Trace gluten contamination may play a role in mucosal and clinical recovery in a subgroup of diet-adherent non-responsive celiac disease patients

Exopeptidase combination enhances the degradation of isotopically labelled gluten immunogenic peptides in humans

Introduction

Celiac disease is a common autoimmune-like enteropathy caused by an aberrant response to incompletely digested dietary gluten. Gluten immunogenic peptides including the immunodominant 33-mer are thought to be resistant to proteolytic digestion by human gastrointestinal peptidases. We developed a novel enzyme therapy approach to support gluten peptide digestion using a combination of two tandem-acting exopeptidases, AMYNOPEP, that complement the intrinsic enzymatic activity of intestinal brush border enterocytes.

Methods

We evaluated the effects of AMYNOPEP supplementation on 33-mer degradation in vitro and in vivo. In a cross-over clinical study, healthy volunteers with no gastrointestinal disorders were given stable isotope (SI) labelled 33-mer peptides in the presence of varying peptide substrates and caloric loads, with and without AMYNOPEP. 33-mer degradation products (SI-labelled single amino acids) were measured in the blood plasma using LC-MS/MS.

Results

AMYNOPEP achieved rapid, complete amino-to-carboxyl terminal degradation of the 33-mer in vitro, generating single amino acids and dipeptides. In healthy volunteers, AMYNOPEP supplementation significantly increased 33-mer degradation and absorption of SI-labelled amino acids even in the presence of competing substrates. Specifically, we observed a 2.8-fold increase in the Cmax of stable isotope-labelled amino acids in the presence of wheat gluten. The absorption kinetics of labelled amino acids derived from 33-mer digestion with AMYNOPEP closely resembled that of SI-labelled X-Proline dipeptides administered without enzyme supplementation, highlighting the rapid hydrolytic activity of AMYNOPEP on polypeptides.

Conclusions

AMYNOPEP achieved complete degradation of the 33-mer into single amino acids and dipeptides in vitro and significantly improved 33-mer degradation kinetics in healthy volunteers, as measured by labelled amino acid detection, warranting further investigation into the potential therapeutic benefits of exopeptidase combinations for patients with gluten-related health disorders including celiac disease.

Refractory Celiac Disease: What the Gastroenterologist Should Know

Fewer than 1% of patients with celiac disease (CD) will develop refractory CD (RCD). As such, most gastroenterologists might never need to manage patients with RCD. However, all gastroenterologists must be familiarized with the basic concepts of RCD and non-responsive CD (NRCD), since it can present as a severe disease with high mortality, not only due to intestinal failure, but also due to progression to enteropathy-associated T cell lymphoma (EATL) and a higher susceptibility to life-threatening infections. The diagnostic workup and differential diagnosis with other causes of gastrointestinal symptoms and villous atrophy, as well as the differentiation between type I and II RCD, are complex, and may require specialized laboratories and reference hospitals. Immunosuppression is efficient in the milder RCDI; however, the treatment of RCDII falls short, with current options probably only providing transient clinical improvement and delaying EATL development. This review summarizes the current diagnostic and therapeutic approach for patients with RCD that all doctors that manage patients with CD should know.

Evolution in coeliac disease diagnosis and management

The traditional gut-centric view of coeliac disease is evolving as immune and genetic insights underscore the central importance of a systemic, T cell immune response to gluten in disease pathogenesis. As the field increasingly recognize the limitations of small intestinal histology as the diagnostic standard, data supporting the accuracy of an immune (serologic) diagnosis of coeliac disease - well demonstrated in children - are growing for adults. Novel biomarkers such as interleukin-2 that identify the gluten-specific T cell demonstrate high sensitivity and specificity for coeliac disease and offer the potential for a diagnostic approach that avoids the need for gluten challenge. Asymptomatic disease and manifestations outside the gut pose considerable challenges for diagnosis using a case-finding strategy and enthusiasm for population screening is growing. The gluten-free diet remains a highly restrictive treatment and there is a paucity of controlled data to inform a safe gluten intake threshold. Ongoing symptoms and enteropathy are common and require systematic evaluation. Slowly-responsive disease is prevalent in the older patient diagnosed with coeliac disease, and super-sensitivity to gluten is an emerging concept that may explain many cases of nonresponsive disease. While there is great interest in developing novel therapies for coeliac disease, no drug has yet been registered. Efficacy studies are generally assessing drugs in patients with treated coeliac disease who undergo gluten challenge or in patients with nonresponsive disease; however, substantial questions remain around specific endpoints relevant for patients, clinicians and regulatory agencies and optimal trial design. Novel immune tools are providing informative readouts for clinical trials and are now shaping their design.

Celiac Disease Affects 1% of Global Population: Who Will Manage All These Patients?

Celiac disease is a common gastrointestinal condition with an estimated global prevalence of up to 1%. Adequate long-term surveillance of patients is imperative to ensure strict adherence to treatment with a gluten-free diet and the ensuing clinical and histologic recovery. Traditionally, this has been accomplished by means of regular on-site attendance at specialist health care facilities, accompanied for most patients by follow-up endoscopic and laboratory tests. However, the rapidly increasing prevalence of celiac disease and the limited health care resources challenge the current centralized and nonindividualized follow-up strategies. The improved noninvasive surveillance tools and online health care services are further changing the landscape of celiac disease management. There is a clear need for more personalized and on-demand follow-up based on early treatment response and patient-related factors associated with long-term prognosis. Additional scientific evidence on the optimal implementation of follow-up for pediatric and adulthood celiac disease is nevertheless called for.

Nutrition Assessment and Management in Celiac Disease

Celiac disease (CeD) is the most common immune condition affecting the gastrointestinal tract; it is triggered by gluten and the only available treatment is a strict gluten-free diet (GFD). Therefore, for patients with CeD, adopting a GFD is not a lifestyle choice. The major problem is that a GFD is restrictive and, like all restrictive diets, it has the potential for adverse nutritional outcomes, especially if adopted for a long term. It is well known that GFD can be nutritionally inadequate and is frequently associated with vitamin and mineral deficiencies; it is also associated with excessive sugar and fat intake, particularly when gluten-free substitutes are consumed. Consequently, people with CeD are affected by higher rates of overweight and obesity and metabolic complications, such as fatty liver and cardiovascular disease. Therefore, assessment of nutritional status and diet quality at diagnosis and while on a long-term GFD is key in the management of CeD. This narrative review addresses nutritional considerations in CeD and management of common challenges associated with a GFD.

