Comparative evaluation of serologic tests for celiac disease: a European initiative toward standardization

Clinical presentations and outcomes of celiac disease in children and adolescents at a tertiary care center in Lebanon

Introduction

Studies on the clinical presentation of celiac disease and its impact on the growth of children in Lebanon are limited. The aim of this 10-year-retrospective study was to describe the common clinical presentations, diagnostic modalities, and the effect of the gluten-free- diet (GFD) on the growth of children and adolescents with celiac disease.

Methods

This was a retrospective chart review of subjects aged 6 months to 18 years who visited the Pediatric Gastroenterology clinic at the American University of Beirut Medical Center (AUBMC) between January 1, 2013, and June 30, 2023, and who were diagnosed with celiac disease based on serological markers and/or changes on histology of the small intestinal mucosal biopsies for those who underwent upper endoscopy, or HLA typing expressing the HLA-DQ2 or DQ8 gene for few subjects.

Results

The study included 90 patients with celiac disease, of whom 64 were newly diagnosed during the study period. The mean age at diagnosis of celiac disease was 6.93 years. Females represented 60% of the pediatric subjects with celiac disease. The most common symptoms reported were abdominal pain (51.1%), weight loss or failure to thrive (45.6%), and diarrhea (24.4%). There was a significant increase in the mean weight-for-age Z-score (WAZ) and mean body mass index (BMI)-for-age Z-score (BMIZ) 12 months following initiation of GFD; however, the change in height-for-age Z-score (HAZ) at 12 months was not statistically significant. Half of the subjects were in remission at the last clinic follow-up.

Conclusion

The most common symptoms that children with celiac disease in this cohort presented with are diarrhea, abdominal pain and failure to thrive. In this cohort, there was a significant increase in the weight parameters with no significant change in the height at 12 months after initiation of the GFD. The recognition of early manifestations, early diagnosis and strict adherence to the diet are of paramount importance to prevent long term complications.

Current guidelines for the management of celiac disease: A systematic review with comparative analysis

BACKGROUND

Wheat and other gluten-containing grains are widely consumed, providing approximately 50% of the caloric intake in both industrialised and developing countries. The widespread diffusion of gluten-containing diets has rapidly led to a sharp increase in celiac disease prevalence. This condition was thought to be very rare outside Europe and relatively ignored by health professionals and the global media. However, in recent years, the discovery of important diagnostic and pathogenic milestones has led to the emergence of celiac disease (CD) from obscurity to global prominence. These modifications have prompted experts worldwide to identify effective strategies for the diagnosis and follow-up of CD. Different scientific societies, mainly from Europe and America, have proposed guidelines based on CD's most recent evidence.

AIM

To identify the most recent scientific guidelines on CD, aiming to find and critically analyse the main differences.

METHODS

We performed a database search on PubMed selecting papers published between January 2010 and January 2021 in the English language. PubMed was lastly accessed on 1 March 2021.

RESULTS

We distinguished guidelines from 7 different scientific societies whose reputation is worldwide recognized and representative of the clinical practice in different geographical regions. Differences were noted in the possibility of a no-biopsy diagnosis, HLA testing, follow-up protocols, and procedures.

CONCLUSION

We found a relatively high concordance between the guidelines for CD. Important modifications have occurred in the last years, especially about the possibility of a no-biopsy diagnosis in children. Other modifications are expected in the next future and will probably involve the extension of the non-invasive diagnosis to the adult population and the follow-up modalities.

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.

Value of biopsy in a cohort of children with high-titer celiac serologies: observation of dynamic policy differences between Europe and North America

Background

Healthcare systems implement change at different rates because of differences in incentives, organizational processes, key influencers, and management styles. A comparable set of forces may play out at the national and international levels as demonstrated in significant differences in the diagnostic management of pediatric Celiac Disease (CD) between European and North American practitioners.

Methods

We use retrospective clinical cohorts of 27,868 serum tissue transglutaminase (tTG) immunoglobulin A levels and 7907 upper gastrointestinal endoscopy pathology reports to create a dataset of 793 pathology reports with matching tTG results between July 1 of 2014 and July 1 of 2018. We use this dataset to characterize histopathological findings in the duodenum, stomach and esophagus of patients as a function of serum tTG levels. In addition, we use the dataset to estimate the local and national cost of endoscopies performed in patients with serum tTG levels greater than 10 times the upper limit of normal.

Results

Using evidence from a US tertiary care center, we show that in the cohort of pediatric patients with high pre-test probability of CD as determined by serum tTG levels, biopsy provides no additional diagnostic value for CD, and that it counter-intuitively introduces diagnostic uncertainty in a number of patients. We estimate that using the European diagnostic algorithms could avoid between 4891 and 7738 pediatric endoscopies per year in the US for evaluation of CD.

Conclusions

This study considers the North American and European management guidelines for the diagnosis of pediatric CD and highlights the slow adoption in North America of evidence-based algorithms developed and applied in Europe for triage of endoscopy and biopsy. We suggest that system dynamics influences that help maintain the status quo in North America include a variety of social and economic factors in addition to medical evidence. This work contributes to the growing body of evidence that the dynamics that largely favor maintaining status quo management policies in a variety of systems extend to clinical medicine and potentially influence clinical decisions at the level of individual patients and the population.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12913-020-05815-0.

Celiac disease and Sjögren's syndrome: A case report and review of literature

BACKGROUND

Celiac disease (CD) is a systemic, chronic immune-mediated disease triggered by gluten ingestion in genetically-susceptible individuals, with a prevalence of 1% worldwide. Sjogren's syndrome (SS) is also a systemic autoimmune disease, mainly characterized by ocular and oral sicca symptoms and signs. Sharing a common genetic background, CD and SS are known associated autoimmune diseases, but currently available guidelines are not reporting it.

CASE SUMMARY

We report the case of a 39-year-old woman, who was in the care of her rheumatologist for 2 years with SS. On routine follow-up she was found to have iron deficiency, without anemia. She had no gastrointestinal complaints and denied any obvious source of blood loss. IgA tissue transglutaminase antibodies were positive and endoscopy with duodenal biopsies revealed crypt hyperplasia and villous atrophy. A diagnosis of CD was set and gluten-free diet was recommended.

CONCLUSION

We present a review of existing data in the literature regarding the association of the two diseases, summarizing prevalence studies of CD in SS patients and the other way around. Screening recommendations and future research perspectives are also discussed, highlighting clinically relevant unanswered questions with respect to the association of CD with SS.

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.

Automatic classification of IgA endomysial antibody test for celiac disease: a new method deploying machine learning

Widespread use of endomysial autoantibody (EmA) test in diagnostics of celiac disease is limited due to its subjectivity and its requirement of an expert evaluator. The study aimed to determine whether machine learning can be applied to create a new observer-independent method of automatic assessment and classification of the EmA test for celiac disease. The study material comprised of 2597 high-quality IgA-class EmA images collected in 2017–2018. According to standard procedure, highly-experienced professional classified samples into the following four classes: I - positive, II - negative, III - IgA deficient, and IV - equivocal. Machine learning was deployed to create a classification model. The sensitivity and specificity of the model were 82.84% and 99.40%, respectively. The accuracy was 96.80%. The classification error was 3.20%. The area under the curve was 99.67%, 99.61%, 100%, and 99.89%, for I, II, III, and IV class, respectively. The mean assessment time per image was 16.11 seconds. This is the first study deploying machine learning for the automatic classification of IgA-class EmA test for celiac disease. The results indicate that using machine learning enables quick and precise EmA test analysis that can be further developed to simplify EmA analysis.

Prevalence and Clinical Features of Celiac Disease in Healthy School-Aged Children

BACKGROUND/AIMS

The aim of this study was to determine the prevalence of celiac disease (CD) in healthy school-aged children in the northern region of Cyprus and to investigate the existence of potential markers that may accompany CD. This is the first study to measure the prevalence of CD in the northern region of Cyprus.

METHODS

This study included 3792 school-aged children who were between the ages of 6 and 10 years between January 2015 and October 2016. CD was screened using total serum IgA, IgA anti-tissue transglutaminase (tTG), and IgA antiendomysial (EMA) antibodies. Subjects with selective IgA deficiency were further tested for IgG-tTG. Small intestinal biopsies were performed on all subjects with tTG antibody positivity. Risk factors and symptoms related to CD were evaluated using questionnaires in both the CD and control groups.

