The humoral immune system in coeliac disease

Development of Cell-Assembled Human Endomysial-Type Biomatrix Substrate for the Detection of Celiac Disease Autoantibodies

The endomysial antibody (EMA) immunofluorescent test is a highly specific method to detect disease-specific autoantibodies in celiac disease (CD) by their binding to natural transglutaminase-2 autoantigen in tissue sections, and it is used as a compulsory confirmatory test in the non-invasive diagnosis of CD. The classical EMA substrates are the monkey esophagus and the human umbilical cord. It is increasingly difficult to use these tissues due to ethical concerns and animal welfare regulations. In this study, we developed, in cell culture, an endomysium-type extracellular biomatrix assembled by human umbilical cord vein-derived endothelial cells which binds CD antibodies in a similar pattern as monkey esophagus and has similar macromolecular composition. Evaluating retrospectively and prospectively tested patient cohorts, including 130 CD cases and 105 non-celiac controls, IgA-class celiac antibody detection on the biomatrix was equally specific (100%) as EMA testing on tissues, and had higher sensitivity (95.6% versus 91.2%). Both EMA tests were less sensitive, but more specific than transglutaminase-based ELISA measurements. The decellularization of the biomatrix improved sensitivity, enabled the detection of IgG-class celiac antibodies, and allowed for simple reading without previous training. This easily available cell-assembled biomatrix substrate may replace substrate tissues in diagnostic EMA testing in the future.

Measured levels of positive transglutaminase 2 antibodies are not associated with presentation or incidental endoscopic findings at celiac disease diagnosis

OBJECTIVES

It has been suggested that celiac disease could be diagnosed non-invasively in adults with transglutaminase antibody (TGA) levels >10x upper limit of normal (ULN). It is, however, unclear if high values signify more advanced disease and higher risk of co-morbidities. We investigated the association between the TGA levels, clinical characteristics and non-celiac endoscopic findings.

METHODS

Medical data on 450 celiac disease patients at diagnosis were collected. They were further divided into those with high positive (>10x ULN, n = 164), moderately positive (1-10x ULN, n = 219), and negative (n = 67) TGA.

RESULTS

Median age of patients was 50 years and 60% were women. Patients with negative TGA were older (median age 58 vs. 51 vs. 46 years respectively, p = 0.002) and had more often weight loss (27% vs. 10% vs. 9%, p < 0.001) and abdominal pain or dyspepsia (40% vs 27% vs. 22%, p = 0.017) than did those with moderately positive/high TGA. The groups did not differ in sex, BMI, or other symptoms. Major endoscopic findings included one esophageal adenocarcinoma presenting with dysphagia, six esophagitis, three gastric ulcers, and 39 H. Pylori or other active gastritis. High, moderately positive or negative TGA levels were not associated with these findings in crude or age-adjusted analyses.

CONCLUSIONS

Presentation was similar in patients with moderate or high levels of TGA, whereas patients with negative TGA were different. The level of TGA was not associated with incidental endoscopic findings and the only malignancy presented with an alarm symptom atypical to celiac disease.

Genome-Wide Transcriptomic Analysis of Intestinal Mucosa in Celiac Disease Patients on a Gluten-Free Diet and Postgluten Challenge

BACKGROUND & AIMS

Gluten challenge studies are instrumental in understanding the pathophysiology of celiac disease. Our aims in this study were to reveal early gluten-induced transcriptomic changes in duodenal biopsies and to find tools for clinics.

METHODS

Duodenal biopsies were collected from 15 celiac disease patients on a strict long-term gluten-free diet (GFD) prior to and post a gluten challenge (PGC) and from 6 healthy control individuals (DC). Biopsy RNA was subjected to genome-wide 3' RNA-Seq. Sequencing data was used to determine the differences between the three groups and was compared to sequencing data from the public repositories. The biopsies underwent morphometric analyses.

RESULTS

In DC vs. GFD group comparisons, 167 differentially expressed genes were identified with 117 genes downregulated and 50 genes upregulated. In PGC vs. GFD group comparisons, 417 differentially expressed genes were identified with 195 genes downregulated and 222 genes upregulated. Celiac disease patients on a GFD were not "healthy". In particular, genes encoding proteins for transporting small molecules were expressed less. In addition to the activation of immune response genes, a gluten challenge induced hyperactive intestinal wnt-signaling and consequent immature crypt gene expression resulting in less differentiated epithelium. Biopsy gene expression in response to a gluten challenge correlated with the extent of the histological damage. Regression models using only four gene transcripts described 97.2% of the mucosal morphology and 98.0% of the inflammatory changes observed.

CONCLUSIONS

Our gluten challenge trial design provided an opportunity to study the transition from health to disease. The results show that even on a strict GFD, despite being deemed healthy, patients reveal patterns of ongoing disease. Here, a transcriptomic regression model estimating the extent of gluten-induced duodenal mucosal injury is presented.

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.

Celiac disease is not more prevalent in patients undergoing in vitro fertilization and does not affect reproductive outcomes with or without treatment: a large prospective cohort study

OBJECTIVE

To study the prevalence of celiac disease in the infertile population undergoing in vitro fertilization (IVF) and assess outcomes.

DESIGN

Prospective cohort study.

SETTING

A single infertility center from January 2016 to March 2017.

PATIENT(S)

Women 18-45 years of age participating in IVF.

INTERVENTION(S)

Patients had serum tissue transglutaminase (tTG) and endomysial (EMA) IgA testing to screen for celiac disease and completed a 10-question "yes or no" survey to assess their medical history, previous testing, dietary habits, and pertinent symptoms.

MAIN OUTCOME MEASURE(S)

IVF cycle outcomes were compared between seronegative and seropositive patients.

RESULT(S)

Of 1,000 patients enrolled, 995 completed serologic screening and 968 underwent oocyte retrieval. Eighteen patients screened positive for both tTG and EMA (1.8%) and 10 additional patients (1.0%) screened positive for one of the two antibodies. The number of mature oocytes retrieved, fertilization rates, and blastulation rates were equivalent between seronegative and seropositive patients. There were 987 patients who completed the questionnaire (98.7%), and 84 reported being gluten free (8.5%). Those who reported being gluten free were no more likely to be antibody positive than the general population. Furthermore, a low-gluten diet was not associated with markers of ovarian reserve, oocytes retrieved, fertilization, blastulation, sustained implantation and pregnancy loss rates.

CONCLUSION(S)

The prevalence of seropositive celiac disease was consistent with that of the general population (2.8%). Patients who were seropositive for celiac disease-related antibodies had outcomes equivalent to seronegative patients, and patients with a gluten-free diet did not have improved outcomes.

Gluten-Induced Extra-Intestinal Manifestations in Potential Celiac Disease-Celiac Trait

Celiac disease patients may suffer from a number of extra-intestinal diseases related to long-term gluten ingestion. The diagnosis of celiac disease is based on the presence of a manifest small intestinal mucosal lesion. Individuals with a normal biopsy but an increased risk of developing celiac disease are referred to as potential celiac disease patients. However, these patients are not treated. This review highlights that patients with normal biopsies may suffer from the same extra-intestinal gluten-induced complications before the disease manifests at the intestinal level. We discuss diagnostic markers revealing true potential celiac disease. The evidence-based medical literature shows that these potential patients, who are “excluded” for celiac disease would in fact benefit from gluten-free diets. The question is why wait for an end-stage disease to occur when it can be prevented? We utilize research on dermatitis herpetiformis, which is a model disease in which a gluten-induced entity erupts in the skin irrespective of the state of the small intestinal mucosal morphology. Furthermore, gluten ataxia can be categorized as its own entity. The other extra-intestinal manifestations occurring in celiac disease are also found at the latent disease stage. Consequently, patients with celiac traits should be identified and treated.

