Serological markers for coeliac disease: is it time to change?

Background. Anti-gliadin and anti-endomysium antibodies are useful markers in the screening and follow-up of coeliac disease. The recent finding that tissue transglutaminase is the main auto-antigen of anti-endomysium has led to the discovery of anti-tissue transglutaminase antibodies Aim. To compare, in a prospective study, the diagnostic accuracy of anti-ti ssue transglutaminase, anti-gliadin and anti-endomysium antibodies in a lar ge series of adult patients. Methods. The study involved 80 consecutive subjects undergoing upper gastro intestinal tract endoscopy for suspected coeliac disease (subsequently conf irmed in 40 cases), 195 coeliac patients an a gluten-free diet, and 70 pati ents with different gastrointestinal disorders and normal duodenal histolog y. Anti-gliadin, anti-endomysium and anti-tissue transglutaminase antibodie s levels were measured using commercial kits. Results. The diagnostic sensitivity and specificity of anti-gliadin, anti-e ndomysium and anti-tissue transglutaminase antibodies were, respectively, 9 5% and 89.1%, 100% and 97.3%, and 100% and 98.2%: the agreement between the markers was substantial or, almost perfect. In terms of follow-up, the pos itivity of the markers varied according to the strict adherence to, and dur ation of the gluten-free diet; the agreement between anti-endomysium and an ti-tissue transglutaminase antibodies was almost perfect. Conclusions. Anti-endomysium and anti-tissue transglutaminase antibodies ar e both highly efficient for routine laboratory screening: the choice of one or the other will depend on the available facilities. However, neither can replace intestinal biopsy for general population screening because, in thi s case, their respective positive predictive values are only 15.7% and 21.8 %. During follow-up, and-gliadin retain their value as an early predictor, of gluten ingestion.