In Screening for Celiac Disease, Deamidated Gliadin Rarely Predicts Disease When Tissue Transglutaminase Is Normal

Celiac Disease, Gluten Sensitivity, and Diet Management

PURPOSE OF REVIEW

Celiac disease is a common chronic inflammatory condition of the small bowel triggered by gluten in wheat, rye and barley in the diet. Non-celiac gluten sensitivity presents with symptoms similar to celiac disease with the ingestion of gluten or other components of wheat. In this article, we review challenges presented by a gluten free diet for the treatment of both disorders.

RECENT FINDINGS

Wheat is ubiquitous in the diet and medications/products. A registered dietitian is mandatory for patient education on the gluten free diet. Naturally gluten free foods provide a healthy diet for those with celiac disease. Whole grains labelled gluten free, including oats, are encouraged in the diet as refined grains may be deficient in fiber, protein, and micronutrients, particularly folate. Gluten contamination is the most common cause of persistent symptoms in celiac disease though shared equipment of food preparation may not be as large a problem as suspected. Most with celiac disease on a gluten free diet will fully recover and gain weight that poses a problem for those overweight to start. The gluten free diet may have a negative impact on quality of life for both celiac patients and their families. Those with hypervigilance of the gluten free diet and avoidance of dining out have the lowest quality of life. The gluten free diet is currently the only effective treatment for celiac disease. A registered dietitian is needed to educate patients on the complexity of the gluten free diet with a goal of healthy eating, maintaining a healthy weight, and avoiding disordered eating or diet hypervigilance; key to a good quality of life.

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.

Study of the immune response in celiac patients with selective IgA deficiency who start a gluten-free diet

Studies are scarce regarding IgG anti-tissue transglutaminase 2 (tTG) normalization in selective IgA deficient (SIgAD) celiac disease (CD) patients after beginning a gluten free diet (GFD). The aim of this study is to analyse the decreasing dynamics of IgG anti-tTG in patients diagnosed with CD who start a GFD. To achieve this objective, IgG and IgA anti-tTG levels at diagnosis and during follow-up in 11 SIgAD CD patients and in 20 IgA competent CD patients were retrospectively evaluated. At diagnosis, statistical differences were not found when comparing IgA anti-tTG levels of IgA competent subjects with IgG anti-tTG levels of SIgAD subjects. Regarding the decreasing dynamics, even though no statistical differences were found (p = 0.06), normalization rates were slower for SIgAD CD patients. After 1 and 2 years on GFD, respectively, only 18.2% and 36.3% of the SIgAD CD patients normalized IgG anti-tTG levels; otherwise, IgA anti-tTG reached values under the reference values in 30% and 80% of the IgA competent patients in the same time-points. Although IgG anti-tTG has demonstrated a high diagnostic efficiency in SIgAD CD pediatric patients, this test does not appear to be as precise for long-term GFD response monitoring as IgA anti-tTG levels in IgA sufficient patients.

Do Serological Tests Eliminate the Need for Endoscopic Biopsy for the Diagnosis of Symptomatic Patients with Celiac Disease? A Retrospective Study with Review of Literature

Background: Celiac disease is one of the most common genetic allergies worldwide. The prevalence of celiac disease in Iran is similar to or even higher than the global prevalence. Celiac disease is a chronic inflammatory disease that affects the small intestine. Affected patients are allergic to gluten protein that exists in some grains, such as wheat and barley. Methods: Serological endomysial IgA antibody (EMA-AB) and tissue transglutaminase IgA antibody (TTG-IgA) tests were performed on 114 patients aged the ages of 0-18 years with histopathological findings of celiac disease. The results of these tests were compared to the results of the histopathological study of the duodenal biopsy. Results: Based on the receiver operating characteristic (ROC) curve and a calculation of the TTG-IgA test's sensitivity and specificity, the best diagnostic limit for the TTG-IgA test is 144, which has the best sensitivity and specificity. At this value (cut-off), the test's sensitivity was 62%, and the specificity was 93.7%. For the endomysial test, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 80%, 93%, 90%, and 75%, respectively. Conclusion: The diagnostic accuracy of the endomysial test is better than that of the TTG-IgA test in general for diagnosing patients with celiac disease. In the TTG-IgA test, false-positive cases are high due to a cut-off of 20, reducing the test's specificity. In these false-positive cases, the endomysial test helps in better diagnosis.