The Relationship Between Child Mortality Rates and Prevalence of Celiac Disease

OBJECTIVES

Some evidence suggests that prevalence of celiac disease in the general population is increasing over time. Because the prognosis of celiac disease was a dismal one before discovering the role of gluten, our aim was to investigate a possible relationship between children under-5 mortality rates and prevalence rates of celiac disease.

METHODS

Thanks to a literature review, we found 27 studies performed in 17 different countries describing the prevalence of celiac disease in schoolchildren; between 1995 and 2011, 4 studies were performed in Italy. A meta-analysis of prevalence rates was performed. Prevalence was compared between specific country under-5 mortality groups, publication year, and age.

RESULTS

In the last decades, under-5 mortality rates have been decreasing all over the world. This reduction is paralleled by an increase of the prevalence of celiac disease. The Spearman correlation coefficient was -63%, 95% confidence interval -82% to -33% (P < 0.001). So, the higher the mortality rate, the lower the prevalence of CD. This finding is confirmed by the meta-analysis of the 4 studies conducted in Italy over time.

CONCLUSIONS

The under-5 mortality rate seems to influence the prevalence of celiac disease in the general population. In the near future, the number of patients with celiac disease will increase, thanks to the better environmental conditions that nowadays allow a better survival of children with celiac disease.

Associations of tissue transglutaminase antibody seropositivity with coronary heart disease: Findings from a prospective cohort study

BACKGROUND AND AIMS

Clinical experience and observational studies suggest that individuals with coeliac disease are at increased risk of coronary heart disease (CHD), but the precise mechanism for this is unclear. Laboratory studies suggest that it may relate to tissue transglutaminase antibodies (tTGAs). Our aim was to examine whether seropositivity for tTGA and endomysial antibodies (EMAs) are associated with incident CHD in humans.

METHODS AND RESULTS

We used data from Mini-Finland Health Survey, a prospective cohort study of Finnish men and women aged 35-80 at study baseline 1978-80. TTGA and EMA seropositivities were ascertained from baseline blood samples and incident CHD events were identified from national hospitalisation and death registers. Cox regression was used to examine the associations between antibody seropositivity and incident CHD. Of 6887 men and women, 562 were seropositive for tTGAs and 72 for EMAs. During a median follow-up of 26 years, 2367 individuals experienced a CHD event. We found no clear evidence for an association between tTGA positivity (hazard ratio, HR: 1.04, 95% confidence interval, CI: 0.83, 1.30) or EMA positivity (HR: 1.16, 95% CI: 0.77, 1.74) and incident CHD, once pre-existing CVD and known CHD risk factors had been adjusted for.

CONCLUSION

We found no clear evidence for an association of tTGA or EMA seropositivity with incident CHD outcomes, suggesting that tTG autoimmunity is unlikely to be the biological link between coeliac disease and CHD.

Associations of coeliac disease with coronary heart disease and cerebrovascular disease: A systematic review and meta-analysis

AIMS

Clinical experience suggests that atherosclerotic disease is common in individuals with coeliac disease, but epidemiological studies have had contradicting findings. To summarise the currently available evidence, we systematically reviewed and analysed observational studies of the association of coeliac disease or dermatitis herpetiformis with coronary heart disease (CHD) or stroke.

DATA SYNTHESIS

We searched for studies comparing CHD or stroke outcomes with individuals with and without coeliac disease or dermatitis herpetiformis. Three investigators independently searched electronic databases, identified relevant studies and extracted data. Study-specific results were combined in random-effects meta-analyses, and heterogeneity was quantified using the I(2) statistic and meta-regression. Twenty-one studies were included in our systematic review and 18 in the meta-analyses. For CHD, the pooled hazard ratio for incident disease was 1.05 (95% confidence interval (CI): 0.93, 1.19) and the overall standardised mortality ratio was 1.21 (0.99, 1.49). For stroke and brain haemorrhage, the corresponding estimates were 1.10 (95% CI: 1.00, 1.21) and 1.43 (0.97, 2.10), respectively. There was moderate to considerable heterogeneity among the study-specific estimates. In addition, many estimates were based on small numbers of outcomes and they had limitations in terms of adjustment for potential confounders.

CONCLUSION

Our meta-analyses lend some support to an association between coeliac disease and CHD or cerebrovascular disease, but the evidence base was heterogeneous and had limitations. Our systematic review highlighted a need in this area for adequately powered prospective studies with appropriate adjustment for potentially confounding factors.

Adaptive diagnosis of coeliac disease

Coeliac disease has for a long time simply been regarded as a gluten-dependent enteropathy and a duodenal biopsy was required in all patients for the diagnosis. It is now accepted that autoimmunity against transglutaminase 2 is an earlier, more universal and more specific feature of coeliac disease than histologic lesions. Moreover, high serum levels of combined anti-transglutaminase 2 and anti-endomysium antibody positivity have excellent predictive value for the presence of enteropathy with villous atrophy. This makes the histology evaluation of the gut no longer necessary in well defined symptomatic paediatric patients with compatible HLA-DQ2 and/or DQ8 background. The biopsy-sparing diagnostic route is not yet recommended by gastroenterologists for adults, and certain clinical circumstances (immunodeficiency conditions, extraintestinal manifestations, type-1 diabetes mellitus, age less than 2 years) may require modified diagnostic approaches. Coeliac patients with preserved duodenal villous structure do exist and these need a more extended evaluation by immunologic and molecular biology tools.

Celiac disease evolving into dermatitis herpetiformis in patients adhering to normal or gluten-free diet

OBJECTIVE

Dermatitis herpetiformis (DH) is a cutaneous form of celiac disease affecting ∼ 17% of celiac disease patients. The aim was to determine how often celiac disease precedes the development of DH, and what is the impact of gluten-free diet (GFD) in this phenotype change.

MATERIAL AND METHODS

Our prospectively collected DH series from 1970 comprised 514 patients. We analyzed all DH patients who at least 2 years earlier had been diagnosed with celiac disease. DH diagnosis was confirmed by showing immunoglobulin A deposits in dermis. Serological and small bowel mucosal findings were analyzed, and the strictness of GFD treatment before and after the diagnosis of DH was evaluated.

RESULTS

Twenty (4%) DH patients had a prior diagnosis of celiac disease. The median time interval between celiac disease and DH detection was 9.5 years. Before DH appeared 4 patients had been on a normal gluten-containing diet, 10 had dietary lapses on a GFD, and 6 were on a strict GFD. Celiac autoantibodies were positive in 7 out of 19 patients, and 5 out of 7 undergoing small bowel biopsy had partial villous atrophy. Following DH diagnosis the rash was controlled after a median of 6 months on a strict GFD.

CONCLUSIONS

Patients with celiac disease may develop DH by time. This is most often an indicator of poor adherence to GFD, and a rigorous dietary intervention is necessary. In the majority of cases, DH will be detected without prior celiac disease diagnosis, but the physicians should recognize this phenotype alteration.