From an understanding of etiopathogenesis to novel therapies-what is new in the treatment of celiac disease?

Celiac disease, a chronic autoimmune disorder caused by genetic factors and exposure to gluten, is increasingly being recognized and diagnosed in both children and adults. Scientists have been searching for a cure for this disease for many years, but despite the impressive development of knowledge in this field, a gluten-free diet remains the only recommended therapy for all patients. At the same time, the increasing diagnosis of celiac disease in adults, which was considered a childhood disease in the 20th century, has opened a discussion on the etiopathology of the disease, which is proven to be very complex and involves genetic, immunological, nutritional, environmental and gut microbiota-related factors. In this review, we extensively discuss these factors and summarize the knowledge of the proposed state-of-the-art treatments for celiac disease to address the question of whether a better understanding of the etiopathogenesis of celiac disease has opened new directions for therapy.

Gluten-Free Diet and Other Celiac Disease Therapies: Current Understanding and Emerging Strategies

A lifelong gluten-free diet (GFD) is the only treatment for celiac disease and other gluten-related disorders. Nevertheless, strict adherence to the GFD is often challenging due to concerns about social isolation, risk of gluten contaminations, high cost, poor quality and the taste of gluten-free products. Moreover, although the GFD is effective in achieving mucosal healing, it may lead to dietary imbalances due to nutrient deficiencies over a long period of time. To overcome these issues, several gluten-free wheat flours have been developed to create products that closely resemble their gluten-containing counterparts. Furthermore, given the critical importance of adhering to the GFD, it becomes essential to promote adherence and monitor possible voluntary or involuntary transgressions. Various methods, including clinical assessment, questionnaires, serology for celiac disease, duodenal biopsies and the detection of Gluten Immunogenic Peptides (GIPs) are employed for this purpose, but none are considered entirely satisfactory. Since adherence to the GFD poses challenges, alternative therapies should be implemented in the coming years to improve treatment efficacy and the quality of life of patients with celiac disease. The aim of this narrative review is to explore current knowledge of the GFD and investigate its future perspectives, focusing on technology advancements, follow-up strategies and insights into a rapidly changing future.

Unraveling the Immunopathological Landscape of Celiac Disease: A Comprehensive Review

Celiac disease (CD) presents a complex interplay of both innate and adaptive immune responses that drive a variety of pathological manifestations. Recent studies highlight the role of immune-mediated pathogenesis, pinpointing the involvement of antibodies against tissue transglutaminases (TG2, TG3, TG6), specific HLA molecules (DQ2/8), and the regulatory role of interleukin-15, among other cellular and molecular pathways. These aspects illuminate the systemic nature of CD, reflecting its wide-reaching impact that extends beyond gastrointestinal symptoms to affect other physiological systems and giving rise to a range of pathological landscapes, including refractory CD (RCD) and, in severe cases, enteropathy-associated T cell lymphoma. The existing primary therapeutic strategy, a gluten-free diet (GFD), poses significant challenges, such as low adherence rates, necessitating alternative treatments. Emerging therapies target various stages of the disease pathology, from preventing immunogenic gluten peptide absorption to enhancing intestinal epithelial integrity and modulating the immune response, heralding potential breakthroughs in CD management. As the understanding of CD deepens, novel therapeutic avenues are emerging, paving the way for more effective and sophisticated treatment strategies with the aim of enhancing the quality of life of CD patients. This review aims to delineate the immunopathology of CD and exploring its implications on other systems, its complications and the development of novel treatments.

Systematic Review and Dose-Response Meta-Analysis on the Relationship between Different Gluten Doses and Risk of Coeliac Disease Relapse

Gluten proteins are known as immunological triggers for inflammation resulting in mucosal lesions in patients with coeliac disease (CD). Adherence to a strict gluten-free diet (GFD) is currently known as the only effective treatment for CD. In this study, we performed a systematic review and dose-response meta-analysis on data from previous studies to investigate the association between different gluten doses administered and the risk of CD relapse. Electronic databases were systematically searched to retrieve studies that investigated the response of CD patients to different amounts of gluten intake and evaluated the clinical, serologic, and/or histologic evidence to recognize disease relapse. Study-specific relative risks (RRs) were combined using a random effects model. A total of 440 identified published papers were screened, of which 7 records were selected following full-text reviewing and eligibility assessment for dose-response meta-analysis. According to our analysis, the risk of CD relapse is estimated to be 0.2% (RR: 1.002; 95% CI: 1.001 to 1.004) following the consumption of 6 mg gluten/day, which was increased to 7% (RR: 1.07; 95% CI: 1.03 to 1.10), 50% (RR: 1.50; 95% CI: 1.23 to 1.82), 80% (RR: 1.80; 95% CI: 1.36 to 2.38), and 100% (RR: 2.00; 95% CI: 1.43 to 2.78) by the daily intake of 150, 881, 1276, and 1505 mg gluten, respectively. Although good adherence to a GFD can adequately control CD-related symptoms, disease relapse might happen even with a very low dose of gluten, and the duration of exposure to gluten is also an important matter. The current literature has substantial limitations, such as relying on the data from just a few countries that were different in terms of the amount of gluten administered, the duration of the challenge, etc. Therefore, more randomized clinical trials using a standardized gluten challenge protocol are needed to confirm the findings of the present study.

New Developments in Celiac Disease Treatment

Celiac disease (CD) is a common autoimmune disease affecting around 1% of the population. It consists of an immune-mediated enteropathy, triggered by gluten exposure in susceptible patients. All patients with CD, irrespective of the presence of symptoms, must endure a lifelong gluten-free diet (GFD). This is not an easy task due to a lack of awareness of the gluten content in foods and the extensive incorporation of gluten in processed foods. Furthermore, a GFD imposes a sense of limitation and might be associated with decreased quality of life in CD patients. This results in gluten contamination in the diet of four out of five celiac patients adhering to a GFD. Furthermore, one in three adult patients will report persistent symptoms and two in three will not achieve full histological recovery when on a GFD. In recent years, there has been extensive research conducted in the quest to find the holy grail of pharmacological treatment for CD. This review will present a concise description of the current rationale and main clinical trials related to CD drug therapy.

