Antibodies to deamidated gliadin peptides: an accurate predictor of coeliac disease in infancy

The Celiac-Disease Superantigen Oligomerizes and Increases Permeability in an Enterocyte Cell Model

Celiac disease (CeD) is an autoimmune disorder triggered by gluten proteins, affecting approximately 1 % of the global population. The 33-mer deamidated gliadin peptide (DGP) is a metabolically modified wheat-gluten superantigen for CeD. Here, we demonstrate that the 33-mer DGP spontaneously assembles into oligomers with a diameter of approximately 24 nm. The 33-mer DGP oligomers present two main secondary structural motifs-a major polyproline II helix and a minor β-sheet structure. Importantly, in the presence of 33-mer DGP oligomers, there is a statistically significant increase in the permeability in the gut epithelial cell model Caco-2, accompanied by the redistribution of zonula occludens-1, a master tight junction protein. These findings provide novel molecular and supramolecular insights into the impact of 33-mer DGP in CeD and highlight the relevance of gliadin peptide oligomerization.

American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease

This guideline presents an update to the 2013 American College of Gastroenterology Guideline on the Diagnosis and Management of Celiac Disease with updated recommendations for the evaluation and management of patients with celiac disease (CD). CD is defined as a permanent immune-mediated response to gluten present in wheat, barley, and rye. CD has a wide spectrum of clinical manifestations that resemble a multisystemic disorder rather than an isolated intestinal disease, and is characterized by small bowel injury and the presence of specific antibodies. Detection of CD-specific antibodies (e.g., tissue transglutaminase) in the serum is very helpful for the initial screening of patients with suspicion of CD. Intestinal biopsy is required in most patients to confirm the diagnosis. A nonbiopsy strategy for the diagnosis of CD in selected children is suggested and discussed in detail. Current treatment for CD requires strict adherence to a gluten-free diet (GFD) and lifelong medical follow-up. Most patients have excellent clinical response to a GFD. Nonresponsive CD is defined by persistent or recurrent symptoms despite being on a GFD. These patients require a systematic workup to rule out specific conditions that may cause persistent or recurrent symptoms, especially unintentional gluten contamination. Refractory CD is a rare cause of nonresponsive CD often associated with poor prognosis.

Diagnostic Value of Immunoglobulin G Anti-Deamidated Gliadin Peptide Antibody for Diagnosis of Pediatric Celiac Disease: A Study from Shiraz, Iran

PURPOSE

Screening serologic tests are important tools for the diagnosis of celiac disease (CD). Immunoglobulin (Ig)G anti-deamidated gliadin peptide (anti-DGP) is a relatively new autoantibody thought to have good diagnostic accuracy, comparable to that of anti-tissue transglutaminase (anti-tTG) antibody.

METHODS

Pediatric patients (n=86) with a clinical suspicion of CD were included. Duodenal biopsy, anti-tTG, and IgG anti-DGP antibody tests were performed. The patients were divided into CD and control groups based on the pathological evaluation of duodenal biopsies. The diagnostic accuracy of serological tests was determined.

RESULTS

IgA anti-tTG and IgG anti-DGP antibodies were positive in 86.3% and 95.4% of patients, respectively. The sensitivity, specificity, and diagnostic accuracy of the IgA anti-tTG test were 86.3%, 50.0%, and 68.6%, respectively, and those of the IgG anti-DGP test were 95.4%, 85.7%, and 90.7%, respectively. The area under the receiver operating characteristic (ROC) curve was 0.84 (95% confidence interval [CI], 0.74-0.91) for IgA anti-tTG test and 0.93 (95% CI, 0.86-0.97) for IgG anti-DGP test. The comparison of IgA anti-tTG and IgG anti-DGP ROC curves showed a higher sensitivity and specificity of the IgG anti-DGP test.

CONCLUSION

IgG anti-DGP is a reliable serological test for CD diagnosis in children. High tTG and DGP titers in the serum are suggestive of severe duodenal atrophy. The combined use of IgA anti-tTG and IgG anti-DGP tests for the initial screening of CD can improve diagnostic sensitivity.

Biomarkers to Monitor Adherence to Gluten-Free Diet by Celiac Disease Patients: Gluten Immunogenic Peptides and Urinary miRNAs

Celiac disease (CD) is a multifactorial autoimmune enteropathy with a prevalence greater than 1% in the pediatric population. The only therapy for CD patients is a strict gluten-free diet (GFD). Gluten-free food contamination by other cereals during packaging and cooking or accidental ingestion of gluten may cause several intestinal and extraintestinal symptoms in CD patients. Therefore, the monitoring of gluten contamination in food and assessing the level of ingested gluten by analytical biomarkers has been of great interest in recent years. To this aim, small gluten immunogenic peptides (GIPs) obtained by the hydrolysis of gluten and present in urine and feces have been studied as biomarkers of gluten intake and to monitor adherence to GFD by CD patients. More recently, the use of circulating, fecal and urinary miRNAs has emerged as a novel diagnostic tool that can be potentially applied to assess adherence to GFD. Moreover, the presence of GIPs and miRNAs in both feces and urine suggests a similar excretion modality and the possibility of using urinary miRNAs, similarly to GIPs, as potential biomarkers of GFD in CD patients.