Celiac disease autoimmunity and hip fracture risk: findings from a prospective cohort study

The impact of celiac disease autoimmunity on bone health is unclear. We investigated the associations of seropositivity for tissue transglutaminase antibodies (tTGA) and endomysial antibodies (EMA) with incident hip fractures using data from a prospective cohort study, Mini-Finland Health Survey. Baseline serum samples, taken in 1978-80, were tested for tTGA and EMA. Incident hip fractures up to the year 2011 were ascertained from a national hospitalization register. Associations between seropositivity and hip fractures were modeled using Cox proportional hazards regression adjusted for age, sex, body mass index, vitamin D, gamma-glutamyl transferase, smoking, and self-rated health. Our analyses were based on 6919 men and women who had no record of celiac disease or hip fracture before the study baseline. A total of 382 individuals had a hip fracture during a median follow-up of 30 years. Compared with the tTGA-negative individuals (n = 6350), tTGA-positive participants (n = 569; with hip fracture, n = 51) had a higher risk of hip fractures (hazard ratio [HR] = 1.59, 95% confidence interval [CI] 1.17, 2.14). The findings were similar for another tTGA test (n 200; with hip fracture, n = 26; HR = 2.23, 95% CI 1.49, 3.34). We found no evidence for an association between EMA positivity and hip fracture risk (HR = 0.92, 95% CI 0.34, 2.47; n = 74; with hip fracture, n = 4). In our prospective population-based study of Finnish adults, seropositivity for tTGA was associated with an increased hip fracture risk.

Testing for antireticulin antibodies in patients with celiac disease is obsolete: a review of recommendations for serologic screening and the literature

Celiac disease (CD) is an autoimmune disorder that occurs in genetically susceptible individuals of all ages and is triggered by immune response to gluten and related proteins. The disease is characterized by the presence of HLA-DQ2 and/or -DQ8 haplotypes, diverse clinical manifestations, gluten-sensitive enteropathy, and production of several autoantibodies of which endomysial, tissue transglutaminase, and deamidated gliadin peptide antibodies are considered specific. Although antireticulin antibodies (ARA) have historically been used in the evaluation of CD, these assays lack optimal sensitivities and specificities for routine diagnostic use. This minireview highlights the advances in CD-specific serologic testing and the rationale for eliminating ARA from CD evaluation consistent with recommendations for diagnosis.

Recent advances in the development of new treatments for celiac disease

INTRODUCTION

Celiac disease is a common autoimmune condition induced by dietary gluten in genetically susceptible individuals. So far, the only available treatment for the disorder is a lifelong strict gluten-free diet, because of which small intestinal histological changes recover and symptoms disappear. However, gluten-free dieting is restrictive, and nutritionally less than optimal, and gluten is difficult to avoid.

AREAS COVERED

With improving insight into the pathogenesis of celiac disease, several possible drug targets have been suggested. The new strategies include degradation of gluten intraluminally, reduction of mucosal permeability, inhibition of the transglutaminase 2 enzyme, blocking antigen presentation by HLA-DQ2 or HLA-DQ8, modulation of the immune responses of many cytokines, and vaccination.

EXPERT OPINION

Non-dietary treatment options are warranted either as adjunctive therapy together with dieting or to replace the gluten-free diet. The key question is whether the envisaged novel drug is able to prevent gluten-induced small intestinal mucosal injury as efficiently as a strict gluten-free diet, alleviating symptoms and signs of the disease. Furthermore, the gluten dose that can be detoxified, if at all, must be established. The new drug should also be as safe as dietary treatment. Several novel treatment options are under development.

The interplay between diet and emerging allergy: what can we learn from Indigenous Australians?

The pathophysiology of atopic diseases, including asthma and allergy, is the result of complex gene-environment interactions. Since European colonization the Indigenous population of Australia has undergone significant changes with respect to their lifestyle as hunter-gatherers. These changes have had a detrimental effect on Aboriginal health, in part due to immunological modification. This review provides a comparative look at both the traditional Aboriginal/Indigenous diet and modern Western diets, examines some common allergies increasingly reported in contemporary Indigenous populations, and reviews concepts such the effect of vitamin deficiencies and changes in gut microbiota on immune function.

Role of transglutaminase 2 in celiac disease pathogenesis

A number of lines of evidence suggest that transglutaminase 2 (TG2) may be one of the earliest disease-relevant proteins to encounter immunotoxic gluten in the celiac gut. These and other investigations also suggest that the reaction catalyzed by TG2 on dietary gluten peptides is essential for the pathogenesis of celiac disease. If so, several questions are of critical significance. How is TG2 activated in the celiac gut? What are the disease-specific and general consequences of activating TG2? Can local inhibition of TG2 in the celiac intestine suppress gluten induced pathogenesis in a dose-responsive manner? And what are the long-term consequences of suppressing TG2 activity in the small intestinal mucosa? Answers to these questions will depend upon the development of judicious models and chemical tools. They also have the potential of yielding powerful next-generation drug candidates for treating this widespread but overlooked chronic disease.

Antibodies in celiac disease: implications beyond diagnostics

Celiac disease is a multisystemic dietary, gluten-induced autoimmune disorder characterized by the presence of transglutaminase (TG) 2 serum autoantibodies. Distinct autoantibodies targeting members of the TG family (TG2, TG3 and TG6) are found deposited in small-bowel mucosa and in extraintestinal tissues affected by the disease. Serum autoantibodies against other self-antigens also emerge in untreated celiac disease patients. Although villous atrophy and crypt hyperplasia in small-bowel biopsy samples are still the gold standards in diagnostics, celiac disease-specific antibodies are widely used as diagnostic aids. Gluten-induced small-bowel mucosal T-cell response is the cornerstone in the pathogenesis of the disorder, but humoral immunity may also play a central role. This review article is focused on the autoantibodies that occur in the context of celiac disease. The article summarizes the diagnostic utility of different celiac-related antibodies and discusses their roles in the pathogenesis of the disease.

Usefulness of small-bowel mucosal transglutaminase-2 specific autoantibody deposits in the diagnosis and follow-up of celiac disease

BACKGROUND

Diagnosis of celiac disease may be problematic in that small-bowel villous atrophy sometimes occurs in conjunction with other enteropathies, develops gradually and may be patchy. Furthermore, as the often compromised quality of biopsy specimens renders diagnosis difficult, new diagnostic tools are warranted.

GOALS

As the celiac disease-specific autoantibodies are found deposited at their production site, in the small-bowel mucosa, they may be useful in diagnostics, especially in problematic cases. We therefore systematically assessed the occurrence of celiac-specific autoantibody deposits in a large cohort of celiac patients, and established how IgA deposits decline after initiation of a gluten-free diet.

METHODS

Transglutaminase-2 specific mucosal IgA autoantibody deposits were determined from small-bowel mucosal biopsies in 261 untreated, 71 short-term (1 y), and 105 long-term (2 to 41 y) treated celiac disease patients and in 78 nonceliac controls. The presence of the deposits was compared with celiac serology, mucosal villous morphology and density of intraepithelial lymphocytes.

RESULTS

All untreated celiac disease patients had mucosal autoantibody deposits and their intensity was moderate or strong in 90% of cases. In contrast, 18% of the controls had weak depositions. During a gluten-free diet the intensity of the deposits diminished, but was still faintly positive in 56% of long-term treated celiac patients. The efficiency of the test in determining mucosal autoantibody deposits was superior to serology and inflammatory markers.

