Masked bolus gluten challenge low in FODMAPs implicates nausea and vomiting as key symptoms associated with immune activation in treated coeliac disease

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.

Clinical Presentation and Spectrum of Gluten Symptomatology in Celiac Disease

Views on the clinical presentation and symptomatology of celiac disease have evolved alongside advances in disease detection and understanding of disease pathogenesis. Although historically regarded as a pediatric illness characterized by malabsorption, it is now better viewed as an immune illness of gluten-specific T cells with systemic manifestations affecting all ages. Its broad presentation, including frequent extraintestinal manifestations and asymptomatic disease, contributes to suboptimal disease detection. Adverse symptoms greatly impact patient quality of life and can result from chronic gluten exposure in untreated disease or those poorly responsive to the gluten-free diet. They can also present as acute symptoms after episodic gluten exposure. Functional gastrointestinal disease is a common comorbidity. Biomarkers like interleukin-2 that are highly sensitive and specific for celiac disease highlight a role for gluten-specific T cells in acute gluten symptomatology. A mechanistic understanding of symptoms will inform approaches to better measure and treat them effectively.

Development and validation of a brain fog scale for coeliac disease

BACKGROUND

Brain fog is a subjective cognitive impairment commonly reported in coeliac disease. A standardised tool to define and assess it is an important unmet need.

AIMS

To develop a patient-informed tool to assess brain fog in coeliac disease to support clinical care, research and drug development.

METHODS

A pilot online study defined patient descriptors of brain fog. A second study evaluated the factor structure and performance of the scale across two-time points ('Now' and in the 'Past week'). One month later, participants were invited to repeat the study with two online cognitive processing tests, the Stroop task and the trail making test.

RESULTS

Among adults with treated coeliac disease, 37 (91.9% F) participated in the pilot study and 510 (88.8% F) in the second study of whom 99 repeated the study 1 month later with 51 completing cognitive testing. The most common brain fog descriptors were 'difficulty focusing', 'difficulty thinking' and 'difficulty finding the right words and communicating'. The 12-item scale reflects 'cognitive impairment' and 'somatic and affective experience' and demonstrates strong psychometric properties. It tracked with patients report of brain fog being present or absent across two-time points. It did not significantly correlate with the cognitive tests.

CONCLUSION

The brain fog assessment and severity scale is the first patient-informed clinical outcomes assessment tool measuring brain fog in coeliac disease. It is brief and validated for two time-based formats. Further research coupling it with biomarker discovery is needed to confirm its validity as a predictor of cognitive performance.

Tolerance-inducing therapies in coeliac disease - mechanisms, progress and future directions

Coeliac disease is an autoinflammatory condition caused by immune reactions to cereal gluten proteins. Currently, the only available treatment for the condition is a lifelong avoidance of gluten proteins in the diet. There is an unmet need for alternative therapies. Coeliac disease has a strong association with certain HLA-DQ allotypes (DQ2.5, DQ2.2 and DQ8), and these disease-associated HLA-DQ molecules present deamidated gluten peptides to gluten-specific CD4+ T cells. The gluten-specific CD4+ T cells are the drivers of the immune reactions leading to coeliac disease. Once established, the clonotypes of gluten-specific CD4+ T cells persist for decades, explaining why patients must adhere to a gluten-free diet for life. Given the key pathogenic role of gluten-specific CD4+ T cells, tolerance-inducing therapies that target these T cells are attractive for treatment of the disorder. Lessons learned from coeliac disease might provide clues for treatment of other HLA-associated diseases for which the disease-driving antigens are unknown. Thus, intensive efforts have been and are currently implemented to bring an effective tolerance-inducing therapy for coeliac disease. This Review discusses mechanisms of the various approaches taken, summarizing the progress made, and highlights future directions in this field.

Stool Gluten Peptide Detection Is Superior to Urinary Analysis, Coeliac Serology, Dietary Adherence Scores and Symptoms in the Detection of Intermittent Gluten Exposure in Coeliac Disease: A Randomised, Placebo-Controlled, Low-Dose Gluten Challenge Study

Monitoring adherence to a gluten-free diet is an important goal of coeliac disease management. Urine and stool gluten immunogenic peptide (GIP) assays provide an objective readout of gluten ingestion, with the former favoured due to its convenience and acceptability. This study assessed stool GIP excretion after low-dose gluten challenge designed to mimic accidental gluten exposure. A total of 52 coeliac participants undertook a randomised, double-blind gluten (50-1000 mg) or placebo challenge. Stool and urinary GIP, serology, dietary adherence and symptoms were assessed. Stool GIP was 100% sensitive for gluten intake ≥250 mg and 71% for 50 mg. Peak GIP detection was 12-36 h after gluten exposure. The mean stool GIP after 1000 mg gluten ingestion remained above the limit of quantification for 5 days. Urine GIP assessment had poor sensitivity for GIP excretion compared to stool. Serology, dietary adherence score and symptoms did not correlate with gluten excretion during lead-in. We conclude that stool GIP detection is highly sensitive, with levels related to gluten dose and time from ingestion. Weekly or bi-weekly testing will detect low-level exposure more effectively than urine GIP assessments or traditional methods. In this seronegative, apparently well-treated cohort, a high frequency of baseline-positive GIP suggests ongoing gluten exposure, but the assessment of patient behaviour and assay specificity is needed.

