Small-bowel mucosal transglutaminase 2-specific IgA deposits in coeliac disease without villous atrophy: a prospective and randomized clinical study

OBJECTIVE: In coeliac disease, autoantibodies directed against transglutaminase 2 are produced in small-bowel mucosa, and they have been found to be deposited extracellularly. The aim of this study was to investigate whether such mucosal IgA deposits are important in the diagnostic work-up of early-stage coeliac disease without small-bowel mucosal villous atrophy. MATERIAL AND METHODS: Forty-one adults suspected of coeliac disease owing to increased density of mucosal gamma(delta)+ intraepithelial lymphocytes but normal villous morphology were randomized to gluten challenge or a gluten-free diet for 6 months. Clinically and histologically verified gluten dependency was compared with existence of small-bowel mucosal transglutaminase 2-specific extracellular IgA deposits and (coeliac disease-type) HLA DQ2 and DQ8; 34 non-coeliac subjects and 18 patients with classical coeliac disease served as controls. RESULTS: Of the 41 patients, 5 in the challenge group and 6 in the gluten-free diet group were clinically gluten sensitive; all 11 had HLA DQ2 or DQ8. Ten of these 11 patients showed transglutaminase 2-targeted mucosal IgA deposits, which were dependent on gluten consumption. Minimal IgA deposits were seen in only 3 out of 30 patients with suspected coeliac disease without any clinically detected gluten dependency. The deposits were found in all classical coeliac patients and in none of the non-coeliac control subjects. CONCLUSIONS: Clinically pertinent coeliac disease exists despite normal small-bowel mucosal villous architecture. Mucosal transglutaminase 2-specific IgA deposits can be utilized in detecting such patients with genetic gluten intolerance.     

Small-bowel mucosal transglutaminase 2-specific IgA deposits in coeliac disease without villous atrophy: A prospective and randomized clinical study

Objective In coeliac disease, autoantibodies directed against transglutaminase 2 are produced in small-bowel mucosa, and they have been found to be deposited extracellularly. The aim of this study was to investigate whether such mucosal IgA deposits are important in the diagnostic work-up of early-stage coeliac disease without small-bowel mucosal villous atrophy.

Material and methods Forty-one adults suspected of coeliac disease owing to increased density of mucosal γδ+ intraepithelial lymphocytes but normal villous morphology were randomized to gluten challenge or a gluten-free diet for 6 months. Clinically and histologically verified gluten dependency was compared with existence of small-bowel mucosal transglutaminase 2-specific extracellular IgA deposits and (coeliac disease-type) HLA DQ2 and DQ8; 34 non-coeliac subjects and 18 patients with classical coeliac disease served as controls.

Results Of the 41 patients, 5 in the challenge group and 6 in the gluten-free diet group were clinically gluten sensitive; all 11 had HLA DQ2 or DQ8. Ten of these 11 patients showed transglutaminase 2-targeted mucosal IgA deposits, which were dependent on gluten consumption. Minimal IgA deposits were seen in only 3 out of 30 patients with suspected coeliac disease without any clinically detected gluten dependency. The deposits were found in all classical coeliac patients and in none of the non-coeliac control subjects.

Conclusions Clinically pertinent coeliac disease exists despite normal small-bowel mucosal villous architecture. Mucosal transglutaminase 2-specific IgA deposits can be utilized in detecting such patients with genetic gluten intolerance.     

Diagnostic methods beyond conventional histology in coeliac disease diagnosis

BackgroundCoeliac disease diagnostic criteria currently require the detection of small bowel mucosal villous atrophy and crypt hyperplasia.AimsTo 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 methodsStudy comprised consecutive adult patients with coeliac disease suspicion; villous height–crypt depth ratio (Vh/CrD), the densities of CD3+, γδ+ 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.ResultsVh/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. γδ+ and villous tip IELs proved more reliable than CD3+ IELs.ConclusionsConventional 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.     