CONCLUSIONS

Mucosal transglutaminase-2 specific autoantibody deposits proved to be accurate gluten-dependent markers of celiac disease and would thus be of value in the diagnostics and dietary monitoring of this disorder.

Diagnostic methods beyond conventional histology in coeliac disease diagnosis

BACKGROUND

Coeliac disease diagnostic criteria currently require the detection of small bowel mucosal villous atrophy and crypt hyperplasia.

AIMS

To compare conventional histological examination to the determination of small bowel mucosal intraepithelial lymphocytes (IELs) and to serum and intestinal coeliac autoantibodies in untreated coeliac disease with villous atrophy and in mild enteropathy coeliac disease.

PATIENTS AND METHODS

Study comprised consecutive adult patients with coeliac disease suspicion; villous height-crypt depth ratio (Vh/CrD), the densities of CD3+, gammadelta+ and villous tip IELs and serum and intestinal transglutaminase 2 (TG2)-targeted autoantibodies were studied. Coeliac disease was diagnosed in 223 and excluded in 608 patients. Further, 66 patients were considered to suffer from mild enteropathy coeliac disease. Control group consisted of 138 patients.

RESULTS

Vh/CrD determination detected 77% of untreated coeliac disease patients. Serum coeliac autoantibodies had 84% sensitivity for untreated coeliac disease with villous atrophy and 70% sensitivity for mild enteropathy coeliac disease; the specificity was 100%. Intestinal TG2-targeted autoantibodies had sensitivities of 100% and 93%, and 100% specificity, respectively. gammadelta+ and villous tip IELs proved more reliable than CD3+ IELs.

CONCLUSIONS

Conventional histological examination as the golden standard in coeliac disease diagnosis is questionable. Serum and especially intestinal TG2-targeted autoantibodies seem promising in future coeliac disease diagnostics.

Seasonality of birth month of children with celiac disease differs from that in the general population and between sexes and is linked to family history and environmental factors

BACKGROUND

Patients with autoimmune diseases, such as type 1 diabetes mellitus, atopic dermatitis, autoimmune thyroid diseases, and multiple sclerosis have a different seasonality of month of birth (MOB) from the general population. This study was undertaken to determine the seasonality of MOB in children with celiac disease (CD), an autoimmune-mediated enteropathy.

PATIENTS AND METHODS

The medical records of 431 children with CD (239 girls, 192 boys) were included in the study; 138 girls and 81 boys were under the age of 24 months. Data were analyzed by the cosinor method, which, in addition to statistical significance, provides parameters of rhythms. Statistical differences between groups were also analyzed by the chi test.

RESULTS

Patients with CD showed different patterns from that in the general population, which peaks in September. Boys and girls with CD were found to have a different seasonality of MOB (P < 0.02). Girls whose CD was diagnosed before age 24 months (peak July-August) had a different seasonality of MOB from those whose CD was diagnosed after age 24 months (no rhythm; P < 0.005) and showed a different seasonality from boys whose CD was diagnosed above 24 months (peak July; P < 0.02). In addition, we found a different seasonality of MOB in children with a family history of CD compared with those with no family history (P < 0.001).

CONCLUSIONS

Girls with the diagnosis of CD and patients of both sexes with a family history of CD have a different pattern of seasonality of birth from the general population. This is suggestive of a perinatal virus infection as a plausible candidate for the primary trigger.

Comparison of a novel whole blood transglutaminase-based ELISA with a whole blood rapid antibody test and established conventional serological celiac disease assays

OBJECTIVES

Serum immunoglobulin A-class tissue transglutaminase (tTG-ab) and endomysial antibody (EMA) tests play a key role in the diagnostic evaluation of celiac disease. Recently, a novel whole blood rapid test based on self-tissue transglutaminase (tTG) was developed for celiac disease case finding. Based on the same principle, a whole blood self-tTG enzyme-linked immunosorbent assay (ELISA), especially applicable to large-scale screening of celiac disease, has been produced. We assessed the value of this new test in celiac disease antibody detection.

PATIENTS AND METHODS

The new test uses endogenous tTG found in red blood cells of whole blood in IgA-class tTG-ab measurement by detecting tTG-tTG-ab complexes formed after hemolysis of the whole blood sample. Stored whole blood samples from 150 untreated celiac disease patients and 107 control individuals without celiac disease were evaluated, and the test results were compared with those of the whole blood rapid test, 2 conventional serum-based tTG-ab ELISA tests, and 2 EMA tests.

RESULTS

A total of 15 whole blood samples were found to be clotted or dried after storage and were excluded from further evaluation. The whole blood ELISA test had a specificity (98%) comparable to that of the conventional serological tests, the sensitivity (91%) being slightly lower. The test was concordant with the whole blood rapid test in 92% of cases, with 2 serological ELISA tests in 91% and 94% of cases and with EMA tests in 94% and 93% of cases.

CONCLUSIONS

Whole blood self-tTG-based testing is accurate in celiac antibody detection, also when an ELISA method is applied. The testing requires no serum separation or external tTG.

Gluten-dependent small bowel mucosal transglutaminase 2-specific IgA deposits in overt and mild enteropathy coeliac disease

OBJECTIVES

In coeliac disease, immunoglobulin (Ig)A-class autoantibodies against transglutaminase-2 are produced in the small intestinal mucosa, where they are deposited extracellularly. It remains unclear whether positive intestinal transglutaminase-2-targeted IgA deposits in subjects having normal small bowel mucosal morphology are signs of early-stage coeliac disease. We evaluated the gluten dependency of these deposits in overt and mild enteropathy coeliac disease.

PATIENTS AND METHODS

All together 48 subjects suspected of coeliac disease but having normal small bowel mucosal villi were enrolled; 28 of them had latent coeliac disease. The remaining 20 having positive intestinal IgA deposits adopted a gluten-free diet before villous atrophy had developed. For comparison, 13 patients with overt coeliac disease and 42 noncoeliac controls were studied. Small bowel mucosal transglutaminase-2-specific autoantibodies were compared with villous morphology, intraepithelial lymphocyte densities, and serum coeliac autoantibodies.

RESULTS

Intestinal IgA deposits were seen in all but 1 of the patients with latent coeliac disease, when the morphology was still intact; the intensity of these deposits increased as villous atrophy developed and decreased again on a gluten-free diet. In 20 patients with intestinal IgA deposits in normal villi, the intensity of the deposits decreased with the diet similarly to that seen in patients with overt coeliac disease. Mucosal IgA deposits were seen initially only in 5% of noncoeliac controls and in 8% after extended gluten consumption.

CONCLUSIONS

The response of small bowel mucosal transglutaminase-2-specific IgA deposits for dietary intervention was similar in overt and mild enteropathy coeliac disease. Detection of such IgA deposits thus offers a good diagnostic tool to uncover early-stage coeliac disease.

Immunoglobulin A anti-tissue transglutaminase antibody deposits in the small intestinal mucosa of children with no villous atrophy

OBJECTIVES

Anti-tissue transglutaminase (anti-TG2) immunoglobulin A (IgA) autoantibodies are detectable in the serum of most patients with untreated celiac disease (CD). Their deposits in the intestine of patients with CD with severe enteropathy are considered specific for this condition. The histological spectrum of CD includes cases with normal villous architecture. The aim of this study was to look for anti-TG2 IgA deposits in the intestine of children with normal villous architecture and to relate them with other markers of gluten sensitivity.