Standardizing Randomized Controlled Trials in Celiac Disease: An International Multidisciplinary Appropriateness Study

BACKGROUND & AIMS

There is a need to develop safe and effective pharmacologic options for the treatment of celiac disease (CeD); however, consensus on the appropriate design and configuration of randomized controlled trials (RCTs) in this population is lacking.

METHODS

A 2-round modified Research and Development/University of California Los Angeles Appropriateness Method study was conducted. Eighteen gastroenterologists (adult and pediatric) and gastrointestinal pathologists voted on statements pertaining to the configuration of CeD RCTs, inclusion and exclusion criteria, gluten challenge, and trial outcomes. Two RCT designs were considered, representing the following distinct clinical scenarios for which pharmacotherapy may be used: trials incorporating a gluten challenge to simulate exposure; and trials evaluating reversal of histologic changes, despite attempted adherence to a gluten-free diet. Each statement was rated as appropriate, uncertain, or inappropriate, using a 9-point Likert scale.

RESULTS

For trials evaluating prevention of relapse after gluten challenge, participants adherent to a gluten-free diet for 12 months or more with normal or near-normal-sized villi should be enrolled. Gluten challenge should be FODMAPS (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) free, and efficacy evaluated using histology with a secondary patient-reported outcome measure. For trials evaluating reversal of villus atrophy, the panel voted it appropriate to enroll participants with a baseline villus height to crypt depth ratio ≤2 and measure efficacy using a primary histologic end point. Guidance for measuring histologic, endoscopic, and patient-reported outcomes in adult and pediatric patients with CeD are provided, along with recommendations regarding the merits and limitations of different end points.

CONCLUSIONS

We developed standardized recommendations for clinical trial design, eligibility criteria, outcome measures, gluten challenge, and disease evaluations for RCTs in patients with CeD.

A Clinician's Guide to Gluten Challenge

Gluten challenge is an essential clinical tool that involves reintroducing or increasing the amount of gluten in the diet to facilitate diagnostic testing in celiac disease (CD). Nevertheless, there is no consensus regarding the applications of gluten timing, dosing, and duration in children. This review aims to summarize the current evidence, discuss practical considerations, and proposes a clinical algorithm to help guide testing in pediatric patients. Childhood development, social circumstances, and long-term health concerns must be considered when identifying a candidate for gluten challenge. Based on previous studies, the authors suggest baseline serology followed by a minimum of 3-6 grams of gluten per day for over 12 weeks to optimize diagnostic accuracy for evaluation of CD. A formal provider check-in at 4-6 weeks is essential so the provider and family can adjust dosing or duration as needed. Increasing the dose of gluten further may improve diagnostic yield if tolerated, although in select cases a lower dose and shorter course (6-12 weeks) may be sufficient. There is consensus that mild elevations in celiac serology (<10 times the upper limit of normal) or symptoms, while supportive are not diagnostic for CD. Current North American Society for Pediatric Gastroenterology, Hepatology and Nutrition guidelines recommend histologic findings of intraepithelial lymphocytosis, crypt hyperplasia, and villous atrophy as the accurate and most appropriate endpoint for gluten challenge.

Prevalence of vomiting and nausea and associated factors after chronic and acute gluten exposure in celiac disease

BACKGROUND

Vomiting and nausea seem to be relatively specific symptoms related to gluten ingestion in treated celiac disease. However, the overall prevalence and associated factors of these symptoms after chronic gluten exposure at celiac disease diagnosis and acute re-exposure during gluten challenge remain obscure.

METHODS

Medical data on 815 adult celiac disease patients were collected at diagnosis from the medical records and through supplementary interviews. An additional 74 patients underwent a three-day (10 g/day) gluten challenge (wheat, barley, rye or a combination of the three grains) while in remission. Prevalence of vomiting/nausea and associated factors were evaluated in both cohorts. A literature review was conducted to summarize earlier studies.