The Gluten-Free Diet for Celiac Disease: Critical Insights to Better Understand Clinical Outcomes

The gluten-free diet (GFD) remains a complex paradigm in managing celiac disease (CeD) in children and adults, and there are many reasons why GFD adherence should be strict to improve outcomes. However, this is a challenging task for patients, since they need to have access to quality healthcare resources that facilitate optimal GFD adherence. Understanding the strengths and weaknesses of the GFD, tackling coexisting nutritional deficiencies, and dealing with complex situations, such as seronegative CeD or non-responsive CeD, all require the involvement of a multidisciplinary team. The short- and long-term follow-up of CeD patients should preferably be performed by a combined Gastroenterology and Nutrition service with well-defined quality standards and the multidisciplinary involvement of physicians, nurses, dietitians, and psychologists. Nutritional advice and counseling by an experienced dietitian can reduce the costs associated with long-term follow-up of CeD patients. Likewise, psychological interventions may be essential in specific scenarios where implementing and sustaining a lifelong GFD can cause a significant psychological burden for patients. This manuscript aims to provide guidelines to improve clinical practice in the follow-up and monitoring of CeD patients and provide information on the nutritional risks of an ill-advised GFD. Clinicians, biochemists, food technologists, dietitians, and psychologists with a global view of the disease have been involved in its writing.

Mode of presentation and performance of serology assays for diagnosing celiac disease: A single-center study in the United Arab Emirates

Objective

To characterize patients with celiac disease (CD), examines the clinical spectrum of CD, and evaluate the performance of serologic tests used for CD screening, in the United Arab Emirates (UAE).

Methods

Medical charts of patients received at the Digestive Diseases Institute of Cleveland Clinic Abu Dhabi from January 2015 to December 2020 were reviewed. Patients who were screened for four serologic biomarkers (anti-tissue transglutaminase IgA [Anti-tTG-IgA], anti-tissue transglutaminase IgG [Anti-TtG-IgG], anti-deamidated gliadin peptide IgG [Anti-DGP-IgG], and anti-deamidated gliadin peptide IgA [Anti-DGP-IgA]) were included. Histopathology was performed on patients with the seropositive test. Marsh score &gt; 1 considered to confirm CD. Characteristics of the Anti-tTG-IgA seropositive patients were described and that correlated with histopathologically confirmed CD were explored.

Results

Of the 6,239 patients, 1.4, 2.9, 4.7, and 4.9%, were seropositive to Anti-tTG-IgG, Anti-TtG-IgA, Anti-DGP-IgA, and Anti-DGP-IgG, respectively. Overall, 7.7% were seropositive to either of the four biomarkers. Of the biopsy-screened 300 patients, 38.7% (1.9% of the total serologically screened) were confirmed with CD. The mean age of Anti-TtG-IgA seropositive patients was 32.1 ± 10.3 SD years, 72% of them were females, and 93.4% were Emirati. In those patients, overweight (28.7%) and obesity (24.7%) were common while 5.8% of patients were underweight. Anemia prevalence was 46.7%, 21.3% had Gastroesophageal reflux disease (GERD), 7.7% with autoimmune thyroid disease, 5.5% (type 1), and 3.3% (type 2) were diabetic. Vitamin D deficiency was observed in 47.8% of the Anti-TtG IgA seropositive patients. Twelve (10.3%) histopathologically confirmed CD patients were seronegative to Anti-TtG-IgA but seropositive to anti-DGP-IgA and/or Anti-DGP-IgG. Body mass index, GERD, autoimmune thyroid disease, type 1 diabetes, asthma, hemoglobin, and vitamin D concentration, were all correlated with biopsy-confirmed CD (P &lt; 0.05). Compared to the gold-standard biopsy test, Anti-TtG-IgA had the highest sensitivity (89.7%) and specificity (83.7%).