The low-FODMAP diet and the gluten-free diet in the management of functional abdominal bloating and distension

This review summarizes current knowledge on the role of low-FODMAP diet and gluten-free diet in functional abdominal bloating and distension, an emerging disorder of gut-brain interaction characterized by remarkable costs for healthcare systems and a significant impact on the patient's quality of life. Ingested food plays a key role in the pathophysiology of disorders of gut-brain interaction as up to 84% of patients with irritable bowel syndrome (IBS) report food-triggered symptoms. Potential pathogenetic mechanisms of food-related symptoms in these patients are discussed, focusing on bloating and abdominal distension. These mechanisms provide the rationale for dietary treatment in patients with functional abdominal bloating and distension. The role of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) and gluten in functional abdominal bloating and distension is examined. Current literature evaluating the efficacy of the low-FODMAP diet and the gluten-free diet in abdominal bloating and distension is analyzed. Available evidence originates mainly from studies on patients with IBS, since clinical studies on selected cohorts of patients with only functional abdominal bloating and distension have been missing to date. Promising evidence on the potential efficacy of the low-FODMAP diet in functional abdominal bloating and distension is provided by the reduction of the bloating observed in patients with IBS. Regarding the gluten-free diet, there is insufficient evidence to recommend it to reduce bloating and abdominal distension. In conclusion, this review asserts the need for a close collaboration with experts in nutrition to optimize the management of these patients and reduce the risks associated with elimination diets.

Budesonide and the Gluten Containing Elimination Diet as Treatments for Non-responsive Celiac Disease in Children

OBJECTIVES

Non-responsive celiac disease (NRCD) is defined as patients having persistent symptoms and enteropathy (Marsh 3 histology) suggestive of active celiac disease (CeD), after following a gluten-free diet (GFD) for at least 12 months. NRCD is suggested to affect 15% of children with CeD but data are limited and there is no research to date describing treatment of children with this condition. The aim of this study was to describe our center's approach to identifying and treating NRCD with budesonide and the Gluten Containing Elimination Diet (GCED).

METHODS

We performed a retrospective, single center analysis over a 5-year period of patients with CD less than 18 years of age (inclusive) who underwent treatment for persistent symptoms and enteropathy despite following a GFD.

RESULTS

We identified 22 patients with NRCD. Thirteen were treated with the GCED for 3 months with 46% achieving both histological and symptomatic resolution. Nine patients were treated with budesonide (6-9 mg), with 89% achieving both symptomatic and histologic resolution after a median 3-month treatment course. Further, 67% of patients who responded to the GCED and 100% of patients who responded to budesonide remained in remission for at least 6 months following treatment transition back to exclusive GFD.

CONCLUSIONS

The GCED and budesonide can provide benefit for NRCD. Most patients with NRCD can return to a GFD after 3 months of treatment.

Novel Drug Therapeutics in Celiac Disease: A Pipeline Review

Celiac disease (CeD) is a chronic, autoimmune systemic disorder triggered by the ingestion of gluten, a protein found in foods such as wheat, rye, and barley. The only effective treatment for CeD is complete removal of gluten from the diet. A strict gluten-free diet (GFD) results in symptomatic, serologic, and histologic remission in most patients. However, GFD may fail to induce clinical or histologic improvement and some patients may alternatively have difficulty strictly adhering to the GFD for other reasons. Despite this, there are currently no FDA-approved drugs for the treatment of CeD. The complex pathogenic process of CeD is becoming increasingly studied and better understood, enabling the identification of various targets for future therapies. Mechanisms under evaluation include probiotics, digestion of peptides, gluten sensitization, tight junction modulation, deamidation, and immune targets. Multiple investigational drugs are in the pipeline, and several drug candidates have entered late-phase clinical trials. Indeed, current and future studies are needed to target specific etiological mechanisms and provide an alternative to GFD alone. This review provides a broad overview of the various investigative treatment approaches for CeD, summarizing the latest progress in the pipeline.

Guidelines of the Italian societies of gastroenterology on the diagnosis and management of coeliac disease and dermatitis herpetiformis

INTRODUCTION

Coeliac disease and dermatitis herpetiformis are immune-mediated diseases triggered by the consumption of gluten in genetically predisposed individuals. These guidelines were developed to provide general practitioners, paediatricians, gastroenterologists, and other clinicians with an overview on the diagnosis, management and follow-up of coeliac patients and those with dermatitis herpetiformis.

METHODS

Guidelines were developed by the Italian Societies of Gastroenterology. Following a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the certainty of the evidence. Statements and recommendations were developed by working groups consisting of gastroenterologists and a paediatrician with expertise in this field.

RESULTS

These guidelines provide a practical guidance for the diagnosis, management and follow-up of coeliac patients and dermatitis herpetiformis in children and adults, both in primary care and in specialist settings. We developed four sections on diagnosis, gluten-free diet, follow-up and risk of complications in adults, one section focused on diagnosis and follow-up in children and one on the diagnosis and management of dermatitis herpetiformis.

CONCLUSIONS

These guidelines may support clinicians to improve the diagnosis and management of patients with coeliac disease.

Celiac Disease in the Elderly

Purpose of review

This review highlights literature from the past several years and explores the impact on current understanding of celiac disease diagnosis, complications, and management in older adults.

Recent findings

Celiac disease in the elderly is becoming increasingly prevalent but remains underdiagnosed, with a high potential burden of downstream morbidity and modestly increased risk of mortality. Clinical presentations are often related to extraintestinal symptoms and can be subtle. Duodenal biopsy remains the gold-standard for diagnosis in older adults, along with supporting serologies. Refractory celiac disease is a particular concern in the aging population, and treatment for this rare condition remains unsatisfactory. Older adults exhibit lower rates of mucosal healing, though the reasons for this are poorly understood.

Summary

Current understanding of celiac disease in the elderly continues to advance, though significant knowledge gaps persist. Large, prospective studies are needed to further characterize celiac disease pathogenesis, complications, and management in older adults.