RESULTS

Twenty-eight (3%) patients presented with vomiting at diagnosis. They were less often screen-detected and suffered from extra-intestinal symptoms, and had more often abdominal pain (71% vs. 49%, p = 0.021), diarrhea (61% vs. 40%, p = 0.031), weight loss (36% vs. 17%, p = 0.019) and childhood symptoms (61% vs. 33%, p = 0.002) than those without vomiting (n = 787). The groups were comparable in other clinical-demographic data and in genetic, serological, and histological findings. Short-term gluten challenge provoked vomiting/nausea in 14/74 (19%) patients. They consumed gluten-free oats less often than those without these symptoms (64% vs. 92%, p = 0.017), whereas the groups did not differ in clinical-demographic features at diagnosis, presence of comorbidities, duration of gluten-free diet, or in other symptoms or grain used ingested during the challenge. According to the literature, prevalence of vomiting/nausea at celiac disease diagnosis has varied 3-46% and during gluten challenge 13-61%.

CONCLUSIONS

In chronic gluten exposure at celiac disease diagnosis, vomiting was associated with other gastrointestinal symptoms and onset of symptoms already in childhood, whereas regular consumption of oats may increase the tolerance against vomiting/nausea after acute re-exposure in treated celiac disease.

The role of gluten challenge in the diagnosis of celiac disease: a review

INTRODUCTION

Duodenal biopsy is the gold standard in the diagnosis of celiac disease, with increasing utilization of serology. A gluten challenge may be required, for example, when dietary gluten reduction precedes appropriate diagnostic evaluations. Evidence on the best challenge protocol is currently sparse. Pharmaceutical trials in recent years may have provided new insights into the challenge and advanced the development of novel sensitive histological and immunological methods.

AREAS COVERED

This review outlines the current perspectives on the use of gluten challenge in the diagnosis of celiac disease and explores future directions in this area.

EXPERT OPINION

Comprehensive elimination of celiac disease before dietary gluten restriction is essential to avoid diagnostic uncertainties. Gluten challenge continues to have an important role in certain clinical scenarios, although it is important to understand its limitations in the diagnostic evaluation. The evidence so far permits no unequivocal recommendation considering the timing, duration, and amount of gluten used in the challenge. Thus, these decisions should be made on a case-by-case basis. Further studies with more standardized protocols and outcome measures are called for. In the future novel immunological methods may help to shorten or even avoid gluten challenge.

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.

Efficacy and safety of gluten peptide-based antigen-specific immunotherapy (Nexvax2) in adults with coeliac disease after bolus exposure to gluten (RESET CeD): an interim analysis of a terminated randomised, double-blind, placebo-controlled phase 2 study

BACKGROUND

A gluten-free diet is insufficient to treat coeliac disease because intestinal injury persists and acute reactions with cytokine release follow gluten exposure. Nexvax2 is a specific immunotherapy using immunodominant peptides recognised by gluten-specific CD4⁺ T cells that might modify gluten-induced disease in coeliac disease. We aimed to assess the effects of Nexvax2 on gluten-induced symptoms and immune activation in patients with coeliac disease.

METHODS

This was a randomised, double-blind, placebo-controlled phase 2 trial done at 41 sites (29 community, one secondary, and 11 tertiary centres) in the USA, Australia, and New Zealand. Patients with coeliac disease aged 18-70 years who had excluded gluten for at least 1 year, were HLA-DQ2.5 positive, and had a worsening of symptoms after an unmasked 10 g vital gluten challenge were eligible for inclusion. Patients were stratified by HLA-DQ2.5 status (HLA-DQ2.5 non-homozygous vs homozygous). Patients who were non-homozygous were centrally (ICON; Dublin, Ireland) randomly assigned (1:1) to receive subcutaneous Nexvax2 (non-homozygous Nexvax2 group) or saline (0·9% sodium chloride; non-homozygous placebo group) twice a week escalating from 1 μg to 750 μg during the first 5 weeks followed by 11 weeks of maintenance therapy at 900 μg per dose. The exploratory homozygous group was centrally randomly assigned (2:1) to receive Nexvax2 (homozygous Nexvax2 group) or placebo (homozygous placebo group); patients who were homozygous received the same doseage as those who were non-homozygous. The primary endpoint was change in coeliac disease patient reported outcomes (total gastrointestinal domain) from pretreatment baseline to the day of masked bolus 10 g vital gluten challenge given in week 14 analysed in the non-homozygous intention-to-treat population. The trial is registered with ClinicalTrials.gov, NCT03644069.

