Serum cytokines elevated during gluten-mediated cytokine release in coeliac disease

Changes upon the gluten-free diet of HLA-DQ2 and TRAFD1 gene expression in peripheral blood of celiac disease patients

Background

Celiac disease (CD) is a chronic immuno-mediated enteropathy caused by dietary gluten in genetically susceptible individuals carrying HLA (Human Leukocytes Antigen) genes that encode for DQ2.5 and DQ8 molecules. TRAFD1 (TRAF-type zinc finger domain 1) is a gene recently found associated with CD and defined as a master regulator of IFNγ signalling and of MHC class I antigen processing/presentation. There is no specific drug therapy and the only effective treatment is the gluten-free diet (GFD). The great majority of celiac patients when compliant with GFD have a complete remission of symptoms and recovery of gut mucosa architecture and function. Until now, very few studies have investigated molecular differences occurring in CD patients upon the GFD therapy.

Methods

We looked at the expression of both HLA DQ2.5 and TRAFD1 risk genes in adult patients with acute CD at the time of and in treated patients on GFD. Specifically, we measured by qPCR the HLA-DQ2.5 and TRAFD1 mRNAs on peripheral blood mononuclear cells (PBMC) from the two groups of patients.

Results

When we compared the HLA-DQ mRNA expression, we didn't find significant variation between the two groups of patients, thus indicating that GFD patients have the same capability to present gliadin antigens to cognate T cells as patients with active disease. Conversely, TRAFD1 was more expressed in PBMC from treated CD subjects. Notably, TRAFD1 transcripts significantly increased in the patients analyzed longitudinally during the GFD, indicating a role in the downregulation of gluten-induced inflammatory pathways.

Conclusion

Our study demonstrated that HLA-DQ2.5 and TRAFD1 molecules are two important mediators of anti-gluten immune response and inflammatory process.

Global Approach to Follow-Up of Celiac Disease

Celiac disease, an autoimmune disorder induced by the ingestion of gluten, affects approximately 1.4% of the population. Gluten damages the villi of the small intestine, producing symptoms such as abdominal pain, bloating and a subsequent loss of nutrient absorption, causing destabilization of the nutritional status. Moreover, gluten can trigger extra intestinal symptoms, such as asthma or dermatitis, but also mental disorders such as depression or anxiety. Moreover, people suffering from celiac disease sometimes feel misunderstood by society, mainly due to the lack of knowledge about the disease and the gluten-free diet. Thus, the treatment and follow-up of patients with celiac disease should be approached from different perspectives, such as the following: (1) a clinical perspective: symptomatology and dietary adherence monitorization; (2) nutritional assessment: dietary balance achievement; (3) psychological assistance: mental disorders avoidance; and (4) social inclusion: educating society about celiac disease in order to avoid isolation of those with celiac disease. The aim of this narrative review is to gain deep insight into the different strategies that currently exist in order to work on each of these perspectives and to clarify how the complete approach of celiac disease follow-up should be undertaken so that the optimum quality of life of this collective is reached.

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.

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 and 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.

IL-10-producing regulatory cells impact on celiac disease evolution

Celiac Disease (CD) is a T-cell mediated disorder caused by immune response to gluten, although the mechanisms underlying CD progression are still elusive. We analyzed immune cell composition, plasma cytokines, and gliadin-specific T-cell responses in patients with positive serology and normal intestinal mucosa (potential-CD) or villous atrophy (acute-CD), and after gluten-free diet (GFD). We found: an inflammatory signature and the presence of circulating gliadin-specific IFN-γ+ T cells in CD patients regardless of mucosal damage; an increased frequency of IL-10-secreting dendritic cells (DC-10) in the gut and of circulating gliadin-specific IL-10-secreting T cells in potential-CD; IL-10 inhibition increased IFN-γ secretion by gliadin-specific intestinal T cells from acute- and potential-CD. On GFD, inflammatory cytokines normalized, while IL-10-producing T cells accumulated in the gut. We show that IL-10-producing cells are fundamental in controlling pathological T-cell responses to gluten: DC-10 protect the intestinal mucosa from damage and represent a marker of potential-CD.