RESULTS

Of the 3792 subjects, 39 were antibody positive (IgA-tTG was positive only in 14 subjects, IgA-tTG plus IgA-EMA in 21 subjects, and IgG-tTG in 4 subjects). IgA deficiency was detected in 11 subjects (0.29%). IgG-tTG was positive in 4 subjects with IgA deficiency (36.3%). Intestinal biopsies were performed on 28 of the 39 seropositive subjects. The biopsy findings of 15 children were consistent with CD (IgA-tTG positive in 3, IgA-tTG and IgA-EMA positive in 10, and IgG-tTG positive in 2). Thus, biopsies confirmed CD in 1:256 children (0.39%).

CONCLUSIONS

Our study, which is the first study of school-aged children from the northern region of Cyprus, revealed that CD is a prevalent disease in this region.

Sex- and age-dependent effects of celiac disease on growth and weight gain in children with type 1 diabetes: Analysis of the type 1 diabetes Exchange Clinic Registry

BACKGROUND

Celiac disease (CD) is common in patients with type 1 diabetes (T1D) and effects of CD on growth in children with T1D remain unclear.

METHODS

We analyzed heights, weights, and body mass index (BMI) in 215 matched pediatric CD/control pairs in the T1D Exchange Clinic Registry. CD was defined by a clinic-reported diagnosis and positive celiac serology (n = 80) and/or positive small bowel biopsy (n = 135). Cases and controls were matched by age (mean: 14 years), diabetes duration (median: 7 years), sex (57% female), and clinic site. There were 5569 height/weight measurements.

RESULTS

Gluten was restricted for varying periods of time in 61% of females and 51% of males with CD. Females with CD were shorter than female controls at all ages (P = 0.01). Weight z-scores were initially lower in preschool females with CD but similar to controls by middle childhood. Males with CD were initially shorter but adult heights were similar. Height in both sexes and weight in males were lower in CD participants diagnosed at younger age. Growth in T1D children with biopsy-proven CD, 76% of them were gluten-restricted, was comparable to that of T1D controls.

CONCLUSION

Concurrent CD impairs linear growth in T1D females at all stages of development and in young T1D males. Young females with CD have lower weights, but both sexes have similar weights by middle childhood. Children younger at CD onset remain shorter throughout childhood; males younger at CD onset have persistently lower weights. Long-term gluten restriction may restore weight gain and linear growth in children with CD and T1D.

Cost-Effectiveness Analysis of Screening for Celiac Disease in the Adult Population

Background . Celiac disease (CD) is common and, when undiagnosed, may result in increased mortality, suggesting that mass screening could be justified. The authors examined the cost-effectiveness (CE) of such an approach, assuming a higher mortality rate in undiagnosed CD and that adhering to a gluten-free diet (GFD) reduces the mortality rate. Methods . The authors developed a state transition Markov model, evaluating the CE of screening an entire population at the age of 18. Screening strategies included no screening v. screening by IgA antiendomysial antibodies (EMA), IgA human antitissue transglutaminase antibodies (TTG), and TTG verified by EMA. All strategies were examined with and without evaluation for IgA deficiency, and they all included an intestinal biopsy. Effects of variables were examined using sensitivity analysis. Effectiveness was assessed by life expectancy for each strategy and the incremental average CE ratio for each. Results . Base-case analysis revealed US$49,491 and US$572,616 per life year gained for screening compared to no screening using EMA or TTG, respectively. The CE of screening with EMA was most influenced by the prevalence of CD and the standardized mortality ratio (SMR) for untreated CD patients. Screening was cost-effective in populations with a relatively high prevalence of CD or when the SMR for untreated CD patients was higher than 1.5. The model was insensitive to changes in the cost of serological markers and diagnostic endoscopy. Conclusion . Assuming an SMR of 1.5 or higher for untreated CD patients, mass screening for CD is cost-effective in populations with a relatively high prevalence of CD over a wide range of ages at screening. From a CE perspective, EMA is the preferred serological marker for mass screening. Screening for CD would be justified only if the uncertainties regarding the validity of our assumptions are substantiated.

Celiac disease in children and adolescents with Hashimoto Thyroiditis

AIM

The aim of this study was to evaluate clinical and laboratory findings and determine the prevalence of celiac disease (CD) in children with Hashimoto thyroiditis (HT).

MATERIAL AND METHODS

The data of a total of 80 patients with positive anti-thyroid antibodies who were aged between 6 and 17.9 years were retrospectively studied. Age, gender, complaints at the time of presentation, family history of thyroid disorders, clinical and laboratory findings were recorded. The levels of thyrotropin, free thyroxin, thyroid autoantibodies (thyroid peroxidase and thyroglobulin antibodies), immunoglobulin A (IgA), anti-tissue transglutaminase antibodies (IgA-tTG), and thyroid ultrasonography findings were enrolled.

RESULTS

Eighty patients (65 females (81.2%) and 15 males (18,8%)) were included in the study. Family history of thyroid disease was present in 38 (47.5%) patients. The most common complaints at the time of presentation were goiter (%30) and weight gain (%25). Forty three (53.8%), 23 (28.7%), and 14 (17.5%) patients presented with euthyroidism, subclinical hypothyroidism and obvious hypothyroidism. Thirty seven (46.2%) patients had goiter. IgA-tTG was found to be positive after a diagnosis of HT was made in only one patient (1.25%) and the diagnosis of CD was confirmed when intestinal biopsy of this patient revealed villus atrophy, crypt hyperplasia and increase in the intraepithelial lymphocyte count.

CONCLUSIONS

In our study, it was found that the most common complaints at presentation in patients with a diagnosis of hashimoto thyroiditis included goiter, weakness and weight gain and the prevalence of celiac diseases was found to be 1.25% (1/80). This study shows that the prevalence of CD in patients with a diagnosis of HT is higher compared to the prevalence in the healthy pediatric population.

Vascular risk factors in children, adolescents, and young adults with type 1 diabetes complicated by celiac disease: results from the DPV initiative

OBJECTIVE

Celiac disease (CD) is a common comorbidity of type 1 diabetes (T1D). Long-term consequences of CD are not completely understood, and adhering to a gluten-free diet is a burden for many patients. We investigated the effect of CD on vascular risk factors in a large cohort of T1D patients aged <20 yr.

RESEARCH DESIGN AND METHODS

Within the longitudinal Diabetes Patienten Verlaufsdokumentation (DPV)-diabetes registry, data were analyzed from 59,909 < 20-yr-old T1D patients treated at 392 centers in Germany and Austria. A total of 974 patients with biopsy-proven celiac disease (BPCD) were compared with 28,398 patients without CD with respect to blood pressure (BP), lipids, glycohemoglobin (HbA1c ), body mass index (BMI), and reported smoking behavior.

RESULTS

Patients with T1D and BPCD showed significantly lower high-density lipoprotein (HDL) cholesterol levels [median (interquartile range): 53.0 (43.0-62.6) mg/dL] than patients without CD [55.0 (45.0-66.0) mg/dL; p < 0.01; p < 0.001 after adjustment for confounding variables]. Systolic BP was lower in patients with CD [105.5 (100.0-112.5) mmHg] than in patients without CD [110.0 (102.0-117.0) mmHg; p < 0.0001; p < 0.001 after adjustment]. There were no significant differences regarding smoking behavior, BMI, or HbA1c . In a subgroup of 335 patients with BPCD, HDL cholesterol was measured 1 yr after diagnosis of CD:HDL increased by 8% (p < 0.01).

CONCLUSION

Young people with T1D and CD have lower HDL cholesterol values than patients without CD. As low HDL cholesterol is associated with vascular risk, our findings support screening for CD and monitoring of HDL cholesterol in young people with T1D.

Going against the grain: an atypical presentation of celiac disease

With the current prevalence of celiac disease, it is important to know the common signs and symptoms of this disease process and to also be aware of atypical presentations. This article describes a toddler who initially presented with recurrent diarrhea and weight loss with a significant secondary hypokalemia. His initial examination included screening for celiac disease, but the serology was negative. After persistent and worsening symptoms, further tests were pursued and a diagnosis of celiac disease was confirmed based on an upper endoscopy and histology.