PATIENTS AND METHODS

A total of 57 children with normal duodenal villous architecture and markers of gluten sensitivity were considered. Of those, 39 showed positive serum anti-endomysium antibodies and/or high levels of anti-TG2 antibodies (group 1), and 18 were seronegative with only a greater density of gammadelta intraepithelial lymphocytes (group 2). Thirty-four children with no markers of gluten sensitivity and a normal mucosa represented the control group (group 3). The duodenal sections of all patients were investigated for deposited anti-TG2 IgA by double immunofluorescence. Human lymphocyte antigen molecular typing was performed.

RESULTS

In group 1 and in group 2, 33 of 39 children (85%) and 12 of 18 children (66%) showed subepithelial anti-TG2 IgA intestinal deposits, respectively. Only in 3 of 34 (8.8%) children with no markers of gluten sensitivity were anti-TG2 IgA deposits noted.

CONCLUSIONS

A subgroup of children with no serum CD-associated autoantibodies, but greater density of gammadelta intraepithelial lymphocytes, shows a clear anti-TG2 IgA deposition in the duodenal mucosa. These children must be investigated further for possible gluten sensitivity.

A non-human primate model for gluten sensitivity

BACKGROUND AND AIMS

Gluten sensitivity is widespread among humans. For example, in celiac disease patients, an inflammatory response to dietary gluten leads to enteropathy, malabsorption, circulating antibodies against gluten and transglutaminase 2, and clinical symptoms such as diarrhea. There is a growing need in fundamental and translational research for animal models that exhibit aspects of human gluten sensitivity.

METHODS

Using ELISA-based antibody assays, we screened a population of captive rhesus macaques with chronic diarrhea of non-infectious origin to estimate the incidence of gluten sensitivity. A selected animal with elevated anti-gliadin antibodies and a matched control were extensively studied through alternating periods of gluten-free diet and gluten challenge. Blinded clinical and histological evaluations were conducted to seek evidence for gluten sensitivity.

RESULTS

When fed with a gluten-containing diet, gluten-sensitive macaques showed signs and symptoms of celiac disease including chronic diarrhea, malabsorptive steatorrhea, intestinal lesions and anti-gliadin antibodies. A gluten-free diet reversed these clinical, histological and serological features, while reintroduction of dietary gluten caused rapid relapse.

CONCLUSIONS

Gluten-sensitive rhesus macaques may be an attractive resource for investigating both the pathogenesis and the treatment of celiac disease.

Humoral immune response to tissue transglutaminase is related to epithelial cell proliferation in celiac disease

BACKGROUND & AIMS

Tissue transglutaminase (tTG) autoantibodies are markers of celiac disease, and the enzyme is required for several crucial biological processes. The aim of this study was to determine whether these autoantibodies are involved in the pathogenesis of the mucosal lesion typical of celiac disease.

METHODS

Using rhodamine-conjugated phalloidin staining, we evaluated whether tTG antibodies, both commercially available and cloned from patients with celiac disease, cause cytoskeletal changes in Caco-2, MCF7, and NIH 3T3 cells. We monitored cell levels of bromodeoxyuridine incorporation to determine whether tTG autoantibodies are able to induce NIH 3T3 fibroblasts and epithelial mucosal cells into S phase.

RESULTS

Treatment with tTG antibodies caused a dose-dependent increase of membrane ruffling in Caco-2, MCF7, and NIH 3T3 cells. It also dose-dependently induced G(0)-synchronized NIH 3T3 fibroblasts into S phase but did not affect the rate of apoptosis. Similarly, tTG antibodies induced S-phase entry of epithelial cells in cultured intestinal biopsy specimens from patients with celiac disease. They did not affect biopsy specimens from patients without celiac disease.

CONCLUSIONS

Our results suggest that tTG autoantibodies per se, by interacting with the extracellular membrane-bound transglutaminase, may play an important role in epithelial cell proliferation in celiac disease.

Recent advances in the understanding of celiac disease: therapeutic implications for the management of pediatric patients

Celiac disease (CD) is an autoimmune condition occurring in genetically susceptible individuals characterized by inflammatory injury to the mucosa of the small intestine after the ingestion of wheat glutens or related barley and rye products. Originally thought to be highly prevalent only in Northern European populations, growing evidence indicates a much higher prevalence in many other regions, including the US as well as South America, North Africa, and Asia. The growing awareness that pediatric patients may present with quite diverse and protean manifestations and the significant impact of CD on childhood development has prompted efforts to increase CD awareness for the early diagnosis and treatment of this disease. The current diagnostic criteria for CD requires characteristic histologic findings in small bowel biopsies and clinical remission when placed on a gluten-free diet. Serologic testing for CD can provide additional support for the diagnosis of CD or a means to assess efficacy and adherence to a gluten-free diet. The mainstay of treatment remains the institution of a gluten-free diet. However, patients with refractory CD may require treatment with immunosuppressant medications. With the increased identification of specific gluten epitopes and understanding of the pathogenesis of CD, future therapies may rely on genetically altering gluten proteins, immunization techniques, or therapies focused on either the development of specific immune tolerance or regulation of mucosal inflammation.

Immunoglobulin A autoantibodies against transglutaminase 2 in the small intestinal mucosa predict forthcoming coeliac disease

BACKGROUND

Reliable markers of early developing coeliac diseases are needed. Coeliac autoantibodies in the serum or Marsh I inflammation may be indicators of subsequent coeliac disease.

AIM

To investigate whether determination of intestinal transglutaminase 2-targeted autoantibody deposits would detect early developing coeliac disease better than previous methods.

METHODS

The study investigated patients previously excluded for coeliac disease: 25 had positive serum coeliac autoantibodies (endomysial), 25 antibody-negative had Marsh I, and 25 antibody-negative had Marsh 0 finding. Seven (median) years after baseline investigation, new coeliac cases were recorded, and small bowel biopsy was offered to the rest of the patients. Serum and intestinal coeliac autoantibodies and intraepithelial lymphocytes were assessed as indicators of developing coeliac disease.

RESULTS

Seventeen patients had developed coeliac disease: 13 in the autoantibody-positive group, three in the Marsh I group and one in the Marsh 0 group. At baseline, intestinal coeliac autoantibody deposits had a sensitivity and specificity of 93% and 93% in detecting subsequent coeliac disease, CD3+ 59% and 57%, gammadelta+ 76% and 60%, and villous tip intraepithelial lymphocytes 88% and 71%, respectively.

CONCLUSIONS

Endomysial antibodies with normal histology indicates early developing coeliac disease. Transglutaminase 2-targeted intestinal autoantibody deposits proved the best predictor of subsequent coeliac disease.

Alteraciones hepáticas en la enfermedad celíaca del adulto. Caracterización clínico-patológica y evolución

BACKGROUND AND AIM

The clinical manifestations of adult celiac disease are highly varied and may include liver disease. The present study aimed to characterize liver abnormalities and outcome after a gluten-free diet in patients with celiac disease diagnosed in a hepatology clinic.

MATERIAL AND METHOD

The clinical records of patients diagnosed with celiac disease during a 7-year period were reviewed.