A Look Into the Future: Are We Ready for an Approved Therapy in Celiac Disease?

As it appears that we are currently at the cusp of an era in which drugs that are new, re-purposed, or "supplements" will be introduced to the management of celiac disease, we need to reflect on whether the framework is set for celiac disease to be treated increasingly with pharmaceuticals as well as diet. This refers to reflecting on the rigor of current diagnostic practices; the limitations of the current standard of care, which is a gluten-free diet; and that we lack objective markers of disease severity. Investigating these issues will help us to identify gaps in technology and practices that could be critical for selecting patients with a well-defined need for an improved or alternative treatment. Both aspects, circumscribed limitations of the gluten-free diet and diagnostics helping to define celiac disease target groups, together with the guiding requirements by the responsible regulatory authorities, will contribute to defining the subgroups of patients with confirmed celiac disease eligible for distinct pharmacologic strategies. Because many patients with celiac disease are diagnosed in childhood, these aspects need to be differentially discussed for the pediatric setting. In this perspective, we aimed to describe these contextual issues and then looked ahead to the future. What might be the major challenges in celiac disease clinics in the coming years once drugs are an option alongside diet? And what will be the future objectives for researchers who further decipher the mucosal immunology of celiac disease? Speculating on the answers to these questions is as stimulating as it is fascinating to be part of this turning point.

Emerging Pharmaceutical Therapies to Address the Inadequacy of a Gluten-Free Diet for Celiac Disease

Celiac disease (CeD) is a chronic autoimmune disorder triggered by the ingestion of gluten, affecting around 1% of the global population. It is a multifactorial disease involving both genetics and environmental factors. Nowadays, the only available treatment for CeD is a life-long gluten-free diet (GFD), which can cause a significant burden for patients, since symptoms and mucosal injury can persist despite apparent compliance with a GFD. This could also lead to psychological consequences and affect the quality of life of these patients. Thankfully, recent advances in understanding the pathogenesis of CeD and the availability of various targets have made it feasible to explore pharmaceutical treatments specific to CeD. Recently, the FDA has highlighted the unmet needs of adult patients on a GFD who experience ongoing symptoms attributed to CeD and also show persistent duodenal villous atrophy. This review will outline the limitations of a GFD, describe the targets of potential novel treatment of CeD and provide an overview of the primary clinical trials involving oral and injectable agents for a non-dietary treatment of CeD.

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.

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.

Context-dependent effects of IL-2 rewire immunity into distinct cellular circuits

Interleukin 2 (IL-2) is a key homeostatic cytokine, with therapeutic applications in both immunogenic and tolerogenic immune modulation. Clinical use has been hampered by pleiotropic functionality and widespread receptor expression, with unexpected adverse events. Here, we developed a novel mouse strain to divert IL-2 production, allowing identification of contextual outcomes. Network analysis identified priority access for Tregs and a competitive fitness cost of IL-2 production among both Tregs and conventional CD4 T cells. CD8 T and NK cells, by contrast, exhibited a preference for autocrine IL-2 production. IL-2 sourced from dendritic cells amplified Tregs, whereas IL-2 produced by B cells induced two context-dependent circuits: dramatic expansion of CD8+ Tregs and ILC2 cells, the latter driving a downstream, IL-5-mediated, eosinophilic circuit. The source-specific effects demonstrate the contextual influence of IL-2 function and potentially explain adverse effects observed during clinical trials. Targeted IL-2 production therefore has the potential to amplify or quench particular circuits in the IL-2 network, based on clinical desirability.