Changes in Non-Deamidated versus Deamidated Epitope Targeting and Disease Prediction during the Antibody Response to Gliadin and Transglutaminase of Infants at Risk for Celiac Disease

Celiac disease (CeD) is a conditional autoimmune disorder with T cell-mediated immune response to gluten coupled with antibody production to gliadin and the self-protein tissue transglutaminase (TG2). TG2 contributes to the CeD pathomechanism by deamidating gliadin, thereby generating more immunogenic peptides. Anti-gliadin antibodies may appear before the autoantibody production. The scope of this study was to dissect these early antibody responses by investigating serum samples collected during the PreventCD prospective double-blind study, where infants with high CeD risk were randomized to 200 mg daily gluten intake or placebo from 4 to 6 months of age, followed by frequent blood testing on regular gluten consumption in both groups. After primary gluten intake, children with or without later CeD produced IgA and IgG antibodies which preferentially recognized non-deamidated gliadin peptides. At CeD development with anti-TG2 seroconversion, there was a significant increase in the antibody reaction toward deamidated gliadin peptides (DGP), with maturation in the binding strength for the PEQPFP gamma-gliadin core peptide. The earliest produced autoantibodies targeted TG2’s celiac epitope 2. Our results reveal a qualitative change in the gliadin-directed humoral immune response at the time when anti-TG2 antibodies appear, but anti-DGP antibodies in the absence of anti-TG2 antibodies are not disease-predictive.

Circulating microRNAs as novel non-invasive biomarkers of paediatric celiac disease and adherence to gluten-free diet

Background

Celiac Disease (CD) is a multifactorial autoimmune enteropathy (with a prevalence of approximately 1% worldwide) that exhibits a wide spectrum of clinical, serological and histological manifestations. For the diagnosis of paediatric CD, the gold standard is the combination of serological tests (with high TGA-IgA values greater than 10 times the upper limit of normal) and duodenal biopsy (with a positive TGA-IgA but low titer). Therefore, a diagnostic test that totally excludes an invasive approach has not been discovered so far and the discovery of novel biological markers would represent an undoubted advantage for the diagnosis of CD and prognostic evaluation. MicroRNAs (miRNAs), small non-coding RNAs (18–22 nucleotides) that regulate gene expression at post-transcriptional level and play important roles in many biological processes, represent a novel class of potential disease biomarkers. Their presence in biological fluids (i.e., serum, plasma, saliva, urine) provides the opportunity to employ circulating miRNAs as novel non-invasive biomarkers.

Methods

In our prospective observational study, we examined the expression of circulating miRNAs in a cohort of CD patients (both at diagnosis and on gluten-free diet, respectively referred as CD and GFD) compared to healthy controls. By small RNA-Seq we discovered a set of circulating miRNAs that were further validated by qPCR with specific assays.

Findings

We found that out of the 13 miRNAs able to discriminate the three groups (i.e., CD, GFD and controls), three of them, namely miR-192-5p, miR-215-5p and miR-125b-5p (alone or in combination), were able to discriminate these three groups with high accuracy and specificity.

Interpretation

Our conclusions emphasize that these circulating miRNAs can be employed not only for the diagnosis of CD patients with a low TGA-IgA titer but also to monitor the adherence to a gluten-free diet by CD patients. In conclusion, we suggest the use of the circulating miRNAs identified in this work as a novel diagnostic and follow-up tool for paediatric CD.

Funding

This work was supported by Fondazione Celiachia Onlus (FC) Grant n° 018/FC/2013 and by Italian Ministry of Health (Ricerca Corrente).

Diagnostic Accuracy of IgA Anti-Transglutaminase and IgG Anti-Deamidated Gliadin for Diagnosis of Celiac Disease in Children under Two Years of Age: A Systematic Review and Meta-Analysis

The need of adding the determination of anti-deamidated gliadin peptide (DGP) IgG to anti-transglutaminase (TTG) IgA antibodies for diagnosis of celiac disease (CD) in children <2 years of age is controversial. We performed a systematic review and meta-analysis to evaluate, by head-to-head comparison, the diagnostic accuracy of TTG IgA and DGP IgG antibodies. We searched PubMed, MEDLINE, and Embase databases up to January 2021. The diagnostic reference was intestinal biopsy. We calculated the sensitivity and specificity of these tests and the odds ratio (OR) between the tests. Fifteen articles were eligible for the systematic review and ten were eligible for the meta-analysis. Sensitivity and specificity were 0.96 (95% confidence interval (CI), 0.91–0.98) and 0.96 (95% CI, 0.85–0.99) for DGP IgG and 0.93 (95% CI, 0.88–0.97) and 0.98 (95% CI, 0.96–0.99) for TTG IgA, respectively. TTG IgA specificity was significantly higher (OR 9.3 (95% CI, 2.3–37.49); p < 0.001) while the sensitivity of DGP IgG was higher without reaching statistical significance (OR: 0.6 (95% CI, 0.24–1.51); p = 0.28). Both the meta-analysis and the systematic review showed that some children with early CD are missed without the DGP IgG test. In children <2 years of age, TTG IgA is the best CD screening test; however, the addition of DGP IgG may increase the diagnostic sensitivity.