Conclusion

Three and two of every 100 patients were serologically (anti-tTG-IgA positive) and histopathologically diagnosed with CD, respectively. Although Anti-TtG-IgA is the most sensitive, specific, and commonly used test, one of every ten histopathologically confirmed patients and Anti-tTG-IgA seronegative were seropositive to Anti-DGP. To avoid missing patients with CD, a comprehensive serological investigation covering DGP-IgG/IgA is warranted.

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.

Isolated positive deamidated gliadin peptide-IgG has limited diagnostic utility in coeliac disease

AIM

Deamidated gliadin peptide-IgG (DGP-IgG) antibody serology testing is widely utilised in screening for coeliac disease in Australia; however, it is used sparingly in Europe. The aim of this study was to assess the diagnostic value of a positive DGP-IgG in the setting of a negative tissue transglutaminase-IgA (tTG-IgA) for gastrointestinal pathology among paediatric patients.

METHODS

We conducted a retrospective cohort study of all children with an elevated DGP-IgG in the setting of a negative tTG-IgA who underwent gastroscopy over a 48-month period (January 2015-December 2018) at a tertiary paediatric centre. They were identified utilising the electronic pathology database and demographic and clinical data were collected from electronic medical records. Patients who had previously been diagnosed with coeliac disease were on a gluten-free diet or over the age of 18 were excluded from the study.

RESULTS

Twenty-six patients with an elevated DGP-IgG in the setting of a negative tTG-IgA underwent gastroscopy. Our study yielded a positive predictive value of 1/26 (3.9% CI 95% 0.7%, 18.9%) for the diagnosis of coeliac disease. Overall, there were 25 histopathological diagnoses including 1 diagnosis of coeliac disease among the total 26 patients who were positive DGP-IgG and negative tTG-IgA and underwent gastroscopy.

CONCLUSIONS

Our findings suggest that an isolated positive DGP-IgG has a very low diagnostic yield for coeliac disease in children and may be indicative of other gastrointestinal pathology.

Population-based screening for celiac disease reveals that the majority of patients are undiagnosed and improve on a gluten-free diet

The impact of a gluten-free diet (GFD) on screen-detected celiac disease (CD) is currently ambiguous. We aimed to identify the population-based prevalence of undiagnosed adult CD and examine the impact of a GFD on screen-detected CD. In total, 12,981 adults participated in a population-based health study in Tromsø, Norway. Participants with increased levels of anti-tissue transglutaminase-2 IgA or anti-deamidated gliadin peptide IgG were invited to undergo gastroduodenoscopy with both histological and immunohistochemical examination of small-bowel biopsies. The prevalence of previously diagnosed CD was 0.37%. Additionally, the prevalence of previously undiagnosed CD was 1.10%. Thus, 1.47% of the population had CD, of whom 75% were previously undiagnosed. A GFD resulted in significant improvements in overall gastrointestinal symptoms, diarrhea, and health-related quality of life, with reduced abdominal discomfort (76%) and improved levels of energy (58%). The large majority of patients with adult CD were undiagnosed and benefited from a GFD with reduced gastrointestinal symptoms and improved health-related quality of life. In clinical practice, there should be a low threshold for CD testing even in the absence of abdominal complaints because most adult patients appear to consider their symptoms a part of their normal state and therefore remain untested and undiagnosed.Trial registration: Clinical Trials. Gov Identifier: NCT01695681.

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.

