Non-Host Factors Influencing Onset and Severity of Celiac Disease.

Celiac disease (CeD) is a chronic autoimmune condition driven by gluten ingestion in genetically predisposed individuals, resulting in inflammatory lesions in the proximal small intestine. Although the presence of specific HLA-linked haplotypes and gluten consumption are necessary for disease development, they alone do not account for the variable onset of CeD in susceptible individuals. This review explores the multifaceted role of non-host factors in CeD development, including dietary and microbial influences. We discuss clinical associations and observations highlighting the impact of these factors on disease onset and severity. Furthermore, we discuss studies in CeD-relevant animal models that offer mechanistic insights into how diet, the microbiome, and enteric infections modulate CeD pathogenesis. Finally, we address the clinical implications and therapeutic potential of understanding these cofactors offering a promising avenue for preventive and therapeutic interventions in CeD management.

Novel Bacteroides Vulgatus strain protects against gluten-induced break of human celiac gut epithelial homeostasis: a pre-clinical proof-of-concept study.

BACKGROUND AND AIMS: We have identified a decreased abundance of microbial species known to have a potential anti-inflammatory, protective effect in subjects that developed Celiac Disease (CeD) compared to those who did not. We aim to confirm the potential protective role of one of these species, namely Bacteroides vulgatus, and to mechanistically establish the effect of bacterial bioproducts on gluten-dependent changes on human gut epithelial functions. METHODS: We identified, isolated, cultivated, and sequenced a unique novel strain (20220303-A2) of B. vulgatus found only in control subjects. Using a human gut organoid system developed from pre-celiac patients, we monitored epithelial phenotype and innate immune cytokines at baseline, after exposure to gliadin, or gliadin plus B. vulgatus cell free supernatant (CFS). RESULTS: Following gliadin exposure, we observed increases in epithelial cell death, epithelial monolayer permeability, and secretion of pro-inflammatory cytokines. These effects were mitigated upon exposure to B. vulgatus 20220303-A2 CFS, which had matched phenotype gene product mutations. These protective effects were mediated by epigenetic reprogramming of the organoids treated with B. vulgatus CFS. CONCLUSIONS: We identified a unique strain of B. vulgatus that may exert a beneficial role by protecting CeD epithelium against a gluten-induced break of epithelial tolerance through miRNA reprogramming. IMPACT: Gut dysbiosis precedes the onset of celiac disease in genetically at-risk infants. This dysbiosis is characterized by the loss of protective bacterial strains in those children who will go on to develop celiac disease. The paper reports the mechanism by which one of these protective strains, B. vulgatus, ameliorates the gluten-induced break of gut epithelial homeostasis by epigenetically re-programming the target intestinal epithelium involving pathways controlling permeability, immune response, and cell turnover.

Microbiome signatures of progression toward celiac disease onset in at-risk children in a longitudinal prospective cohort study.

Other than exposure to gluten and genetic compatibility, the gut microbiome has been suggested to be involved in celiac disease (CD) pathogenesis by mediating interactions between gluten/environmental factors and the host immune system. However, to establish disease progression markers, it is essential to assess alterations in the gut microbiota before disease onset. Here, a prospective metagenomic analysis of the gut microbiota of infants at risk of CD was done to track shifts in the microbiota before CD development. We performed cross-sectional and longitudinal analyses of gut microbiota, functional pathways, and metabolites, starting from 18 mo before CD onset, in 10 infants who developed CD and 10 matched nonaffected infants. Cross-sectional analysis at CD onset identified altered abundance of six microbial strains and several metabolites between cases and controls but no change in microbial species or pathway abundance. Conversely, results of longitudinal analysis revealed several microbial species/strains/pathways/metabolites occurring in increased abundance and detected before CD onset. These had previously been linked to autoimmune and inflammatory conditions (e.g., Dialister invisus, Parabacteroides sp., Lachnospiraceae, tryptophan metabolism, and metabolites serine and threonine). Others occurred in decreased abundance before CD onset and are known to have anti-inflammatory effects (e.g., Streptococcus thermophilus, Faecalibacterium prausnitzii, and Clostridium clostridioforme). Additionally, we uncovered previously unreported microbes/pathways/metabolites (e.g., Porphyromonas sp., high mannose-type N-glycan biosynthesis, and serine) that point to CD-specific biomarkers. Our study establishes a road map for prospective longitudinal study designs to better understand the role of gut microbiota in disease pathogenesis and therapeutic targets to reestablish tolerance and/or prevent autoimmunity.