The Progression of Celiac Disease, Diagnostic Modalities, and Treatment Options

Celiac disease (CD) is an autoimmune disorder that affects genetically predisposed individuals who are sensitive to gluten and related proteins. It affects children and adults with increasing prevalence in the older age groups. Both adaptive and innate immune responses play role in CD pathogenesis which results in damage of lamina propria and deposition of intraepithelial lymphocytes. There are other proposed mechanisms of CD pathogenesis like gastrointestinal infections, intestinal microbiota, and early introduction of gluten. The diagnosis of CD is based on clinical symptoms and serological testing, though a majority of cases are asymptomatic, and small intestinal biopsies are required to confirm the diagnosis. Celiac disease is generally associated with other autoimmune diseases, and it is advisable to test these patients for diseases like type 1 diabetes mellitus, Addison’s disease, thyroid diseases, inflammatory bowel disease, and autoimmune hepatitis. The patient with a new diagnosis of CD requires close follow-up after starting treatment to see symptom improvement and check dietary compliance. A newly diagnosed patient is advised to follow with a dietitian to better understand the dietary restrictions as about 20% of patients stay symptomatic even after starting treatment due to noncompliance or poor understanding of diet restrictions. The most effective treatment for CD is a gluten-free diet, but work on non-dietary therapy is in process and few medications are in the clinical trial phase.

Diagnosing coeliac disease: A literature review

Coeliac disease (CD) is an autoimmune gastroenteropathy triggered by gliadin and gliadin-tissue transglutaminase (tTG) complexes. CD is one of the few autoimmune diseases with an accurate, non-invasive serological test. Anti-endomysial, anti-tTG and anti-deaminated gliadin peptides (DGP) antibodies are currently used for serological tests with tTG ELISAs being the superior test. Duodenal biopsy, although invasive, is the gold standard for CD diagnosis. HLA genotyping and flow cytometry can also be used as supplementary tests. The incidence of CD is rising globally although the reasons for this remain unclear. In addition, the true incidence of coeliac disease in African populations remains unknown although recent work suggests that South African populations express the alleles associated with this disease. This review examines the pathogenesis and diagnosis of coeliac disease and considers novel and innovative biomarkers in its diagnosis specifically in an African population.

Life-threatening onset of coeliac disease: a case report and literature review

BACKGROUND

Coeliac disease (CD) results from an immune-mediated reaction to gluten in genetically predisposed individuals. In rare cases CD may occur with acute features deferring the diagnosis and exposing these patients to possible life-threatening complications. Herein we present the case of a young woman with a coeliac crisis, that is, a sudden clinical onset characterised by severe electrolyte imbalance due to an unknown (previously unrecognised) CD.

METHODS

This is a case report and literature review revealing that coeliac crisis is under-reported, with a total of 48 adult cases so far published. The diagnosis in our case was established by histopathological analysis of multiple duodenal biopsies. The patient's serum was tested by enzyme-linked immunoassay to detect antitransglutaminase IgA antibodies.

RESULTS

In contrast to cases reported in the literature, with male gender predominance and a mean age of 50±17 years, our patient was a young female case of coeliac crisis. However, like in our patient, a higher incidence of coeliac crisis was associated with the human leucocyte antigen (HLA)-DQ2 haplotype, versus HLA-DQ8, and a severe (Marsh-Oberhüber 3c) duodenal mucosa atrophy. Notably, there is no clear correlation between the antitissue transglutaminase 2 IgA antibody titre and coeliac crisis onset/severity, as confirmed by our case report.

CONCLUSIONS

The present case highlights that CD may manifest quite abruptly with a severe malabsorption syndrome, that is, electrolyte abnormalities and hypoproteinaemia. Our case should alert physicians, in particular those in the emergency setting, that even a typically chronic disorder, such as CD, may show life-threatening complications requiring urgent management.

Does Having Rotavirus Infection in Early Childhood Increase the Risk of Celiac Disease?

Objective With the increasing prevalence of celiac disease (CD) in the population, possible risk factors are under investigation. Environmental and genetic factors that trigger the immune response have been analyzed for many years. This study investigates the presence of CD in children with rotavirus infection. Rotavirus infection is thought to be a risk factor for CD.