Overview of biomarkers for diagnosis and monitoring of celiac disease

Among the adverse reactions caused by wheat, celiac disease (CD) is the longest studied and best-known pathology. The more recently defined non-celiac gluten sensitivity (NCGS) presents with symptoms which are often indistinguishable from CD. Diagnosis of CD is based on serologic, molecular, and bioptic testing. The IgA anti-transglutaminase (tTG) test is considered highly important, as it shows high sensitivity and specificity and its levels correlate to the degree of intestinal damage. Small bowel biopsy can be avoided in symptomatic patients with IgA anti-tTG levels above 10× the manufacturer's cut-off. Recently, tests of anti-deamidated peptides of gliadin (DGP) have replaced classic anti-native gliadin (AGA) tests. DGP assays have a considerably higher diagnostic accuracy than AGA assays, especially in the IgG class, and can replace anti-tTG tests in patients with selective IgA deficiency. The combination of IgG anti-DGP plus IgA anti-tTG assays show greater sensitivity than a single test, with very high specificity. EMA tests have great diagnostic accuracy but are not recommended by all the latest guidelines because they are observer dependent. Biopsy must still be considered the gold standard for CD diagnosis. HLA-DQ genotyping can be used to screen asymptomatic children and in cases of histology/serology disagreement. About half of NCGS patients are DQ2 positive and have IgG AGA. To diagnose NCGS, first CD and wheat allergy must be excluded; then the wheat dependence of symptoms must be verified by a gluten-free diet and subsequent gluten challenge.

Antibodies in the diagnosis of coeliac disease: a biopsy-controlled, international, multicentre study of 376 children with coeliac disease and 695 controls

Diagnosis of coeliac disease (CD) relies on a combination of clinical, genetic, serological and duodenal morphological findings. The ESPGHAN suggested that biopsy may not be necessary in all cases. New guidelines include omission of biopsy if the concentration of CD-specific antibodies exceeds 10 times the upper limit of normal (10 ULN) and other criteria are met. We analysed the 10 ULN criterion and investigated multiple antibody-assays. Serum was collected from 1071 children with duodenal biopsy (376 CD patients, 695 disease-controls). IgA-antibodies to tissue transglutaminase (IgA-aTTG), IgG-antibodies to deamidated gliadin peptides (IgG-aDGL) and IgA-endomysium antibodies (IgA-EMA) were measured centrally. We considered 3 outcomes for antibody test procedures utilizing IgA-aTTG and/or IgG-aDGL: positive (≥10 ULN, recommend gluten-free diet), negative (<1 ULN, no gluten-free diet) or unclear (perform biopsy). Positive (PPV) and negative (NPV) predictive values were based on clear test results. We required that they and their lower confidence bounds (LCB) be simultaneously very high (LCB >90% and PPV/NPV >95%). These stringent conditions were met for appropriate antibody-procedures over a prevalence range of 9–57%. By combining IgG-aDGL with IgA-aTTG, one could do without assaying total IgA. The PPV of IgG-aDGL was estimated to be extremely high, although more studies are necessary to narrow down the LCB. The proportion of patients requiring a biopsy was <11%. The procedures were either equivalent or even better in children <2 years compared to older children. All 310 of the IgA-aTTG positive children were also IgA-EMA positive. Antibody-assays could render biopsies unnecessary in most children, if experienced paediatric gastroenterologists evaluate the case. This suggestion only applies to the kits used here and should be verified for other available assays. Confirming IgA-aTTG positivity (≥10 ULN) by EMA-testing is unnecessary if performed on the same blood sample. Prospective studies are needed.

Anti-TCR gamma antibody in celiac disease: the value of count on formalin-fixed paraffin-embedded biopsies

Small bowel intraepithelial lymphocytosis (IL) may depend from different causes, including celiac disease (CD). Demonstration of increased number of duodenal T cell receptor gamma-delta (TCRγδ) positive intraepithelial lymphocytes (IELs) has been used to support CD diagnosis on frozen material. This work evaluates a new commercially available anti-TCRγ antibody on formalin-fixed paraffin embedded (FFPE) small bowel biopsies. Anti-CD3 and anti-TCR CγM1 (clone γ3.20) from Thermo Scientific were applied by immunohistochemistry on 59 FFPE biopsies from 18 cases of CD with mild/severe atrophy, 19 cases of IL in CD patients on gluten-free diet (IL-GFD), 14 cases of IL (6/14 with positive CD-related serology), and 8 controls (CTR) with mild duodenitis and negative CD serology and genotyping. IELs/100 epithelial cells were counted in at least six high power fields. CD3+ and TCRγ+ IELs were significantly higher in CD, IL-GFD, and IL compared with CTR, but in contrast to CD3+ IELs, TCRγ+ IELs were significantly increased in CD and IL-GFD compared with IL. Furthermore, TCRγ+ IELs discriminated between IL with negative and positive CD-related serology (p = 0.02). TCRγ+ IELs can be identified on FFPE samples and their evaluation adds useful information for the work-up of small bowel biopsies in CD diagnosis. In fact, TCRγ staining coupled with CD3, may represent an additional tool to recognize cases of latent/potential CD when serology and clinical data are not conclusive or when the histological diagnosis remains equivocal.

Atypical celiac disease: from recognizing to managing

The nonclassic clinical presentation of celiac disease (CD) becomes increasingly common in physician's daily practice, which requires an awareness of its many clinical faces with atypical, silent, and latent forms. Besides the common genetic background (HLA DQ2/DQ8) of the disease, other non-HLA genes are now notably reported with a probable association to atypical forms. The availability of high-sensitive and specific serologic tests such as antitissue transglutuminase, antiendomysium, and more recent antideamidated, gliadin peptide antibodies permits to efficiently uncover a large portion of the submerged CD iceberg, including individuals having conditions associated with a high risk of developing CD (type 1 diabetes, autoimmune diseases, Down syndrome, family history of CD, etc.), biologic abnormalities (iron deficiency anemia, abnormal transaminase levels, etc.), and extraintestinal symptoms (short stature, neuropsychiatric disorders, alopecia, dental enamel hypoplasia, recurrent aphtous stomatitis, etc.). Despite the therapeutic alternatives currently in developing, the strict adherence to a GFD remains the only effective and safe therapy for CD.

Celiac disease: Management of persistent symptoms in patients on a gluten-free diet

AIM: To investigate all patients referred to our center with non-responsive celiac disease (NRCD), to establish a cause for their continued symptoms.

METHODS: We assessed all patients referred to our center with non-responsive celiac disease over an 18-mo period. These individuals were investigated to establish the eitiology of their continued symptoms. The patients were first seen in clinic where a thorough history and examination were performed with routine blood work including tissue transglutaminase antibody measurement. They were also referred to a specialist gastroenterology dietician to try to identift any lapses in the diet and sources of hidden gluten ingestion. A repeat small intestinal biopsy was also performed and compared to biopsies from the referring hospital where possible. Colonoscopy, lactulose hydrogen breath testing, pancreolauryl testing and computed tomography scan of the abdomen were undertaken if the symptoms persisted. Their clinical progress was followed over a minimum of 2 years.

RESULTS: One hundred and twelve consecutive patients were referred with NRCD. Twelve were found not to have celiac disease (CD). Of the remaining 100 patients, 45% were not adequately adhering to a strict gluten-free diet, with 24 (53%) found to be inadvertently ingesting gluten, and 21 (47%) admitting non-compliance. Microscopic colitis was diagnosed in 12% and small bowel bacterial overgrowth in 9%. Refractory CD was diagnosed in 9%. Three of these were diagnosed with intestinal lymphoma. After 2 years, 78 patients remained well, eight had continuing symptoms, and four had died.

CONCLUSION: In individuals with NRCD, a remediable cause can be found in 90%: with continued gluten ingestion as the leading cause. We propose an algorithm for investigation.

Improving serological test ordering patterns for the diagnosis of celiac disease through clinical laboratory audit of practice

BACKGROUND

Clinical Practice Guidelines (CPG) from both adult medicine and pediatrics recommend tTG to screen for celiac disease (CD).

DESIGN AND METHODS

Serological test orders for celiac disease were evaluated against the guidelines. Ordering physicians were categorized as gastroenterologists, immunologists, pediatricians, other hospital physicians and non-hospital physicians. Interventions based on initial audit were implemented, including interacting with physicians, revising test menu and changing test ordering policy. After implementation of interventions, test orders were re-evaluated.

RESULTS

After corrective interventions celiac panel (CP) orders were decreased from 48.4% to 3.6% in children, and from 72.3% to 28.1% in adults. Physicians ordered tTG alone for more than 90% of children. In adults the ordering of tTG alone was significantly increased from 7.2% to 61.3% (from 8.9% to 63.9% for gastroenterologists and from 8.1% to 44.4% for other physicians (p<0.05)).