Review article: Diagnosis of coeliac disease: a perspective on current and future approaches

Diagnostics will play a central role in addressing the ongoing dramatic rise in global prevalence of coeliac disease, and in deploying new non-dietary therapeutics. Clearer understanding of the immunopathogenesis of coeliac disease and the utility of serology has led to partial acceptance of non-biopsy diagnosis in selected cases. Non-biopsy diagnosis may expand further because research methods for measuring gluten-specific CD4+ T cells and the acute recall response to gluten ingestion in patients is now relatively straightforward. This perspective on diagnosis in the context of the immunopathogenesis of coeliac disease sets out to highlight current consensus, limitations of current practices, gluten food challenge for diagnosis and the potential for diagnostics that measure the underlying cause for coeliac disease, gluten-specific immunity.

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.

Assessing Hydrolyzed Gluten Content in Dietary Enzyme Supplements Following Fermentation

Partially digested gluten fragments from grains including wheat, rye, spelt and barley are responsible for triggering an inflammatory response in the intestinal tract of Celiac Disease (CD) and Non-Celiac Gluten Sensitive (NCGS) individuals. Fermentation is an effective method to metabolize gluten, with enzymes from bacterial or fungal species being released to help in this process. However, the levels of gluten in commercially available enzymes, including those involved in gluten fermentation, are unknown. In this study we investigated gluten levels in commercially available dietary enzymes combined with assessing their effect on inflammatory response in human cell culture assays. Using antibodies that recognize different gluten epitopes (G12, R5, 2D4, MloBS and Skerritt), we employed ELISA and immunoblotting methodologies to determine gluten content in crude gluten, crude gliadin, pepsin-trypsin digested gluten and a selection of commercially available enzymes. We further investigated the effect of these compounds on inflammatory response in immortalized immune and intestinal human cell lines, as well as in peripheral blood mononuclear cells (PBMCs) from coeliac individuals. All tested supplemental enzyme products reported a gluten concentration that was equivalent to or below 20 parts per million (ppm) as compared with an intact wheat reference standard and a pepsin-trypsin digested standard. Similarly, the inflammatory response to IL-8 and TNF-α inflammatory cytokines in mammalian cell lines and PBMCs from coeliac individuals to the commercial enzymes was not significantly different to 20 ppm of crude gluten, crude gliadin or pepsin-trypsin digested gluten. This combined approach provides insight into the extent of gluten breakdown in the fermentation process and the safety of these products to gluten-sensitive individuals.

High Frequency of Glucose-6-Phosphate Dehydrogenase Deficiency in Patients Diagnosed with Celiac Disease

Celiac disease (CD) is characterized by a proinflammatory state associated with the production of reactive oxygen species, i.e., a condition of oxidative stress. In this study, we tested the hypothesis that the inherited deficiency of glucose-6-phosphate dehydrogenase (G6PD), by causing impaired antioxidant defense, may increase the risk of CD.

METHODS

A retrospective monocentric case-control study was performed using the clinical records of 8338 outpatients (64.6% women) scheduled for upper endoscopy between 2002 and 2021 in Northern Sardinia. Overall, 627 were found to have CD (7.5%), and 1027 resulted to be G6PD-deficiency carriers (12.3%). Since randomization was impractical, the potential covariates imbalance between cases and controls was minimized using a 1:2 propensity-score-matched (PSM) analysis.

RESULTS

Overall, G6PD deficiency was associated with increased risk of CD (odds ratio (OR) 1.50; 95% confidence interval (CI) 1.19-1.90). The PSM procedure identified 1027 G6PD-deficient and 2054 normal patients. Logistic regression including the propensity score detected for G6PD deficiency an OR of 1.48 (95%CI 1.13-1.95; p = 0.004).

CONCLUSIONS

Our findings show that the enzyme defect was significantly and positively associated with CD, in line with the pro-oxidant impact of the enzyme defect observed in animal models and humans.

Plasma IL-2 and Symptoms Response after Acute Gluten Exposure in Subjects With Celiac Disease or Nonceliac Gluten Sensitivity

INTRODUCTION

Treated patients with celiac disease (CeD) and nonceliac gluten sensitivity (NCGS) report acute, transient, incompletely understood symptoms after suspected gluten exposure. To determine whether (i) blinded gluten exposure induces symptoms, (ii) subjects accurately identify gluten exposure, and (iii) serum interleukin-2 (IL-2) levels distinguish CeD from NCGS subjects after gluten exposure.