Methods Included in the study were 105 of 160 pediatric patients hospitalized due to symptomatic rotavirus infection between 2012 and 2018. These children were screened for CD 45.6 ± 18.2 (14–90) months following the rotavirus infection diagnosed with CD as per ESPGHAN guidelines.

Results A total of 105 pediatric patients who had rotavirus gastroenteritis were included in the study. The age of the children with rotavirus infection was 3.98 ± 1 (2–6) months. In terms of CD, it was 45.6 ± 18.2 months. Around 14 to 90 months later, patients were called for control. CD developed in four (3.8%) of the children with rotavirus, whereas none of the children in the control group developed CD.

Conclusion Rotavirus infection may be a risk factor for CD through immune mechanisms. There are genetic and various environmental factors for the development of CD. Although the CD's occurrence on children who had rotavirus gastroenteritis in our study also supported this situation, there was no statistically significant difference.

Effect of Gluten-Free Diet on Gut Microbiota Composition in Patients with Celiac Disease and Non-Celiac Gluten/Wheat Sensitivity

Celiac disease (CD) and non-celiac gluten/wheat sensitivity (NCG/WS) are the two most frequent conditions belonging to gluten-related disorders (GRDs). Both these diseases are triggered and worsened by gluten proteins ingestion, although other components, such as amylase/trypsin inhibitors (ATI) and fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), seem to be involved in the NCG/WS onset. Therefore, the only effective treatment to date is the long-life adherence to a strictly gluten-free diet. Recently, increasing attention has been paid to the intestinal barrier, a dynamic system comprising various components, which regulate the delicate crosstalk between metabolic, motor, neuroendocrine and immunological functions. Among the elements characterizing the intestinal barrier, the microbiota plays a key role, modulating the gut integrity maintenance, the immune response and the inflammation process, linked to the CD and NCG/WS outbreak. This narrative review addresses the most recent findings on the gut microbiota modulation induced by the gluten-free diet (GFD) in healthy, CD and NCG/WS patients.

Celiac disease: a comprehensive current review

BACKGROUND

Celiac disease remains a challenging condition because of a steady increase in knowledge tackling its pathophysiology, diagnosis, management, and possible therapeutic options.

MAIN BODY

A major milestone in the history of celiac disease was the identification of tissue transglutaminase as the autoantigen, thereby confirming the autoimmune nature of this disorder. A genetic background (HLA-DQ2/DQ8 positivity and non-HLA genes) is a mandatory determinant of the development of the disease, which occurs with the contribution of environmental factors (e.g., viral infections and dysbiosis of gut microbiota). Its prevalence in the general population is of approximately 1%, with female predominance. The disease can occur at any age, with a variety of symptoms/manifestations. This multifaceted clinical presentation leads to several phenotypes, i.e., gastrointestinal, extraintestinal, subclinical, potential, seronegative, non-responsive, and refractory. Although small intestinal biopsy remains the diagnostic 'gold standard', highly sensitive and specific serological tests, such as tissue transglutaminase, endomysial and deamidated gliadin peptide antibodies, have become gradually more important in the diagnostic work-up of celiac disease. Currently, the only treatment for celiac disease is a life-long, strict gluten-free diet leading to improvement in quality of life, ameliorating symptoms, and preventing the occurrence of refractory celiac disease, ulcerative jejunoileitis, and small intestinal adenocarcinoma and lymphoma.

CONCLUSIONS

The present review is timely and provides a thorough appraisal of various aspects characterizing celiac disease. Remaining challenges include obtaining a better understanding of still-unclear phenotypes such as slow-responsive, potential (minimal lesions) and seronegative celiac disease. The identification of alternative or complementary treatments to the gluten-free diet brings hope for patients unavoidably burdened by diet restrictions.

Celiac Disease: Clinical Features and Diagnosis

The presentation in celiac disease is shifting from the classical malabsorptive presentation to more nonclassical presentations, requiring clinicians to maintain a high level of suspicion for the disease and to be aware of the possible extraintestinal manifestations. The diagnosis of celiac disease is guided by initial screening with serology, followed by confirmation with an upper endoscopy and small intestinal biopsy. In some pediatric cases, biopsy may be avoided.

Novel screening test for celiac disease using peptide functionalised gold nanoparticles

AIM

To develop a screening test for celiac disease based on the coating of gold nanoparticles with a peptide sequence derived from gliadin, the protein that triggers celiac disease.

METHODS

20 nm gold nanoparticles were first coated with NeutrAvidin. A long chain Polyethylene glycol (PEG) linker containing Maleimide at the Ω-end and Biotin group at the α-end was used to ensure peptide coating to the gold nanoparticles. The maleimide group with the thiol (-SH) side chain reacted with the cysteine amino acid in the peptide sequence and the biotinylated and PEGylated peptide was added to the NeutrAvidin coated gold nanoparticles. The peptide coated gold nanoparticles were then converted into a serological assay. We used the peptide functionalised gold nanoparticle-based assay on thirty patient serum samples in a blinded assessment and compared our results with the previously run serological and pathological tests on these patients.