Early Antibody Dynamics in a Prospective Cohort of Children At Risk of Celiac Disease.

INTRODUCTION: The purpose of this study was to identify possible serum biomarkers predicting celiac disease (CD) onset in children at risk. METHODS: A subgroup from an ongoing, international prospective study of children at risk of CD was classified according to an early trajectory of deamidated gliadin peptides (DGPs) immunoglobulin (Ig) G and clinical outcomes (CD, potential CD, and CD autoimmunity). RESULTS: Thirty-eight of 325 children developed anti-tissue transglutaminase IgA antibody (anti-tTG IgA) seroconversion. Twenty-eight of 38 children (73.6%) showed an increase in anti-DGPs IgG before their first anti-tTG IgA seroconversion. DISCUSSION: Anti-DGPs IgG can represent an early preclinical biomarker predicting CD onset in children at risk.

No Increased Risk of Taking Additional Intestinal Mucosal Research Biopsies From the Duodenum During Pediatric Endoscopy.

Studies involving human intestinal tissue are essential for advancing the field of celiac disease (CeD), as diagnosis requires duodenal biopsies. Performing studies in children helps to better understand CeD in this important subpopulation. This study aims to determine the risk in obtaining duodenal research biopsies during pediatric endoscopy. In this retrospective chart review from 2016 to 2022 of 1180 research subjects and controls, there were 18 procedure-related adverse events within 48 hours. Most adverse events were for symptoms of pain and fever. There was no increased risk of adverse events if additional duodenal research biopsies were taken during pediatric endoscopy.

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.

The Spectrum of Duodenal Histologic Findings in Patients With Trisomy 21: A Multicenter Study.

OBJECTIVES: Patients with Trisomy 21 (T21) commonly have gastrointestinal symptoms and diseases that prompt evaluation with esophagogastroduodenoscopy (EGD). Our objective is to characterize duodenal histological abnormalities in these patients when undergoing EGD. A secondary aim is to explore associations of histologic findings with different therapies. METHODS: Patients 30 years old or younger with T21 who underwent EGD from 2000 to 2020 at 6 hospitals were included in this retrospective cohort study. Duodenal biopsies were categorized based on reported histopathology findings as normal or abnormal. Abnormal pathology reports were reviewed and categorized into villous atrophy (VA) and duodenitis without VA. The VA group was further categorized based on the presence or absence of celiac disease (CD). RESULTS: We identified 836 patients with T21 who underwent EGD, 419 (50.1%) of whom had duodenal histologic abnormalities. At the time of the first (index) abnormal duodenal biopsy, 290 of 419 had VA and of those, 172 of 290 met CD diagnostic criteria, while 118 of 290 did not meet CD criteria (nonspecific VA). Among the patients with an abnormal biopsy, acid suppression at the time of the index biopsy was less common in patients with VA-CD compared to patients without VA or patients with nonspecific VA (12.2% vs 45.7% vs 44.9%). CONCLUSIONS: Half of the T21 patients in this cohort had abnormal duodenal biopsies including a subgroup with nonspecific VA. In this cohort, acid suppression use was more prevalent in patients with abnormalities other than CD.

AGA Clinical Practice Update on the Evaluation and Management of Seronegative Enteropathies: Expert Review.