METHODS

Sixty subjects (n = 20 treated, healed CeD; n = 20 treated NCGS; n = 20 controls) were block randomized to a single, double-blind sham (rice flour) or 3-g gluten challenge with 72-hours follow-up. Twelve serial questionnaires (100 mm visual analog scale; pain, bloating, nausea, and fatigue) and 10 serial plasma samples were collected. Mucosal permeability was assessed using both urinary lactulose-13C mannitol ratios and endoscopic mucosal impedance.

RESULTS

Thirty-five of 40 (83%) subjects with CeD and NCGS reported symptoms with gluten (8 CeD, 9 NCGS) and sham (9 CeD, 9 NCGS) compared with 9 of 20 (45%) controls after gluten (n = 6) and sham (n = 3). There was no significant difference in symptoms among groups. Only 2 of 10 subjects with CeD and 4 of 10 NCGS identified gluten, whereas 8 of 10 subjects with CeD and 5 of 10 NCGS identified sham. A significant plasma IL-2 increase occurred only in subjects with CeD after gluten, peaking at 3 hours and normalizing within 24 hours postchallenge despite no significant intestinal permeability change from baseline.

DISCUSSION

Symptoms do not reliably indicate gluten exposure in either subjects with CeD or NCGS. IL-2 production indicates a rapid-onset gluten-induced T-cell activation in CeD despite long-standing treatment. The effector site is unknown, given no increased intestinal permeability after gluten.

Expression of Selected Genes and Circulating microRNAs in Patients with Celiac Disease

Background and Objectives: Celiac disease (CD) is an immune-mediated enteropathy with characteristic intestinal alterations. CD occurs as a chronic inflammation secondary to gluten sensitivity in genetically susceptible individuals. Until now, the exact cause of the disease has not been established, which is why new studies have appeared that address the involvement of various genes and microRNAs (miRNAs) in the pathogenesis. The aim of the study is to describe the expression of selected genes (Wnt family member 3, WNT3; Wnt family member 11, WNT11; tumor necrosis factor alpha, TNFα; mitogen-activated protein kinase 1, MAPK1; AKT serine/threonine kinase 3, AKT3; phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha, PIK3CA; and cyclin D1, CCND1) and miRNAs (miR-192-5p, miR-194-5p, miR-449a and miR-638) in adult patients with CD. Materials and Methods: In total, 15 patients with CD at diagnosis (newly diagnosed), 33 patients on a gluten-free diet (GFD) for at least 1 year and 10 controls (control) were prospectively included. Blood samples were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Results: The results show that TNFα, MAPK1 and CCND1 were significantly overexpressed (p = 0.0249, p = 0.0019 and p = 0.0275, respectively) when comparing the newly diagnosed group to the controls. The other genes studied in CD patients were mostly with high values compared to controls, without reaching statistical significance. Among the miRNAs, the closest to a statistically significant value was miR-194-5p when the newly diagnosed group versus control (p = 0.0510) and GFD group versus control (p = 0.0671) were compared. The DIANA and miRNet databases identified significant functional activity for miR-449a and miR-192-5p and an interconnection of miR-194-5p and miR-449a with CCND1. Conclusions: In conclusion, genes and circulating miRNAs require further studies as they could represent important biomarkers in clinical practice.

