Production of anti-endomysial antibodies in cultured duodenal mucosa: usefulness in coeliac disease diagnosis

Emerging Biomarkers for Screening and Management of Celiac Disease

Celiac disease (CeD) is a chronic, immune-mediated enteropathy that is precipitated by dietary gluten in genetically predisposed individuals expressing HLA-DQ2 and/or HLA-DQ8. In the current clinical practice, there are many serologic studies to aid in the diagnosis of CeD which include autoantibodies like IgA antitissue transglutaminase, antiendomysium, and antideamidated forms of gliadin peptide antibodies. Small intestinal biopsy has long been considered an essential step for the diagnosis of CeD. However, in the recent era, researchers have explored the possibility of CeD screening and diagnosis without endoscopy or biopsy. The newer emerging biomarkers of CeD appear promising in diagnostic evaluation and subsequent monitoring of disease. In this review of literature, we have explored the emerging biomarker-based diagnostic evaluation and monitoring of CeD.

Intestinal Anti-tissue Transglutaminase2 Autoantibodies: Pathogenic and Clinical Implications for Celiac Disease

Celiac disease (CD) is a systemic disease that primarily affects the small intestine. The presence of anti-tissue transglutaminase 2 (anti-TG2) antibodies in the serum, as well as the presence of autoimmune phenomena, account for the inclusion of CD among autoimmune diseases. Anti-TG2 autoantibodies are produced at intestinal level, where they are deposited even before they appear in circulation. The pathogenic events that lead to their production are still not completely defined, but a central role seems to be played by gliadin-specific T cells. Interestingly, limited somatic mutations have been observed in VH and VL genes in TG2-specific plasma cells, another important aspect being the biased use of a heavy chain encoded by the VH5 gene. Conflicting data have been produced over the years on the effect of anti-TG2 antibodies on TG2 function. Although the presence of anti-TG2 antibodies in serum is considered a hallmark of CD and relevant from a clinical viewpoint, the role of these autoantibodies in the development of the celiac lesion remains to be defined. In the years, different technical approaches have been implemented to detect and measure intestinal CD-associated autoantibody production. Two aspects can make intestinal anti-TG2 antibodies relevant: from a clinical viewpoint: the first is their proposed ability in potential coeliac patients to predict the development of a full-blown enteropathy; the second is their possible role in revealing a condition of reactivity to gluten in patients with no circulating CD-associated autoantibodies. In fact, the detection of CD-specific autoantibodies production in the intestine, in the absence of serum positivity for the same antibodies, could be suggestive of a very early condition of gluten reactivity; alternatively, it could be not specific for CD and merely attributable to intestinal inflammation. In conclusion, the role of mucosal anti-TG2 antibodies in pathogenesis of CD is unknown. Their presence, the modalities of their production, their gluten dependence render them a unique model to study autoimmunity.

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

Background

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

Case presentation

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

Conclusions

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

Suspected Nonceliac Gluten Sensitivity Confirmed in Few Patients After Gluten Challenge in Double-Blind, Placebo-Controlled Trials

A double-blind, placebo-controlled, gluten challenge has been proposed to confirm a diagnosis of nonceliac gluten sensitivity (NCGS) in patients without celiac disease who respond to a gluten-free diet. To determine the accuracy of this approach, we analyzed data from 10 double-blind, placebo-controlled, gluten-challenge trials, comprising 1312 adults. The studies varied in the duration of the challenge (range, 1 d to 6 wk), daily doses for the gluten challenge (range, 2-52 g; 3 studies administered <8 g/d), and composition of the placebo (gluten-free products, xylose, whey protein, rice, or corn starch containing fermentable carbohydrates). Most of the studies found gluten challenge to significantly increase symptom scores compared with placebo. However, only 38 of 231 NCGS patients (16%) showed gluten-specific symptoms. Furthermore, 40% of these subjects had a nocebo response (similar or increased symptoms in response to placebo). These findings reveal heterogeneity and potential methodology flaws among studies of gluten challenge, cast doubt on gluten as the culprit food component in most patients with presumptive NCGS, and highlight the importance of the nocebo effect in these types of studies.

In Vitro Gluten Challenge Test for Celiac Disease Diagnosis

OBJECTIVES

The in vitro gluten challenge test is an important diagnostic modality in celiac disease (CD), especially in patients who begin treatment with a gluten-free diet before adequate diagnostic workup or in cases with atypical CD. Available literature was reviewed regarding the accuracy of the in vitro gluten challenge test for CD diagnosis.