RESULTS

A stable colloidal suspension of peptide coated gold nanoparticles was obtained without any aggregation. An absorbance peak shift as well as color change was caused by the aggregation of gold nanoparticles following the addition of anti-gliadin antibody to peptide coated nanoparticles at levels associated with celiac disease. The developed assay has been shown to detect anti-gliadin antibody not only in quantitatively spiked samples but also in a small-scale study on real non-hemolytic celiac disease patient’s samples.

CONCLUSION

The study demonstrates the potential of gold nanoparticle-peptide based approach to be adapted for developing a screening assay for celiac disease diagnosis. The assay could be a part of an exclusion based diagnostic strategy and prove particularly useful for testing high celiac disease risk populations.

Prospective Evaluation of the ESPGHAN Guidelines for Diagnosis of Celiac Disease in New Zealand Children

OBJECTIVE

The 2012 European Society of Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guideline for diagnosis of celiac disease (CD) questioned the requirement for intestinal biopsy to confirm the diagnosis. The guideline recommends that in symptomatic patients with consistent human leukocyte antigen (HLA) subtypes, the diagnostic accuracy of strongly positive serology is sufficient to confirm the diagnosis. We prospectively assessed these guidelines in a "real-life" clinical setting.

METHODS

One hundred and four children referred for evaluation of possible CD were prospectively recruited. Following informed consent, blood was drawn for serological testing and HLA analysis at upper gastrointestinal endoscopy. Histological findings according to Marsh criteria were correlated with blood results and the accuracy of the guideline analyzed.The study also examined the role of deamidated gliadin peptide (DGP) in the diagnosis of CD.

RESULTS

For symptomatic patients with consistent HLA subtypes, strongly positive serology (as described in the ESPGHAN guidelines) accurately predicted biopsy-proven CD in >95% of cases. DGP was positive in fewer patients than anti-TG2 or EMA. Incorporation of DGP as a second confirmatory serological test in place of EMA was associated with maintained predictive value of guideline, but fewer patients fulfilling criteria for biopsy-free diagnosis.

CONCLUSIONS

The ESPGHAN guideline performs well in our population. Adoption of the guideline would reduce the number of patients requiring endoscopy without compromise in diagnostic accuracy. The involvement of pediatric gastroenterological expertise, however, remains key to diagnosis of CD.

Gluten-related disorders: certainties, questions and doubts

In the last decade, the ingestion of gluten, a heterogeneous complex of proteins present in wheat, rice, barley and probably in oats, has been associated with clinical disorders, such as celiac disease, wheat allergy and recently to non-celiac gluten sensitivity or wheat intolerance syndrome. Gluten-related disorders, which are becoming epidemiologically relevant with an estimated global prevalence of about 5%, require the exclusion of gluten from the diet. For the past 5 years, an important shift in the availability of gluten-free products, together with increased consumption in the general population, has been recorded and is estimated to be about 12-25%. Many people follow a self-prescribed gluten-free diet, despite the fact that the majority have not first been previously excluded, or confirmed, as having gluten disorders. They rely on claims that a gluten-free diet improves general health. In this review, we provide an overview of the clinical disorders related to gluten or wheat ingestion, pointing out the current certainties, open questions, possible answers and several doubts in the management of these conditions. KEY MESSAGE Incidence of gluten-related disorders is increased in the last decade and self-diagnosis is frequent with inappropriate starting of a gluten-free diet. Gluten and wheat are considered as the most important triggers to coeliac disease, wheat allergy and non-celiac gluten sensitivity. Pediatricians, allergologist and gastroenterologist are involved in the management of these conditions and appropriate diagnostic protocols are required.

Increasing Incidence and Altered Presentation in a Population-based Study of Pediatric Celiac Disease in North America

OBJECTIVES

Celiac disease (CD) is a common immune-mediated disorder that affects up to 1% of the general population. Recent reports suggest that the incidence of CD has reached a plateau in many countries. We aim to study the incidence and altered presentation of childhood CD in a well-defined population.

METHODS

Using the Rochester Epidemiology Project, we retrospectively reviewed Mayo Clinic and Olmsted Medical Center medical records from January 1994 to December 2014. We identified all CD cases of patients ages 18 years or younger at the time of diagnosis. Incidence rates were calculated by adjusting for age, sex, and calendar year and standardizing to the 2010 US white population.