Frontiers in Celiac Disease: Where Autoimmunity and Environment Meet

Celiac disease is a chronic, immune-mediated enteropathy driven by dietary gluten found in genetically susceptible hosts. It has a worldwide distribution, is one of the most common autoimmune disorders globally, and is the only autoimmune condition for which the trigger is known. Despite advances in characterizing mechanisms of disease, gaps in understanding of celiac disease pathogenesis remain. A "frontier" concept is considering what moves an HLA-DQ2 or DQ8-positive individual from asymptomatic gluten tolerance to celiac disease manifestation. In this arena, environmental triggers, including age at the time of initial gluten exposure, the occurrence of usual childhood viral infections, and microbiome alterations have emerged as key events in triggering the symptomatic disease. Pathologists play a major role in frontier aspects of celiac disease. This includes the discovery that duodenal mucosal histology in follow-up biopsies does not correlate with ongoing patient symptoms, antitissue transglutaminase antibody titers and diet adherence in celiac disease patients. Further, in light of recent evidence that the detection of monoclonal T-cell populations in formalin-fixed biopsies is not specific for type II refractory celiac disease, pathologists should resist performing such analyses until common causes of "apparent" refractoriness are excluded. The promise of therapies in celiac disease has led to clinical trials targeting many steps in the inflammatory cascade, which depend upon a pathologist's confirmation of the initial diagnosis and evaluation of responses to therapies. As pathologists continue to be active participants in celiac disease research, partnering with other stakeholders, we will continue to impact this important autoimmune disease.

Physical abuse during childhood predicts IL-2R levels in adult panic disorder patients

BACKGROUND

Childhood maltreatment confers higher risk of adulthood mental disease. However, the biological mechanism mediating this association remains largely unknown, with evidence suggesting dysregulation of the immune system as a possible biological mediator. The present paper conducted a case-control study to establish whether early-life adversity contributes to potentially pathogenic pro-inflammatory phenotypes in adult Panic Disorder (PD) individuals.

METHODS

Eighty-four PD patients and seventy-eight matched healthy controls were assessed for peripheral serum levels of interleukin (IL)-2R, IL-1β, IL-10, and for specific trauma types through child trauma questionnaire evaluation.

RESULTS

Analyses for specific types of trauma (sexual, physical or emotional abuse or neglect) revealed that these impact differentially the single inflammatory markers, and a significant association between physical abuse and the inflammatory marker IL-2R in PD patients was observed (β = 0.40, p = 0.013). The analysis demonstrates that childhood trauma contributes to a proinflammatory state in adulthood, with specific inflammatory profiles counting on the specific type of traumatic event.

CONCLUSION

This study is unique in providing inflammatory biomarkers evidence of distinct biological modifications in PD in the presence or absence of exposure to childhood abuse. These results contribute to a better understanding of the extent of influence of differences in trauma exposure on pathophysiological processes in PD and may have implications for personalized medicine.

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.

Co-factors, Microbes, and Immunogenetics in Celiac Disease to Guide Novel Approaches for Diagnosis and Treatment

Celiac disease (CeD) is a frequent immune-mediated disease that affects not only the small intestine but also many extraintestinal sites. The role of gluten proteins as dietary triggers, HLA-DQ2 or -DQ8 as major necessary genetic predisposition, and tissue transglutaminase (TG2) as mechanistically involved autoantigen, are unique features of CeD. Recent research implicates many cofactors working in synergism with these key triggers, including the intestinal microbiota and their metabolites, nongluten dietary triggers, intestinal barrier defects, novel immune cell phenotypes, and mediators and cytokines. In addition, apart from HLA-DQ2 and -DQ8, multiple and complex predisposing genetic factors and interactions have been defined, most of which overlap with predispositions in other, usually autoimmune, diseases that are linked to CeD. The resultant better understanding of CeD pathogenesis, and its manifold manifestations has already paved the way for novel therapeutic approaches beyond the lifelong strict gluten-free diet, which poses a burden to patients and often does not lead to complete mucosal healing. Thus, supported by improved mouse models for CeD and in vitro organoid cultures, several targeted therapies are in phase 2-3 clinical studies, such as highly effective gluten-degrading oral enzymes, inhibition of TG2, cytokine therapies, induction of tolerance to gluten ingestion, along with adjunctive and preventive approaches using beneficial probiotics and micronutrients. These developments are supported by novel noninvasive markers of CeD severity and activity that may be used as companion diagnostics, allow easy-to perform and reliable monitoring of patients, and finally support personalized therapy for CeD.