METHODS

MEDLINE, Scopus, and Google Scholar were searched, and studies that used serology and bowel biopsy as the criterion standard for diagnosis were included in our study. Data on authors, publication year, characteristics of the patient and control groups, patients' diet, duration of the gluten challenge test, histology findings, endomysial antibody (EMA) and anti-tissue transglutaminase (tTG) levels, CD markers, and intercellular cell adhesion molecule-1, and human leukocyte antigens before and after the gluten challenge test were extracted.

RESULTS

Overall, 15 studies were included in this meta-analysis. Pooled sensitivity %/specificity % was 84/99 for EMA after the challenge, 52/96 for EMA without the challenge, 95.5/98.3 for anti-tTG after the challenge, and 95.1/98.3 for anti-tTG without the challenge test. Sensitivity/specificity for immunological markers were 89/97 for the percentage of CD25⁺-lamina propria lymphocytes, 96/91 for the percentage of CD3⁺-lamina propria lymphocytes, and 96.1/85.7 for the percentage of intercellular cell adhesion molecule-1-lamina propria lymphocytes. The factors that increased the sensitivity of EMA were longer test duration, and the evaluation of patients on a gluten-containing diet or short-term gluten-free diet.

CONCLUSIONS

The in vitro gluten challenge test can be a useful part of the diagnostic workup of CD, rather than only a model to evaluate its mechanisms.

Effect of anti-gliadin IgY antibody on epithelial intestinal integrity and inflammatory response induced by gliadin

BACKGROUND

Pepsin-trypsin resistant gliadin (PT-gliadin) promotes intestinal tissue inflammation and increases paracellular permeability of immunogenic gliadin peptides into the lamina propria. This leads to the complications seen in the pathogenesis of celiac disease (CD). In this study, specific anti-gliadin IgY antibody was produced and evaluated for its efficacy on gliadin induced intestinal integrity impairment and proinflammatory effects on intestinal epithelial (Caco-2) cell culture model for CD.

METHODS

Caco-2 (passages 20-24) monolayers were subjected to 7 experimental conditions (n=3 each): phosphate buffered saline (PBS; control), pancreatic digested-casein (PD-casein; negative control), PT-gliadin (positive control), non-specific IgY with PT-gliadin, and anti-wheat gliadin IgY with PT-gliadin at a ratio of 1:6,000, 1:3,000 and 1:1,500. Caco-2 monolayers were then evaluated for effects of gliadin and/or anti-wheat gliadin IgY after 24 h exposure. Enzyme-linked immunosorbent assay (ELISA) was used to quantify anti-inflammatory markers (TNF-α and IL-1β) 5 days after cells were exposed to PT-gliadin and/or anti-wheat gliadin IgY.

RESULTS

Among other conditions, anti-wheat gliadin IgY at a ratio of 1:3,000 (anti-gliadin IgY: PT-gliadin) significantly prevented gliadin toxicity on Caco-2 by maintaining intestinal integrity, inhibiting phenol red permeation, and inhibiting gliadin absorption and production of proinflammatory cytokines (TNF-α and IL-1β) as compared to PT-gliadin stimulated cultures (P < 0.05).

CONCLUSION

The anti-wheat gliadin IgY antibody produced in this study has proved to inhibit absorption of gliadin and gliadin-induced inflammatory response in Caco2 cell culture model of CD. Anti-gliadin IgY, therefore has potential to be used as an oral passive antibody therapy to treat CD.

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.

Non-celiac gluten sensitivity: literature review

BACKGROUND

A significant percentage of the general population report problems caused by wheat and/or gluten ingestion, even though they do not have celiac disease (CD) or wheat allergy (WA), because they test negative both for CD-specific serology and histopathology and for immunoglobulin E (IgE)-mediated assays. Most patients report both gastrointestinal and nongastrointestinal symptoms, and all report improvement of symptoms on a gluten-free diet. This clinical condition has been named non-celiac gluten sensitivity (NCGS).

AIM

We attempt to define the current pathogenic, clinical, and diagnostic criteria of this "new" disease, to provide a practical view that might be useful to evaluate, diagnose, and manage NCGS patients.

METHODS

We reviewed the international literature through PubMed and Medline, using the search terms "wheat (hyper)sensitivity," "wheat allergy," "wheat intolerance," "gluten (hyper)sensitivity," and "gluten intolerance," and we discuss current knowledge about NCGS.