Sensitivity of serum tissue transglutaminase antibodies for endomysial antibody positive and negative coeliac disease

BACKGROUND: Serum antibodies to tissue transglutaminase (tTGA) are reported to have high sensitivity and specificity for coeliac disease and to correlate closely with endomysial antibodies (EmA). We assessed their performance in a coeliac population with a high proportion of EmA-negative patients, who have been under-represented in previous studies. METHODS: We used a commercial ELISA kit to test for IgA class tTGA in sera from a population of 73 untreated coeliac patients with normal serum IgA and a high percentage (19%) EmA-negative, taking 58 patients with normal duodenal biopsies as controls. EmA was measured using indirect immunofluorescence. RESULTS: Forty-six (63%) patients with villous atrophy (VA) had both tTGA and EmA. However, when considered separately, sensitivities of tTGA and EmA for VA were similar (75% versus 81%) and both had high specificity (98% versus 97%). As 9 patients were tTGA-positive only and 13 had EmA only, selection of patients for biopsy on the presence of either antibody would have had a sensitivity of 93% (68 of 73), with 5 (7%) patients seronegative for both. CONCLUSION: Although the ELISA tTGA assay is more convenient than EmA testing, it offers no advantages in sensitivity or specificity if used in isolation. However, incomplete concordance between EmA and tTGA positivity means that combination screening with both assays offers higher sensitivity, as almost a third of patients have only one antibody. As some coeliac patients with normal serum IgA are negative for both antibodies, biopsies should still be performed in seronegative individuals deemed at high risk for coeliac disease.     

Reliance on Serum Endomysial Antibody Testing Underestimates the True Prevalence of Coeliac Disease by One Fifth

Background: Although IgA endomysial antibody (EmA) is currently the serologic test of choice in selecting suspected coeliac patients for duodenal biopsies, false-negative cases have been reported and may be more common than previous studies suggest. We assessed the sensitivity of EmA for patients with biopsy-confirmed villous atrophy (VA). Methods: We studied 89 patients without IgA deficiency for whom biopsy had not been primarily prompted by a positive EmA result. VA was graded as partial, subtotal, or total (PVA, STVA, TVA). Serum EmA was assayed with indirect immunofluorescence. Results: The sensitivity of EmA for VA was 78% (69 of 89) and was similar for PVA (79%) and ST/TVA (77%). Only 4 of the 20 EmA-negative patients had increased serum IgA-class antigliadin antibody levels as measured with enzyme-linked immunosorbent assay. All seronegative patients who complied with dietary gluten exclusion responded clinically, with histologic improvement after 12 months in 8 (67%) of 12 patients who had follow-up biopsies. Conclusions: EmA-negative coeliac disease is common. Reliance on EmA testing to select patients for biopsy will result in significant underdiagnosis.     

Sensitivity of Serum Tissue Transglutaminase Antibodies for Endomysial Antibody Positive and Negative Coeliac Disease

Background: Serum antibodies to tissue transglutaminase (tTGA) are reported to have high sensitivity and specificity for coeliac disease and to correlate closely with endomysial antibodies (EmA). We assessed their performance in a coeliac population with a high proportion of EmA-negative patients, who have been under-represented in previous studies. Methods: We used a commercial ELISA kit to test for IgA class tTGA in sera from a population of 73 untreated coeliac patients with normal serum IgA and a high percentage (19%) EmA-negative, taking 58 patients with normal duodenal biopsies as controls. EmA was measured using indirect immunofluorescence. Results: Forty-six (63%) patients with villous atrophy (VA) had both tTGA and EmA. However, when considered separately, sensitivities of tTGA and EmA for VA were similar (75% versus 81%) and both had high specificity (98% versus 97%). As 9 patients were tTGA-positive only and 13 had EmA only, selection of patients for biopsy on the presence of either antibody would have had a sensitivity of 93% (68 of 73), with 5 (7%) patients seronegative for both. Conclusion: Although the ELISA tTGA assay is more convenient than EmA testing, it offers no advantages in sensitivity or specificity if used in isolation. However, incomplete concordance between EmA and tTGA positivity means that combination screening with both assays offers higher sensitivity, as almost a third of patients have only one antibody. As some coeliac patients with normal serum IgA are negative for both antibodies, biopsies should still be performed in seronegative individuals deemed at high risk for coeliac disease.     