To DGP-IgG or not? A comparison of TTG-IgA and DGP-IgG

BACKGROUND

We assessed the diagnostic utility of deamidated gliadin peptide immunoglobulin G (DGP-IgG) in pediatric patients without immunoglobulin A deficiency who underwent tissue transglutaminase immunoglobulin A (TTG-IgA) screening and biopsy.

METHODS

Patients who had TTG-IgA performed in our laboratory had sample frozen over a 1.5 y. If a patient underwent biopsy within 6 months of serology, DGP-IgG was performed on frozen sample. All testing was performed on the BioPlex 2200. Biopsies were assigned a modified Marsh-Oberhuber score. The sensitivity, specificity, and positive and negative predictive values were calculated for TTG-IgA and DGP-IgG for values ≥ 15 u/ml, 15-149 u/ml, and > 150 u/ml using biopsy as gold standard.

RESULTS

A total of 458 patients were included. Sensitivity and specificity for DGP-IgG ≥ 15 u/ml and Marsh ≥ 2 was 76% and 87.5% and TTG-IgA ≥ 15 was notably higher at 93.3% and 92.2%. Sensitivity and specificity of DGP-IgG were 66% and 88.9% at moderate and 29.3% and 98.4% at high increases. The positive predictive value of DGP-IgG for celiac disease in TTG-IgA negative patients was 2.8%.

CONCLUSIONS

Our study suggests DGP-IgG does not add significant value in patients screened for celiac disease.

Usefulness of deamidated gliadin peptide antibodies in diagnosing coeliac disease in children younger than 3 years old

AIM

The standard serological test to screen for coeliac disease (CD) is tissue transglutaminase (tTG) but some experts recommend including deamidated gliadin peptide (DGP) antibodies for children younger than 3 years old. This study evaluated the utility of DGP-immunoglobulin A (IgA) and DGP-immunoglobulin G (IgG) serologies when screening children younger than 3 years old for CD.

METHODS

A retrospective chart review was conducted including children 3 years old and under, who had DGP and/or tTG serologies along with duodenal biopsies during their initial diagnostic evaluation. Serology results were compared to the gold-standard histopathology by χ² to determine the significance of including DGP-IgG/IgA serologies when screening for CD in this age group.

RESULTS

We identified 478 patients, 52 who were younger than 3 years old, 43 of whom met inclusion criteria. The positive predictive value (PPV) of the DGP-IgA test was 91.7% whereas, DGP-IgG was 77.8%. When DGP serology was examined in conjunction with tTG-IgA, the PPV with DGP-IgA was 90.9% and with DGP-IgG was 87.5%.

CONCLUSIONS

In isolation, DGP-IgA provides a high PPV and specificity for CD in children younger than 3 years old, whereas DGP-IgG had a much lower PPV in this age group. When used alone or in conjunction with tTG-IgA, the DGP-IgA test results in a high PPV of 91.7 and 90.9%, respectively. Based on our study, we recommend obtaining both the DGP-IgA and the tTG-IgA serology when screening infants and children younger than 3 years old for coeliac disease.

The global burden of coeliac disease: opportunities and challenges

Coeliac disease is a systemic disorder characterized by immune-mediated enteropathy, which is caused by gluten ingestion in genetically susceptible individuals. The clinical presentation of coeliac disease is highly variable and ranges from malabsorption through solely extra-intestinal manifestations to asymptomatic. As a result, the majority of patients with coeliac disease remain undiagnosed, misdiagnosed or experience a substantial delay in diagnosis. Coeliac disease is diagnosed by a combination of serological findings of disease-related antibodies and histological evidence of villous abnormalities in duodenal biopsy samples. However, variability in histological grading and in the diagnostic performance of some commercially available serological tests remains unacceptably high and confirmatory assays are not readily available in many parts of the world. Currently, the only effective treatment for coeliac disease is a lifelong, strict, gluten-free diet. However, many barriers impede patients' adherence to this diet, including lack of widespread availability, high cost, cross-contamination and its overall restrictive nature. Routine follow-up is necessary to ensure adherence to a gluten-free diet but considerable variation is evident in follow-up protocols and the optimal disease management strategy is not clear. However, these challenges in the diagnosis and management of coeliac disease suggest opportunities for future research.