RESULTS

It has been demonstrated that patients suffering from NCGS are a heterogeneous group, composed of several subgroups, each characterized by different pathogenesis, clinical history, and, probably, clinical course. NCGS diagnosis can be reached only by excluding CD and WA. Recent evidence shows that a personal history of food allergy in infancy, coexistent atopy, positive for immunoglobulin G (IgG) antigliadin antibodies and flow cytometric basophil activation test, with wheat and duodenal and/or ileum-colon intraepithelial and lamina propria eosinophil counts, could be useful to identify NCGS patients.

CONCLUSIONS

Future research should aim to identify reliable biomarkers for NCGS diagnosis and to better define the different NCGS subgroups. Key teaching points: • Most patients report both gastrointestinal and nongastrointestinal symptoms, and all agree that there is an improvement of symptoms on a gluten-free diet. • NCGS diagnosis can be reached only by excluding celiac disease and wheat allergy. • Patients suffering from NCGS are a heterogeneous group, composed of several subgroups, each characterized by different pathogenesis, clinical history, and, probably, clinical course. • A personal history of food allergy in infancy, coexistent atopy, positive IgG antigliadin antibodies (AGA) and flow cytometric basophil activation test, with wheat and duodenal and/or ileum-colon intraepithelial and lamina propria eosinophil counts, could be useful to identify NCGS patients. • Future research should aim to identify reliable biomarkers for NCGS diagnosis and to better define the different NCGS subgroup.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD.

All that glitters is not always gold

Biopsies from the second part of the duodenum are routinely performed in patients with unintentional weight loss. When villous atrophy and an increased intraepithelial lymphocytosis are detected, the commonest cause of it is coeliac disease. Severe villous atrophy with increased intraepithelial lymphocytosis (Marsh IIIc) is highly specific for coeliac disease. However, coeliac disease with this presentation is very rare. Milder abnormalities such as Marsh I-II (microscopic enteritis) and Marsh IIIa are not specific for coeliac disease and could occur in other conditions like those listed in the discussion. We present the case of a 74-year-old woman who, after being diagnosed with seronegative coeliac disease, failed to improve on a gluten-free diet. We discuss the differential diagnosis of coeliac disease and the possible alternative causes for villous blunting, paying particular attention to the diagnosis of small intestinal bacterial overgrowth.

Non-celiac wheat sensitivity as an allergic condition: personal experience and narrative review

OBJECTIVES

Non-celiac wheat sensitivity (NCWS) is a newly described clinical entity characterized by symptoms, which can involve the gastrointestinal tract, the nervous system, the skin, and other organs. There is little data on the pathogenesis of NCWS and it is probable that different pathogenic mechanisms are involved in the different clinical manifestations of the disease. The only common denominator of NCWS "syndrome" is wheat consumption: the symptoms disappear on exclusion of wheat from the diet, and reappear on wheat consumption. The objective of this study was to review our prior data regarding NCWS and to review relevant medical literature regarding NCWS, with particular attention to the hypothesis that NCWS patients could suffer from non-immunoglobulin E (IgE)-mediated wheat allergy.

METHODS

We reviewed our data on 276 patients diagnosed with NCWS by means of double-blind placebo-controlled (DBPC) wheat challenge. The data indicating a possible wheat allergy diagnosis were examined and other data in the literature were reviewed; we review the role of serum immunoglobulin G antibodies and the basophil activation assay in food allergy, and the histology findings in the food allergy diagnosis.

RESULTS

The comparison between patients suffering from NCWS and presenting with irritable bowel syndrome (IBS) and controls with IBS not due to NCWS showed that NCWS was characterized by: a personal history of food allergy in the pediatric age (0.01), coexistent atopic diseases (0.0001), positive serum anti-gliadin (0.0001) and anti-betalactoglobulin (0.001) antibodies, positive cytofluorimetric assay revealing in vitro basophil activation by food antigens (0.0001), and a presence of eosinophils in the intestinal mucosa biopsies (0.0001).

CONCLUSIONS

Patients with NCWS and multiple food sensitivity show several clinical, laboratory, and histological characteristics that suggest they might be suffering from non-IgE-mediated food allergy. However, other pathogenic mechanisms need to be considered.