Food Safety and Cross-Contamination of Gluten-Free Products: A Narrative Review

A gluten-free diet (GFD) is currently the only effective treatment for celiac disease (CD); an individual’s daily intake of gluten should not exceed 10 mg. However, it is difficult to maintain a strict oral diet for life and at least one-third of patients with CD are exposed to gluten, despite their best efforts at dietary modifications. It has been demonstrated that both natural and certified gluten-free foods can be heavily contaminated with gluten well above the commonly accepted threshold of 20 mg/kg. Moreover, meals from food services such as restaurants, workplaces, and schools remain a significant risk for inadvertent gluten exposure. Other possible sources of gluten are non-certified oat products, numerous composite foods, medications, and cosmetics that unexpectedly contain “hidden” vital gluten, a proteinaceous by-product of wheat starch production. A number of immunochemical assays are commercially available worldwide to detect gluten. Each method has specific features, such as format, sample extraction buffers, extraction time and temperature, characteristics of the antibodies, recognition epitope, and the reference material used for calibration. Due to these differences and a lack of official reference material, the results of gluten quantitation may deviate systematically. In conclusion, incorrect gluten quantitation, improper product labeling, and poor consumer awareness, which results in the inadvertent intake of relatively high amounts of gluten, can be factors that compromise the health of patients with CD.

Enteric-Release Budesonide May Be Useful in the Management of Non-Responsive Celiac Disease

BACKGROUND

Non-responsive celiac disease (NRCD) has many aetiologies, including gluten exposure. Budesonide may be used for refractory celiac disease (RCD) and celiac crisis.

AIMS

We reviewed the effectiveness of budesonide to induce clinical and histologic response in NRCD with villous atrophy (VA).

METHODS

Case series of adult cases with NRCD and VA prescribed budesonide at two celiac centers. Clinical variables and mucosal recovery (i.e., normal villous architecture within 1 year of treatment) were evaluated.

RESULTS

Forty-two cases [77% female, median age 45.0 (IQR 28.3-60.0) years] were included. Most common symptoms were diarrhea (64%) and abdominal pain (62%). Budesonide was initiated at 9 mg (83%) for a median duration of 16.0 weeks (IQR 6.8-25.0 weeks). In total, 57% exhibited a clinical response, positively associated with diarrhea (adjusted OR 6.08 95% CI 1.04-35.47) and negatively with fatigue (adjusted OR 0.18 95% CI 0.03-0.98). Clinical response was higher among those with dietitian counseling prior to budesonide (n = 29, 70 vs. 23%, p < 0.01). Mucosal recovery was observed in 11/24 with follow-up duodenal biopsies. There was no association between clinical response and mucosal recovery, and 79% of clinical responders had a symptomatic relapse. RCD (48%) and chronic gluten exposure (24%) were the main suspected aetiologies of NRCD. Most individuals without a clinical response subsequently received an IBS-related diagnosis.

CONCLUSIONS

Budesonide may be effective to induce clinical response in NRCD presenting with diarrhea and VA, but clinical recurrence and lack of mucosal recovery are frequent after tapering. Other diagnoses, including coexisting IBS, may be considered in non-responders to budesonide therapy.

Detection of gluten in duplicate portions to determine gluten intake of coeliac disease patients on a gluten-free diet

This study determined the gluten content of foods and meals consumed by coeliac disease (CD) patients who adhere to a gluten-free diet, and to estimate the total daily intake of gluten of these patients. CD patients fulfilling defined inclusion criteria were preselected and approached for participation in the study. Duplicate portions (DP) of foods and mixed dishes were collected from the CD patients for evaluating complete daily food intake during two individual days. Also, for these days, written food records were completed by the participants. From each DP, a laboratory sample was prepared and analysed for its gluten concentration and total daily gluten intake was calculated. Each individual's total daily intakes of energy and macronutrients were calculated using the Dutch food composition database. In total, twenty-seven CD patients participated, seven males and twenty females, aged between 21 and 64 years. In thirty-two (6 %) of 499 food samples collected in total, more than 3 mg/kg gluten was present. In four of these thirty-two samples, the gluten concentration was above the European legal limit of 20 mg/kg and three of the four samples had a gluten-free label. The maximal gluten intake was 3·3 mg gluten/d. The gluten tolerance for sensitive CD patients (>0·75 mg/d) was exceeded on at least six out of fifty-four study days. To also protect these sensitive CD patients, legal thresholds should be re-evaluated and the detection limit of analytical methods for gluten analysis lowered.

Persistent Villous Atrophy in De Novo Adult Patients With Celiac Disease and Strict Control of Gluten-Free Diet Adherence: A Multicenter Prospective Study (CADER Study)

INTRODUCTION

A substantial proportion of adult patients with celiac disease on a gluten-free diet exhibit persistent villous atrophy, and inadvertent gluten exposure may be one of the causes. The aim of the present study was to evaluate villous atrophy persistence after 2 years on a gluten-free diet in de novo adult patients with celiac disease with strict control of gluten exposure.

METHODS

Symptomatic de novo adult patients with celiac disease were prospectively included. Clinical visits and dietary surveillance were scheduled every 6 months during a 2-year follow-up period. At each visit, fecal samples were collected and stored at -20 °C until analysis for gluten immunogenic peptides (f-GIPs). A follow-up duodenal biopsy was performed at 2 years. We evaluated the variables associated with persistent villous atrophy.

RESULTS

Seventy-six patients completed the study (36.5 ± 1.6 years, 73% women); persistent villous atrophy was observed in 40 (53%), whereas 72.5% were asymptomatic and 75% had negative serology. Detectable f-GIP >0.08 μg/g in at least 1 fecal sample was seen in 69% of patients. There were no significant differences in the median f-GIP at each visit and median area under the curve over the serial measurements between patients with persistent villous atrophy and those who recovered. On multivariate analysis, only older age was associated with persistent villous atrophy (32% for 16-30 years; 67% for >30 years; P = 0.016).

DISCUSSION

The rate of persistent villous atrophy after 2 years was high in adult patients with celiac disease on an intentionally strict gluten-free diet. Low-level ongoing inadvertent gluten exposure could be a contributing factor to persistent villous atrophy.

All Things Gluten: A Review

Gluten is a common dietary component with a complex protein structure. It forms incomplete products of digestion, which have the potential to mount an immune response in genetically predisposed individuals, resulting in celiac disease. It also has been linked with nonceliac gluten sensitivity and irritable bowel syndrome due to wheat allergy. A gluten-free diet is an effective treatment of these conditions; however, it can lead to micronutrient and mineral deficiencies and a macronutrient imbalance with higher sugar and lipid intake. Recent popularity has led to greater availability, but increasing cost, of commercially available gluten-free products.