RESULTS

Of 1916 patients attending a first consultation at the clinic, 10 were finally diagnosed with celiac disease. All patients had been referred for evaluation of persistent elevation of liver enzyme levels. All patients were young (mean age 30 years, range 21-39 years) and there were more women than men (eight women, 80%). Six patients (60%) had additional manifestations attributable to undiagnosed celiac disease, sometimes since childhood. In all patients, elevation of liver enzyme levels was moderate and overall liver function was preserved. Liver biopsy was performed in five patients and all showed chronic periportal infiltrate. Immunohistochemical studies revealed that the infiltrate was mainly composed of CD8-positive T lymphocytes. In all patients, a gluten-free diet was followed by normalization of liver enzyme levels.

CONCLUSIONS

Although celiac disease is not highly frequent, it should be considered in the differential diagnosis of patients with persistent abnormalities of liver markers. The most conspicuous histopathological change is periportal T-cell infiltrate. Liver abnormalities in celiac disease are generally mild and improve after a gluten-free diet.

Self transglutaminase-based rapid coeliac disease antibody detection by a lateral flow method

BACKGROUND

The conventional coeliac disease antibody tests require patient's sera, and are laborious and time-consuming.

AIM

To evaluate a newly developed rapid whole blood test in coeliac disease antibody detection, and its suitability for office use.

METHODS

Endogenous tissue transglutaminase found in red blood cells in a whole blood fingertip or venous sample is liberated upon haemolysis and complexes with tissue transglutaminase antibodies, if present. The complexes, captured by a lateral flow system, are visualized within 5 min. Stored samples from 121 untreated, 106 treated coeliac disease patients and 107 controls were evaluated and compared with serum endomysium and tissue transglutaminase antibody tests and histology; 150 patients were prospectively tested on site in the doctor's office.

RESULTS

The rapid test showed sensitivity (96.7%) comparable with the serum endomysium and tissue transglutaminase antibody tests from stored samples; specificity was slightly lower (93.5%). When tested on site the results were concordant in 96.7% of cases compared with endomysium and tissue transglutaminase antibody results. The test recognized the disappearance of tissue transglutaminase antibodies on a gluten-free diet.

CONCLUSIONS

The self tissue transglutaminase-based rapid test can be easily carried out from a fingertip blood sample on site in the physician's office for both coeliac disease case finding and dietary monitoring purposes.

Unexpected role of surface transglutaminase type II in celiac disease

BACKGROUND & AIMS

In celiac disease (CD), transglutaminase type II (TG2) has 2 fundamental roles: (1) as the autoantigen recognized by highly specific autoantibodies and (2) the modifier of pathogenic gliadin T-cell epitopes. It follows that inhibition of TG2 might represent an attractive strategy to curb the toxic action of gliadin. Here we studied the validity of this strategy using the organ culture approach.

METHODS

Duodenal biopsy specimens from 30 treated patients with CD, 33 untreated patients with CD, and 24 controls were cultured with or without gliadin peptides p31-43, palpha-9, and deamidated palpha-9 for 20 minutes, 3 hours, and 24 hours. In 31 patients with CD and 16 controls, TG2 inhibitor R283 or anti-TG CUB 7402 or anti-surface TG2 (6B9) mAbs were used in cultures. T84 cells were also cultured with or without peptides with or without TG inhibitors. Mucosal modifications after culture were assessed by immunofluorescence, in situ detection of TG activity, confocal microscopy, and fluorescence-activated cell sorter analysis.

RESULTS

The enzymatic inhibition of TG2 only controlled gliadin-specific T-cell activation. The binding of surface TG2 contained gliadin-specific T-cell activation and p31-43-induced actin rearrangement, epithelial phosphorylation, and apoptosis, both in organ cultures and T84 cells.

CONCLUSIONS

These data indicate a novel and unexpected biological role for surface TG2 in the pathogenesis of CD suggesting a third role for TG2 in CD. These results have a specific impact for celiac disease, with wider implications indicating a novel biologic function of TG2 with possible repercussions in other diseases.

Serological screening for celiac disease in premenopausal women with idiopathic osteoporosis

The aim of this study was to perform serological testing to screen for celiac disease (CD) among premenopausal women with idiopathic osteoporosis and to investigate the bone turnover in patients who are seropositive for CD. We studied 89 premenopausal women with idiopathic osteoporosis. The serological screening protocol was based on a two-level evaluation. The first level consisted of determining serum level of IgA antigliadin antibodies (AGA). Subjects who were negative for IgA AGA were classified as not having CD, while samples testing positive for IgA AGA underwent a second level of the screening process. For the second level of screening, the serum IgA endomysial antibody (EMA) test was performed. Bone metabolism was evaluated by serum calcium (Ca), phosphorus, alkaline phosphatase, parathyroid hormone (PTH), 25 (OH) vitamin D, osteocalcin (OC), urinary deoxypyridinoline (dPD), and 24-h urinary calcium levels. Of the 89 patients evaluated, 17 were found to have positive IgA AGA tests (19%) and 9 were found to be positive for EMA (10.11%). EMA-positive patients showed lower values of serum Ca (p<0.05) and 25 (OH) vitamin D (p<0.01) and significantly higher values of PTH (p<0.01) compared with the EMA-negative patients. The level of urinary dPD was found to be significantly higher in EMA-positive patients (p<0.05). The results of this study suggest that all patients with idiopathic osteoporosis should be screened for CD by measurement of EMA. Additionally, we believe that serological screening for CD and detection of such patients will allow determination of the most convenient treatment strategies for osteoporosis.

Gliadin and tissue transglutaminase complexes in normal and coeliac duodenal mucosa

Tissue transglutaminase (tTG) seems to be the target self-antigen for endomysial antibodies in coeliac disease (CD) and to catalyse the critical deamidation of gliadin which strengthens its recognition by HLA-restricted gut-derived T cells. To date, it has not been demonstrated whether gliadin is cross-linked to tTG within the gut wall, a phenomenon known to occur in vitro. We therefore investigated the putative presence of tTG and gliadin complexes directly in duodenal mucosa. The immunoprecipitation and Western blotting experiments were performed on mucosal biopsies obtained from untreated, treated CD patients and biopsied controls, by using either anti-tTG or anti-gliadin antibodies, in both denaturating/reducing or nondenaturating/nonreducing conditions. A subset of experiments was performed by using anti-tTG antibodies purified by affinity chromatography from sera of untreated coeliac patients. The localization of tTG and gliadin was studied by immunofluorescence at confocal laser microscopy on seriate sections of diseased and normal duodenal mucosa by using the same antibodies of the coimmunoprecipitation section. The amounts of tTG and gliadin coimmunoprecipitated with anti-tTG monoclonal antibody in untreated CD mucosa were significantly increased compared to those of the other two groups. When performing the experiments in nondenaturating/nonreducing conditions, a high molecular weight band formed by both molecules, was evidenciated. Also the anti-tTG antibodies purified from patients' sera turned out to be able to coimmunoprecipitate the two molecules. The analysis by confocal microscopy showed that tTG colocalizes with gliadin at the epithelial and subepithelial levels in active CD, and only in the lamina propria of the villi in normal mucosa. Our findings firstly demonstrated that gliadin was directly bound to tTG in duodenal mucosa of coeliacs and controls, and the ability of circulating tTG-autoantibodies to recognize and immunoprecipitate the tTG-gliadin complexes.