Diagnosing and Monitoring Celiac Patients with Selective IgA Deficiency: Still an Open Issue

Although, the association between celiac disease (CD) and selective immunoglobulin A deficiency (SIgAD) has been known for more than fifty years, the procedures for diagnosing and monitoring patients with both conditions are still far from definitive. When serological markers were introduced as pre-bioptic investigations, it was immediately clear that searching for specific IgA antibodies without checking total serum IgA could lead to a failure in diagnosing IgA-deficient CD patients, while specific IgG antibodies could be useful as additional tests, because they are frequently found in the serum of affected patients. Nonetheless, until recently the diagnosis of CD in IgA-deficient patients was based on the few, fragmentary and often contradictory data available in literature. The introduction of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidelines in 2012 provided the current criteria for diagnosing CD in IgA-deficient patients, although some issues remained open, such as the selection of patients who should undergo specific IgG antibody testing and the choice of the most reliable IgG-based test for both diagnosis and follow-up. A real-life study recently assessed the impact of the 2012 ESPGHAN guidelines in diagnosing and monitoring CD in SIgAD patients, highlighting several pitfalls that can lead to operational uncertainties and difficulties in patient management. In the present report, the evolution of diagnostic tools and criteria for CD in SIgAD patients has been critically assessed, both strengths and open issues have been highlighted, and future perspectives for improving the current diagnostic protocols have been suggested.

Deamidated Gliadin Antibodies: Do They Add to Tissue Transglutaminase-IgA Assay in Screening for Celiac Disease?

OBJECTIVES

Use of deamidated gliadin peptide (DGP) test kits as adjunctive to tissue-transglutaminase-IgA (TTG-IgA) for the diagnosis of celiac disease (CD) has been a controversial issue. The objectives of our study were to evaluate the diagnostic performance of DGP antibodies compared with TTG-IgA and to evaluate the correlation between DGP-antibody titers and degree of enteropathy.

METHODS

We included children who underwent endoscopy and biopsies because of positivity of any of the serology tests in the "celiac profile" (TTG-IgA, DGP-IgA, and DGP-IgG) from 2012 to 2019. We divided children into clinically suspected cases of CD (group 1) and asymptomatic cases screened as they were from a high-risk group (group 2).

RESULTS

Group 1 constituted 52 children and group 2 included 81 children (76 type-1 diabetes [T1D]). The sensitivity and positive-predictive value (PPV) of DGP-IgG in group 1 (90%, 98%) and group 2 (91%, 85.5%) were comparable with TTG-IgA (98%, 92% in group 1; 100%, 80% in group 2). By adding DGP-IgG to TTG-IgA, the performance of TTG-IgA has improved marginally in group 1 (sensitivity 100%, PPV 92.3%). All cases with DGP-IgG titer 2 times ULN in group 1, and >4 times ULN in group 2 had villous atrophy. All T1D patients with TTG IgA >10 times ULN had villous atrophy.

CONCLUSIONS

DGP-IgG assay did not add to the performance of TTG-IgA. DGP-IgG titer correlated with enteropathy. The diagnosis of CD can be made in asymptomatic T1D child with TTG-IgA titer >10 times ULN and positive endomyseal antibodies.

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.

Update on celiac disease

PURPOSE OF REVIEW

The purpose of this review is to describe current updates in celiac disease.