FINDINGS

Between Sept 21, 2018, and April 24, 2019, 383 volunteers were screened for inclusion, of whom 179 (47%; 133 [74%] women, 46 [26%] men; median age 41 years [IQR 33-55]) were randomly assigned. One (1%) of 179 patients was excluded from analysis due to misassignment of genotype. The non-homozygous Nexvax2 group included 76 patients, the non-homozygous placebo group included 78 patients, the homozygous Nexvax2 group included 16 patients, and the homozygous placebo group included eight patients. The study was discontinued after planned interim analysis of 66 patients who were non-homozygous. We report an unmasked post-hoc analysis of all available data for the primary endpoint and secondary symptom-based endpoints combining data from 67 (66 were assessed in the planned interim analysis for the primary endpoint). Mean change from baseline to day of first masked gluten challenge in total gastrointestinal score for the non-homozygous Nexvax2 group was 2·86 (SD 2·28) compared with 2·63 (2·07) for the non-homozygous placebo group (p=0·43). Adverse events were similar between all patients who received Nexvax2 and those who received placebo. Serious adverse events were reported in five (3%) of 178 patients (two [2%] of 92 who received Nexvax2 and three [4%] of 82 who received placebo). One patient in the non-homozygous Nexvax2 group had a serious adverse event that occurred during gluten challenge (left-sided mid-back muscle strain with imaging suggestive of partial left kidney infarction). Serious adverse events were reported for three (4%) of 78 patients in the non-homozygous placebo group (one each with exacerbation of asthma and appendicitis, and one who had forehead abscess, conjunctivitis, and folliculitis) and one (1%) patient in the non-homozygous Nexvax2 group developed a pulmonary embolism. The most frequent adverse events in all 92 patients who received Nexvax2 compared with all 86 patients who received placebo were nausea (44 [48%] of 92 patients who received Nexvax2 vs 29 (34%) of 86 patients who received placebo), diarrhoea (32 [35%] vs 25 [29%]), abdominal pain (31 [34%] vs 27 [31%]), headache 32 [35%] vs 20 [23%]), and fatigue (24 [26%] vs 31 [36%]).

INTERPRETATION

Nexvax2 did not reduce acute gluten-induced symptoms. Masked bolus vital gluten challenge provides an alternative to extended gluten challenge in efficacy studies for coeliac disease.

FUNDING

ImmusanT.

ESPGHAN Position Paper on Management and Follow-up of Children and Adolescents With Celiac Disease

OBJECTIVES

To gather the current evidence and to offer recommendations for follow-up and management.

METHODS

The Special Interest Group on Celiac Diseases of the European Society of Paediatric Gastroenterology Hepatology and Nutrition formulated ten questions considered to be essential for follow-up care. A literature search (January 2010-March 2020) was performed in PubMed or Medline. Relevant publications were identified and potentially eligible studies were assessed. Statements and recommendations were developed and discussed by all coauthors. Recommendations were voted upon: joint agreement was set as at least 85%.

RESULTS

Publications (n = 2775) were identified and 164 were included. Using evidence or expert opinion, 37 recommendations were formulated on: The need to perform follow-up, its frequency and what should be assessed, how to assess adherence to the gluten-free diet, when to expect catch-up growth, how to treat anemia, how to approach persistent high serum levels of antibodies against tissue-transglutaminase, the indication to perform biopsies, assessment of quality of life, management of children with unclear diagnosis for which a gluten-challenge is indicated, children with associated type 1 diabetes or IgA deficiency, cases of potential celiac disease, which professionals should perform follow-up, how to improve the communication to patients and their parents/caregivers and transition from pediatric to adult health care.

CONCLUSIONS

We offer recommendations to improve follow-up of children and adolescents with celiac disease and highlight gaps that should be investigated to further improve management.

A Low-FODMAP Diet Provides Benefits for Functional Gastrointestinal Symptoms but Not for Improving Stool Consistency and Mucosal Inflammation in IBD: A Systematic Review and Meta-Analysis

Background: A low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet (LFD) is claimed to improve functional gastrointestinal symptoms (FGSs). However, the role of LFD in inflammatory bowel disease (IBD) patients with FGSs remains unclear. Objective: To systematically assess the efficacy of LFD in IBD patients with FGSs. Methods: Six databases were searched from inception to 1 January 2022. Data were synthesized as the relative risk of symptoms improvement and normal stool consistency, mean difference of Bristol Stool Form Scale (BSFS), Short IBD Questionnaire (SIBDQ), IBS Quality of Life (IBS-QoL), Harvey-Bradshaw index (HBi), Mayo score, and fecal calprotectin (FC). Risk of bias was assessed based on study types. A funnel plot and Egger’s test were used to analyze publication bias. Results: This review screened and included nine eligible studies, including four randomized controlled trials (RCTs) and five before–after studies, involving a total of 446 participants (351 patients with LFD vs. 95 controls). LFD alleviated overall FGSs (RR: 0.47, 95% CI: 0.33–0.66, p = 0.0000) and obtained higher SIBDQ scores (MD = 11.24, 95% CI 6.61 to 15.87, p = 0.0000) and lower HBi score of Crohn’s disease (MD = −1.09, 95% CI −1.77 to −0.42, p = 0.002). However, there were no statistically significant differences in normal stool consistency, BSFS, IBS-QoL, Mayo score of ulcerative colitis, and FC. No publication bias was found. Conclusions: LFD provides a benefit in FGSs and QoL but not for improving stool consistency and mucosal inflammation in IBD patients. Further well-designed RCTs are needed to develop the optimal LFD strategy for IBD.