DESCRIPTION: Our aim was to provide a consensus statement for the best approaches for diagnosis and management of patients with suspected enteropathy, but negative results from serologic tests for celiac disease (seronegative enteropathy). METHODS: We collected findings from published cohort, case-control, and cross-sectional studies of diagnosis and case series and descriptive studies of management of patients believed to have celiac disease or other enteropathies unrelated to gluten, but negative results from serologic tests. BEST PRACTICE ADVICE 1: Review histologic findings with experienced pathologists who specialize in gastroenterology. BEST PRACTICE ADVICE 2: Serologic tests are essential for an accurate diagnosis of celiac disease. For patients with suspected celiac disease but negative results from serologic tests, total IgA level should be measured; patients should also be tested for anti-tissue transglutaminase, IgA against deamidated gliadin peptide, and endomysial antibody (IgA). Patients with total IgA levels below the lower limit of detection and IgG against tissue transglutaminase or deamidated gliadin peptide, or endomysial antibody, should be considered to have celiac disease with selective IgA deficiency rather than seronegative celiac disease. BEST PRACTICE ADVICE 3: Patients' diets should be carefully reviewed and duodenal biopsies should be collected and analyzed at the time of serologic testing to determine exposure to gluten and accuracy of test results. BEST PRACTICE ADVICE 4: Thorough medication histories should be collected from patients, with attention to angiotensin II receptor blockers, such as olmesartan, along with travel histories to identify potential etiologies of villous atrophy. This will guide additional testing. BEST PRACTICE ADVICE 5: Patients should be analyzed for disease-associated variants in human leukocyte antigen genes; results must be carefully interpreted. Negative results can be used to rule out celiac disease in seronegative patients. BEST PRACTICE ADVICE 6: Patients with suspected celiac disease who are seronegative but have villous atrophy and genetic risk factors for celiac disease must undergo endoscopic evaluation after 1-3 years on a gluten-free diet to evaluate improvements in villous atrophy. A diagnosis of seronegative celiac disease can then be confirmed based on clinical and histologic markers of improvement on the gluten-free diet. BEST PRACTICE ADVICE 7: Seronegative patients with an identified cause for enteropathy should be treated accordingly; a follow-up biopsy might or might not be necessary. BEST PRACTICE ADVICE 8: Patients with persistent signs and symptoms who do not respond to a gluten-free diet, and for whom no etiology of enteropathy is ultimately identified, should be treated with budesonide. CONCLUSIONS: These best practice guidelines will aid in diagnosis and management of patients with suspected celiac disease, but negative results from serologic tests.

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.

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

OBJECTIVES: Non-responsive celiac disease (NRCD) is defined as patients having persistent symptoms and enteropathy (Marsh 3 histology) suggestive of active celiac disease (CeD), after following a gluten-free diet (GFD) for at least 12 months. NRCD is suggested to affect 15% of children with CeD but data are limited and there is no research to date describing treatment of children with this condition. The aim of this study was to describe our center's approach to identifying and treating NRCD with budesonide and the Gluten Containing Elimination Diet (GCED). METHODS: We performed a retrospective, single center analysis over a 5-year period of patients with CD less than 18 years of age (inclusive) who underwent treatment for persistent symptoms and enteropathy despite following a GFD. RESULTS: We identified 22 patients with NRCD. Thirteen were treated with the GCED for 3 months with 46% achieving both histological and symptomatic resolution. Nine patients were treated with budesonide (6-9 mg), with 89% achieving both symptomatic and histologic resolution after a median 3-month treatment course. Further, 67% of patients who responded to the GCED and 100% of patients who responded to budesonide remained in remission for at least 6 months following treatment transition back to exclusive GFD. CONCLUSIONS: The GCED and budesonide can provide benefit for NRCD. Most patients with NRCD can return to a GFD after 3 months of treatment.