RECENT FINDINGS

Recent developments in the understanding of the pathogenesis of celiac disease continue to emerge that may implicate the role of gluten exposure. Several studies have shown that the amount of gluten consumed by the infant may affect the age of onset of celiac disease in genetically predisposed individuals. New guidelines from the European Society of Paediatric Gastroenterology, Hepatology and Nutrition allow serology-based celiac diagnosis, omitting endoscopic biopsies, in children. Recent data and updated guidelines in adults no longer support biopsies in all patients who are genetically susceptible with celiac disease who have been identified by serology with clinical signs and symptoms of celiac disease. A new assay was identified in the immune response to epitopes of the tissue transglutaminase-deamidated gliadin peptide complex. In addition, a recent study shows that serum IL-2 elevations correlate with timing and severity of symptoms after gluten ingested in celiac disease patients. Measuring gluten immunogenic peptides (GIPs) in the stool of celiac patients may help monitor adherence to a gluten-free diet (GFD). Of importance, we should be aware that the quality of life is affected in celiac disease patients. During adolescence, the education on the importance of long-term follow-up with an adult gastroenterologist is associated with more successful rates of medical care transition for young adults with celiac disease. Latiglutenase, an orally administered mixture of two gluten-specific recombinant proteases that degrades gluten proteins into small physiologically irrelevant fragments, is currently in a phase 2 trial. Latiglutenase has shown to be safe and effective in reducing symptoms of celiac disease patients upon a GFD with improvement of quality of life. Lastly, a recent study describes a mouse model that is characteristic of celiac disease.

SUMMARY

Our knowledge of celiac disease continues to grow with increasing evidence of contributory factors to its pathogenesis. There is some evidence that the quantity ingested of gluten by the infant effects the age of onset of celiac disease in genetically susceptible patients. Changes have been made to the guidelines in the diagnosis of celiac disease proposed by new studies. Recent studies have shown the significant effects on quality of life for celiac patients. As improved laboratory methods continue to be developed, these tests can have utility in both diagnosis of celiac disease and monitoring adherence to the GFD. Current therapeutic trials offer promising nondietary treatment for celiac patients. The development of an animal model can provide a better understanding of the pathogenesis of celiac disease.

Chronic diarrhoea in children: A practical algorithm-based approach

Diarrhoea is a leading cause of morbidity and mortality world-wide. Most diarrhoeal episodes are acute and infectious in origin. Diarrhoea lasting for longer than 4 weeks with no discernible infectious aetiology warrants thorough evaluation. The aim of this review is to elucidate an approach to evaluation of diarrhoea based on its pathophysiologic mechanisms with focus on aetiology, investigation and management of chronic diarrhoea. It includes a brief description of normal fluid homeostasis in the gut and pathophysiology of diarrhoea. Further, diarrhoea is classified as 'watery', 'fatty' and 'bloody' based on stool characteristics. Relevant history, physical examination findings, first and second-line investigations which help in differentiating the different types of diarrhoea are listed and an algorithmic approach to individual types of diarrhoea has been devised. Principles of management and recent advances in diagnostics and therapeutics of diarrhoea are briefly discussed.

Optimization of serologic diagnosis of celiac disease in the pediatric setting

BACKGROUND

The clinical presentation of celiac disease (CD) varies between children. The objective of this study was to document the pre-test probability for CD based on symptoms and routine laboratory test and to evaluate the performance of two IgA anti-tissue transglutaminase (tTG) assays. We critically reviewed the concept of using multiples of the manufacturer's upper limit of normal (ULN), as proposed in the ESPGHAN guidelines (if IgA tTG is >10 times ULN, no biopsy is needed).

METHODS

The retrospective study included 91 children with newly diagnosed CD and 605 controls (<16 years). All underwent upper endoscopy with small bowel biopsies. Four laboratory parameters and 16 symptoms were registered. All patients were tested for IgA anti-tTG antibodies with assays from Inova Diagnostics and Thermo Fisher Scientific.