RESULTS

We identified 100 patients with CD. Incidence of CD has increased from 8.1 per 100,000 person-years (2000-2002) to 21.5 per 100,000 person-years (2011-2014). There was an increase in CD prevalence in children from 2010 (0.10%) to 2014 (0.17%). Thirty-four patients (34%) presented with classical CD symptoms, 43 (43%) had nonclassical CD, and 23 (23%) were diagnosed by screening asymptomatic high-risk patients. Thirty-six patients (36%) had complete villous atrophy, 51 (51%) had partial atrophy, and 11 (11%) had increased intraepithelial lymphocytes. Two patients were diagnosed without biopsy. Most patients (67%) had a normal body mass index, 17% were overweight/obese, and only 9% were underweight.

CONCLUSIONS

Both incidence and prevalence of CD have continued to increase in children during the past 15 years in Olmsted County, Minnesota. Clinical and pathologic presentations of CD are changing over time (more nonclassical and asymptomatic cases are emerging).

Celiac disease: from etiological factors to evolving diagnostic approaches

Celiac disease has advanced from a medical rarity to a highly prevalent disorder. Patients with the disease show varying degrees of chronic inflammation within the small intestine due to an aberrant immune response to the digestion of gliadin found in wheat. As a result, cytokines and antibodies are produced in celiac patients that can be used as specific biomarkers for developing diagnostic tests. This review paper describes celiac disease in terms of its etiological cause, pathological effects, current diagnostic tests based on mucosal biopsy, and the genetic basis for the disease. In addition, it discusses the use of gliadin-induced cytokines, antibodies and autoantibodies as a diagnostic tool for celiac disease. Despite good initial results in terms of sensitivity and specificity, when these immunological tests were used on a large scale, even in combination with genetic testing, the results showed lower predictive value. This review addresses that issue and ends with an outlook on future work required to develop diagnostic tests with greater accuracy in predicting celiac disease in the general public, thus avoiding the need for endoscopy and mucosal biopsy.

Coeliac disease in infants: antibodies to deamidated gliadin peptide come first!

Background

The onset of coeliac disease (CD) in the first year of life is uncommon and the diagnosis can be challenging due to the suboptimal sensitivity of tissue transglutaminase antibodies (tTG) at this age and the many other possible causes of malabsorption in infants. Antibodies to deamidated gliadin peptides (anti-DGPs), especially IgG, may appear earlier than IgA anti-tTG in very young children with CD.

Case presentation

We report here on an 8-month-old child who was evaluated for failure to thrive, constipation and developmental delay. The symptoms started following gluten introduction in the diet. Laboratory tests showed high fecal elastase concentration, normal serum IgA levels with positive IgG and IgA anti-DGPs, whereas anti-tTG were not detected. The duodenal biopsy revealed a complete villous atrophy (Marsh-Oberhuber 3C). The culture of biopsy fragments in the presence of gliadin peptides did not stimulate the production of IgA anti-endomysial antibodies. Genetic testing proved the child was positive for HLA-DQ2 (DQA1*05; DQB1*02) and HLA-DQ8 (DQA1*03, DQB1*0302). Having initiated the gluten-free diet, the symptoms disappeared and the infant experienced rapid catch-up growth with normalization of psychomotor development.

Conclusions

This case report highlights the utility of anti-DGPs for screening infants with suspected CD. The pattern with positivity for IgG and IgA anti-DGPs only is rare in IgA-competent children with biopsy-proven CD. It could be explained in infancy as immaturity of the adaptive immune system.

Review paper. Gluten-related disorders and schizophrenia - potential linking mechanisms, diagnostic and therapeutic challenge

More and more evidence confirms the theory that the intake of cereal products containing gluten may play an important role in the pathogenesis of many diseases. There are also premises indicating the relationship between the so-called gluten-related diseases and the development and course of mental disorders, including schizophrenia.

The aim of this article is to review the literature on the potential relationship between the consumption of gluten and schizophrenia, considering the etiopathogenesis and the role of gluten-free diet in the treatment of schizophrenia.

Methods: There were analysed available research papers in PubMed and Google Scholar with the key words: schizophrenia, gluten- related disorders, allergy to grain products, celiac disease, microbiota, immune system, exorphins and time span: 1960-2016 .

Conclusions: Existing research results indicate a possible relationship between diet rich in grain products with high gluten content and the occurrence or exacerbation of schizophrenia symptoms. However, further studies are necessary to: 1) identify groups of patients for whom the consumption of cereal products (gluten) is associated with a particular risk of schizophrenia exacerbation, 2) determine the mechanisms relating the consumption of gluten with the mental state of schizophrenic patients, 3) get the possible benefits of implementing gluten-free diet in patients with schizophrenia.

Celiac disease: a clinical review

Celiac disease (CD) is an immune-mediated inflammatory enteropathy triggered by gluten exposure in genetically susceptible individuals. It has a high prevalence approaching 1% of the US population. A high index of suspicion is warranted to diagnose CD as frequently patients present with extraintestinal or atypical manifestations. CD is diagnosed by a combination of serum serologies and duodenal biopsies. The majority of patients will respond to a lifelong gluten-free diet which is the cornerstone of therapy. Complications such as refractory CD, ulcerative jejunoileitis, enteropathy associated T-cell lymphoma and small bowel adenocarcinoma occur in a minority of patients.