Proteomics identification of acyl-acceptor and acyl-donor substrates for transglutaminase in a human intestinal epithelial cell line. Implications for celiac disease

Transglutaminase (TG)-catalyzed cross-linking of both intracellular and extracellular proteins is an important biochemical event. However, increased concentrations of cross-linked proteins have been observed in many disorders. Moreover, TG-catalyzed modification of proteins might generate new self-antigens responsible for the autoimmune response, as in celiac disease. The identification of available substrates may offer an understanding of how the TG-catalyzed post-translational modification has an impact on physiology and disease. We used a proteomic approach to identify TG-modified protein targets in human intestinal epithelial cells to determine the extent to which transglutaminase specifically contributes to celiac disease. Two probes were used for endogenous TG activity: 5-(biotinamido)pentylamine, which represents the acyl-acceptor, and a biotinylated glutamine-containing peptide, which represents the acyl-donor. This approach identified >25 proteins, which range from 30,000 to 300,000 Daltons and can serve as acyl-acceptor and/or acyl-donor for transglutaminase. Some of them were known transglutaminase substrates, whereas others had not been previously identified. These targets include proteins involved in cytoskeletal network organization, folding of proteins, transport processes, and miscellaneous metabolic functions.

Endocrinological disorders and celiac disease

Celiac disease is a permanent intolerance to dietary gluten. Its well known features are abdominal symptoms, malabsorption of nutrients, and small-bowel mucosal inflammation with villous atrophy, which recover on a gluten-free diet. Diagnosis is challenging in that patients often suffer from subtle, if any, symptoms. The risk of clinically silent celiac disease is increased in various autoimmune conditions. The endocrinologist, especially, should maintain high suspicion and alertness to celiac disease, which is to be found in 2-5% of patients with insulin-dependent diabetes mellitus or autoimmune thyroid disease. Patients with multiple endocrine disorders, Addison's disease, alopecia, or hypophysitis may also have concomitant celiac disease. Similar heredity and proneness to autoimmune conditions are considered to be explanations for these associations. A gluten-free diet is essential to prevent celiac complications such as anemia, osteoporosis, and infertility. The diet may also be beneficial in the treatment of the underlying endocrinological disease; prolonged gluten exposure may even contribute to the development of autoimmune diseases. The diagnosis of celiac disease requires endoscopic biopsy, but serological screening with antiendomysial and antitissue transglutaminase antibody assays is an easy method for preliminary case finding. Celiac disease will be increasingly detected provided the close association with autoimmune endocrinological diseases is recognized.

Type 1A diabetes mellitus-associated autoimmunity

Type 1A diabetes mellitus has become one of the most intensively studied autoimmune disorders, with characterized animal models and extensive prospective studies of the development of anti-islet autoimmunity. It is now possible to predict the development of type 1A diabetes mellitus, beginning with HLA-encoded genetic susceptibility, followed by the development of a series of anti-islet autoantibodies. Prediction primarily is based on the detection of multiple anti-islet autoantibodies reacting with cloned islet antigens. Multiple international workshops fostered the development of specific and sensitive radioassays for autoantibodies reacting with GAD65 (glutamic acid decarboxylase), ICA512 (also termed IA-2, a tyrosine phosphatase-like protein), and insulin. Similar high throughput radioassays have been applied using autoantigens for additional autoimmune disorders including celiac disease and Addison's disease. Relatives of patients with type 1A diabetes mellitus inherit susceptibility to express multiple autoantibodies, and a subset of autoantibody-positive individuals inherit susceptibility to progress to overt disease. This article reviews autoimmune disorders associated with type 1A diabetes mellitus.

Basement membrane and connective tissue proteins in intestinal mucosa of patients with coeliac disease

AIMS

Gluten ingestion in coeliac disease is associated with alterations of the intestinal mucosa, especially the expansion of the lamina propria. Antiendomysium and antireticulin antibodies may result from interactions between gliadin and extracellular matrix components. By behaving as autoantigens, connective tissue proteins could initiate mucosal damage. This study evaluates changes in the distribution of laminin, type IV collagen, and fibronectin in the mucosa of patients with coeliac disease in an attempt to explain the alterations of mucosal morphology.

METHODS

Intestinal biopsies were obtained from patients with coeliac disease on admission and while on a gluten free diet. The distribution of type IV collagen, laminin, fibronectin, and alpha-smooth muscle actin was evaluated by immunofluorescence and by immunogold labelling and electron microscopy.

RESULTS

In patients with coeliac disease, the intensity of type IV collagen, laminin, and fibronectin immunofluorescent staining was decreased and less well defined than in controls, with frequent breaches in the basement membrane; fibronectin staining was weak in the distal third of the elongated crypts and absent under the flat surface. The distribution of smooth muscle fibre in the distal lamina propria of flat mucosae was altered. The distribution of these proteins was normal as assessed by immunoelectron microscopy.

CONCLUSIONS

The intensity of staining of some components of the basement membrane is decreased in coeliac disease and the distribution of smooth muscle fibres is altered. These changes may result from interactions between gliadin and components of the extracellular matrix and may play a role in the genesis of mucosal lesions and in the damage to the epithelium.

Primary biliary cirrhosis and autoimmune cholangitis are not associated with coeliac disease in Crete

BACKGROUND

An increased prevalence of coeliac disease in patients with primary biliary cirrhosis has been recently reported. However, in other studies the association has not been confirmed. There have been no formal attempts to systematically evaluate patients with autoimmune cholangitis for coeliac disease.

METHODS

Sera from 62 patients with primary biliary cirrhosis, 17 with autoimmune cholangitis and 100 blood donors were screened for anti-gliadin, anti-endomysial, anti-reticulin, and IgA class antibodies to guinea pig liver-derived tissue transglutaminase. Eighteen untreated coeliacs served as methodological controls. Analyses were performed by using the chi2 and Fischer's exact tests.

RESULTS

Anti-gliadin antibodies were detected in 21% of patients with primary biliary cirrhosis, 35% of patients with autoimmune cholangitis, and 3% of controls (p < 0.001). IgA class gliadin antibodies positivity was more pronounced in patients with Scheuer's stage III-IV disease (p < 0.05). Anti-transglutaminase antibodies were detected in 10% and in 18% of patients with primary biliary cirrhosis and autoimmune cholangitis respectively (p < 0.001). Anti-reticulin and anti-endomysial antibodies were negative in all patients. Duodenal biopsies were performed in 59% and 71% of patients with primary biliary cirrhosis and autoimmune cholangitis respectively, tested positive for at least one antibody class. No histological features of coeliac disease were found.

CONCLUSIONS

We were unable to demonstrate an increased risk of coeliac disease in patients with primary biliary cirrhosis and autoimmune cholangitis. Our results confirm the previously reported high prevalence of false-positive anti-gliadin and guinea pig liver-derived anti-tissue transglutaminase antibodies in patients with chronic liver disease.