Targeting tissular immune response improves diagnostic performance of anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease

Antibodies against Saccharomyces cerevisiae (ASCA) and Escherichia coli outer membrane porin C (anti-OmpC) are known to be detectable in the serum of patients with Crohn’s disease (CD) but display a very poor sensitivity for the disease especially in forms with isolated colonic involvement. In this study we aimed at evaluating performances of these markers in supernatant of cultured colonic biopsies.

Patients with colonic CD (n =  67), ulcerative colitis (UC) (n = 35) and control individuals (n = 37) were prospectively recruited for colonoscopy pinch biopsies and blood sampling. Serum and supernatant of culture tissues were analyzed for ASCA and anti-OmpC. Direct immunofluorescence was also performed on colonic tissues for total IgA detection.

We detected for the first time ASCA IgA/IgG and anti-OmpC IgA in cultured colonic tissue supernatants. For both markers, sensitivities for diagnosing CD were better in supernatants (ASCA: 53.7%, anti-OmpC: 28.4%) than in serum (ASCA: 31.3%, anti-OmpC: 22.4%). Combination of results from a panel of these tests gave the greatest sensitivity ever described for CD diagnosis in colonic forms (70.2%).

In this study, we described, for the first time, ASCA in supernatant of colonic tissue cultures. This assaying approach in CD diagnosis should be taken into consideration in the future especially in CD forms with isolated colonic involvement.

Non-celiac gluten sensitivity: clinical relevance and recommendations for future research

BACKGROUND

There has been increasing interest in the entity of Non-Celiac Gluten Sensitivity (NCGS) in recent years; however, it still remains a controversial topic and its pathogenesis is not well understood. Celiac Disease, in contrast, is a well-studied condition that has become increasingly recognized as a prevalent condition arising from a heightened immunological response to gluten. Wheat allergy is an IgE-mediated condition capable of causing a variety of gastrointestinal symptoms. However, the number of patients who have neither celiac disease nor wheat allergy, but appear to derive benefit from a gluten-free diet, is also increasing substantially. The use of the term NCGS as a way of describing this condition has become increasingly prevalent in recent years.

PURPOSE

In this review, we will focus on gastrointestinal manifestations of NCGS and discuss the evidence for the condition and its putative pathogenesis. We will discuss areas of controversy and areas for potential future research.

Usefulness of the organ culture system when villous height/crypt depth ratio, intraepithelial lymphocyte count, or serum antibody tests are not diagnostic for celiac disease

The existence of mild forms of celiac disease (CD) can make the histology-based diagnosis difficult to reach. Since anti-endomysium (EMA) and anti-tissue transglutaminase (anti-tTG) are detectable in culture supernatants of duodenal biopsies from CD patients, our aim was to assess if this system can support the histology in the diagnostic work-up. A total of 559 suspected CD patients underwent serum EMA/anti-tTG detection, upper endoscopy with duodenal biopsy sampling, histologic analysis, and organ culture to detect EMA/anti-tTG in supernatants. A subgroup of 30 patients with organ culture positive results were put on a gluten-free diet (GFD). Their gluten-dependency was evaluated by the psychological general well-being and beck depression inventory indexes. Statistical analysis was performed by Cohen k inter-test, Friedman test, and Dunn multiple comparison. Two hundred forty-one out of 559 (43.1%) patients showed intestinal villous atrophy, whereas serum and organ culture EMA/anti-tTG were positive in 293/559 (52.4%) and 334/559 (59.7%) patients, respectively. The strength of agreement resulted good for serology vs histology (k = 0.730), good for organ culture vs histology (k = 0.662), and very good for serology vs organ culture (k = 0.852). After 12 months of GFD, psychological general well-being index significantly increased, and beck depression inventory index significantly decreased (P < 0.001 for each one). Data highlight the organ culture system as a useful tool to assist the histology in diagnosing CD, mainly in cases without villous atrophy or in seronegative patients. The marked improvement in quality of life after a GFD further supports the reliability of this system in diagnosing CD.