Recent Advances in Celiac Disease

Recent diagnostic advances have demonstrated that celiac disease is relatively common although most patients have less florid symptoms than previously recognised. The mucosal lesion of this autoimmune disorder depends on both adaptive and innate immune responses. The characteristic antibodies to tissue transglutaminase-2 (tTG-2) and deamidated gliadin peptides may be produced in persons possessing the relevant HLA-DQ genotypes if intact gliadin peptides can penetrate the epithelial barrier to reach antigen presenting cells. Progression from celiac autoimmunity to overt disease may depend on innate immune mechanisms, not HLA-restricted, where IL-15 is generated within the epithelial compartment. A specific innate immune response previously thought restricted to invertebrates, the encapsulation reaction, may contribute to mucosal volume expansion through recruitment of syndecan-expressing leukocytes and stimulated matrix production. It is notable that tissue transglutaminase is critical in this reaction in insects, and that the very few insects that can predate wheat, possess specific salivary or intestinal enzymes that degrade gluten. Animal models in HLA-DQ transgenic mice suggest that the microbial flora of the intestine may play a role in host responses and modulate the evolution of the disease. This suggests that therapeutic modulation of the microbiome may contribute to management of celiac disease. In developing world countries, there is a potential difficulty in histological diagnosis because of the widespread incidence of environmental enteropathy amongst apparently healthy children. Thus, recognition of local patterns of enteropathy will be important for histopathologists, and high titre tTG-2 autoantibody titres may hold considerable diagnostic significance.

Immunopathogenesis and therapeutic approaches in pediatric celiac disease

Celiac Disease is an autoimmune enteropathy with increasing incidence worldwide in both adults and children. It occurs as an inflammatory condition with destruction of the normal architecture of villi on consumption of gluten and related protein products found in wheat, barley and rye. However, the exact pathogenesis is not yet fully understood. A gluten-free diet remains the main modality of therapy to date. While some patients continue to have symptoms even on a gluten-free diet, adherence to this diet is also difficult, especially for the children. Hence, there is continued interest in novel methods of therapy and the current research focus is on the promising novel non-dietary modalities of treatment. Here, we critically reviewed the existing literature regarding the pathogenesis of celiac disease in children including the role of in-utero exposure leading to neonatal and infant sensitization and its application for the development of new therapeutic approaches for these patients.

Celiac Disease: Diagnostic Standards and Dilemmas

Celiac Disease (CD) affects at least 1% of the population and evidence suggests that prevalence is increasing. The diagnosis of CD depends on providers being alert to both typical and atypical presentations and those situations in which patients are at high risk for the disease. Because of variable presentation, physicians need to have a low threshold for celiac testing. Robust knowledge of the pathogenesis of this autoimmune disease has served as a catalyst for the development of novel diagnostic tools. Highly sensitive and specific serological assays including Endomysial Antibody (EMA), tissue transglutaminase (tTG), and Deamidated Gliadin Peptide (DGP) have greatly simplified testing for CD and serve as the foundation for celiac diagnosis. In addition, genetic testing for HLA DQ2 and DQ8 has become more widely available and there has been refinement of the gluten challenge for use in diagnostic algorithms. While diagnosis is usually straightforward, in special conditions including IgA deficiency, very young children, discrepant histology and serology, and adoption of a gluten free diet prior to testing, CD can be difficult to diagnose. In this review, we provide an overview of the history and current state of celiac disease diagnosis and provide guidance for evaluation of CD in difficult diagnostic circumstances.

Advances in diagnosis and management of celiac disease

Celiac disease is an autoimmune disorder that is induced by dietary gluten in genetically predisposed individuals. It has a prevalence of approximately 1% in many populations worldwide. New diagnoses have increased substantially, owing to increased awareness, better diagnostic tools, and probable real increases in incidence. The breadth of recognized clinical presentations continues to expand, making the disorder highly relevant to all physicians. Newer diagnostic tools, including serologic tests for antibodies against tissue transglutaminase and deamidated gliadin peptide, greatly facilitate diagnosis. Tests for celiac-permissive HLA-DQ2 and HLA-DQ8 molecules are useful in defined clinical situations. Celiac disease is diagnosed by histopathologic examination of duodenal biopsy specimens. However, according to recent controversial guidelines, a diagnosis can be made without a biopsy in certain circumstances, especially in children. Symptoms, mortality, and risk for malignancy each can be reduced by adherence to a gluten-free diet. This treatment is a challenge, however, because the diet is expensive, socially isolating, and not always effective in controlling symptoms or intestinal damage. Hence, there is increasing interest in developing nondietary therapies.