Reliance on serum endomysial antibody testing underestimates the true prevalence of coeliac disease by one fifth

BACKGROUND: Although IgA endomysial antibody (EmA) is currently the serologic test of choice in selecting suspected coeliac patients for duodenal biopsies, false-negative cases have been reported and may be more common than previous studies suggest. We assessed the sensitivity of EmA for patients with biopsy-confirmed villous atrophy (VA). METHODS: We studied 89 patients without IgA deficiency for whom biopsy had not been primarily prompted by a positive EmA result. VA was graded as partial, subtotal, or total (PVA, STVA, TVA). Serum EmA was assayed with indirect immunofluorescence. RESULTS: The sensitivity of EmA for VA was 78% (69 of 89) and was similar for PVA (79%) and ST/TVA (77%). Only 4 of the 20 EmA-negative patients had increased serum IgA-class antigliadin antibody levels as measured with enzyme-linked immunosorbent assay. All seronegative patients who complied with dietary gluten exclusion responded clinically, with histologic improvement after 12 months in 8 (67%) of 12 patients who had follow-up biopsies. CONCLUSIONS: EmA-negative coeliac disease is common. Reliance on EmA testing to select patients for biopsy will result in significant underdiagnosis.     

Coeliac disease in patients with autoimmune thyroiditis

BACKGROUND AND AIMS: The close association between coeliac disease and autoimmunity prompted us to perform an antibody screening for gluten-sensitive enteropathy in patients with autoimmune thyroid dysfunction. METHODS: Sera from 220 patients with autoimmune thyroiditis, 50 euthyroid subjects with thyroid nodules and 250 blood donors were tested for IgA anti-tissue transglutaminase (anti-tTG) and antiendomysial antibodies (EmA). RESULTS: IgA anti-tTG was positive in 7 patients with autoimmune thyroiditis, whereas IgA EmA was found only in 6 of them. Duodenal biopsy confirmed coeliac disease diagnosis disclosing marked and mild villous atrophy in 6 and 1 of them, respectively. All but 2 of the 7 coeliacs did not show any sign of malabsorption. All euthyroid controls were negative for IgA antibodies, whereas 1 blood donor, positive for both IgA anti-tTG and EmA, was found to be coeliac. The prevalence of coeliac disease in patients with autoimmune thyroiditis (3.2%) was significantly higher than that found in blood donors (0.4%) (p = 0.022, Fisher's exact test). CONCLUSIONS: Antibody screening for coeliac disease should be included in the work-up of patients with autoimmune thyroiditis. Either IgA anti-tTG or EmA may be used, even though the former seems to be slightly more sensitive than the latter.     

The natural history of gluten sensitivity: report of two new celiac disease patients resulting from a long-term follow-up of nonatrophic, first-degree relatives

OBJECTIVE: Early studies revealed that up to 50% of non-atrophic, first-degree relatives of celiac disease patients exhibit features of gluten sensitivity. However, whether these features progress to a fully expressed celiac disease remain partially known. Our aim was to report two new patients resulting from a prospective, long-term surveillance of relatives who were nonatrophic at initial assessment. METHODS: After a median time of 86 months (range: 42-102 months) from the baseline assessment, we re-evaluated 44 first-degree relatives of propositi who had taken part in family studies and in whom baseline small intestinal biopsies were normal. At the baseline screening, 21 relatives had positive serum antigliadin antibodies and/or increased intraepithelial lymphocyte infiltration, and 23 did not. In addition, 11 of 18 had a celiac-like response to rectal gluten challenge and 16 of 34 possessed the characteristic HLA DQ2 haplotype (DQA1 0501 DQB1 0201). Re-evaluation was based on celiac-related serology antigliadin (AGA) and endomysial (EmA) antibodies. EmA-positive subjects underwent intestinal biopsy. RESULTS: At the end of the study, EmA was positive in only two subjects. Histological examination revealed flat small bowel mucosa in both. At baseline, both cases were EmA-negative and no minor histological changes were observed. One was a woman with positive baseline IgA and IgG AGA and a rectal gluten challenge with a celiac-like response; the other patient has presented only with a positive IgG AGA. In both cases, progression was detected in a clinically silent context. Both new patients had the characteristic HLA DQ2 haplotype. CONCLUSIONS: Our data suggest the need to re-evaluate relatives who have been negative on initial screening for celiac disease. Up to now, the progression to severe enteropathy was only observed in relatives who had presented some evidence of gluten sensitivity and the characteristic HLA DQ2 haplotype. Longer longitudinal studies are necessary to obtain definitive conclusions.     