Multidimensional Disadvantages of a Gluten-Free Diet in Celiac Disease: A Narrative Review

A gluten-free diet is the mainstay method of treatment and the prevention of celiac disease complications. However, an inadequately balanced gluten-free diet can increase the risk of obesity, negatively affect glucose and lipid metabolism, and increase the risk of the metabolic syndrome. Therefore, an adequate nutritional counselling is necessary for patients diagnosed with celiac disease in order to prevent and treat the components of the metabolic syndrome.

Molecular Biomarkers for Celiac Disease: Past, Present and Future

Celiac disease (CeD) is a complex immune-mediated disorder that is triggered by dietary gluten in genetically predisposed individuals. CeD is characterized by inflammation and villous atrophy of the small intestine, which can lead to gastrointestinal complaints, malnutrition, and malignancies. Currently, diagnosis of CeD relies on serology (antibodies against transglutaminase and endomysium) and small-intestinal biopsies. Since small-intestinal biopsies require invasive upper-endoscopy, and serology cannot predict CeD in an early stage or be used for monitoring disease after initiation of a gluten-free diet, the search for non-invasive biomarkers is ongoing. Here, we summarize current and up-and-coming non-invasive biomarkers that may be able to predict, diagnose, and monitor the progression of CeD. We further discuss how current and emerging techniques, such as (single-cell) transcriptomics and genomics, can be used to uncover the pathophysiology of CeD and identify non-invasive biomarkers.

Gluten cross-contact from common food practices and preparations

Patients with celiac disease continue to be exposed to gluten despite efforts to maintain a gluten-free diet (GFD). Gluten exposure in those with celiac disease leads to pathological changes in the small intestine that may or may not be associated with gastrointestinal distress. While several studies have investigated a GFD, little is known about sources of gluten contamination that prevent proper maintenance of such a diet by celiac patients. In this study, we investigate common food practices that could lead to gluten cross-contact. Three different practices were examined for gluten cross-contact: gluten-free foods fried in a fryer also used for gluten containing foods, gluten-free bread toasted in a toaster also used for gluten-containing bread, and popular sandwich spreads applied with a knife used on gluten-containing bread (mayonnaise, jam, and peanut butter). We used the ALLER-TEK™ Gluten ELISA test kit and the sandwich ELISA RIDASCREEN Gliadin test kit, which is endorsed for determination of gluten content and used for the evaluation of food cross-contact. Using both kits gave the advantage of using the 401.2 antibody as well as the better established R5 antibody, providing increased confidence in our results. We found these practices resulted in small amounts of gluten cross-contact, although the majority of the results (93.6%) showed no significant cross-contact. Mayonnaise and peanut butter samples were contaminated with gluten above the limit designated by the FDA as gluten-free <20 kg/mg (ppm).

Coeliac disease and noncoeliac wheat or gluten sensitivity

Coeliac disease (CD) and noncoeliac wheat or gluten sensitivity (NCWS/NCGS) are common gluten-related disorders. Both conditions can present with gastrointestinal and extraintestinal manifestations, which can be a challenge for physicians to discern between. Whilst coeliac serology and histological assessment are required for the diagnosis of CD, there are no clear biomarkers for the diagnosis of NCGS. The management of both conditions is with a gluten-free diet (GFD), although the duration, as well as strictness of adherence to a GFD in NCGS, is unclear. Adherence to a GFD in CD can also be challenging, with recent developments of noninvasive assessments, although histological assessment via duodenal biopsies remains the gold standard. The management of refractory coeliac disease remains particularly challenging, often requiring specialist input. Whilst wheat is noted to be a trigger for symptom generation in NCGS, it is unclear which components of wheat are responsible for symptom generation in this group, with further research required to elucidate the pathophysiology.

Incidence of Celiac Disease in Down Syndrome: A Longitudinal, Population-Based Birth Cohort Study

American Academy of Pediatrics (AAP) guidelines for children with Down syndrome (DS) include assessment for celiac disease (CD), although data to support this recommendation have been inconsistent. We determined the incidence of CD among children with DS in a population-based birth cohort of children born from 1976 to 2000 in Olmsted County, Minnesota. Individuals with karyotype-confirmed DS and CD (using diagnosis codes, positive serology, and duodenal biopsies) were identified. The incidence of CD in DS was compared with the published incidence of CD for Olmsted County residents (17.4 [95% confidence interval = 15.2-19.6] per 100 000 person-years). Among 45 individuals with DS from the birth cohort, 3 (6.7%) were identified with positive celiac serology and confirmatory biopsies at ages 9, 12, and 23 years, for an incidence of 325 per 100 000 person-years. Thus, individuals with DS have more than 18 times the incidence rate of CD compared with the general population, supporting the AAP guidelines.

Should the Glu Be Ten or Twenty? An Update on the Ongoing Debate on Gluten Safety Limits for Patients with Celiac Disease

The only currently accepted and recommended treatment for individuals diagnosed with celiac disease (CD) is a strict life-long gluten-free diet (GFD). While the use of the GFD is well-established, strict adherence to diet is not easy to accomplish. In addition, the administration of a GFD may be compromised by inadvertent exposure to small amounts of gluten. International guidelines define a gluten-free product as one containing less than 20 parts per million (ppm), (20 milligrams of gluten per 1 kg of food) gluten. A number of reports have assessed the safe upper limit for gluten exposure for patients with CD, with general consensus that patients with CD should limit their daily intake to less than 50 mg.

Refractory coeliac disease: what should we be doing different?

PURPOSE OF REVIEW

The aim of this review is to provide insight into the diagnosis and management of patients with refractory coeliac disease (RCD) and highlight recent advances in this field.

RECENT FINDINGS

The diagnosis of RCD can be more accurately confirmed with flow cytometry in addition to immunohistochemistry. Dietary input and excretion of gluten immunogenic peptides can help rule out gluten contamination, and therefore, substantiate a diagnosis of RCD type I. Small bowel capsule endoscopy (SBCE) is important at diagnosis and follow-up in addition to duodenal histology. Apart from ruling out complications, it can give information on extent of disease in the small bowel, and therefore, help assess response to therapy. Those patients with a poor response can have earlier intensification of therapy, which may result in an improved outcome. RCD also occurs in patients with serology negative coeliac disease but with an increased mortality compared with patients with serology-positive coeliac disease.

SUMMARY

Patients with RCD can present with persistent symptoms of malnutrition but can also be completely asymptomatic. Serology is not a reliable marker to detect refractory disease. Immunostaining and flow cytometry are necessary for a diagnosis of RCD. Small bowel endoscopy enables disease extent to be assessed and allows for small bowel biopsies to be taken in case of suspicious lesions. Small bowel radiology can be complementary to small bowel endoscopy.