Review article: therapeutic targets for the pharmacologic management of coeliac disease-the future beyond a gluten-free diet

BACKGROUND

Coeliac disease (CeD) is an immune-mediated small bowel enteropathy resulting from dietary gluten exposure. Presently, the only effective treatment is adoption of a gluten-free diet (GFD), although strict adherence is challenging to maintain, and inadvertent gluten exposures are inevitable for most patients. Hence, there is substantial interest in drug development in CeD and multiple novel therapies are under investigation.

AIMS

To review existing and upcoming clinical trial programmes for pharmacologic agents for CeD.

METHODS

A narrative review was performed, informed by a search of MEDLINE, Embase, the Cochrane CENTRAL Library and clinicaltrials.gov.

RESULTS

We summarise the pathophysiology of CeD and the specific steps that are potentially amenable to pharmacologic treatment. We evaluate the evidence supporting existing and future drug targets, including trials of peptidases, gluten sequestrants, tight junction regulators, anti-transglutaminase 2 therapies, immune tolerizing agents, advanced biologics and small molecules, and microbiome-targeted strategies. We highlight unique considerations for conducting CeD trials, including identifying appropriate study populations, assessing results in the context of a gluten challenge, and interpreting CeD-specific clinical and histologic outcomes. Understanding these factors is crucial for accurately appraising the evidence. Finally, we outline what the future of CeD therapy may hold with the introduction of pharmacotherapies.

CONCLUSIONS

There is a need for pharmacologic options for CeD, either used adjunctively with a GFD for accidental or intentional gluten exposures or for refractory disease. Multiple promising agents are in development, and these trials are likely to lead to approvals for the first generation of pharmacologic agents for CeD within the next 5 years.

Impact of Celiac Disease on Dating

BACKGROUND/AIMS

When seeking a romantic partner, individuals with celiac disease (CD) must navigate challenging social situations. We aimed to investigate dating-related behaviors in adults with CD.

METHODS

A total of 11,884 affiliates of the Celiac Disease Center at Columbia University were invited to participate in an online survey. Adults (≥ 18 years) with biopsy-diagnosed CD were included. Among the 5,249 who opened the email, 538 fully completed the survey (10.2%). The survey included a CD-specific dating attitudes/behaviors questionnaire, a Social Anxiety Questionnaire (SAQ), a CD-specific quality of life instrument (CD-QOL), and a CD Food Attitudes and Behaviors scale (CD-FAB).

RESULTS

Respondents were primarily female (86.8%) and the plurality (24.4%) was in the 23-35 year age range. 44.3% had dated with CD, and among them, 68.4% reported that CD had a major/moderate impact on their dating life. A major/moderate impact was more commonly reported among females (69.3%, p  < 0.001), 23-35-year-olds (77.7%, p = 0.015), those with a household income < $50 K (81.7%, p = 0.019), and those with a lower CD-QOL score (50.5 vs. 73.4, p = 0.002). While on dates, 39.3% were uncomfortable explaining precautions to waiters, 28.2% engaged in riskier eating behaviors, and 7.5% intentionally consumed gluten. 39.0% of all participants were hesitant to kiss their partner because of CD; females more so than males (41.1% vs. 22.7%, p = 0.005).

CONCLUSIONS

The majority of participants felt that CD had a major/moderate impact on their dating life. This impact may result in hesitation toward dating and kissing, decreased QOL, greater social anxiety, and less adaptive eating attitudes and behaviors. CD and the need to adhere to a gluten free diet have a major impact on dating and intimacy.

Gut tissue-resident memory T cells in coeliac disease

This mini-review describes observations of the 1990ies with culturing of gluten-specific and astrovirus-specific CD4⁺ T cells from duodenal biopsies from subjects who presumably had a long time between the exposure to gluten or astrovirus antigens and the sampling of the biopsy. In these studies, it was also observed that antigen-specific CD4⁺ T cells migrated out of the gut biopsies during overnight culture. The findings are suggestive of memory T cells in tissue which are resident, but which also can be mobilised on antigen stimulation. Of note, these findings were made years before the term tissue-resident memory T cells was invoked. Since that time, many observations have accumulated on these gut T cells, particularly the gluten-specific T cells, and we have insight into the turnover of CD4⁺ T cells in the gut lamina propria. These data make it evident that human antigen-specific CD4⁺ T cells that can be cultured from gut biopsies indeed are bone fide tissue-resident memory T cells.