Endomysial antibodies predict celiac disease irrespective of the titers or clinical presentation

AIM: To investigate the association between serum antibody levels and a subsequent celiac disease diagnosis in a large series of children and adults.METHODS: Besides subjects with classical gastrointestinal presentation of celiac disease, the study cohort included a substantial number of individuals with extraintestinal symptoms and those found by screening in at-risk groups. Altogether 405 patients underwent clinical, serological and histological evaluations. After collection of data, the antibody values were further graded as low [endomysial (EmA) 1:5-200, transglutaminase 2 antibodies (TG2-ab) 5.0-30.0 U/L] and high (EmA 1: ≥ 500, TG2-ab ≥ 30.0 U/L), and the serological results were compared with the small intestinal mucosal histology and clinical presentation.RESULTS: In total, 79% of the subjects with low and 94% of those with high serum EmA titers showed small-bowel mucosal villous atrophy. Furthermore, 96% of the 47 EmA positive subjects who had normal mucosal villi and remained on follow-up either subsequently developed mucosal atrophy while on a gluten-containing diet, or responded positively to a gluten-free diet.CONCLUSION: Irrespective of the initial serum titers or clinical presentation, EmA positivity as such is a very strong predictor of a subsequent celiac disease diagnosis.     

In vivo targeting of intestinal and extraintestinal transglutaminase 2 by coeliac autoantibodies

BACKGROUND: IgA class serum autoantibodies against type 2 (tissue) transglutaminase (TG2) bind to both intestinal and extraintestinal normal tissue sections in vitro, eliciting endomysial, reticulin, and jejunal antibody reactions. It is not known whether similar binding also occurs in coeliac patients in vivo, and may thereby contribute to disease manifestations. AIMS: To investigate intestinal and extraintestinal coeliac tissues for the presence of in vivo bound TG2 specific IgA and its relation to small intestinal mucosal atrophy. PATIENTS: We investigated jejunal samples with normal villous morphology from 10 patients with developing coeliac disease who subsequently progressed to a flat lesion, from 11 patients with dermatitis herpetiformis, and from 12 non-coeliac controls. Six extrajejunal biopsy samples (liver, lymph node, muscle, appendix), obtained based on independent clinical indications from patients with active coeliac disease, were also studied. METHODS: Double colour immunofluorescent studies for in situ IgA, TG2, and laminin were performed. IgA was eluted from tissue sections and tested for TG2 specificity by enzyme linked immunosorbent assay and indirect immunofluorescence. RESULTS: IgA (in one IgA deficient case IgG) deposition on extracellularly located TG2 was detected in jejunal and extrajejunal specimens of all coeliac patients, and also in seven of 11 dermatitis herpetiformis patients, of whom two had no circulating endomysial antibodies. IgA eluted from extraintestinal coeliac tissues was targeted against TG2. CONCLUSIONS: Coeliac IgA targets jejunal TG2 early in disease development even when endomysial antibodies are not present in the circulation. Extraintestinal target sites of coeliac IgA further indicate that humoral immunity may have a pathogenetic role.     