Intestinal anti-tissue transglutaminase antibodies in potential coeliac disease

Anti-tissue transglutaminase 2 (anti-TG2) antibodies are present in the serum of the great majority of untreated coeliac disease (CD) patients. They are produced and deposited in the small intestinal mucosa. Potential CD patients present serum anti-TG2 antibodies higher than cut-off, but a normal duodenal mucosa where mucosal deposits of anti-TG2 are not always detectable. The aim of our work was to investigate the presence of anti-TG2 intestinal antibodies in patients with potential CD, and identify the most sensitive test to detect them. Twelve active CD patients, 28 potential CD patients and 39 non-CD controls were enrolled. Biopsy fragments from all patients were analysed by double immunofluorescence to detect mucosal deposits of anti-TG2 antibodies. Fragments from the same subjects were also cultured for 24 h with medium in the presence or absence of gliadin peptides. Anti-TG2 autoantibodies secreted into supernatants were measured by enzyme-linked immunosorbent assay. All active CD, 68% of potential CD patients and 20% of non-CD controls showed mucosal deposits of immunoglobulin (Ig)A anti-TG2; at the same time 100, 96 and 8% of active CD, potential CD and non-CD control patients secreted these antibodies in culture supernatants, respectively. Our data showed that, to detect intestinal anti-TG2 antibodies, the measurement of antibodies secreted into culture supernatants has higher sensitivity and specificity (97·5 and 92·3%, respectively) than the detection of mucosal deposits (77·5 and 80·0%, respectively). The measurement of intestinal anti-TG2 antibodies may prove useful in clinical practice to predict evolution towards mucosal atrophy in potential coeliac patients and identify patients with gluten sensitivity.

In vitro gliadin challenge: diagnostic accuracy and utility for the difficult diagnosis of celiac disease

OBJECTIVES

Diagnosis of celiac disease is difficult when treatment with gluten-free diet (GFD) is started before diagnosis and/or when the results of tests are inconsistent. The objective of this study was to evaluate the in vitro gliadin challenge.

METHODS

The study cohort included patients without celiac disease (negative controls, n=57), patients with celiac disease (positive controls, n=166 untreated and n=55 on GFD), and patients with difficult diagnosis (n=59). All patients underwent endoscopy for collection of duodenal samples, which served for the diagnosis of celiac disease and for the in vitro evaluation of the gliadin-induced mucosal expression of seven inflammatory markers: PY99, ICAM-1 (intercellular cell adhesion molecule), HLA-DR, CD3, CD25, CD69, and transglutaminase 2 IgA. Diagnostic work-up for celiac disease included the search of specific serum antibodies. Patients of the difficult diagnosis group were asked to stop GFD for repeated search of these antibodies under untreated conditions. The area under the receptor-operated curve (ROC) was used for statistical analyses on accuracy.

RESULTS

HLA-DR had the highest accuracy for celiac disease diagnosis in analyses on negative controls and positive controls also excluding patients on GFD (area under ROC=0.99). Accuracy of test did not increase combining data of HLA-DR with data of other markers. Findings were similar in the 39 patients of the difficult diagnosis group undergoing the search celiac disease-specific antibodies under untreated conditions.

CONCLUSIONS

The in vitro response of mucosal HLA-DR to gliadin is an accurate tool for the diagnosis of celiac disease also in patients with difficult diagnosis.

Sero-negative celiac disease with dermatitis herpetiformes: a case report

Introduction

We report a case of sero-negative celiac disease in Pakistan.

Case presentation

A 20-year-old female presented with papulovesicular rash for 15 years, diarrhea for 8 years, spasms of hands and twitching of face for 4-5 months. She had mild anemia, low vitamin-D3 and serum calcium. On exclusion of other causes of malabsorption, anti-tissue transglutaminase antibodies (immunoglobulin-A & immunoglobulin-G), anti-endomysial antibodies, total immunoglobulin-A levels and skin biopsy were performed, which were normal. Intestinal biopsy revealed subtotal villous atrophy. Patient was prescribed gluten-free diet, to which she responded with alleviation of symptoms.

Conclusion

Negative serology should not rule out celiac disease; intestinal biopsy should be performed if there is strong clinical suspicion.

High incidence of celiac disease in patients with systemic sclerosis

OBJECTIVE

To evaluate the presence of celiac disease in patients with systemic sclerosis (SSc). The association of autoimmune diseases with celiac disease has been reported, but few publications deal with the combination of SSc and celiac disease.

METHODS

We investigated the presence of anti-tissue transglutaminase (anti-tTG) antibodies and serum antiendomysial antibodies (anti-EMA) in 50 patients with SSc. All subjects were on a gluten-containing diet. Duodenal mucosa histology and biopsy culture were performed in anti-tTG-positive patients; anti-EMA and IgA, IgG1 anti-tTG were detected in culture supernatants.

RESULTS

The incidence of celiac disease in patients with SSc was found to be 8%. Serum anti-tTG antibody-positive results were detectable in 5 out of 50 patients with SSc, but only in 4 of them was the diagnosis confirmed by histological results (Marsh classification).