Activated gut-homing CD8+ T cells for coeliac disease diagnosis on a gluten-free diet

BACKGROUND

The diagnosis of coeliac disease (CD) in individuals that have started a gluten-free diet (GFD) without an adequate previous diagnostic work-out is a challenge. Several immunological assays such as IFN-γ ELISPOT have been developed to avoid the need of prolonged gluten challenge to induce the intestinal damage. We aimed to evaluate the diagnostic accuracy of activated gut-homing CD8⁺ and TCRγδ⁺ T cells in blood after a 3-day gluten challenge and to compare it with the performance of IFN-γ ELISPOT in a HLA-DQ2.5 subsample.

METHODS

A total of 22 CD patients and 48 non-CD subjects, all of them following a GFD, underwent a 3-day 10-g gluten challenge. The percentage of two T cell subsets (CD8⁺ CD103⁺ β7^hi CD38⁺/total CD8⁺ and TCRγδ⁺ CD103⁺ β7^hi CD38⁺/total TCRγδ⁺) in fresh peripheral blood drawn baseline and 6 days after the challenge was determined by flow cytometry. IFN-γ ELISPOT assays were also performed in HLA-DQ2.5 participants. ROC curve analysis was used to assess the diagnostic performance of the CD8⁺ T cell response and IFN-γ ELISPOT.

RESULTS

Significant differences between the percentage of the two studied subsets of CD8⁺ and TCRγδ⁺ cells at days 0 and 6 were found only when considering CD patients (p < 10^-3 vs. non-CD subjects). Measuring activated CD8⁺ T cells provided accurate CD diagnosis with 95% specificity and 97% sensitivity, offering similar results than IFN-γ ELISPOT.

CONCLUSIONS

The results provide a highly accurate blood test for CD diagnosis in patients on a GFD of easy implementation in daily clinical practice.

TGF-β Signaling in Liver, Pancreas, and Gastrointestinal Diseases and Cancer

Genetic alterations affecting transforming growth factor-β (TGF-β) signaling are exceptionally common in diseases and cancers of the gastrointestinal system. As a regulator of tissue renewal, TGF-β signaling and the downstream SMAD-dependent transcriptional events play complex roles in the transition from a noncancerous disease state to cancer in the gastrointestinal tract, liver, and pancreas. Furthermore, this pathway also regulates the stromal cells and the immune system, which may contribute to evasion of the tumors from immune-mediated elimination. Here, we review the involvement of the TGF-β pathway mediated by the transcriptional regulators SMADs in disease progression to cancer in the digestive system. The review integrates human genomic studies with animal models that provide clues toward understanding and managing the complexity of the pathway in disease and cancer.

Interplay Between Gluten, HLA, Innate and Adaptive Immunity Orchestrates the Development of Coeliac Disease

Several environmental, genetic, and immune factors create a "perfect storm" for the development of coeliac disease: the antigen gluten, the strong association of coeliac disease with HLA, the deamidation of gluten peptides by the enzyme transglutaminase 2 (TG2) generating peptides that bind strongly to the predisposing HLA-DQ2 or HLA-DQ8 molecules, and the ensuing unrestrained T cell response. T cell immunity is at the center of the disease contributing to the inflammatory process through the loss of tolerance to gluten and the differentiation of HLA-DQ2 or HLA-DQ8-restricted anti-gluten inflammatory CD4⁺ T cells secreting pro-inflammatory cytokines and to the killing of intestinal epithelial cells by cytotoxic intraepithelial CD8⁺ lymphocytes. However, recent studies emphasize that the individual contribution of each of these cell subsets is not sufficient and that interactions between these different populations of T cells and the simultaneous activation of innate and adaptive immune pathways in distinct gut compartments are required to promote disease immunopathology. In this review, we will discuss how tissue destruction in the context of coeliac disease results from the complex interactions between gluten, HLA molecules, TG2, and multiple innate and adaptive immune components.