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

BACKGROUND: Although anti-endomysial antibodies (EmA) have been found in the supernatants of cultured intestinal mucosa from patients with coeliac disease (CD), in no study has the clinical reliability of this new diagnostic tool been investigated. Our aims were to evaluate the clinical usefulness of the in vitro production of EmA in CD diagnosis in consecutive patients with suspected CD, and to evaluate the reliability of the in vitro challenge in CD patients on a gluten-free diet (GFD). METHODS: For the former aim, consecutive patients who were due to undergo intestinal biopsy for suspected diagnosis of CD were enrolled: according to the final diagnosis, these patients were divided into two groups: Group 1 comprised 91 newly diagnosed CD patients (40 males; age range 7 months to 84 years), Group 2 included 100 subjects with diseases other than CD (44 males; age range 9 months to 76 years). For the latter aim, we also studied 21 CD patients on a gluten-free diet after 16-123 months (8 males; age range 3-51 years), with normal intestinal architecture (Group 3) and 22 patients who served as controls (12 males; age range 4-60 years) with gastroesophageal reflux disease-like symptoms (Group 4). All patients underwent determination of serum anti-gliadin (AGA) and EmA antibodies, histology evaluation of the intestinal biopsies and EmA assay in the supernatants of in vitro gliadin-challenged duodenal mucosa. RESULTS: EmA assay in the supernatants showed a sensitivity and specificity of 96% and 100%, respectively; these were not significantly different from those observed for serum EmA (88% and 99%, respectively). However, EmA assay in the supernatants was useful in CD patients with mild intestinal histology lesions (infiltrative/hyperplastic type): in this subgroup it was positive in 9/12 of cases, but serum EmA was positive in only 2/12. As regards the reliability of the in vitro gliadin challenge, EmA production in supernatants was recorded only in 10/21 CD patients on a gluten-free diet. The patients with a positive in vitro challenge had a higher number of intra-epithelial lymphocytes than patients with a negative challenge. CONCLUSIONS: 1) EmA assay in the medium of cultured intestinal biopsy can detect gluten-sensitive enteropathy, characterized by an infiltrative/hyperplastic histological pattern, which is often associated with negative serum EmA. 2) The in vitro challenge in CD patients on a gluten-free diet detects EmA production in the culture medium only in half of the cases and other studies must be performed to evaluate whether EmA production after in vitro challenge can be considered a reliable test for confirming CD diagnosis.     

Prevalence of coeliac disease in the adult population of central Greece

OBJECTIVES: Recent studies from several countries have shown that coeliac disease (CD) is increasingly being diagnosed in adults, as the availability of new, accurate serologic tests has made screening in the general population possible. No data exist regarding the prevalence of CD in Greece. The aim of this study was the implementation of a serologic screening procedure for CD in the adult general population of Thessaly, an area of central Greece, using a novel diagnostic algorithm. METHODS: The study included 2230 participants (1226 women, 1004 men, median age 46 years, range 18-80 years), selected by systematic random sampling, from the adult general population of Thessaly. All the serum samples were tested for total immunoglobulin A (IgA)-serum levels, to exclude IgA deficiency. Samples with total IgA within the normal range were tested for IgA antibodies against native human-tissue transglutaminase (anti-tTG); samples that were anti-tTG positive were tested for IgA antiendomysial antibodies (EmA). Samples from participants with selective IgA deficiency were examined for IgG antigliadin antibodies. Participants who were EmA-positive or antigliadin antibody-positive were referred for intestinal biopsy and human leucocyte antigen (HLA) typing. RESULTS: No participant with selective IgA deficiency was detected. Four individuals tested positive for EmA, all of whom were biopsy-proven coeliacs. Therefore, the CD prevalence in this general population sample is 1 : 558 or 1.8 per 1000 (SE 0.13). The four new patients with abnormal histology (two men, two women) were aged between 18 and 35 years. Two of them were considered to be asymptomatic and two presented with a subclinical course. All four had the heterodimer HLA-DQ2. CONCLUSIONS: This first serological screening study for CD in Greece has demonstrated that CD prevalence in Thessaly is among the lowest reported in Europe.     