CONCLUSION

Our data show an increased prevalence of celiac disease in patients with SSc.

Diagnostic value of duodenal antitissue transglutaminase antibodies in gluten-sensitive enteropathy

BACKGROUND

In gluten-sensitive enteropathy, antitissue transglutaminase antibodies are synthesized in the duodenum.

AIM

To compare the diagnostic yield of these autoantibodies in cultured duodenal biopsies, duodenal aspirate and serum.

METHODS

Patients (n = 315, 135 female, 180 male; age: 37.3 +/- 1.1 years) referred for duodenal biopsies, were recruited and HLA-DQ2/DQ8 haplotyped. Histological measurements were made from duodenal biopsies and cultured duodenal biopsies were used for antitissue transglutaminase antibodies analysis by enzyme-linked immunosorbent assay. Duodenal aspirate was collected in a subgroup of 81 patients. Patients were classified, according to their histology, response to a gluten-free diet and DQ2/DQ8 status, as definite, likely or nongluten-sensitive enteropathy.

RESULTS

Histology was normal in 59% of patients; 28% had lymphocytic enteritis, 1% had crypt hyperplasia and 13% showed atrophy. In Marsh III patients, there was complete agreement between duodenal and serological antitissue transglutaminase antibodies measurements. Marsh I patients showed a slight antitissue transglutaminase antibodies sensitivity improvement in cultured duodenal biopsy compared to serum in definite (22% vs. 19%) and likely gluten-sensitive enteropathy (20% vs. 14%) patients. Combined serum and cultured duodenal biopsy antitissue transglutaminase antibodies assessment increased serological sensitivity from 19% to 30% in Marsh I patients.

CONCLUSION

Duodenal antitissue transglutaminase antibodies detection improves serological determination sensitivity in Marsh I patients, providing diagnostic value and therapeutic impact.

Secretion of celiac disease autoantibodies after in vitro gliadin challenge is dependent on small-bowel mucosal transglutaminase 2-specific IgA deposits

Background

In celiac disease gluten, the disease-inducing toxic component in wheat, induces the secretion of autoantibodies which are targeted against transglutaminase 2 (TG2). These autoantibodies are produced in the small-intestinal mucosa, where they can be found deposited extracellularly below the epithelial basement membrane and around mucosal blood vessels. In addition, during gluten consumption these autoantibodies can also be detected in patients' serum but disappear from the circulation on a gluten-free diet. Interestingly, after adoption of a gluten-free diet the serum autoantibodies disappear from the circulation more rapidly than the small-intestinal mucosal autoantibody deposits. The toxicity of gluten and the secretion of the disease-specific autoantibodies have been widely studied in organ culture of small-intestinal biopsy samples, but results hitherto have been contradictory. Since the mucosal autoantibodies disappear slowly after a gluten-free diet, our aim was to establish whether autoantibody secretion to organ culture supernatants in treated celiac disease patient biopsies is related to the duration of the diet and further to the pre-existence of mucosal TG2-specific IgA deposits in the cultured biopsy samples.

Results

In the organ culture system conducted with biopsies derived from treated celiac disease patients, gliadin induced secretion of autoantibodies to culture supernatants, reduced epithelial cell height and increased the density of lamina proprial CD25+ cells. However, these changes could be demonstrated only in biopsies from short-term treated celiac disease patients, where the small-intestinal mucosal TG2-specific IgA autoantibody deposits were still present. Furthermore, in these biopsies autoantibody secretion could be stimulated fully only after a 48-hour gliadin challenge.

Conclusion

Our results show that studies focusing on the toxic effects of gliadin in the organ culture system should be carried out with biopsy samples from short-term treated celiac disease patients who are likely still to have mucosal IgA deposits present. In addition to providing an explanation for the discrepancies in previous publications, the present study also enables further validation of the organ culture method.

Oral mucosa of coeliac disease patients produces antiendomysial and antitransglutaminase antibodies: the diagnostic usefulness of an in vitro culture system

BACKGROUND

Antiendomysial (EmA) and antitransglutaminase (anti-tTG) antibodies are the most specific indirect marker of coeliac disease (CD). It is not known whether the oral mucosa of patients with CD is able to produce these antibodies or not.

AIMS

To evaluate the ability of the oral mucosa of patients with CD to produce antibodies in an in vitro culture system.