CONCLUSIONS

The audit reduced the CPG-practice gap that existed in the screening of CD.

Are immunoglobulin A anti-gliadin antibodies helpful in diagnosing coeliac disease in children younger than 2 years?

The usefulness of immumoglobulin (Ig) A antibodies to gliadin (AGA-IgA) in addition to IgA anti-endomysium and tissue transglutaminase antibodies was evaluated in 4122 children younger than 2 years with a suspicion of coeliac disease (CD). Eight percent (312/4122) displayed IgA anti-endomysium and/or IgA anti-tissue transglutaminase, whereas 2.1% (85/4122) displayed only AGA-IgA. Clinical data were obtained for 62 of 85 children with isolated AGA-IgA, and 33 children underwent a duodenal biopsy. Histologically proven CD was established for 5 patients, whereas 57 children were diagnosed to experience other diseases. The systematic detection of AGA-IgA using native gliadin conferred no additional diagnostic benefit for the diagnosis of CD in children younger than 2 years of age, except for rare cases.

The old and new tests for celiac disease: which is the best test combination to diagnose celiac disease in pediatric patients?

BACKGROUND

In the diagnosis of celiac disease (CD), serum assays for anti-endomysium (EMA) and anti-transglutaminase (anti-tTG) antibodies have excellent diagnostic accuracy. However, these assays are less sensitive in young pediatric patients. Recently, a new ELISA test using deamidated gliadin peptides (DGP) as antigen has proved to be very sensitive and specific even in pediatric patients. In addition, anti-actin IgA antibodies (AAA) is another test that can be used in CD patients because antibody concentrations correlate with the degree of villous atrophy. This study evaluated the clinical accuracy of anti-tTG, EMA, AGA, anti-DGP and AAA and the effectiveness of these in different combinations for diagnosing CD in a large cohort of pediatric patients.

METHODS

Sera of 150 children under 6 years of age were tested: 95 patients had a diagnosis of CD, while 55 patients who did not suffer from CD were used as controls. Anti-DGP IgA/IgG and AAA were assayed with ELISA kits, while anti-tTG IgA/IgG and AGA IgG/IgA were assayed using a quantitative fluoroimmunoassay. The EMA test was conducted by indirect immunofluorescence.

RESULTS

Seventy-six of 95 (80%) CD patients were positive for DGP IgA and/or tTG IgA. Eighty of 95 (84.2%) patients were positive for DGP IgG and/or tTG IgA. None of the controls were positive for these antibodies. Eighty-four of 95 (88.4%) patients and 8/55 (14.5%) controls were positive for AAA and/or anti-tTG IgA.

CONCLUSIONS

In very young children, association of anti-tTG IgA with anti-DGP IgG is the best test combination for diagnosing CD, yielding a cumulative sensitivity of 84.2% and a specificity of 100%.

Prevalence of celiac disease in healthy Turkish school children

OBJECTIVES

Epidemiological studies of celiac disease (CD) in Turkey have been performed only within some regions of the country. The aim of this study was to determine the prevalence of CD in Turkish school children.

METHODS

Between 2006 and 2008, serum samples were collected from 20,190 students (age range, 6-17 years) in 139 schools in 62 cities from different regions of Turkey. CD was screened using IgA antitissue transglutaminase (IgA-tTG) and total serum IgA. Subjects with selective IgA deficiency were further tested for IgG-tTG. Serum samples positive for IgA or IgG-tTG were further tested for IgA antiendomysial antibodies (IgA-EMAs) using an indirect immunofluorescence method. Small-intestinal biopsy was offered to all subjects with tTG antibody positivity.

RESULTS

Of the 20,190 subjects, 489 were antibody positive (IgA-tTG only in 270, both IgA-tTG and IgA-EMA in 215, and IgG-tTG in 4). Selective IgA deficiency was detected in 108 patients, and 4 of them were positive for IgG-tTG. An intestinal biopsy was conducted in 215 subjects (IgA-tTG positive in 110, IgA-tTG and IgA-EMA positive in 104, and IgG-tTG positive in 1). The biopsy findings of 95 children were consistent with CD. Thus, the estimated biopsy-proven prevalence was 1:212 children. The positive predictive value (PPV) for IgA-tTG plus EMA was 75.9%. PPV was 44.3% when only IgA-tTG was used.

CONCLUSIONS

We estimate that the prevalence of CD is at least 0.47% in healthy Turkish school children. Screening for IgA-tTG plus EMA provided better results for diagnosis when compared with testing for IgA-tTG alone.

Anthropometry, metabolic control, and follow-up in children and adolescents with type 1 diabetes mellitus and biopsy-proven celiac disease

OBJECTIVE

To evaluate the influence of biopsy-proven celiac disease (BPCD) on somatic development and metabolic parameters in children with type 1 diabetes mellitus (T1DM) in a multicenter survey.

STUDY DESIGN

Within the Diabetes Patienten Verlaufsdokumentationssystem-Wiss project, data of 41 951 patients with T1DM, aged <20 years (52% males, mean age 13.9 years; mean duration of diabetes 5.5 years) were collected in 297 centers in Germany and Austria from 1995 to 2009.

RESULTS

The number of BPCD (0.6% in 1995; 1.3% in 2008) has increased over time. Patients with BPCD were significantly younger at diabetes onset (5.9 vs 8.3 years), had a significantly lower weight standard deviation score (SDS); (0.20 vs 0.43) and height SDS (-0.28 vs -0.03) (P < .001, each) compared with patients without celiac disease. No differences were found in hemoglobin A1c or numbers of severe hypoglycemia. In a subgroup of 9805 patients (183 with BPCD) significantly lower height and weight SDS (P < .001) were still found after a 5-year follow-up.

CONCLUSIONS

Screening for celiac disease is important in children with T1DM to prevent persistent growth failure.

Celiac disease: diagnostic criteria in progress

Until a few years ago, celiac disease (CD) was thought to be a rare food intolerance that was confined to childhood and characterized by severe malabsorption and flat intestinal mucosa. Currently, CD is regarded as an autoimmune disorder that is common in the general population (affecting 1 in 100 individuals), with possible onset at any age and with many possible presentations. The identification of CD is challenging because it can begin not only with diarrhea and weight loss but also with atypical gastrointestinal (constipation and recurrent abdominal pain) and extra-intestinal symptoms (anemia, raised transaminases, osteoporosis, recurrent miscarriages, aphthous stomatitis and associated autoimmune disorders), or it could be completely symptomless. Over the last 20 years, the diagnostic accuracy of serology for CD has progressively increased with the development of highly reliable tests, such as the detection of IgA tissue transglutaminase and antiendomysial and IgG antideamidated gliadin peptide antibodies. The routine use of antibody markers has allowed researchers to discover a very high number of 'borderline' cases, characterized by positive serology and mild intestinal lesions or normal small intestine architecture, which can be classified as potential CD. Therefore, it is evident that the 'old celiac disease' with flat mucosa is only a part of the spectrum of CD. It is possible that serology could identify CD in its early stages, before the appearance of severe intestinal damage. In cases with a positive serology but with mild or absent intestinal lesions, the detection of HLA-DQ2 and HLA-DQ8 can help reinforce or exclude the diagnosis of gluten sensitivity.

The prevalence of celiac disease in Europe: results of a centralized, international mass screening project

INTRODUCTION

Although the prevalence of celiac disease (CD) has been extensively investigated in recent years, an accurate estimate of CD frequency in the European population is still lacking. The aims of this study were: 1) to establish accurately the prevalence of CD in a large sample of the European population (Finland, Germany, Italy, and UK), including both children and adults; and 2) to investigate whether the prevalence of CD significantly varies between different areas of the European continent.

MATERIALS AND METHODS

Samples were drawn from the four populations. All 29,212 participants were tested for CD by tissue transglutaminase (tTG) antibody test. Positive and border-line findings were further tested for serum endomysial antibodies (EMA). All serological determinations were centrally performed. Small-bowel biopsies were recommended to autoantibody-positive individuals. Previously diagnosed cases were identified.

RESULTS

The overall CD prevalence (previously diagnosed plus anti-tTG and EMA positives) was 1.0% (95% CI 0.9-1.1). In subjects aged 30-64 years CD prevalence was 2.4% in Finland (2.0-2.8), 0.3% in Germany (0.1-0.4), and 0.7% in Italy (0.4-1.0). Sixty-eight percent of antibody-positive individuals showed small-bowel mucosal changes typical for CD (Marsh II/III lesion).