Continuous Infusion of Cholecystokinin Leads to Down-Regulation of the Cholecystokinin-A Receptor in the Rat Pancreas

Background: Coeliac disease may present with dyspepsia or reflux. There are characteristic duodenal appearances associated with villous atrophy (mosaic pattern mucosa and loss, reduction in number or scalloping of duodenal folds) which may prompt small-bowel biopsy during routine upper gastrointestinal endoscopy. These appearances were sought in patients referred by their general practitioners for open-access endoscopy (OAE), to determine the prevalence and significance of coeliac disease as a cause of symptoms. Methods: Five hundred consecutive patients undergoing OAE by one consultant gastroenterologist were studied. Forceps biopsy specimens from the distal duodenum were taken if appearances were suggestive. If villous atrophy was confirmed, the response of symptoms to dietary gluten exclusion was assessed. Results: Ten patients had suggestive endoscopic appearances, of whom eight had villous atrophy, giving a prevalence of coeliac disease of 1.6% (1:63). All eight had mosaic pattern mucosa, with three also having reduction of duodenal folds, and four having scalloped folds. All had serum endomysial antibodies (EmA). Apart from diarrhoea, described by one patient, there were no symptoms of `typical' coeliac disease at diagnosis: three patients were overweight. After dietary gluten exclusion all reported symptomatic improvement, with disappearance of EmA in five patients to date. Conclusions: There is a high prevalence of coeliac disease among patients undergoing OAE, which is relevant to their clinical symptoms and which can be identified by careful endoscopic inspection of the duodenum.     

HLA-DQ typing in the diagnosis of celiac disease

OBJECTIVE: More than 95% of celiac patients share the major histocompatibility complex II class human leukocyte antigen (HLA) DQ2 or DQ8 haplotype; patients negative for both types are unlikely to suffer from celiac disease. Our aim was to investigate whether HLA-DQ2 and -DQ8 typing is helpful when diagnosis is uncertain because of the absence of unequivocal small bowel villous atrophy. METHODS: HLA-DQ2 and -DQ8 typing was carried out in 59 patients evincing nondiagnostic small bowel mucosal lesion or positive celiac serology, and in 17 patients maintaining a gluten-free diet without biopsy-proven celiac disease. HLA findings were compared to small bowel mucosal morphology; intraepithelial lymphocytes; and serum endomysial (EmA), reticulin, tissue transglutaminase (anti-tTG) and gliadin antibodies. RESULTS: Of the 59 patients evincing only minor small bowel mucosal changes or positive celiac disease serology, 22 (37%) were negative for DQ2 and DQ8. All EmA-positive patients had celiac-type HLA, but antireticulin antibody, anti-tTg, and antigliadin antibody were also present in HLA-DQ2- and -DQ8-negative individuals. Eleven of 17 patients (65%) observing a gluten-free diet before small bowel biopsy did not share celiac-type HLA. None of the 17 had apparent villous atrophy. Serum EmA and anti-tTG were negative in all. HLA-DQ typing is less expensive than follow-up biopsy in the exclusion of celiac disease. CONCLUSIONS: HLA-DQ2 and -DQ8 determination is useful in exclusion, probably lifelong, of celiac disease in individuals with an equivocal small bowel histological finding. The low specificity of this test must, however, be borne in mind.     

Prevalence of celiac disease in Argentina: screening of an adult population in the La Plata area

