IgA antibodies to tissue transglutaminase: An effective diagnostic test for celiac disease

Objective: Tissue transglutaminase (tTG) is the main autoantigen recognized by endomysial antibodies. The aim of this study was to assess sensitivity specificity, and predictive value of IgA and IgG antibodies to tTG in the d iagnosis of celiac disease compared with endomysial antibodies. Study design: We established enzyme-linked immunosorbent assay procedures t o measure IgA and Ige antibodies to tTG in sera from 48 untreated and 33 tr eated patients with celiac disease and from 63 patients with gastrointestin al disease who were in a control group. Sera from 10 patient-a with celiac disease were examined at various times after gluten uas reintroduced into t he patients' diet. Results: Both IgA and Ige to tTG were significantly (P < .001) higher in se rum of untreated patients with celiac disease versus those in the control g roup; IgA but not. Ige was significantly (P < .001) higher in untreated ver sus treated patients with celiac disease. IgA and IgG antitissue tTG had a diagnostic sensitivity, specificity, and positive predictive value of 92% a nd 21%, 98% and 97%, and 98% and 83%, respectively. The concordance rate of IgA anti-tTG with IgA antiendomysial antibodies was 95%, In 5 of the 10 pa tients undergoing gluten challenge, IgA antiendomysium antibodies were dete cted earlier than IgA anti-tTG antibodies. Conclusions: tTG-based enzyme-linked immunosorbent assay is an effective di agnostic test, although immunofluorescent-based assays are more sensitive, particularly during gluten challenge.