The serum IgA class anti-tissue transglutaminase antibodies in the diagnosis and follow up of coeliac disease. Results of an international multi-centre study. International Working Group on Eu-tTG.
OBJECTIVE
So far the reliability of the anti-tissue transglutaminase (anti-tTG) test for the diagnosis of coeliac disease has mostly been evaluated using slightly different enzyme-linked immunosorbent assays (ELISAs) in selected and usually small groups of patients. The aims of this study were: (1) to evaluate the reliability of the IgA anti-tTG antibodies for the diagnosis of coeliac disease; and (2) to define the sensitivity and specificity of a commercially available kit for the anti-tTG antibodies' quantitative determination.


METHODS
Each centre in this international multi-centre study collected sera from three groups of subjects: coeliac disease patients at the onset of (1) or on a gluten-free diet for at least 12 months (2); disease and healthy controls (3).


METHODS
The anti-tTG antibodies were determined in duplicate using an ELISA-based commercially available kit (Eu-tTG Eurospital, Trieste, Italy).


RESULTS
The following overall cases and controls have been enrolled: (1) 399 subjects with active coeliac disease; (2) 351 treated coeliac disease cases; (3) 432 controls. The centralized re-testing was performed on: (1) group a: 176 patients with active coeliac disease (mean anti-tTG, 21 arbitrary units [AU]); (2) group b: 172 treated coeliac disease cases (mean anti-tTG, 5 AU); (3) group c: 206 controls (mean anti-tTG, 3 AU). In active coeliacs, the anti-tTG antibodies showed a significant progressive decrease with age, while in controls an opposite trend was found. In active coeliac disease patients, the anti-tTG antibodies were significantly higher in coeliacs with a grade III enteropathy than in those showing a grade II lesion. In treated coeliacs, the mean anti-tTG values were significantly lower in patients strictly adhering to a gluten-free diet than in those reporting dietary transgressions. The sensitivity and the specificity of the Eu-tTG assay were 90% and 96%, respectively.


CONCLUSIONS
The results of this study show that the commercially available test for the anti-tTG antibodies' determination is a reproducible and valuable tool for the diagnosis and follow up of coeliac disease.
Fabiani
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E
University of Department of Paediatrics, Ancona, Italy. elisabetta.fab@tiscalinet.it
Catassi
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D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000032:analysis / Q000097:blood*; D002446:Celiac Disease / Q000175:diagnosis* / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis / Q000097:blood*; D007223:Infant; D007391:International Cooperation; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011503:Transglutaminases / Q000276:immunology*
D001323:Autoantibodies; D007070:Immunoglobulin A; D011503:Transglutaminases