Emergence of an adaptive immune paradigm to explain celiac disease: a perspective on new evidence and implications for future interventions and diagnosis

INTRODUCTION

Recent patient studies have shown that gluten-free diet is less effective in treating celiac disease than previously believed, and additionally patients remain vulnerable to gluten-induced acute symptoms and systemic cytokine release. Safe and effective pharmacological adjuncts to gluten-free diet are in preclinical and clinical development. Clear understanding of the pathogenesis of celiac disease is critical for drug target identification, establishing efficacy endpoints and to develop non-invasive biomarkers suitable to monitor and potentially diagnose celiac disease.

AREAS COVERED

The role and clinical effects of CD4+ T cells directed against deamidated gluten in the context of an "adaptive immune paradigm" are reviewed. Alternative hypotheses of gluten toxicity are discussed and contrasted. In the context of recent patient studies, implications of the adaptive immune paradigm for future strategies to prevent, diagnose, and treat celiac disease are outlined.

EXPERT OPINION

Effective therapeutics for celiac disease are likely to be approved and necessitate a variety of new clinical instruments and tests to stratify patient need, monitor remission, and confirm diagnosis in uncertain cases. Sensitive assessments of CD4+ T cells specific for deamidated gluten are likely to play a central role in clinical management, and to facilitate research and pharmaceutical development.

Randomized, Placebo Controlled Trial of Experimental Hookworm Infection for Improving Gluten Tolerance in Celiac Disease

INTRODUCTION:

Celiac disease is an autoimmune disorder where intestinal immunopathology arises after gluten consumption. Previous studies suggested that hookworm infection restores gluten tolerance; however, these studies were small (n = 12) and not placebo controlled.

METHODS:

We undertook a randomized, placebo-controlled trial of hookworm infection in 54 people with celiac disease. The 94-week study involved treatment with either 20 or 40 Necator americanus third-stage larvae (L3-20 or L3-40) or placebo, followed by escalating gluten consumption (50 mg/d for 12 weeks, 1 g intermittent twice weekly for 12 weeks, 2 g/d sustained for 6 weeks, liberal diet for 1 year).

RESULTS:

Successful study completion rates at week 42 (primary outcome) were similar in each group (placebo: 57%, L3-20: 37%, and L3-40: 44%; P = 0.61), however gluten-related adverse events were significantly reduced in hookworm-treated participants: Median (range) adverse events/participant were as follows: placebo, 4 (1–9); L3-20, 1 (0–9); and L3-40, 0 (0–3) (P = 0.019). Duodenal villous height:crypt depth deteriorated similarly compared with their enrolment values in each group (mean change [95% confidence interval]: placebo, −0.6 [−1.3 to 0.2]; L3-20, −0.5 [−0.8 to 0.2]; and L3-40, −1.1 [−1.8 to 0.4]; P = 0.12). A retrospective analysis revealed that 9 of the 40 L3-treated participants failed to establish hookworm infections. Although week 42 completion rates were similar in hookworm-positive vs hookworm-negative participants (48% vs 44%, P = 0.43), quality of life symptom scores were lower in hookworm-positive participants after intermittent gluten challenge (mean [95% confidence interval]: 38.9 [33.9–44] vs 45.9 [39.2–52.6]).

DISCUSSION:

Hookworm infection does not restore tolerance to sustained moderate consumption of gluten (2 g/d) but was associated with improved symptom scores after intermittent consumption of lower, intermittent gluten doses.

A Sensitive Whole Blood Assay Detects Antigen-Stimulated Cytokine Release From CD4+ T Cells and Facilitates Immunomonitoring in a Phase 2 Clinical Trial of Nexvax2 in Coeliac Disease