RESULTS

Some combinations of clinical symptoms and laboratory parameters had a high pre-test probability for CD, such as (combinations of) anorexia, failure to thrive, low ferritin level and elevated AST. The diagnostic performance of both IgA anti-tTG assays was excellent and comparable (no difference in ROC curve area under the curve). At a threshold that corresponds to a specificity of 100% (5 times ULN for Inova Diagnostics and 2 times ULN for Thermo Fisher), the sensitivity was 82% for both assays. At the 10 times ULN threshold, the sensitivity differed between the assays (77% vs. 57%), indicating that such threshold does not completely align interpretation across companies.

CONCLUSIONS

Our study showed that some combinations of symptoms and aberrant laboratory parameters had a high pre-test probability. The use of the ESPGHAN non-biopsy approach could reduce small bowel biopsies, but thresholds for IgA-tTG levels are not aligned across assays and should be based on predefined likelihood ratios or specificity.

Celiac Disease

Celiac disease (CD) affects approximately 1% of the general population, although most cases remain unrecognized. Because CD is a multisystem disorder with protean clinical manifestations, a high index of suspicion is needed to make an appropriate diagnosis. A diagnosis of CD is made in a patient who is genetically predisposed based on the presence of compatible clinical features, positive highly specific celiac serologic findings, duodenal biopsies that document enteropathy, and improvement with a gluten-free diet. The differential diagnoses for the clinical features and the histologic findings seen in patients with CD are numerous and need to be considered; because the management of celiac disease consists of a lifelong gluten-free diet, ensuring that the diagnosis is correctly established is of utmost importance. The aim of this review is to provide practicing clinicians with the most current information on the diagnosis and management of CD, including new developments and the approach to controversial issues.

Misuse of serological screening tests for celiac disease in children: A prospective study in Italy

BACKGROUND

Despite a well-established diagnostic algorithm for celiac disease, it remains unclear whether prescriptions for celiac serological tests comply with the current pediatric guidelines.

AIM

To analyze the appropriateness of test prescription in children investigated for celiac disease in Italy, compared to the current European pediatric guidelines.

METHODS

All children who had performed a first evaluation for celiac disease were prospectively enrolled. Prescribed tests and related indications for testing were recorded, and compared to the European pediatric guidelines.

RESULTS

Overall, 202 children were enrolled (females 59%, mean age 7.1 years ±4.1) in two centers. The reasons for celiac disease testing were typical, atypical symptoms or celiac disease-associated conditions in 46.5%, 49%, and 4.5% of cases, respectively. First-line tests were IgA and IgG anti-transglutaminase antibodies in 88.1% and 29.7% of children, IgA and IgG anti-deamidated gliadin peptide antibodies in 43% and 47%, IgA and IgG anti native gliadin in 15.8%, IgA anti-endomysium antibodies in 44.5%, HLA predisposing genes in 10% of patients. Test redundancy was very common, and the current diagnostic guidelines were correctly followed only in 23/202 patients (11.4%).

CONCLUSIONS

Diagnostic European guidelines for celiac disease screening are often disregarded in Italy. Intervention to implement adherence to these guidelines is needed, with the aim of improving resource utilization, and quality of patient care.

Deamidated gliadin peptide in pediatric patients with moderately increased tissue transglutaminase; does it help?

BACKGROUND

Deamidated gliadin peptide (DGP) is a relatively new serologic assay used in diagnosis and monitoring of celiac disease. DGP IgG is recommended by some in pediatric patients <2 y. Use in other pediatric populations is not well established. The utility of the DGP screen (IgG + IgA) in patients with moderate increase of tissue transglutaminase (TTG) IgA has not been studied.

METHODS

Cases between January 2015 and October 2017 in which a patient had TTG IgA greater >19 and <100, DGP screen, and biopsy were collected. Indication for biopsy and diabetes diagnosis were recorded. Of 495 patients screened, 31 met criteria.

RESULTS

The sensitivity and specificity of DGP screen were calculated, and were 87.4% and 56%, respectively; though lower in patients with diabetes.

CONCLUSIONS

The study suggests in patients with moderately increased TTG-IgA, DGP screen lacks specificity and does not provide additional information about whether or not to biopsy.