CONCLUSIONS

CD is common in Europe. CD prevalence shows large unexplained differences in adult age across different European countries.

Clinics of coeliac disease in children in the 2000s

OBJECTIVE

To describe the clinical picture of patients with coeliac disease (CD) and the change in its presentation over the past decades.

STUDY DESIGN

Patients with CD were identified and clinical data collected from hospital records over a 6-year period (2000-2005).

RESULTS

Altogether 197 patients aged 0.6-15.9 (mean 7.2) years were identified. They were found amongst the child population served by the hospital, the mean number of children at age 0.5-16 years was 268 000 during 2000-2005. The presenting symptom amongst the youngest patients (<3 years) was chronic diarrhoea (in 67%), and amongst older patients, abdominal pain. At the time of diagnosis, growth was severely retarded (height <2 SD for age) in 6.6%; mean height was -0.06 SD and weight + 1% for height. After diet treatment for a mean of 6 months, both height and weight increased significantly. Anaemia and iron deficiency were present in 25% and 43% of patients respectively. Intraepithelial T-cell receptor gamma/delta cells were pathologic in all 150 specimens studied.

CONCLUSIONS

The presentation of CD depends on age. Even when we found six times more patients than during years 1976-1985 in the same hospital, published data on the prevalence of CD suggest that we found only a small minority of children with CD.

Infiltration of Foxp3- and Toll-like receptor-4-positive cells in the intestines of children with food allergy

OBJECTIVES

Regulatory T (Treg) cells together with intestinal microflora play a central role in controlling allergic inflammation. We examined the markers related to Treg cells, and bacterial signaling, such as Toll-like receptors (TLR)-2 and -4, in the duodenal mucosa of patients with food allergy (FA).

PATIENTS AND METHODS

Small intestinal samples were collected from patients with FA on a normal or an elimination diet, from healthy controls and patients with untreated celiac disease. Single and double immunohistochemistry were used to enumerate the densities of Foxp3-positive cells and TLR2- and TLR4-positive cells in the mucosa and evaluate the colocalization of Foxp3 expression in CD4, CD25, and CTLA-4 cells. The mRNA expression of CD25, Foxp3, TLR2, and TLR4 was measured by reverse transcriptase-polymerase chain reaction.

RESULTS

The densities of Foxp3 and TLR4 cells were significantly increased in patients with untreated FA compared with healthy controls (P = 0.003, P = 0.033), and the Foxp3 cells were higher in untreated than in treated allergic patients (P < 0.001). The immense majority of Foxp3 cells were CD4 (median 100%), CTLA-4 (100%), or CD25 (81%). The ratio of Foxp3 mRNA to Foxp3 cells was decreased in patients with FA and in patients with celiac disease compared with controls (P = 0.036, P = 0.035).

CONCLUSIONS

Foxp3 cells are increased in the duodenum of patients with untreated FA, but these cells are not able to suppress the harmful immune response, indicated by the low expression of Foxp3 transcripts. The increase of TLR4 cells and their correlation with TCRgammadelta intraepithelial lymphocytes suggest a role for the innate immunity and intestinal microbiota in FA.

Celiac disease in Middle Eastern and North African countries: a new burden?

Celiac disease (CD) is now recognized as a common disorder among Middle Eastern (ME) and North African (NA) populations. The aim of this review is to assess the available data regarding CD in the ME and NA and to compare this information with that of Western countries. A literature review was performed using the electronic databases PubMed and Medline (1950-2008) as search engines, and "celiac disease" was used as a Mesh term. The search was limited to ME and NA countries. The prevalence of CD in ME and NA countries among low risk populations is similar to that of Western countries, but is higher in high risk populations such as those with type 1 diabetes. It is underestimated because of lack of clinical suspicion and lack of patient awareness. Clinical presentations in term of gastrointestinal, hematologic, skeletal, and liver manifestations are similar between both populations except for a high prevalence of short stature in some ME and NA countries. Few studies have addressed atypical or silent CD. As in the West, diagnosis is initially made by serological tests and is confirmed by small intestinal biopsies. Gluten-free diet is the main mode of treatment with a higher apparent adherence rate than in the West. Most disease complications result from malabsorption. The disease is strongly associated with HLA DQ2 and to a lesser extent with HLA DQ8 alleles. In conclusion, CD prevalence is underestimated, with little data available about its malignant complications. Disease parameters in the ME and NA are otherwise similar to those in Western countries.

[Seroprevalence of celiac disease at a general pediatric outpatient clinic]

BACKGROUND

Celiac disease is a common problem affecting children and adults, for which early diagnosis and treatment prevent complications and deaths. Seroprevalence studies in our environment are still scarce.

AIMS

To determine the seroprevalence of celiac disease by using human tissue antiendomysial and anti-transglutaminase antibodies, among children and adolescents who were attended at a general pediatric outpatient clinic.

METHODS

This was a seroprevalence study of descriptive cross-sectional design. First, assays for guinea pig tissue anti-transglutaminase antibodies were performed. Subsequently, in the positive cases, assays for human tissue antiendomysial and anti-transglutaminase antibodies were performed.

RESULTS

The seroprevalence of celiac disease by means of anti-guinea pig tissue anti-transglutaminase antibodies was 5% (42/831; 95% CI: 3.76%-6.90%). Considering three positive tests, the seroprevalence was 1.9% (16/831; 95% CI: 1.83%-1.97%). The concordance of human anti-transglutaminase with antiendomysial was 71%.

CONCLUSIONS

The seroprevalence of celiac disease was high. Serological screening for celiac disease among children and adolescents who present signs and/or symptoms compatible with celiac disease should be performed routinely, as well as in groups already known to be at risk, given the high seroprevalence of celiac disease observed in our environment.

Clinical presentation of celiac disease and the diagnostic accuracy of serologic markers in children

There has been growing recognition of a changing clinical presentation of celiac disease (CD), with the manifestation of milder symptoms. Serologic testing is widely used to screen patients with suspected CD and populations at risk. The aim of this retrospective analysis was to evaluate the clinical presentation of CD in childhood, assess the diagnostic value of serologic tests, and investigate the impact of IgA deficiency on diagnostic accuracy. We evaluated 206 consecutive children with suspected CD on the basis of clinical symptoms and positive serology results. Ninety-four (46%) had biopsy-proven CD. The median age at diagnosis of CD was 6.8 years; 15% of the children were <2 years of age. There was a higher incidence of CD in girls (p = 0.003). Iron deficiency and intestinal complaints were more frequent in children with CD than those without CD (61% vs. 33%, p = 0.0001 and 71% vs. 55%, p = 0.02, respectively), while failure to thrive was less common (35% vs. 53%, p = 0.02). The sensitivity of IgA tissue transglutaminase (IgA-tTG) was 0.98 when including all children and 1.00 after excluding children with selective IgA deficiency. The specificity of IgA-tTG was 0.73 using the recommended cut-off value of 20 IU, and this improved to 0.94 when using a higher cut-off value of 100 IU. All children with CD and relative IgA deficiency (IgA levels that are measurable but below the age reference [n = 8]) had elevated IgA-tTG. In conclusion, CD is frequently diagnosed in school-age children with relatively mild symptoms. The absence of intestinal symptoms does not preclude the diagnosis of CD; many children with CD do not report intestinal symptoms. While the sensitivity of IgA-tTG is excellent, its specificity is insufficient for the diagnostic confirmation of a disease requiring life-long dietary restrictions. Children with negative IgA-tTG and decreased but measurable IgA values are unlikely to have CD.

Comparison of commercially available serologic kits for the detection of celiac disease

BACKGROUND

The sensitivity and specificity of current antihuman tissue transglutaminase (tTG) IgA assays used to detect celiac disease reportedly approach 100%. In addition, the sensitivity of new generation deamidated gliadin peptide (alpha-DGP) antibody assays has also been reported to be similar to the tTG IgA assays. In routine clinical practice, however, the sensitivities and specificities of these tests for diagnosing celiac disease seem to be lower.

AIM

We analyzed sensitivities and specificities of 4 IgA tTG and 3 deamidated gliadin peptide (alpha-DGP) kits.