Gluten contamination in labelled and naturally gluten-free grain products in southern India

Consumption of a gluten-free diet or avoiding exposure to gluten is the only feasible and effective treatment available for coeliac patients to date. Although many grains and their products are naturally gluten-free, the possibility of gluten cross-contamination must be considered. Since such data are not available for Indian markets, we carried out this pilot study (n = 160) to assess gluten contamination in various grain-based food products from the category of breakfast products, flours, and batters made from grain that are naturally gluten free. The gluten was extracted from samples using 60% ethanol and gluten analysis was carried out using a commercially available competitive ELISA, which utilises a monoclonal antibody. Nearly 9.8% of the products labelled as gluten-free and 36.7% of the products made from naturally gluten-free grain were found to contain gluten above 20 mg/kg. Among products made from naturally gluten-free grain, 35.9% of the flour samples and 85% of the oat samples (11.67-1830 mg/kg) were contaminated with gluten. In the case of flours, unbranded samples collected from local markets (70%) and directly from local mills (30%) showed gluten content above Codex safety levels (20-400 mg/kg). Among products labelled as gluten free (n = 51), only 5 samples showed gluten contamination above 20 mg/kg although levels were well within 100 mg/kg (32.5 ± 5.8). Our study suggests that there is a likelihood of gluten contamination in products that are sourced from local retailers and millers.

Phenotypic shift of small intestinal intra-epithelial type 1 innate lymphoid cells in celiac disease is associated with enhanced cytotoxic potential

The small intestinal (SI) epithelium harbors a heterogeneous population of lymphocytes that mediate mucosal damage and repair in celiac disease (CD). The composition and roles of human proximal SI intra-epithelial innate lymphoid cells (ILCs), and their alterations in CD, are not well understood. We report that duodenal intra-epithelial ILCs predominantly consist of natural killer (NK)p44⁺ CD127^- cytotoxic ILC1s and NKp44^- CD127⁺ helper ILC1s, while ILC3s only represent a minor population. In patients with newly diagnosed or active CD (ACD) and refractory CD type 1 (RCD I), the frequency of SI NKp44⁺ ILCs is decreased, with restoration of NKp44⁺ ILC frequency observed in patients adhering to a gluten-free diet who show evidence of mucosal healing. Moreover, the frequency of SI NKp44^- ILCs is increased in ACD and RCD I patients and correlates with the severity of villous atrophy and epithelial damage, as assessed by serum levels of fatty acid binding protein 2 (FABP2). We show that the ILC alterations in CD represent a phenotypic shift of cytotoxic ILC1s rather than an increase in helper ILC1s or transdifferentiation of ILC1s to ILC3s, and activation-induced loss of NKp44 by cytotoxic ILC1s is associated with increased interferon (IFN)-γ expression and release of lytic granules. These findings suggest that intra-epithelial NKp44^- CD127^- cytotoxic ILC1s may contribute to mucosal damage in CD.

Nutrition Assessment, Interventions, and Monitoring for Patients with Celiac Disease: An Evidence Analysis Center Scoping Review

The objectives of this scoping review were to identify and characterize studies examining nutrition assessment, interventions, and measures to monitor gluten-free diet (GFD) adherence/compliance in patients with celiac disease (CD). An electronic literature search of four databases (Cochrane Database for systematic reviews, CINAHL, Embase, and Ovid MEDLINE) was conducted to identify articles examining nutrition care in CD individuals. Except for narrative review, grey literature, and case study/report, all types of peer-reviewed articles published between January 2007 and August 2018 were eligible. There were a total of 10,823 records; 10,368 were excluded during the first round of screening due to irrelevancy and/or duplication. Of the 455 full-text articles that were assessed, 292 met the criteria and were included. Most of the studies were observational studies (n=212), followed by experimental trials (n=50), evidence-based practice guideline (EBPG)/report/statement (n=16), and systematic review (SR) (n=14). Nine original studies examined assessment, focusing mainly on different tools/ways to assess GFD adherence. The majority of the included original articles (n=235) were in the nutrition intervention category with GFD, oats, and prebiotics/probiotics as the top-three most studied interventions. There were eight SRs on GFD and five on oats. One SR and 21 original studies investigated the effectiveness of different measures to monitor GFD adherence/compliance. Although recent CD EBPGs were identified, different methods with varying levels of rigor, in terms of literature search and assessment of evidence strength, were used. Based on this scoping review, interventions focused on gluten-free diet and oats have been significantly covered by either SRs or EBPGs. Studies related to prebiotics/probiotics and education program/counseling focused interventions, as well as assessment, in CD patients have increased in recent years. Thus, it might be beneficial to conduct SRs/EBPGs focused on these topics to guide practitioners.

Non-Responsive Coeliac Disease: A Comprehensive Review from the NHS England National Centre for Refractory Coeliac Disease

Coeliac disease is a common small intestinal enteropathy which manifests following ingestion of gluten in genetically susceptible individuals. Since gluten was identified as the driving factor in coeliac disease, the gluten-free diet (GFD) has remained the mainstay of treatment. While most individuals will display improvement in symptoms and signs of coeliac disease following institution of the GFD, up to 30% will continue to experience symptoms and/or have persisting intestinal inflammation. These individuals can be classified as having non-responsive coeliac disease (NRCD), which may be associated with dietary indiscretion, slow healing, refractory coeliac disease, and/or an alternative condition. The purpose of this review is to provide an overview of the causes of NRCD in adults, highlight a systematic approach to investigate these patients, and appraise the latest management aspects of this subset of coeliac disease.

