effects on gliadin-specific T cells, which may be exploited for future therapeutic application in celiac disease.

Validation of morphometric analyses of small-intestinal biopsy readouts in celiac disease.

BACKGROUND: Assessment of the gluten-induced small-intestinal mucosal injury remains the cornerstone of celiac disease diagnosis. Usually the injury is evaluated using grouped classifications (e.g. Marsh groups), but this is often too imprecise and ignores minor but significant changes in the mucosa. Consequently, there is a need for validated continuous variables in everyday practice and in academic and pharmacological research. METHODS: We studied the performance of our standard operating procedure (SOP) on 93 selected biopsy specimens from adult celiac disease patients and non-celiac disease controls. The specimens, which comprised different grades of gluten-induced mucosal injury, were evaluated by morphometric measurements. Specimens with tangential cutting resulting from poorly oriented biopsies were included. Two accredited evaluators performed the measurements in blinded fashion. The intraobserver and interobserver variations for villus height and crypt depth ratio (VH:CrD) and densities of intraepithelial lymphocytes (IELs) were analyzed by the Bland-Altman method and intraclass correlation. RESULTS: Unevaluable biopsies according to our SOP were correctly identified. The intraobserver analysis of VH:CrD showed a mean difference of 0.087 with limits of agreement from -0.398 to 0.224; the standard deviation (SD) was 0.159. The mean difference in interobserver analysis was 0.070, limits of agreement -0.516 to 0.375, and SD 0.227. The intraclass correlation coefficient in intraobserver variation was 0.983 and that in interobserver variation 0.978. CD3(+) IEL density countings in the paraffin-embedded and frozen biopsies showed SDs of 17.1% and 16.5%; the intraclass correlation coefficients were 0.961 and 0.956, respectively. CONCLUSIONS: Using our SOP, quantitative, reliable and reproducible morphometric results can be obtained on duodenal biopsy specimens with different grades of gluten-induced injury. Clinically significant changes were defined according to the error margins (2SD) of the analyses in VH:CrD as 0.4 and in CD3(+)-stained IELs as 30%.

Association between ipilimumab and celiac disease.

A 62-year-old man with chemotherapy-naive, castration-resistant metastatic prostate cancer presented with refractory diarrhea despite prolonged high-dose corticosteroid treatment after receiving 3 doses of ipilimumab as part of a phase 3 clinical trial. The investigative work-up and response to a gluten-free diet essentially confirm celiac disease. Although ipilimumab-induced enterocolitis is a well-reported complication, there have been no reported cases of celiac disease with ipilimumab therapy, to our knowledge. We suspect that ipilimumab may have amplified the symptomatic presentation of previously unrecognized celiac disease or perhaps even triggered the disease itself. With ipilimumab being used more commonly in the treatment of melanoma and prostate cancer, we believe that physicians should be aware of this potential adverse outcome when evaluating a patient who experiences persistent diarrhea during or after ipilimumab treatment.

Validation of a new enzyme-linked immunosorbent assay to detect the triggering proteins and peptides for celiac disease: interlaboratory study.

The performance of Gluten-Tec (EuroProxima, Arnhem, The Netherlands) was tested through an interlaboratory study in accordance with AOAC guidelines. Gluten-Tec is a competitive ELISA that detects an immunostimulatory epitope of a-gliadin in dietary food for celiacs. Fifteen laboratories, representing 14 different countries, announced their interest in taking part in this study. Of the 12 laboratories that sent the results within the established timeframe, two submitted inappropriate standard curves and were excluded from the statistical analysis. Four different food matrixes (rice-based baby food, maize bread, chocolate cake mix, and beer) were selected for preparing the test samples. Two gliadin extraction procedures were used: the conventional 60% ethanol, and a new method based on the reducing reagent dithiothreitol. The 38 samples (19 blind duplicates) tested in this study were prepared by diluting the different extracts in order to cover a wide range of gliadin levels. Both sample extraction and dilution were performed by EuroProxima; the present interlaboratory study was focused only on testing the ELISA part of the Gluten-Tec kit protocol. Repeatability values (within-laboratory variance), expressed as RSD(r) ranged from 6.2 to 25.7%, while reproducibility values (interlaboratory variance), expressed as RSD(R), ranged from 10.6 to 45.9%. Both statistical parameters were in the acceptable range of ELISAs under these conditions, and the method will be presented to the Codex Alimentarius as a preferred method for gluten analysis.