METHODS

The performance of 4 tTG IgA assays, A: Inova (Hu red blood cell), B: Binding site (rHu Ag), C: Eurospital (rHu Ag), D: Immco (rHu Ag) and 3 Inova alpha-DGP assays, E: alpha-DGP-IgA, F: alpha-DGP-IgG, and G: alpha-DGP-IgA+G was evaluated using sera from different subsets of celiac disease patients and controls; group 1: active celiac disease n=28, group 2: gluten-free diet n=54, group 3: healthy controls n=40, group 4: disease controls n=57(Crohn's disease n=17, chronic hepatitis n=40).

RESULTS

Using the manufacturer's cut-off values, the sensitivities and specificities of different kits ranged from 71.4% to 96.4% and 87.5% to 100%, respectively. When group 1 was compared with disease controls, sensitivities remained the same but specificities decreased. Receiver operating characteristic plot derived cut-off values modified decision thresholds in all assays except kit (G). Kappa analysis demonstrated variable degrees of agreement. All assays demonstrated higher sensitivities for patients with higher grades of villous atrophy.

CONCLUSIONS

Overall sensitivity was at or below 90%, which is lower than that reported in the literature. Performance of the recombinant and red blood cell antigen-based tTG assays was similar, whereas the alpha-DGP assays demonstrated lower values. Receiver operating characteristic plot derived cut-off values altered test results. Many factors affect the results of these tests and clinicians should be aware of their limitations.

A report on the International Transglutaminase Autoantibody Workshop for Celiac Disease

OBJECTIVES

Measurement of transglutaminase autoantibodies (TGAA) is considered to be the most efficient single serologic test for celiac disease (CD) by the American Gastroenterological Association Institute. We hypothesized that a large international collaborative effort toward improving and standardizing TGAA measurement is both feasible and necessary. The primary aim of this workshop is to compare TGAA assays among various research and clinical laboratories to examine assay concordance and improve (and eventually standardize) the TGAA assay.

METHODS

A total of 20 laboratories (5 commercial laboratories, 15 research and clinical laboratories) participated that included enzyme-linked immunosorbent assay (ELISA) and radiobinding assays. A total of 150 serum samples were distributed to each laboratory, with each laboratory receiving an equal aliquot that was coded and blinded, composed of 100 healthy control sera and 50 CD sera.

RESULTS

Laboratory sensitivity ranged from 69% to 93% and specificity ranged from 96% to 100%. By receiver operator characteristic analysis, the area under the curve (C index) ranged from 0.9488 to 0.9904. When analyzing for linear correlation, r-squared was as high as 0.8882 but as low as 0.4244 for the celiac samples between different laboratories performing ELISA.

CONCLUSIONS

This transglutaminase autoantibody workshop allows for larger-scale international participation for the purposes of improving and eventually standardizing the TGAA assay with subsequent workshops.

Prognosis of unrecognized coeliac disease as regards mortality: a population-based cohort study

BACKGROUND AND AIM

Clinically diagnosed coeliac disease patients carry an increased risk of mortality. As coeliac disease is markedly underdiagnosed, we aimed to quantify the risk of mortality in subjects with unrecognized and thus untreated coeliac disease.

METHOD

Blood samples from 6,987 Finnish adults were drawn in 1978-80, and sera were tested for immunoglobulin A (IgA)-class tissue transglutaminase antibodies (Eu-tTG) in 2001. Positive sera were further analysed for endomysial (EMA) and tissue transglutaminase antibodies by another test (Celikey tTG). EMA- and Celikey tTG-positive cases were compared to negatives as regards mortality in up to 28 years of surveillance, yielding a total follow-up of 147,646 person years. Dates and causes of death were extracted from the nation-wide database.

RESULTS

Altogether 74 (1.1%) of the participants were EMA- and 204 (2.9%) Celikey tTG-positive. The age- and sex-adjusted relative risk of overall mortality was not increased in either EMA (0.78, 95% CI 0.52-1.18) or Celikey tTG (1.19, 95% CI 0.99-1.42) -positive subjects. However, antibody-positive cases evinced a tendency to die from lymphoma, stroke, and diseases of the respiratory system.

CONCLUSIONS

The prognosis of unrecognized coeliac disease was good as regards overall mortality, which does not support screening of asymptomatic coeliac disease cases.

Unkilned and large amounts of oats in the coeliac disease diet: a randomized, controlled study

OBJECTIVE

There is evidence for the long-term safety of oats as part of a gluten-free diet in coeliac disease (CD). Oats is generally processed by kilning, which theoretically may change its antigenic properties and be the reason that it is tolerated by patients with CD. The aim of this study was to investigate the suitability of large amounts of unkilned oats, comparing its use with kilned oats in adult coeliac patients.

MATERIAL AND METHODS

The study group included 13 men and 19 women with CD in remission. The goal of daily intake of oats was 100 g during one year. These patients using oats as part of their gluten-free diet were randomized to two treatment groups. One group used regular oats and the other unkilned oats. After 6 months the patients changed the treatment groups. Food intake, symptoms, histology of the small intestine and the levels of endomysial antibodies were noted.

RESULTS

No marked changes were found in the duodenal biopsies, in the levels of endomysial antibodies or in the well-being of the patients. Compliance with the diet did not change during the follow-up.

CONCLUSIONS

Large amounts of both unkilned and regular kilned oats are well tolerated by adult patients with CD. Oats is therefore not harmful, even in its unkilned form, which indicates that its antigenic nature is not changed by common industrial food processing in such a way that would prevent the provoking of CD.

Combination testing for antibodies in the diagnosis of coeliac disease: comparison of multiplex immunoassay and ELISA methods

BACKGROUND

Tissue transglutaminase (TTG) antibodies and newly developed deamidated gliadin peptide (DGP) antibodies have better accuracy than native gliadin antibodies. Multiplex immunoassay (MIA) measures multiple antibodies simultaneously providing a complete antibody phenotype with reduced turnaround time and cost.

AIM

To evaluate the agreement between MIA and enzyme-linked immunosorbent assay (ELISA) test results for coeliac autibodies in biopsy-proven coeliac patients and controls and to model the diagnostic utility of combination testing.

METHODS

We compared the sensitivity, specificity and accuracy of MIA and ELISA methods for TTG and DGP antibodies in mainly adult untreated coeliac patients (n = 92) and controls (n = 124).

RESULTS

There was excellent agreement and a significant correlation between the results of MIA and ELISA methods (k > 0.8, r > 0.7) for all tests, except IgG. Diagnostic indices of individual and combination tests measured by the MIA method did not differ significantly from those measured by ELISA. The combination tests slightly increased sensitivity (if any test was positive) and specificity (if all tests were positive) compared to the individual tests.

CONCLUSIONS

Multiplex immunoassay testing for antibodies is as accurate as ELISA for coeliac disease diagnosis and has practical advantages over ELISA method. Rational combination testing can help identify patients who need intestinal biopsy and may reduce unnecessary biopsies.

Prevalence of celiac disease in Shiraz, southern Iran

BACKGROUND/AIM

This study was performed to evaluate the prevalence of celiac disease (CD) in Shiraz, southern Iran.

MATERIALS AND METHODS

Serum samples were collected from 1440 persons (age range = 20-83 years, mean age = 45.4 years) in 2004 and screened for endomysial and tissue transglutaminase antibodies. A questionnaire was completed for all subjects in relation to gastrointestinal (GI) symptoms and cases with positive serology were requested to undergo small-bowel biopsy.

RESULTS

Seven cases (0.5%) were positive for IgA anti-tissue transglutaminase (anti-tTG), and only two (0.14%) were positive for IgA anti-endomysial antibody (anti-EMA), both of whom had highly positive anti-tTg levels (40.4 and 48.0 IU/l). The major clinical symptoms of CD, such as recurrent abdominal pain and change in bowel habits were present in all patients with positive anti-tTG assays. Only five subjects with positive serology agreed to undergo upper GI endoscopy and duodenal biopsy. Three of these cases were reported with Marsh I histologic findings, while in the two cases with positive serologic anti-EMA, more advanced forms of CD were present.

CONCLUSION

The prevalence of CD in apparently healthy adults was lower than the reported series from northern parts of the country; therefore, we suggest a more long-term follow-up study in high-risk groups, especially in the apparently healthy subjects in our region.

IgA endomysium antibodies--an early predictor for celiac disease in children without villous atrophy

AIM

To evaluate possible differences between children with anti-endomysium antibodies (EMA) positivity and normal small bowel mucosa and children with positive EMA and an enteropathy diagnosed as celiac disease (CD).