High-Protein Nutritious Flatbreads and an Option for Gluten-Sensitive Individuals

Whole grain quinoa and wheat, high-protein vegetable flatbreads were evaluated by tasters and a physical analysis was conducted. The objective was to produce nutritious, tasty gluten-free (quinoa) as well as gluten-containing (wheat) flatbreads. Flatbreads were Quinoa Peanut Oilcake Broccoli (QPCBROC), Wheat Peanut Oilcake Broccoli (WPCBROC), Quinoa Peanut Oilcake Beets (QPCBEET) and Wheat Peanut Oilcake Beets (WPCBEET). Peanut Oilcake would increase protein and add value to this farm byproduct. Bile acid binding broccoli and beets with cholesterol-lowering potential were used. Tasters preferred QPCBROC flatbreads for all sensory parameters. Acceptance of flatbreads was QPCBROC (83%), WPCBROC (70%), QPCBEET (78%) and WPCBEET (69%); these values were statistically similar. The objective of ≥25% protein content was exceeded by 5–8% and that of ≥70% acceptance was adequately achieved. These flatbreads were low in fat (5–6%) and contained essential minerals (4%) with only ≤1% added salt. Porosity and expansion data suggest that these flatbreads would take up relatively little shelf space. These flatbreads require only three ingredients and can be made in a household kitchen or by commercial production. These flatbreads offer a nutritious, tasty choice for all, and quinoa flatbreads offer an option for gluten-sensitive individuals.

Accidental Gluten Contamination in Traditional Lunch Meals from Food Services in Brasilia, Brazil

This study aimed to evaluate the occurrence of gluten contamination in naturally gluten-free meals from food services in the Federal District, Brazil. This is an exploratory cross-sectional quantitative study in which a total of 180 samples of naturally gluten-free dishes were collected from 60 food services in Brazil. The enzyme-linked immunosorbent assay was used for the quantification of gluten. As established by the Codex Alimentarius, the threshold of 20 ppm of gluten was considered as the accepted upper gluten level for gluten-free food. A total of 2.8% (95% CI: 0.3-5.2%) gluten contamination was found in the samples. Among the 60 food services, 6.7% (95% CI: 2.7-10.6%) displayed at least one contaminated food in our sample. The occurrence of gluten contamination in naturally gluten-free preparations was uncommon and low on a quantitative basis.

How to manage adult coeliac disease: perspective from the NHS England Rare Diseases Collaborative Network for Non-Responsive and Refractory Coeliac Disease

Adult coeliac disease (CD) affects approximately 1% of the population. Most patients diagnosed will respond to a gluten-free diet; however, up to 30% may have persisting symptoms. Such patients may have ongoing issues associated with adherence, non-responsive CD or refractory CD. This article provides a clinical overview of how to manage this group of patients with persisting symptoms, including an investigational algorithm and details of how to contact the National Health Service England Rare Diseases Collaborative Network for Non-Responsive and Refractory Coeliac Disease. We hope this will be a valuable source of contemporary information for all UK gastroenterologists and internationally.

New/Revised Entities in Gastrointestinal Lymphoproliferative Disorders

The gastrointestinal tract is a common extranodal site of involvement by lymphomas. These may be diagnostically challenging because they can mimic a variety of benign conditions and may be difficult to subclassify when malignant. The classification of gastrointestinal lymphomas is an evolving area with some recent changes. Although some of these entities are rare, they are important to recognize because of the variable clinical presentations, comorbidities, and treatment implications. This article explores new and revised entities in gastrointestinal lymphoproliferative disorders.

Detection of Gluten in Gluten-Free Labeled Restaurant Food: Analysis of Crowd-Sourced Data

INTRODUCTION

Adherence to a gluten-free (GF) diet is the mainstay of therapy for celiac disease. Until now, those wishing to avoid gluten in restaurants had to rely on menu labels, word of mouth, intuition, and restaurant workers' advice, with a relative dearth of supporting data. We used crowd-sourced data from users of a portable gluten detection device to estimate rates of, and identify risk factors for, gluten contamination of supposed GF restaurant foods.

METHODS

We analyzed data from a portable gluten detection device (Nima), collected across the United States during an 18-month period by users who opted to share the results of their point-of-care tests. Data were sorted by region, time of day, median household income in the restaurant's vicinity, restaurant genre, and food items. We used the χ test for bivariate analysis and multiple logistic regression for multivariate analysis to identify predictors of gluten detection in restaurant food.

RESULTS

There were 5,624 tests, performed by 804 users, in the examined period. Gluten was detected in 32% of GF labeled foods. Rates of gluten detection differed by meal, with 27.2% at breakfast and 34.0% at dinner (P = 0.0008). GF labeled pizza and pasta were most likely to test positive for gluten, with gluten detected in 53.2% of pizza and 50.8% of pasta samples. On multivariate analysis, GF labeled food was less likely to test positive for gluten in the West than in the Northeast United States (odds ratio 0.80; 95% confidence interval 0.67-0.95).

CONCLUSIONS

This study of crowd-sourced data suggests that a substantial fraction of GF labeled restaurant foods contain detectable gluten. Although the highly sensitive Nima device may detect gluten at levels <20 parts per million (ppm), leading to gluten exposure of unknown clinical significance, our findings raise a potential concern. In addition, our findings of higher rates of gluten detection in pizza and pasta provide practical data when providing dining strategies for patients with celiac disease.

Gluten immunogenic peptide excretion detects dietary transgressions in treated celiac disease patients

BACKGROUND

Life-long removal of gluten from the diet is currently the only way to manage celiac disease (CeD). Until now, no objective test has proven useful to objectively detect ingested gluten in clinical practice. Recently, tests that determine consumption of gluten by assessing excretion of gluten immunogenic peptides (GIP) in stool and urine have been developed. Their utility, in comparison with conventional dietary and analytical follow-up strategies, has not been fully established.

AIM

To assess the performance of enzyme-linked immunosorbent assay (ELISA) and point-of-care tests (PoCTs) for GIP excretion in CeD patients on gluten-free diet (GFD).

METHODS

We conducted an observational, prospective, cross-sectional study in patients following a GFD for at least two years. Using the Gastrointestinal Symptom Rating Scale questionnaire, patients were classified at enrollment as asymptomatic or symptomatic. Gluten consumption was assessed twice by 3-d dietary recall and GIP excretion (by ELISA in stool and PoCTs (commercial kits for stool and urine) in two consecutive samples. These samples and dietary reports were obtained 10 day apart one from the other. Patients were encouraged to follow their usual GFD during the study period.

RESULTS

Forty-four patients were enrolled, of which 19 (43.2%) were symptomatic despite being on a GFD. Overall, 83 sets of stool and/or urine samples were collected. Eleven out of 44 patients (25.0%) had at least one positive GIP test. The occurrence of at least one positive test was 32% in asymptomatic patients compared with 15.8% in symptomatic patients. GIP was concordant with dietary reports in 65.9% of cases (Cohen´s kappa: 0.317). PoCT detected dietary indiscretions. Both ELISA and PoCT in stool were concordant (concomitantly positive or negative) in 67 out of 74 (90.5%) samples. Excretion of GIP was detected in 7 (8.4%) stool and/or urine samples from patients considered to be strictly compliant with the GFD by dietary reports.