PATIENTS AND METHODS

Twenty-eight patients with new diagnosis of CD (15 adults and 13 children) and 14 adult subjects with other diseases (controls) were studied. All underwent oral mucosa biopsy and subsequent EmA and anti-tTG assays on the mucosa culture medium.

RESULTS

Sensitivity and specificity of EmA and anti-tTG assayed in the oral mucosa culture medium for CD diagnosis were 54% and 100% and 57% and 100%, respectively. The CD clinical presentation, such as the presence of oral mucosa lesions, did not influence the results of the EmA and anti-tTG assays in the oral mucosa culture medium. There was an association between positivity of antibodies and greater severity of the oral mucosa lymphocyte infiltration.

CONCLUSION

This study demonstrates that the oral mucosa contributes to EmA and anti-tTG production in untreated patients with CD.

Anti-transglutaminase antibody assay of the culture medium of intestinal biopsy specimens can improve the accuracy of celiac disease diagnosis

BACKGROUND

We measured anti-transglutaminase (anti-tTG) antibody in the culture medium of intestinal biopsy specimens from patients with suspected celiac disease (CD) and evaluated the relationship between antibody production and severity of intestinal mucosal damage.

METHODS

We performed diagnostic testing for CD on 273 consecutive patients. In addition to routine histologic evaluation of duodenal biopsy specimens, we assayed anti-tTG antibodies in serum and in the culture medium of duodenal biopsy specimens.

RESULTS

CD was diagnosed in 191 of the 273 patients. Sensitivity and specificity of the serum anti-endomysium (EmA) and anti-tTG assays were 83% and 85% and 99% and 95%, respectively, and both had 88% diagnostic accuracy. EmA and anti-tTG assayed in the culture medium had 98% sensitivity, 100% specificity, and 98% diagnostic accuracy (vs serum assays; P <0.0001). Twenty-nine CD patient specimens (16%) were negative for serum anti-tTG and EmA; for 24 of these patients, anti-tTG assay of the culture medium was positive. The CD patients whose biopsy specimens were positive for serum antibodies showed the following intestinal histologies: total villous atrophy, 35%; severe villous atrophy, 25%; mild atrophy, 25%; villi with no atrophy but with increased intraepithelial lymphocytes, 15%. None of the CD patients whose specimens were negative for serum antibodies showed total or severe villous atrophy; 77% had mild villous atrophy, and 23% had no villous atrophy but had increased intraepithelial lymphocyte counts. Mild villous atrophy was also seen in specimens from approximately 15% of patients without CD.

CONCLUSION

Anti-tTG assay of the culture medium of biopsy specimens can improve the accuracy of CD diagnosis in patients negative for serum antibodies.

Usefulness of the organ culture system in the in vitro diagnosis of coeliac disease: a multicentre study

OBJECTIVE

Diagnosis of coeliac disease is based on the presence of villous atrophy which recovers following a gluten-free diet. The presence of circulating antiendomysial antibodies as well as their disappearance after a gluten-free diet supports the diagnosis. It has also been demonstrated that antiendomysial antibodies are detectable in supernatants of cultured intestinal biopsies from patients with coeliac disease. The objective of this study was to compare the histology and antiendomysial antibodies in culture supernatants of intestinal biopsies to validate the in vitro organ culture system as a future diagnostic tool for coeliac disease.

MATERIAL AND METHODS

Seventy-five antiendomysial serum-positive patients on a gluten-containing diet were evaluated. Patients underwent endoscopy with 5 biopsy fragments: 3 for histology, 1 cultured with and the other without gliadin-peptide activator. Antiendomysial antibodies were evaluated in all culture supernatants.

RESULTS

Sixty-eight patients had evidence of villous atrophy, while 73 out of 75 were positive to the organ culture system. The agreement rate between organ culture and histology results was 94%.

CONCLUSIONS

As all the centres participating in the study obtained good agreement between organ culture and histology results, the new system could be considered a reliable tool for the diagnosis of coeliac disease. Nevertheless, it is possible to highlight cases with an organ culture-positive and -negative histology. This feature could be of considerable interest because, as the sensitivity of organ culture seems to be greater than the initial histology, the new system might be useful in uncertain cases where the risk of missing the diagnosis of coeliac disease is high.