Diagnosis of celiac sprue

Celiac sprue is a common lifelong disorder affecting 0.3-1% of the Western world and causing considerable ill health and increased mortality, particularly from lymphoma and other malignancies. Although high prevalence rates have been reported in Western Europe, celiac sprue remains a rare diagnosis in North America. Whether celiac sprue is truly rare among North Americans or is simply underdiagnosed is unclear, although serological screening of healthy American blood donors suggests that a large number of American celiacs go undiagnosed. Celiac sprue is an elusive diagnosis, and often its only clue is the presence of iron or folate deficiency anemia or extraintestinal manifestations, such as osteoporosis, infertility, and neurological disturbances. The challenge for gastroenterologists and other physicians is to identify the large population of undiagnosed patients that probably exists in the community and offer them treatment with a gluten-free diet that will restore the great majority to full health and prevent the development of complications. The advent of highly sensitive and specific antiendomysium and tissue transglutaminase serological tests has modified our current approach to diagnosis and made fecal fat and D-xylose absorption testing obsolete. A single small bowel biopsy that demonstrates histological findings compatible with celiac sprue followed by a favorable clinical and serological response to gluten-free diet is now considered sufficient to definitely confirm the diagnosis. We review the wide spectrum of celiac sprue, its variable clinical manifestations, and the current approach to diagnosis.

Prevalence of silent celiac disease in patients with autoimmune thyroiditis from Northern Sardinia

Celiac disease (CD) is frequently associated with other autoimmune diseases such as Type 1 diabetes mellitus, autoimmune thyroiditis (AT), and Addison's disease. The frequency of these associations varies with the populations studied. We conducted this study to ascertain the prevalence of CD in patients with AT from Sardinia, an area with a very high prevalence of CD. To this aim, 297 consecutive patients with AT (as defined by elevated antithyroid antibody levels and a positive ultrasound scan) were studied. Immunoglobulin A and G-class antigliadin antibodies were assayed in serum; if either or both were positive, antiendomysium antibodies were determined. If two markers were positive, serum ferritin, folate, and vitamin B12 levels were measured and jejunal biopsy was suggested. Thirteen out of the 14 patients who showed at least two positive markers consented to jejunal biopsy and all of them showed histological features of CD. The prevalence of CD in AT patients was 4-fold greater than that observed in the general population (4.37 vs 1.06%, p<0.0001). Ferritin was low in 6 and vitamin B12 in 2 out of 13 patients; serum folates were normal in all patients. Molecular typing of HLA class II alleles showed an increased frequency of the extended haplotype DRB1*0301/DQA1*0501/DQB1*0201. None of our patients had a history of gastrointestinal symptoms. We confirm the increased prevalence of silent CD in patients with AT. Patients with AT ought to be regarded as a high-risk group for CD and should be screened routinely for it; if negative, screening tests should be repeated at regular intervals.

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

BACKGROUND

Serologic methods have been used widely to test for celiac disease and have gained importance in diagnostic definition and in new epidemiologic findings. However, there is no standardization, and there are no reference protocols and materials.

METHODS

The European working group on Serological Screening for Celiac Disease has defined robust noncommercial test protocols for immunoglobulin (Ig)G and IgA gliadin antibodies and for IgA autoantibodies against endomysium and tissue transglutaminase. Standard curves were linear in the decisive range, and intra-assay variation coefficients were less than 5% to 10%. Calibration was performed with a group reference serum. Joint cutoff limits were used. Seven laboratories took part in the final collaborative study on 252 randomized sera classified by histology (103 pediatric and adult patients with active celiac disease, 89 disease control subjects, and 60 blood donors).

RESULTS

IgA autoantibodies against endomysium and tissue transglutaminase rendered superior sensitivity (90% and 93%, respectively) and specificity (99% and 95%, respectively) over IgA and IgG gliadin antibodies. Tissue transglutaminase antibody testing showed superior receiver operating characteristic performance compared with gliadin antibodies. The K values for interlaboratory reproducibility showed superiority for IgA endomysium (0.93) in comparison with tissue transglutaminase antibodies (0.83) and gliadin antibodies (0.82 for IgG, 0.62 for IgA).

CONCLUSIONS

Basic criteria of standardization and quality assessment must be fulfilled by any given test protocol proposed for serologic investigation of celiac disease. The working group has produced robust test protocols and reference materials available for standardization to further improve reliability of serologic testing for celiac disease.

Celiac disease in a Chilean population carrying Amerindian traits

BACKGROUND

Although clinical manifestations of celiac disease may change throughout life, clinical, histologic, immunologic, and genetic studies show that there are incomplete forms of this condition, making it difficult to define the disease at a given moment. Because there is no information published in the Latin American-Amerindian population, this study was conducted to assess relations between these parameters in Chileans with celiac disease and their first-degree relatives.

METHODS

Sixty-two persons with confirmed celiac disease (mean age, 17.9 +/- 5.1 years; 78.3% females) and 126 relatives (mean age, 27.9 +/- 17.2 years; 65.1% females) were evaluated. Clinical manifestations, antiendomysial antibodies (EMAs), and human leukocyte antigen (HLA) haplotypes were studied in patients. Additionally, jejunal biopsy specimens were assessed (light microscopy) in EMA-positive (EMA+) relatives.

RESULTS

Of the patients, 24.1% adhered to a strict gluten-free diet; 26% were oligosymptomatic, and none were malnourished; 45% were EMA+; 13.8% who ingested gluten were EMA-negative (EMA-); one patient consuming a strict gluten-free diet was EMA+. The DQA1*0501 allele was present in the highest frequency (48%, P < 0.0005), whereas combinations of DQ8 were predominant. Of the relatives, 4.8% were EMA+; they had a significantly higher frequency of diarrhea, weight loss, and anorexia (P < 0.03); and all had abnormal histology in biopsy specimens.

CONCLUSIONS

After childhood, celiac disease is oligosymptomatic and is often unrecognized by patients. Disease in 13.8% of patients and in 4.8% relatives appeared as incomplete forms of celiac disease. Predominance of DQ8 HLA haplotypes reflects the genetic Spanish-Mapuche heritage of this population.

Molecular basis of celiac disease

Celiac disease (CD) is an intestinal disorder with multifactorial etiology. HLA and non-HLA genes together with gluten and possibly additional environmental factors are involved in disease development. Evidence suggests that CD4(+) T cells are central in controlling an immune response to gluten that causes the immunopathology, but the actual mechanisms responsible for the tissue damage are as yet only partly characterized. CD provides a good model for HLA-associated diseases, and insight into the mechanism of this disease may well shed light on oral tolerance in humans. The primary HLA association in the majority of CD patients is with DQ2 and in the minority of patients with DQ8. Gluten-reactive T cells can be isolated from small intestinal biopsies of celiac patients but not of non-celiac controls. DQ2 or DQ8, but not other HLA molecules carried by patients, are the predominant restriction elements for these T cells. Lesion-derived T cells predominantly recognize deamidated gluten peptides. A number of distinct T cell epitopes within gluten exist. DQ2 and DQ8 bind the epitopes so that the glutamic acid residues created by deamidation are accommodated in pockets that have a preference for negatively charged side chains. Evidence indicates that deamidation in vivo is mediated by the enzyme tissue transglutaminase (tTG). Notably, tTG can also cross-link glutamine residues of peptides to lysine residues in other proteins including tTG itself. This may result in the formation of complexes of gluten-tTG. These complexes may permit gluten-reactive T cells to provide help to tTG-specific B cells by a mechanism of intramolecular help, thereby explaining the occurrence of gluten-dependent tTG autoantibodies that is a characteristic feature of active CD.