OBJECTIVES: Up to now, the epidemiological characteristic of celiac disease among adults in South America remains unknown. The present prospective screening was designed to determine the prevalence of celiac disease in adults from the general population in an urban area of Argentina. METHODS: Between January. 1998, and May, 2000, all couples attending a centralized laboratory for an obligatory prenuptial examination in the La Plata area were offered participation in a screening program for celiac disease. The study included 2000 subjects (996 women; median age 29 yr, range 16-79 yr). All individuals completed a clinical questionnaire at the time that serum samples were obtained. A three-step screening protocol was used, as follows: 1) all samples were tested for antigliadin antibodies (AGAs) (type IgA and IgG); 2) samples that were IgA AGA positive were tested for antiendomysial antibody (EmA type IgA); samples that were positive for AGA-G but negative for IgA AGAs were tested for total IgA serum levels and EmA type IgG; and 3) subjects who were EmA-positive were referred for intestinal biopsy. RESULTS: At the end of the screening we detected 10 subjects who were EmA-A positive and two others who were IgA-deficient (both were EmA-G positive). Up to now, 11 of the 12 subjects (including nine EmA-positive and two IgA-deficient subjects) had endoscopic intestinal biopsies showing the characteristic celiac histology. The remaining EmA-positive individual was considered to be affected by celiac disease. The overall prevalence assessed was 1:167 (6.0 x 1000 subjects; 95% CI = 3.1-10.5). Eight of the 12 (67%) subjects were female (1:124; 8.0 x 1000; 95% CI = 3.5-15.8) and four (33%) were male (1:251; 4.0 x 1000; 95% Cl = 1.1-10.2). Although eight new patients were considered to be asymptomatic, three presented with a subclinical course and one was classically symptomatic. Only one patient had been previously diagnosed with celiac disease. CONCLUSIONS: Our screening protocol showed a very high prevalence of celiac disease for an urban area of Argentina that is ethnically similar to 90% of the general population of the country. The prevalence among women was double that for men, and the heterogeneous clinical picture of new patients showed predominance of asymptomatic cases.     

Guinea pig transglutaminase immunolinked assay does not predict coeliac disease in patients with chronic liver disease

BACKGROUND: It has been suggested that serological screening for coeliac disease (CD) should be performed in patients with chronic unexplained hypertransaminasaemia. AIMS: To evaluate the specificity for CD diagnosis of serum IgA antitissue transglutaminase (tTG) determination in consecutive patients with chronic hypertransaminasaemia using the most widely utilised ELISA based on tTG from guinea pig as the antigen. PATIENTS AND METHODS: We studied 98 patients with chronic hypertransaminasaemia, evaluated for the first time in a hepatology clinic. Serum anti-tTG and antiendomysial (EmA) assays were performed. Patients positive for EmA and/or anti-tTG were proposed for intestinal biopsy. Finally, all sera were reassayed for anti-tTG using an ELISA based on human recombinant tTG as the antigen. RESULTS: A total of 94/98 hypertransaminasaemic patients were positive for hepatitis virus markers, with 82/98 (83%) positive for anti-hepatitis C virus. Liver histology showed that most patients had mild or moderate chronic hepatitis while severe fibrosis or overt liver cirrhosis was found in 20/98. CD screening showed that 15/98 (16%) hypertransaminasaemic subjects had anti-tTG values in the same range as CD patients; however, IgA EmA were positive in only 2/98 (2%). Distal duodenal biopsy, performed in nine patients, showed subtotal villous atrophy in the two EmA+/anti-tTG+ patients but was normal in 7/7 EmA-/anti-tTG+ subjects. The presence of anti-tTG+ values in EmA- patients was unrelated to particular gastrointestinal symptoms, other associated diseases, severity of liver histology, or distribution of viral hepatitis markers. There was a significantly higher frequency of positive serum autoantibodies (antinuclear, antimitochondrial, antismooth muscle, and anti-liver-kidney microsomal antibodies) in anti-tTG+/EmA- patients than in the other subjects (9/13 v 10/83; p<0.003). Also, a correlation was found between serum gamma globulin and anti-tTG values (p<0.01). When sera were tested with the ELISA based on human tTG as the antigen, no false positive results were observed: only the two EmA+ patients with atrophy of the intestinal mucosa were positive for anti-tTG while all others were negative, including those false positive in the ELISA based on guinea pig tTG as the antigen. CONCLUSIONS: In patients with elevated transaminases and chronic liver disease there was a high frequency of false positive anti-tTG results using the ELISA based on tTG from guinea pig as the antigen. Indeed, the presence of anti-tTG did not correlate with the presence of EmA or CD. These false positives depend on the presence of hepatic proteins in the commercial tTG obtained from guinea pig liver and disappear when human tTG is used as the antigen in the ELISA system. We suggest that the commonly used tTG ELISA based on guinea pig antigen should not be used as a screening tool for CD in patients with chronic liver disease.     