METHODS

Children with suspected CD and positive EMA (>or=1/10) undergoing small bowel biopsy during 1996 to 2002, were investigated (n=133). Data registered were: year and month of birth, timing of the first biopsy, sex, heredity for CD, dermatitis herpetiformis and diabetes mellitus and outcome of the anti-gliadin antibody test (AGA). The case group, with EMA positivity and normal histology (n=39; 59% female, mean age at the first biopsy 7.3 years, range 1.4-16), was compared with the disease control group, with positive EMA and a biopsy suggestive and further on diagnosed as CD (n=94; 56% female; mean age 7.6 years at the first biopsy, range 0.70-17).

RESULTS

AGA positivity and heredity for CD were found to predict the outcome of a pathological jejunal mucosa. Nineteen of the 39 children in the case group were rebiopsied of whom 11 had developed an enteropathy during a follow-up period of 2-7 years (median 4.5 years).

CONCLUSIONS

EMA positivity in the absence of small bowel enteropathy could be a very early predictor for later overt CD, and necessitates further follow-up, especially if the child is AGA positive and there is a family history of CD.

Usefulness of antibodies to deamidated gliadin peptides in celiac disease diagnosis and follow-up

The prevalence of the recently described deamidated gliadin peptide antibodies was compared with that of the routinely used antigliadin, antiendomysial, and tissue transglutaminase antibodies in the sera of 128 untreated celiac patients and 134 controls. Sensitivity and specificity for celiac disease were 83.6 and 90.3% for IgA and 84.4 and 98.5% for IgG antibodies to deamidated gliadin peptides. The new test displayed higher diagnostic accuracy than antigliadin antibodies and, although less sensitive than antiendomysial and tissue transglutaminase antibodies, showed significantly higher specificity than tissue transglutaminase antibodies (P < 0.001). Persistence of peptide antibodies after gluten withdrawal was an expression of low compliance with the diet and of the lack of improvement of the intestinal mucosa. The combined use of tissue transglutaminase and deamidated gliadin peptide antibodies seems to be a very useful tool for celiac disease diagnosis. Moreover, antibodies to deamidated gliadin peptides can be helpful in disease follow-up.

Prevalence of celiac disease in children with type 1 diabetes mellitus increased in the mid-1990 s: an 18-year longitudinal study based on anti-endomysial antibodies

Between 1987 and 2004, 331 consecutive children, all newly diagnosed with type 1 diabetes mellitus in our pediatric clinic, underwent repeated serological screening for celiac disease (CD) by means of anti-endomysial antibodies, measured prospectively between 1994 and 2004, and retrospectively, using frozen banked serum, between 1987 and 1993. There were 22 cases (6.6%) of biopsy-proven CD among the 331 diabetic children. The prevalence of CD was significantly (P = 0.015) higher after 1994 (10.6%) than before 1994 (3.3%). The rapid change in the risk of CD among Italian diabetic children that occurred in the mid-1990 s could be related to changes in environmental factors, namely, eating habits and viral infections.

Diabetes Antibody Standardization Program: evaluation of assays for autoantibodies to glutamic acid decarboxylase and islet antigen-2

AIMS/HYPOTHESIS

Islet autoantibodies are important in diabetes classification and risk assessment, and as endpoints in observational studies. The Diabetes Autoantibody Standardization Program (DASP) aims to improve and standardise measurement of autoantibodies associated with type 1 diabetes. We report results for glutamic acid decarboxylase autoantibodies (GADA) and islet antigen-2 autoantibodies (IA-2A) from three DASP workshops (2002--2005).

METHODS

Up to 60 laboratories in 18 countries participated in each workshop. Participants received coded serum aliquots from 50 patients with newly diagnosed type 1 diabetes (median age 18 years, range 9-35 years) and 100 blood donor controls. Results were analysed using receiver operator characteristic (ROC) curves with sensitivity adjusted to 95% specificity in workshop controls.

RESULTS

GADA assays performed well in all three workshops (median area under the ROC curve [AUC] 0.94; interquartile range 0.91-0.95) and performance was similar to DASP 2000. Performance of IA-2A assays improved over the workshop programme. Median AUC was 0.81 (interquartile range 0.79-0.83) in DASP 2002, 0.82 (interquartile range 0.78-0.84) in 2003, and 0.85 (interquartile range 0.82-0.87) in 2005 (p < 0.0001). Performance of GADA ELISA improved between 2002 and 2005, and, in DASP 2005, achieved higher median AUC and adjusted sensitivity than RIA. IA-2A ELISA improved and, in DASP 2005, achieved AUCs equivalent to in-house RIA. Assays using IA-2ic or full length IA-2 clones were more sensitive than those using IA-2bdc, with higher AUC (p = 0.004).

CONCLUSIONS/INTERPRETATION

GADA and IA-2A assays perform well in discriminating health and disease. The workshop format highlights systematic differences related to assay method and allows full evaluation of novel methods. The programme of autoantibody workshops in type 1 diabetes provides a model for other autoimmune diseases.

[Celiac disease diagnosis in 2008]

Since the 1990's, the widespread use of very sensitive and specific serological tests has completely changed the conditions of the diagnosis of celiac disease (CD). The active form of the disease is now only the tip of the iceberg representing it. Currently, CD is evoked either in front of mild digestive symptoms at the usual age or in the course of screening in siblings of an index case or in patients at risk (insulin dependent diabetes for example) at a later age using IgA anti-endomysium or anti-tissue transglutaminase antibodies, the sensitivities and specificities of which exceed 90%. In some cases, HLA typing is helpful in allowing to exclude a patient who is neither DQ2 nor DQ8. The intestinal biopsy remains the "gold standard" of the diagnosis showing villous atrophy; the latter, however, is less and less often severe as the disease is milder and milder. The diagnosis of CD then rests on the confrontation of the clinical, biological and histological data. Once CD has been diagnosed, it can be classified either as active or silent (positive serology with isolated villous atrophy), or latent (positive serology with a normal mucosa) and the appropriate therapeutic decision can be taken.

Increasing prevalence of coeliac disease over time

BACKGROUND

The number of coeliac disease diagnoses has increased in the recent past and according to screening studies, the total prevalence of the disorder is around 1%.

AIM

To establish whether the increased number of coeliac disease cases reflects a true rise in disease frequency.

METHODS

The total prevalence of coeliac disease was determined in two population-based samples representing the Finnish adult population in 1978-80 and 2000-01 and comprising 8000 and 8028 individuals, respectively. Both clinically-diagnosed coeliac disease patients and previously unrecognized cases identified by serum endomysial antibodies were taken into account.

RESULTS

Only two (clinical prevalence of 0.03%) patients had been diagnosed on clinical grounds in 1978-80, in contrast to 32 (0.52%) in 2000-01. The prevalence of earlier unrecognized cases increased statistically significantly from 1.03% to 1.47% during the same period. This yields a total prevalence of coeliac disease of 1.05% in 1978-80 and 1.99% in 2000-01.

CONCLUSIONS

The total prevalence of coeliac disease seems to have doubled in Finland during the last two decades, and the increase cannot be attributed to the better detection rate. The environmental factors responsible for the increasing prevalence of the disorder are issues for further studies.

Antibodies against synthetic deamidated gliadin peptides as predictors of celiac disease: prospective assessment in an adult population with a high pretest probability of disease

BACKGROUND

Noninvasive serologic tests have shown high diagnostic accuracy for celiac disease (CD) in selected populations. Our aim was to determine prospectively the performance of CD-related serology in individuals undergoing intestinal biopsy because of clinical suspicion of small-bowel disorders.

METHODS

We enrolled 141 unselected consecutive adult patients attending a small-bowel disease clinic. Patients underwent endoscopy and biopsy; serum samples were obtained at that time for measurements of anti-tissue transglutaminase (a-tTG), IgA and IgG anti-deamidated gliadin-related peptide (a-DGP), and IgA antiactin antibodies (AAAs). Characterization of patients was based on histological criteria (Marsh type II lesion or greater).

RESULTS

The prevalence of CD was 42.5%. Sensitivity, specificity, and positive and negative predictive values were >90% for most assays. Diagnostic accuracy based on ROC curve analysis was similar for all assays [area under the curve (95% CI): 0.996 (0.967-0.998) for a-tTG, 0.995 (0.964-0.998) for IgA a-DGP, 0.989 (0.954-0.999) for IgG a-DGP, 0.996 (0.966-0.998) for blended conjugated of IgA + IgG a-DGP in a single assay, and 0.967 (0.922-0.990) for AAA]. The combinations of 2 tests, IgG a-DGP plus IgA a-tTG or the single blended conjugate detecting IgA + IgG a-DGP plus IgA a-tTG had 100% positive and negative predictive values if concentrations of both tests in either combination were above or below the cutoff.