Improved blood tests assessing the functional status of rare gluten-specific CD4+ T cells are needed to effectively monitor experimental therapies for coeliac disease (CD). Our aim was to develop a simple, but highly sensitive cytokine release assay (CRA) for gluten-specific CD4+ T cells that did not require patients to undergo a prior gluten challenge, and would be practical in large, multi-centre clinical trials. We developed an enhanced CRA and used it in a phase 2 clinical trial (“RESET CeD”) of Nexvax2, a peptide-based immunotherapy for CD. Two participants with treated CD were assessed in a pilot study prior to and six days after a 3-day gluten challenge. Dye-dilution proliferation in peripheral blood mononuclear cells (PBMC) was assessed, and IL-2, IFN-γ and IL-10 were measured by multiplex electrochemiluminescence immunoassay (ECL) after 24-hour gluten-peptide stimulation of whole blood or matched PBMC. Subsequently, gluten-specific CD4+ T cells in blood were assessed in a subgroup of the RESET CeD Study participants who received Nexvax2 (maintenance dose 900 μg, n = 12) or placebo (n = 9). The pilot study showed that gluten peptides induced IL-2, IFN-γ and IL-10 release from PBMCs attributable to CD4+ T cells, but the PBMC CRA was substantially less sensitive than whole blood CRA. Only modest gluten peptide-stimulated IL-2 release could be detected without prior gluten challenge using PBMC. In contrast, whole blood CRA enabled detection of IL-2 and IFN-γ before and after gluten challenge. IL-2 and IFN-γ release in whole blood required more than 6 hours incubation. Delay in whole blood incubation of more than three hours from collection substantially reduced antigen-stimulated IL-2 and IFN-γ secretion. Nexvax2, but not placebo treatment in the RESET CeD Study was associated with significant reductions in gluten peptide-stimulated whole blood IL-2 and IFN-γ release, and CD4+ T cell proliferation. We conclude that using fresh whole blood instead of PBMC substantially enhances cytokine secretion stimulated by gluten peptides, and enables assessment of rare gluten-specific CD4+ T cells without requiring CD patients to undertake a gluten challenge. Whole blood assessment coupled with ultra-sensitive cytokine detection shows promise in the monitoring of rare antigen-specific T cells in clinical studies.

Current and emerging therapies for coeliac disease

Coeliac disease is a common enteropathy that occurs in genetically susceptible individuals in response to the ingestion of gluten proteins present in wheat, rye and barley. Currently, the only available treatment for the condition is a strict, life-long gluten-free diet that, despite being safe and often effective, is associated with several challenges. Due to the high cost, particularly restrictive nature and perception of decreased quality of life associated with the diet, some patients are continuously exposed to gluten, which prevents an adequate disease control. Moreover, a subgroup of patients does not respond to the diet adequately, and healing of the small-bowel mucosa can be incomplete. Thus, there is a need for alternative treatment forms. The increasingly understood pathogenetic process of coeliac disease has enabled the identification of various targets for future therapies. Multiple investigational therapies ranging from tolerogenic to immunological approaches are in the pipeline, and several drug candidates have entered phase II/III clinical trials. This Review gives a broad overview of the different investigative treatment modalities for coeliac disease and summarizes the latest advances in this field.

Whole blood interleukin-2 release test to detect and characterize rare circulating gluten-specific T cell responses in coeliac disease

Whole blood cytokine release assays (CRA) assessing cellular immunity to gluten could simplify the diagnosis and monitoring of coeliac disease (CD). We aimed to determine the effectiveness of electrochemiluminescence CRA to detect responses to immunodominant gliadin peptides. HLA-DQ2·5⁺ CD adults (cohort 1, n = 6; cohort 2, n = 12) and unaffected controls (cohort 3, n = 9) were enrolled. Cohort 1 had 3-day gluten challenge (GC). Blood was collected at baseline, and for cohort 1 also at 3 h, 6 h and 6 days after commencing 3-day GC. Gliadin peptide-stimulated proliferation, interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) and 14- and 3-plex electrochemiluminescence CRA were performed. Poisson distribution analysis was used to estimate responding cell frequencies. In cohort 1, interleukin (IL)-2 dominated the gliadin peptide-stimulated cytokine release profile in whole blood. GC caused systemic IL-2 release acutely and increased gliadin peptide-stimulated IFN-γ ELISPOT and whole blood CRA responses. Whole blood CRA after GC was dominated by IL-2, but also included IFN-γ, C-X-C motif chemokine ligand 10/IFN-γ-induced protein 10 (CXCL10/IP-10), CXCL9/monokine induced by IFN-γ (MIG), IL-10, chemokine (C-C motif) ligand 3/macrophage inflammatory protein 1-alpha (CCL3/MIP-1α), TNF-α and IL-8/CXCL8. In cohorts 2 and 3, gliadin peptide-stimulated whole blood IL-2 release was 100% specific and 92% sensitive for CD patients on a gluten-free diet; the estimated frequency of cells in CD blood secreting IL-2 to α-gliadin peptide was 0·5 to 11 per ml. Whole blood IL-2 release successfully mapped human leucocyte antigen (HLA)-DQ2·5-restricted epitopes in an α-gliadin peptide library using CD blood before and after GC. Whole blood IL-2 release assay using electrochemiluminescence is a sensitive test for rare gliadin-specific T cells in CD, and could aid in monitoring and diagnosis. Larger studies and validation with tetramer-based assays are warranted.