The diagnostic accuracy of serologic tests for celiac disease: a systematic review

Clinicians are increasingly utilizing noninvasive serologic tests for the diagnosis and screening of celiac disease (CD). The aim of this study was to conduct a systematic review of the diagnostic performance of serologic tests for the diagnosis and screening of CD. Standard systematic review methodology was used. A literature search was conducted in MEDLINE (1966 to October 2003) and EMBASE (1974 to December 2003) databases. A weighted mean of the sensitivity and specificity along with 95% confidence intervals and summary receiver operating characteristic (ROC) curves were calculated. The pooled specificity of endomyseal antibody (EMA)-monkey esophagus (ME) or EMA-human umbilical cord (HU) was close to 100% in adults and children. The pooled specificity of transglutaminase antibody (tTG)-guinea pig (GP) and tTG-human recombinant (HR) were between 95% and 99%. IgA-EMA-ME demonstrated sensitivities of 96% and 97% in children and adults, respectively. EMA-HU demonstrated a similar sensitivity of 97% in children but 90% in adults. The pooled sensitivity of tTG-GP in adults and children was 90% and 93%, respectively. The sensitivity of tTG-HR was 98% and 96%, respectively. The performance of antigliadin antibody was inferior to that of EMA and tTG. EMA and tTG offer high sensitivity and specificity. The sensitivity of these tests appears to be lower than reported when milder histologic grades are used to define CD (below 90%). If true, the nearly perfect negative predictive value of these tests would drop. The positive predictive value of these tests is likely lower than reported when the tests are applied in low-prevalence populations.

Antiendomysial antibody detection in biopsy culture allows avoidance of gluten challenge in celiac children

OBJECTIVE

Antiendomysial antibody (EMA) production has been induced in vitro by the small bowel mucosa of celiac disease (CD) patients in clinical remission cultured in the presence of gliadin peptides. The aim of the present study was to use this in vitro system to determine whether it could be used to predict the clinical or histologic relapse to gluten challenge in CD children on a gluten-free diet (GFD).

METHODS

Enrolled were 32 CD children and adolescents on GFD (group 1), and 80 controls (group 2) who underwent in vitro gliadin challenge. Subsequently, 24 group 1 CD children underwent in vivo gluten challenge to confirm the diagnosis. Biopsy cultures, with and without gliadin, morphometric analysis, immunoglobulin (Ig)A and IgG1 EMA detection, both in sera and culture supernatants, were performed.

RESULTS

Of the 32 group 1 CD patients, 23 were IgA EMA positive in culture supernatants. The other nine were IgG1 EMA positive. All 24 children who had in vivo gluten challenge showed clinical or histologic relapse. All culture supernatants from disease controls belonging to group 2 were both IgA and IgG1 EMA negative, irrespective of gliadin challenge.

CONCLUSIONS

Organ culture with in vitro gliadin challenge is able to reproduce the results of in vivo challenge. This system could reduce the need for gluten challenge in celiac children.

Diagnostic accuracy of fecal calprotectin assay in distinguishing organic causes of chronic diarrhea from irritable bowel syndrome: a prospective study in adults and children

BACKGROUND

Fecal calprotectin (FC) has been proposed as a marker of inflammatory bowel disease (IBD), but few studies have evaluated its usefulness in patients with chronic diarrhea of various causes. We evaluated the diagnostic accuracy of a FC assay in identifying "organic" causes of chronic diarrhea in consecutive adults and children.

METHODS

We consecutively enrolled 70 adult patients (30 males, 40 females; median age, 35 years) and 50 children (20 males, 30 females; median age, 3.5 years) with chronic diarrhea of unknown origin. All patients underwent a complete work-up to identify the causes of chronic diarrhea. FC was measured by ELISA.

RESULTS

In adult patients, FC showed 64% sensitivity and 80% specificity with 70% positive and 74% negative predictive values for organic causes. False-positive results (8 of 40 cases) were associated with the use of aspirin (3 cases) or nonsteroidal antiinflammatory drugs (1 case) and with the presence of concomitant liver cirrhosis (3 cases). False-negative results mainly included patients suffering from celiac disease (5 cases). Patients with IBD (9 cases) were identified with 100% sensitivity and 95% specificity. In pediatric patients, sensitivity was 70%, specificity was 93%, and positive and negative predictive values were 96% and 56%. False-negative results (11 of 35 cases) were associated mainly with celiac disease (6 cases) or intestinal giardiasis (2 cases).

CONCLUSIONS

FC assay is an accurate marker of IBD in both children and adult patients. In adults, false negatives occur (e.g., in celiac disease) and false-positive results are seen in cirrhosis or users of nonsteroidal antiinflammatory drugs. Diagnostic accuracy is higher in children.