CONCLUSION

GIP detects dietary transgressions in patients on long-term GFD, irrespective of the presence of symptoms. PoCT for GIP detection constitutes a simple home-based method for self-assessment of dietary indiscretions.

Nutritional Considerations of the Gluten-Free Diet

Celiac disease (CD) is an autoimmune-related disease causing inflammation in the small intestine triggered by the ingestion of gluten in the diet. The gluten-free diet (GFD) is the only treatment. Nutritional deficiencies of macronutrients and micronutrients are frequently found in untreated or newly diagnosed CD. A registered dietitian nutritionist is uniquely qualified to educate on the GFD and assess and support nutritional status at diagnosis and long term as well as helping patients with nonresponsive CD. Quality of life is important to address in individuals with CD because the GFD affects all aspects of life.

Gluten in Celiac Disease-More or Less?

To date, the only known effective treatment for celiac disease is a strict gluten-free diet for life. We reviewed the literature to evaluate the upper limit for gluten content in food, which would be safe for patients with celiac disease. Patients with celiac disease should limit their daily gluten intake to no more than 10-50 mg. Most health authorities define gluten-free products as containing less than 20 parts per million gluten.

Pathogenesis of Enteropathy-Associated T Cell Lymphoma

PURPOSE OF REVIEW

To provide an update on the pathogenesis of enteropathy-associated T cell lymphoma (EATL) and its relationship with refractory celiac disease (RCD), in light of current knowledge of immune, genetic, and environmental factors that promote neoplastic transformation of intraepithelial lymphocytes (IELs).

RECENT FINDINGS

EATL frequently evolves from RCD type II (RCD II) but can occur "de novo" in individuals with celiac disease. Recurrent activating mutations in members of the JAK/STAT pathway have been recently described in EATL and RCD II, which suggests deregulation of cytokine signaling to be an early event in lymphomagenesis. Intraepithelial T cells are presumed to be the cell of origin of EATL (and RCD II). Recent in vitro molecular and phenotypic analyses and in vivo murine studies, however, suggest an origin of RCD II from innate IELs (NK/T cell precursors), which could also be the cell of origin of RCD II-derived EATL. The immune microenvironment of the small intestinal mucosa in celiac disease fosters the development of EATL, often in a multistep pathway.

Gluten-Free Diet in Celiac Disease-Forever and for All?

The gluten-free diet is the only effective treatment available for celiac disease. However, it is difficult to adhere to and a closer look on the diet’s implementation and indications reveals several ambiguities: Not only is there controversy on the threshold of gluten that can be tolerated in the frame of a strict gluten-free diet, but it is also unclear whether the gluten-free diet is an appropriate treatment in patient subgroups with asymptomatic or potential celiac disease. Reports from a number of research groups suggest that a certain proportion of patients may effectively develop tolerance to gluten and thus become suitable for gluten reintroduction over time. In this review, we set out to create an overview about the current state of research as regards the definition of a strict gluten-free diet in terms of the gluten thresholds considered tolerable and the indication for a gluten-free diet in the absence of histological abnormalities or symptoms. Furthermore, we discuss the concept that a gluten-free diet must be followed for life by all patients.

Mood Disorders and Gluten: It's Not All in Your Mind! A Systematic Review with Meta-Analysis

Gluten elimination may represent an effective treatment strategy for mood disorders in individuals with gluten-related disorders. However, the directionality of the relationship remains unclear. We performed a systematic review of prospective studies for effects of gluten on mood symptoms in patients with or without gluten-related disorders. Six electronic databases (CINAHL, PsycINFO, Medline, Web of Science, Scopus and Cochrane Library) were searched, from inception to 8 August 2018, for prospective studies published in English. Meta-analyses with random-effects were performed. Three randomised-controlled trials and 10 longitudinal studies comprising 1139 participants fit the inclusion criteria. A gluten-free diet (GFD) significantly improved pooled depressive symptom scores in GFD-treated patients (Standardised Mean Difference (SMD) -0.37, 95% confidence interval (CI) -0.55 to -0.20; p < 0.0001), with no difference in mean scores between patients and healthy controls after one year (SMD 0.01, 95% CI -0.18 to 0.20, p = 0.94). There was a tendency towards worsening symptoms for non-coeliac gluten sensitive patients during a blinded gluten challenge vs. placebo (SMD 0.21, 95% CI -0.58 to 0.15; p = 0.25). Our review supports the association between mood disorders and gluten intake in susceptible individuals. The effects of a GFD on mood in subjects without gluten-related disorders should be considered in future research.

Cross-Contamination with Gluten by Using Kitchen Utensils: Fact or Fiction?

A risk of cross-contamination exists when preparing a gluten-free (GF) meal in kitchen facilities that usually handle gluten-containing (GC) foods. Cross-contamination with gluten may occur during the preparation or cooking process; however, published data are lacking on gluten cross-contamination from kitchenware. This study was conducted to determine whether cross-contamination occurs through shared domestic kitchenware and, if so, which cleaning method is most reliable for avoiding this cross-contamination. Kitchenware (wooden spoon, colander, ladle, and knife) previously used to cook and/or prepare GC foods was used for the preparation of GF foods (bread and pasta). The gluten concentration of the GF foods was then determined using an established enzyme-linked immunosorbent assay. A PCR assay was also used to detect the presence of wheat ω-gliadin DNA in the food samples. Three cleaning methods were assessed to determine the concentrations of gluten and wheat DNA in GF foods cooked with utensils cleaned directly after the preparation of GC foods. Contrary to our expectations, gluten was not detected in relevant and quantifiable amounts in our samples (<20 mg/kg). The cleaning method used did not influence gluten concentrations: all samples contained <10 mg/kg. Based on PCR analyses, the only sample with lower cycle threshold ( C_T) values (i.e., higher concentration of wheat DNA) was from the contaminated ladle used to serve GF pasta. This outcome led to the hypothesis that shared ladles pose a higher risk for contamination of GF foods than do shared wooden spoons, colanders, or knives. Cross-contamination with gluten in a kitchen environment may occur, but kitchen utensils used for preparing GC pasta and for cutting GC bread should not pose a relevant problem to patients with celiac disease, at least in a domestic environment.