The Gluten Gene: Unlocking the Understanding of Gluten Sensitivity and Intolerance

Wheat flour is one of the most important food ingredients containing several essential nutrients including proteins. Gluten is one of the major protein components of wheat consisted of glutenin (encoded on chromosome 1) and gliadin (encoded on chromosome 1 and 6) and there are around hundred genes encoding it in wheat. Gluten proteins have the ability of eliciting the pathogenic immune responses and hypersensitivity reactions in susceptible individuals called “gluten-related disorders (GRDs)”, which include celiac disease (CD), wheat allergy (WA), and non-celiac gluten sensitivity (NCGS). Currently removing gluten from the diet is the only effective treatment for mentioned GRDs and studies for the appropriate and alternative therapeutic approaches are ongoing. Accordingly, several genetic studies have focused on breeding wheat with low immunological properties through gene editing methods. The present review considers genetic characteristics of gluten protein components, focusing on their role in the incidence of gluten-related diseases, and genetic modifications conducted to produce wheat with less immunological properties.

Patient factors influencing acute gluten reactions and cytokine release in treated coeliac disease

BACKGROUND

Patients with coeliac disease (CD) commonly report a variety of adverse symptoms to gluten, but descriptions of the symptomatic response in the literature may have been confounded by the presence of food components such as fermentable carbohydrates (FODMAPs) causing symptoms of irritable bowel syndrome independent of gluten. In recent unmasked and masked low FODMAP gluten challenge studies in small groups of treated CD patients, nausea and vomiting were shown to be the key symptoms associated with serum interleukin (IL)-2 release. Our objective was to utilise a large and diverse cohort of people with CD undertaking a standardised gluten food challenge to characterise the demographic, genetic and clinical factors influencing the severity and timing of acute gluten reactions and IL-2 production.

METHODS

A total of 295 adults treated for CD were observed for 6 h after an unmasked food challenge consisting of 10 g vital wheat gluten (low in FODMAPs) in 100 ml water. Assessments included patient-reported outcomes, serum IL-2 and adverse events. Responses were analysed according to patient characteristics, HLA-DQ genotype, duodenal histology and response to a second gluten challenge.

RESULTS

Peak symptom severity was at 3 h (median severity 5/10). Peak IL-2 was at 4 h (median 4 pg/ml, range undetectable to 1028 pg/ml). Older age, older age at diagnosis, HLA-DQ2.5 positivity and homozygosity for HLA-DQB1*02 were each significantly associated with IL-2 elevations after gluten. Patients positive for HLA-DQ2.5, DQ8, DQ2.2 or DQ7 showed elevated IL-2 after gluten. Patient factors were not significantly associated with severity of digestive symptoms, but symptoms were correlated to one another and serum IL-2. Gluten challenge after 5 months caused more vomiting and higher IL-2 levels, but responses correlated with the first.

CONCLUSIONS

Gluten-induced symptoms and cytokine release is common in adults with treated CD. Age, genetics and previous response to gluten predict these acute reactions to gluten challenge. Structured symptom assessment and serum IL-2 after standardised gluten challenge may inform on patient diagnosis, the role of gluten in symptomatology and the need for adjunctive treatment.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT03644069 Registered 21 May 2018.

Innate and adaptive immunity in celiac disease

PURPOSE OF REVIEW

The current review is prompted by recent studies indicating that adaptive immunity could be sufficient to explain rapid onset symptoms as well as many chronic effects of gluten in celiac disease.

RECENT FINDINGS

Gluten re-exposure in treated celiac disease drives a coordinated systemic cytokine release response implicating T-cell activation within 2 h. Instead of direct effects of gluten on innate immunity, long lasting memory CD4+ T cells activated within 2 h of ingesting gluten or injecting purified gluten peptides now appear to be responsible for acute digestive symptoms. In addition, memory B cells and plasma cells specific for gluten and transglutaminase 2, rather than innate immune cells, are the preferred antigen-presenting cells for gluten in the gut. A variety of innate immune stimuli such as transient infections and local intestinal microbiome, not necessarily gluten itself, may contribute to disease initiation and transition to overt intestinal mucosal injury. Gluten-specific adaptive immunity in the gut and blood are now shown to be closely linked, and systemic cytokine release after gluten provides an additional explanation for extraintestinal manifestations of celiac disease.

SUMMARY

Clinical studies utilizing cytokines as new biomarkers for gluten immunity promise to improve understanding of clinical effects of gluten, accelerate therapeutics development, and augment diagnosis.