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.

The Evolving Landscape of Biomarkers in Celiac Disease: Leading the Way to Clinical Development

Celiac disease is a common immune-mediated disease characterized by abnormal T-cell responses to gluten. For many patients, symptoms and intestinal damage can be controlled by a gluten-free diet, but, for some, this approach is not enough, and celiac disease progresses, with serious medical consequences. Multiple therapies are now under development, increasing the need for biomarkers that allow identification of specific patient populations and monitoring of therapeutic activity and durability. The advantage of identifying biomarkers in celiac disease is that the underlying pathways driving disease are well characterized and the histological, cellular, and serological changes with gluten response have been defined in gluten challenge studies. However, there is room for improvement. Biomarkers that measure histological changes require duodenal biopsies and are invasive. Less invasive peripheral blood cell and cytokine biomarkers are transient and dependent upon gluten challenge. Here, we discuss established biomarkers and new approaches for biomarkers that may overcome current limitations.

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.

Evaluating Responses to Gluten Challenge: A Randomized, Double-Blind, 2-Dose Gluten Challenge Trial

BACKGROUND & AIMS

Gluten challenge is used to diagnose celiac disease (CeD) and for clinical research. Sustained gluten exposure reliably induces histologic changes but is burdensome. We investigated the relative abilities of multiple biomarkers to assess disease activity induced by 2 gluten doses, and aimed to identify biomarkers to supplement or replace histology.

METHODS

In this randomized, double-blind, 2-dose gluten-challenge trial conducted in 2 US centers (Boston, MA), 14 adults with biopsy-proven CeD were randomized to 3 g or 10 g gluten/d for 14 days. The study was powered to detect changes in villous height to crypt depth, and stopped at planned interim analysis on reaching this end point. Additional end points included gluten-specific cluster of differentiation (CD)4 T-cell analysis with HLA-DQ2-gluten tetramers and enzyme-linked immune absorbent spot, gut-homing CD8 T cells, interleukin-2, symptoms, video capsule endoscopy, intraepithelial leukocytes, and tissue multiplex immunofluorescence.

RESULTS

All assessments showed changes with gluten challenge. However, time to maximal change, change magnitude, and gluten dose-response relationship varied. Villous height to crypt depth, video capsule endoscopy enteropathy score, enzyme-linked immune absorbent spot, gut-homing CD8 T cells, intraepithelial leukocyte counts, and HLA-DQ2-restricted gluten-specific CD4 T cells showed significant changes from baseline at 10 g gluten only; symptoms were significant at 3 g. Symptoms and plasma interleukin-2 levels increased significantly or near significantly at both doses. Interleukin-2 appeared to be the earliest, most sensitive marker of acute gluten exposure.

CONCLUSIONS

Modern biomarkers are sensitive and responsive to gluten exposure, potentially allowing less invasive, lower-dose, shorter-duration gluten ingestion. This work provides a preliminary framework for rational design of gluten challenge for CeD research. ClinicalTrials.gov number, NCT03409796.

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.

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.

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.

Gliadin Nanoparticles Induce Immune Tolerance to Gliadin in Mouse Models of Celiac Disease

BACKGROUND & AIMS

Celiac disease could be treated, and potentially cured, by restoring T-cell tolerance to gliadin. We investigated the safety and efficacy of negatively charged 500-nm poly(lactide-co-glycolide) nanoparticles encapsulating gliadin protein (TIMP-GLIA) in 3 mouse models of celiac disease. Uptake of these nanoparticles by antigen-presenting cells was shown to induce immune tolerance in other animal models of autoimmune disease.