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

BACKGROUND: Non-responsive celiac disease (NRCD) has many aetiologies, including gluten exposure. Budesonide may be used for refractory celiac disease (RCD) and celiac crisis. AIMS: We reviewed the effectiveness of budesonide to induce clinical and histologic response in NRCD with villous atrophy (VA). METHODS: Case series of adult cases with NRCD and VA prescribed budesonide at two celiac centers. Clinical variables and mucosal recovery (i.e., normal villous architecture within 1 year of treatment) were evaluated. RESULTS: Forty-two cases [77% female, median age 45.0 (IQR 28.3-60.0) years] were included. Most common symptoms were diarrhea (64%) and abdominal pain (62%). Budesonide was initiated at 9 mg (83%) for a median duration of 16.0 weeks (IQR 6.8-25.0 weeks). In total, 57% exhibited a clinical response, positively associated with diarrhea (adjusted OR 6.08 95% CI 1.04-35.47) and negatively with fatigue (adjusted OR 0.18 95% CI 0.03-0.98). Clinical response was higher among those with dietitian counseling prior to budesonide (n = 29, 70 vs. 23%, p < 0.01). Mucosal recovery was observed in 11/24 with follow-up duodenal biopsies. There was no association between clinical response and mucosal recovery, and 79% of clinical responders had a symptomatic relapse. RCD (48%) and chronic gluten exposure (24%) were the main suspected aetiologies of NRCD. Most individuals without a clinical response subsequently received an IBS-related diagnosis. CONCLUSIONS: Budesonide may be effective to induce clinical response in NRCD presenting with diarrhea and VA, but clinical recurrence and lack of mucosal recovery are frequent after tapering. Other diagnoses, including coexisting IBS, may be considered in non-responders to budesonide therapy.

Pediatric Nonceliac Gluten Sensitivity: A Gluten-related Disorder Treatment Center Experience.

OBJECTIVE: The aim of the study was to identify the prevalence and clinical characteristics of children with nonceliac gluten sensitivity (NCGS) presenting to a tertiary care center specialized for evaluation of gluten-related disorders. METHODS: The medical records of all patients aged 0 to 18 years who presented to our center over a 4-year period (July 2013-June 2018) and consented to participate in our research registry were reviewed. Patients meeting the clinical criteria for NCGS were reviewed in detail. RESULTS: Among 500 pediatric patients who volunteered to participate in the registry during the study period, we identified 26 (5.2%) with NCGS. Both gastrointestinal and extraintestinal symptoms associated with gluten ingestion were common with abdominal pain (57.7%), bloating (53.9%), rash (53.9%), diarrhea/loose stool (42.3%), and emotional/behavioral issues (42.3%) emerging as the predominant complaints. In addition, children with NCGS demonstrated a high personal history (61.5%) and family history (61.5%) of concomitant allergic/atopic disease. CONCLUSIONS: Even within our highly specialized population of patients with a suspected gluten-related disorder, pediatric NCGS is relatively uncommon. The estimated prevalence and clinical features mirror those previously reported in a similarly highly selective population of adults. In the absence of celiac disease, clinical suspicion for NCGS should arise in a child with gastrointestinal and/or extraintestinal complaints alleviated with gluten removal and considered in symptomatic patients with associated allergic/atopic disease. Proper and adequate exclusion of celiac disease and other potential causes of the clinical complaints is essential to justify adoption of the gluten-free diet according to an appropriate stringency and with dietitian supervision to avoid nutritional deficiencies.

Serum Calprotectin Level in Children: Marker of Obesity and its Metabolic Complications.

AIM: Elevated calprotectin levels have been reported in obese adults but have not been evaluated in pediatric population. We investigated the characteristics of serum calprotectin in overweight and obese children and its association with metabolic comorbidities. METHODS: We enrolled 131 children (11.7 ± 4.1 years). According to body mass index (BMI), the subjects were divided into 3 groups: obese > 95th percentile; overweight BMI 75th-95th percentile, and normal weight BMI < 75th percentile. Patients were classified as having Metabolic Syndrome if they met 3 or more of the following criteria for age and sex: BMI > 97th percentile, triglycerides > 95th percentile, high-density lipoprotein cholesterol < 5th percentile, systolic and/or diastolic blood pressure > 95th percentile, and impaired glucose tolerance. In all patients, calprotectin serum levels were also detected. RESULTS: Calprotectin was higher in obese and overweight children than normal weight subjects (p < 0.001), with calprotectin in females being significantly higher than in males (p = 0.04). Increased calprotectin was related to pathological fasting blood glucose (p < 0.001) and insulin resistance (p = 0.03), while BMI (p = 0.001), and diastolic pressure (p = 0.001) are independent factors for increased calprotectin. CONCLUSIONS: Our findings confirm the association between increased calprotectin and obesity also in children and suggest the potential utility of this biomarker in the monitoring of its metabolic complications.