Clinical and diagnostic aspects of gluten related disorders

Gluten is one of the most abundant and widely distributed components of food in many areas. It can be included in wheat, barley, rye, and grains such as oats, barley, spelt, kamut, and triticale. Gluten-containing grains are widely consumed; in particular, wheat is one of the world’s primary sources of food, providing up to 50% of the caloric intake in both industrialized and developing countries. Until two decades ago, celiac disease (CD) and other gluten-related disorders were believed to be exceedingly rare outside of Europe and were relatively ignored by health professionals and the global media. In recent years, however, the discovery of important diagnostic and pathogenic milestones led CD from obscurity to global prominence. In addition, interestingly, people feeding themselves with gluten-free products greatly outnumber patients affected by CD, fuelling a global consumption of gluten-free foods with approximately $2.5 billion in United States sales each year. The acknowledgment of other medical conditions related to gluten that has arisen as health problems, providing a wide spectrum of gluten-related disorders. In February 2011, a new nomenclature for gluten-related disorders was created at a consensus conference in London. In this review, we analyse innovations in the field of research that emerged after the creation of the new classification, with particular attention to the new European Society for Paediatric Gastroenterology, Hepatology and Nutrition guidelines for CD and the most recent research about non-celiac gluten sensitivity.

Celiac Disease: Diagnosis

Historically the diagnosis of celiac disease has relied upon clinical, serological, and histological evidence. In recent years the use of sensitive serological methods has meant an increase in the diagnosis of celiac disease. The heterogeneous nature of the disorder presents a challenge in the study and diagnosis of the disease with patients varying from subclinical or latent disease to patients with overt symptoms. Furthermore the related gluten-sensitive disease dermatitis herpetiformis, while distinct in some respects, shares clinical and serological features with celiac disease. Here we summarize current best practice for the diagnosis of celiac disease and briefly discuss newer approaches. The advent of next-generation assays for diagnosis and newer clinical protocols may result in more sensitive screening and ultimately the possible replacement of the intestinal biopsy as the gold standard for celiac disease diagnosis.

Diagnosing coeliac disease and the potential for serological markers

The diagnosis of coeliac disease has advanced in the past decade owing to increased clinical awareness and improved tests. Coeliac disease is now regarded as a common disease presenting at any age with a broad spectrum of symptoms. Previous guidelines on diagnosis relied on the histological analysis of duodenal biopsy samples. However, contemporary antibody analysis is a diagnostic tool with a comparatively high accuracy that has reduced reliance on performing biopsies. Furthermore, determination of HLA-based genetic susceptibility to coeliac disease has become routine. European and North American guidelines utilize symptoms, coeliac antibodies (primarily tissue transglutaminase 2 IgA and endomysial IgA antibodies), HLA determination and histological analysis of biopsy tissue for diagnosis. Some guidelines conclude that the diagnostic accuracy of tissue transglutaminase 2 IgA antibodies is sufficient to omit duodenal biopsies in selected children with very high antibody levels, in the presence of clear symptom response as well as a positive endomysial antibody test and confirmation of genetic susceptibility. This Review discusses if such a strategy is appropriate for children and adults in all populations. The performance characteristics of antibody tests (particularly of the tissue transglutaminase 2 IgA test) including quality control and characterisation of the population in whom testing is performed are also discussed.

Antibodies against food antigens in patients with autistic spectrum disorders

PURPOSE

Immune system of some autistic patients could be abnormally triggered by gluten/casein assumption. The prevalence of antibodies to gliadin and milk proteins in autistic children with paired/impaired intestinal permeability and under dietary regimen either regular or restricted is reported.

METHODS

162 ASDs and 44 healthy children were investigated for intestinal permeability, tissue-transglutaminase (tTG), anti-endomysium antibodies (EMA)-IgA, and total mucosal IgA to exclude celiac disease; HLA-DQ2/-DQ8 haplotypes; total systemic antibodies (IgA, IgG, and IgE); specific systemic antibodies: α-gliadin (AGA-IgA and IgG), deamidated-gliadin-peptide (DGP-IgA and IgG), total specific gliadin IgG (all fractions: α, β, γ, and ω), β-lactoglobulin IgG, α-lactalbumin IgG, casein IgG; and milk IgE, casein IgE, gluten IgE,-lactoglobulin IgE, and α-lactalbumin IgE.

RESULTS

AGA-IgG and DPG-IgG titers resulted to be higher in ASDs compared to controls and are only partially influenced by diet regimen. Casein IgG titers resulted to be more frequently and significantly higher in ASDs than in controls. Intestinal permeability was increased in 25.6% of ASDs compared to 2.3% of healthy children. Systemic antibodies production was not influenced by paired/impaired intestinal permeability.

CONCLUSIONS

Immune system of a subgroup of ASDs is triggered by gluten and casein; this could be related either to AGA, DPG, and Casein IgG elevated production or to impaired intestinal barrier function.