CONCLUSIONS

In a population with high pretest probability, the newly developed a-DGP tests have diagnostic accuracy that is at least equivalent to that of established assays.

Prevalence of celiac disease in Tunisia: mass-screening study in schoolchildren

BACKGROUND

Celiac disease is reported to be common among North Africans, particularly Tunisians. Nevertheless, the prevalence of coeliac disease in the general population has not been previously investigated.

OBJECTIVE

This study aimed to determine the prevalence of celiac disease among children in Tunisia and to describe the clinical profile of the screened patients.

METHODS

A mass screening study based on drawing lots was carried out on schoolchildren in Ariana, a Tunisian district. A participation agreement was obtained from 6286 children (3175 boys, age: 9.7+/-3 years). Two children of known celiac disease were present in this population. All participants were tested for IgA antitissue transglutaminase antibodies (IgA-tTG) by a commercial enzyme-linked immunosorbent assay (ELISA) and total IgA levels. Sera, found positive by the initial screening, were assessed by immunofluorescence for the presence of IgA antiendomysium antibodies (IgA-AE). Positive participants were also called in for serological control, intestinal biopsy, biological exploration (hemoglobin rate, calcemia and albuminemia) and bone mineral densitometry.

RESULTS

Among the 6284 participants, 139 (1/45) were positive for IgA-tTG. Forty-two of these had low-level IgA-tTG and no one had IgA deficiency. IgA-AE was detected in 40 participants. One hundred and seven children were called in, 28 had both positive tests (IgA-tTG +/IgA-AE+) and 79 were only positive for IgA-tTG (IgA-tTG +/IgA-AE-). Intestinal biopsy was performed in the 28 participants of the first group (IgA-tTG +/IgA-AE+) and confirmed celiac disease in 26 cases. In the second group (IgA-tTG +/IgA-AE-), intestinal biopsy was performed in 26 children and histological examination was normal in all cases. Among the 26 biopsy-proven celiac disease children, six (23%) had typical clinical symptoms of celiac disease, whereas the others had atypical forms with 11 (42%) asymptomatic. In 23 biopsy-proven celiac disease children, bone mineral density was significantly lower than that of a group of 109 normal children (0.850+/-0.06 g/cm2 versus 0.912+/-0.06 g/cm2, P<0.05). Seven participants (30.4%) among the celiac disease children and six (7.5%) among the controls had a total-body Z score for bone mineral density of <-2 (P<0.001).

CONCLUSION

The prevalence of celiac disease in Tunisian schoolchildren, estimated to be about 1/157, is close to the European prevalence. Most of the screened children showed an atypical and asymptomatic form, but even the typical forms were underdiagnosed. Ostopenia was frequently observed in celiac disease patients.

Deamidated Gliadin Peptides as Targets for Celiac Disease‐Specific Antibodies

Celiac disease (CD) is an (auto)immunologically mediated intestinal intolerance against proteins from wheat (gluten) and related cereal proteins. Tissue transglutaminase (tTG) has been identified as the autoantigen in CD. Although ultimate diagnosis is based on histological analysis of small intestinal mucosa obtained via tissue biopsy, assessment of autoantibodies can provide substantial help in the evaluation of CD. Gliadin antibodies are directed against the native disease-provoking cereal proteins. Despite their initial usefulness, these antibodies have lost diagnostic importance due to their poor specificity and sensitivity as CD markers. Recently, it was found, however, that gliadin antibodies from sera of patients with active CD preferentially recognized deamidated gliadin peptides. The use of deamidated gliadin peptides in immunoassays has significantly improved the usefulness of gliadin antibodies in diagnosis of CD to that observed with autoantibody assay methods (endomysium antibodies, antibodies against tTG). The antibody epitopes (B-cell epitopes) reflect substrate specificity of tTG and resemble peptide sequences known to be strongly T-cell stimulatory (T-cell epitopes) in CD. The assay applying deamidated gliadin peptides measures a new species of antibodies, which is different from conventional gliadin antibodies as well as from autoantibodies and will likely provide new information on pathophysiological mechanisms of CD.

An algorithm for family screening for coeliac disease

AIM: To assess the level of undiagnosed coeliac disease (CD) in relatives of patients affected by the condition.

METHODS: We collected blood from 914 relatives of probands. We screened these individuals by ELISA for IgA and IgG tTG antibodies, confirming any positive IgA tTG results with an IgA EMA and looked for evidence of IgA deficiency in those who were IgG tTG positive alone, and performed IgG1 EMA in these individuals. We undertook HLA typing where positive screening was found, and this confirmed a strong prevalence of HLA-DQ2 in the coeliac population. Follow-up small intestinal biopsy was undertaken in cases with positive serological screening, wherever possible.

RESULTS: Use of this serological screening algorithm revealed a prevalence of undiagnosed CD in 5%-6% of first degree relatives of probands.

CONCLUSION: Our data suggests that first degree relatives of individuals with CD should be screened for this condition.

Diagnosis of celiac disease

Celiac disease is an immune mediated enteropathy initiated by ingestion of gluten, in genetically susceptible individuals. With changing epidemiology, celiac disease initially thought to affect only Europeans, has been increasingly reported from other parts of the world including India. However, its true prevalence in India is still not known, as the diagnosis is being missed. The gold standards for diagnosis have been characteristic small intestinal mucosal changes on gluten and a full clinical remission on its removal from the diet. Presence of serological antibodies, which disappear on gluten free diet further confirms the diagnosis. The understanding of the histopathology of celiac disease has changed over the years. The small bowel mucosal lesion of celiac disease is an evolutionary process with normal mucosal architecture and an increase in intraepithelial lymphocytes at one end of the spectrum and classical flat mucosa at the other. In the Indian subcontinent celiac disease has a heterogeneous histological presentation and the diagnosis may be missed if it is based only on severe mucosal changes or the serology is not considered when moderate or mild mucosal changes are present. The last two decades have shown that antiendomysical (Anti EMA) and anti tissue transglutaminase antibodies (anti-tTGA) have a sensitivity and specificity of more than 95% to diagnose celiac disease. Anti EMA tests being operator dependent are more liable to errors and anti- tTGA may be preferred for large scale screening. However, the different source of tTGA antigen, varied techniques of production and the use of arbitrary units by different commercial kits can influence the diagnostic accuracy of the anti-tTGA assay. There is a strong genetic association of celiac disease with HLA-DQ2 or DQ8. The presence of HLA-DQ2 hetrodimer in more than 97% of a group of North Indian patients with celiac disease indicates that this population has a similar genetic risk for the disease. HLA DQ2 typing can be used for ruling out celiac disease where the diagnosis is equivocal as it has a negative predictive value of greater than 95%. Given the protean clinical manifestation and the heterogeneous histology a standard algorithm for diagnosis of celiac disease is important.

Systematic review: the use of serology to exclude or diagnose coeliac disease (a comparison of the endomysial and tissue transglutaminase antibody tests)

BACKGROUND

With the appreciation of the high prevalence of coeliac disease there is increasing use of serology in screening asymptomatic people and testing those with suggestive features.

AIM

To compare the sensitivities and specificities of the endomysial antibody and the tissue transglutaminase antibody tests.

METHODS

Using electronic databases a search was made for relevant papers using the terms tissue transglutaminase and endomysial antibody.

RESULTS

Both the endomysial antibody and tissue transglutaminase antibody have very high sensitivities (93% for both) and specificities (>99% and >98% respectively) for the diagnosis of typical coeliac disease with villous atrophy. Human recombinant tissue transglutaminase performs much better than guinea pig tissue transglutaminase. Review of studies comparing endomysial antibody with human recombinant tissue transglutaminase antibody shows that endomysial antibody more often has a higher specificity and human recombinant tissue transglutaminase antibody more often has a higher sensitivity.

CONCLUSION

The human recombinant tissue transglutaminase antibody is the preferred test for screening asymptomatic people and for excluding coeliac disease in symptomatic individuals with a low pretest probability (i.e. <25%) for coeliac disease. Furthermore, it has a number of practical and financial advantages. If the pretest probability is >25%, biopsy is preferred as the post-test probability of coeliac disease with a negative test is still >2%.