Value of IgA tTG in Predicting Mucosal Recovery in Children With Celiac Disease on a Gluten-Free Diet.

OBJECTIVES: Our objective was to determine the rate of mucosal recovery in pediatric patients with celiac disease on a gluten-free diet. We also sought to determine whether immunoglobulin A tissue transglutaminase (tTG) correlates with mucosal damage at the time of a repeat endoscopy with duodenal biopsy in these patients. METHODS: We performed a retrospective chart review of 103 pediatric patients, younger than 21 years, with a diagnosis of celiac disease defined as Marsh 3 histology, and who underwent a repeat endoscopy with duodenal biopsy at least 12 months after initiating a gluten-free diet. RESULTS: We found that 19% of pediatric patients treated with a gluten-free diet had persistent enteropathy. At the time of the repeat biopsy, tTG was elevated in 43% of cases with persistent enteropathy and 32% of cases in which there was mucosal recovery. Overall the positive predictive value of the autoantibody tTG was 25% and the negative predictive value was 83% in patients on a gluten-free diet for a median of 2.4 years. CONCLUSIONS: Nearly 1 in 5 children with celiac disease in our population had persistent enteropathy despite maintaining a gluten-free diet and immunoglobulin A tTG was not an accurate marker of mucosal recovery. Neither the presence of symptoms nor positive serology were predictive of a patient's histology at the time of repeat biopsy. These findings suggest a revisitation of monitring and management criteria of celiac disease in childhood.

Celiac Disease and Nonceliac Gluten Sensitivity: A Review.

IMPORTANCE: The prevalence of gluten-related disorders is rising, and increasing numbers of individuals are empirically trying a gluten-free diet for a variety of signs and symptoms. This review aims to present current evidence regarding screening, diagnosis, and treatment for celiac disease and nonceliac gluten sensitivity. OBSERVATIONS: Celiac disease is a gluten-induced immune-mediated enteropathy characterized by a specific genetic genotype (HLA-DQ2 and HLA-DQ8 genes) and autoantibodies (antitissue transglutaminase and antiendomysial). Although the inflammatory process specifically targets the intestinal mucosa, patients may present with gastrointestinal signs or symptoms, extraintestinal signs or symptoms, or both, suggesting that celiac disease is a systemic disease. Nonceliac gluten sensitivity is diagnosed in individuals who do not have celiac disease or wheat allergy but who have intestinal symptoms, extraintestinal symptoms, or both, related to ingestion of gluten-containing grains, with symptomatic improvement on their withdrawal. The clinical variability and the lack of validated biomarkers for nonceliac gluten sensitivity make establishing the prevalence, reaching a diagnosis, and further study of this condition difficult. Nevertheless, it is possible to differentiate specific gluten-related disorders from other conditions, based on currently available investigations and algorithms. Clinicians cannot distinguish between celiac disease and nonceliac gluten sensitivity by symptoms, as they are similar in both. Therefore, screening for celiac disease must occur before a gluten-free diet is implemented, since once a patient initiates a gluten-free diet, testing for celiac disease is no longer accurate. CONCLUSIONS AND RELEVANCE: Celiac disease and nonceliac gluten sensitivity are common. Although both conditions are treated with a gluten-free diet, distinguishing between celiac disease and nonceliac gluten sensitivity is important for long-term therapy. Patients with celiac disease should be followed up closely for dietary adherence, nutritional deficiencies, and the development of possible comorbidities.