METHODS

We performed studies with C57BL/6; RAG1^-/- (C57BL/6); and HLA-DQ8, huCD4 transgenic Ab0 NOD mice. Mice were given 1 or 2 tail-vein injections of TIMP-GLIA or control nanoparticles. Some mice were given intradermal injections of gliadin in complete Freund's adjuvant (immunization) or of soluble gliadin or ovalbumin (ear challenge). RAG^-/- mice were given intraperitoneal injections of CD4⁺CD62L^-CD44^hi T cells from gliadin-immunized C57BL/6 mice and were fed with an AIN-76A-based diet containing wheat gluten (oral challenge) or without gluten. Spleen or lymph node cells were analyzed in proliferation and cytokine secretion assays or by flow cytometry, RNA sequencing, or real-time quantitative polymerase chain reaction. Serum samples were analyzed by gliadin antibody enzyme-linked immunosorbent assay, and intestinal tissues were analyzed by histology. Human peripheral blood mononuclear cells, or immature dendritic cells derived from human peripheral blood mononuclear cells, were cultured in medium containing TIMP-GLIA, anti-CD3 antibody, or lipopolysaccharide (controls) and analyzed in proliferation and cytokine secretion assays or by flow cytometry. Whole blood or plasma from healthy volunteers was incubated with TIMP-GLIA, and hemolysis, platelet activation and aggregation, and complement activation or coagulation were analyzed.

RESULTS

TIMP-GLIA did not increase markers of maturation on cultured human dendritic cells or induce activation of T cells from patients with active or treated celiac disease. In the delayed-type hypersensitivity (model 1), the HLA-DQ8 transgenic (model 2), and the gliadin memory T-cell enteropathy (model 3) models of celiac disease, intravenous injections of TIMP-GLIA significantly decreased gliadin-specific T-cell proliferation (in models 1 and 2), inflammatory cytokine secretion (in models 1, 2, and 3), circulating gliadin-specific IgG/IgG2c (in models 1 and 2), ear swelling (in model 1), gluten-dependent enteropathy (in model 3), and body weight loss (in model 3). In model 1, the effects were shown to be dose dependent. Splenocytes from HLA-DQ8 transgenic mice given TIMP-GLIA nanoparticles, but not control nanoparticles, had increased levels of FOXP3 and gene expression signatures associated with tolerance induction.

CONCLUSIONS

In mice with gliadin sensitivity, injection of TIMP-GLIA nanoparticles induced unresponsiveness to gliadin and reduced markers of inflammation and enteropathy. This strategy might be developed for the treatment of celiac disease.

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

BACKGROUND

In patients with coeliac disease, FODMAPs in gluten-containing foods, and participant anticipation of a harmful ('nocebo') effect, may contribute to acute symptoms after gluten challenge.

AIM

To establish acute gluten-specific symptoms linked to immune activation in coeliac disease METHODS: We included 36 coeliac disease patients on a gluten-free diet receiving placebo in the RESET CeD trial. Double-blind, bolus vital wheat gluten (~6-g gluten protein) and sham challenges low in FODMAPs were consumed 2 weeks apart. Assessments included daily Coeliac Disease Patient Reported Outcome (CeD PRO) symptom scores (0-10), adverse events and serum interleukin-2 (baseline and 4 hours).

RESULTS

Median CeD PRO score for nausea increased most (sham: 0 vs gluten: 5.5; P < .001). Apart from tiredness (1 vs 4, P = .005) and headache (0 vs 2, P = .002), changes in other symptoms were small or absent. Only nausea increased significantly in occurrence with gluten (11% vs 69%, P < .001). Without nausea, only tiredness and flatulence were common after gluten. Nausea (6% vs 61%, P < .001; median onset: 1:34 hours) and vomiting (0% vs 44%, P < .001; 1:51 hours) were the only adverse events more common with gluten than sham. Interleukin-2 was always below the level of quantitation (0.5 pg/mL) at baseline, and after sham. Interleukin-2 was elevated after gluten in 97% of patients (median fold-change: 20), and correlated with severity of nausea (r_s  = .49, P = .0025) and occurrence of vomiting (P = .0005).

CONCLUSIONS

Nausea and vomiting are relatively specific indicators of acute gluten ingestion, and correlate with immune activation. IBS-like symptoms without nausea are unlikely to indicate recent gluten exposure.