IgA anti-actin antibodies ELISA in coeliac disease: A multicentre study

BACKGROUND: Previous studies have demonstrated that serum anti-actin antibodies are a reliable marker of intestinal damage severity in coeliac disease. AIMS: To validate in a multicentre study the clinical usefulness of serum IgA anti-actin antibody ELISA and its possible use in monitoring intestinal mucosa lesions during gluten-free diet. PATIENTS AND METHODS: Four centres recruited 205 newly diagnosed coeliac disease patients with villous atrophy, 80 healthy controls and 81 "disease" controls. Twelve coeliac disease patients on gluten-free diet but with persistent symptoms underwent serum IgA anti-actin antibody assay and intestinal histology evaluation. IgA anti-actin antibody ELISA was performed with a commercial kit. All coeliac disease patients underwent intestinal histology study. RESULTS: IgA anti-actin antibodies showed a sensitivity of 80% and a specificity of 85% in the diagnosis of coeliac disease patients with villous atrophy. The area under the receiving operator curve for anti-actin antibodies was 0.873 [95% C.I. 0.805-0.899]. Serum anti-actin antibodies values were significantly higher in coeliac disease patients than in healthy or "disease" controls (P<0.0001). Serum anti-actin antibodies were positive in 41 of the 60 coeliac disease patients with mild intestinal histology lesions (69%) and in 123 of the 145 with severe lesions (85.3%) (P<0.05). There was a significant inverse correlation between anti-actin antibody values and the villi/crypts ratio (r=-0.423; P<0.0001). In the 12 coeliac disease patients on gluten-free diet who underwent re-evaluation as they were persistently symptomatic, intestinal histology showed three cases with persistent villous atrophy: all of these were positive for serum anti-actin antibodies ELISA, whereas both serum anti-tTG and EmAs were negative. The other nine patients showed normal intestinal villi and were negative for serum anti-actin antibodies. CONCLUSIONS: Anti-actin antibodies are a reliable marker of severe intestinal mucosa damage in coeliac disease patients and a simple ELISA technique offers an accurate method for their determination. These antibodies seem to be a very reliable marker of persistent intestinal damage in coeliac disease patients.     

Intolerance to cereals is not specific for coeliac disease

BACKGROUND: Abdominal complaints after ingestion of cereals are not uncommon. We assessed how reliable such a history is as a marker for the presence of overt coeliac disease, and whether we should also take into account latent coeliac disease and cereal allergy. METHODS: The study group comprised 93 consecutive adults from health centres spontaneously reporting abdominal symptoms after consumption of cereals. Small bowel mucosal morphology, CD3+, alphabeta+ and gammadelta+ intraepithelial lymphocytes (IELs), HLA DQ alleles and serum IgA-class endomysial (EmA), tissue transglutaminase (tTg) and gliadin (AGA) antibodies were determined. Skin prick and patch tests and serum radioallergosorbent tests for cereals were carried out. Thirty non-coeliac adults served as biopsy controls. RESULTS: Eight (9%) patients had coeliac disease and one mild partial villous atrophy. Altogether 17 had an increased density of gamma delta+ IELs without atrophy. However, only seven (8%) showed evidence of latent coeliac disease, i.e. both an increase in gammadelta+ IELs and the presence of coeliac disease-type HLA. One or more of the allergy tests for cereals was positive in 19; 9 adopted a gluten-free diet and abdominal symptoms were alleviated in all. In non-coeliac patients, serum EmA and tTg tests were negative in all, whereas AGA was seen in 40%. CONCLUSIONS: Intolerance to cereals is not a specific sign of overt or latent coeliac disease. All experimental dietary interventions before proper diagnosis of coeliac disease are therefore to be discouraged. Allergy to cereals, on the other hand, should be considered even in adults.