Radioimmunoassay to detect antitransglutaminase autoantibodies is the mostsensitive and specific screening method for celiac disease

OBJECTIVE: The aim of this study was to establish the most sensitive and sp ecific screening method for celiac disease. We tested three methods based o n different principles, which all detect autoantibodies against the same an tigen (tissue transglutaminase). METHODS: Sixty-two celiac children at the first biopsy (group 1), 78 celiac children on a gluten-free diet (group 2), 14 celiac children on a gluten-c hallenge (group 3), and 56 controls with a normal duodenal mucosa (group 4) were studied. The methods used were: 1) radioimmunoprecipitation assay usi ng recombinant tissue transglutaminase (RIA); 2) commercial enzyme immunoas say using guinea pig tissue transglutaminase (ELISA); and 3) indirect immun ofluorescence method for detection of antiendomysium antibodies (IF-EMA). RESULTS: RIA antitransglutaminase autoantibodies were detected in 100% of g roup 1, 43.6% of group 2, 100% of group 3, and none of the control subjects . ELISA antitransglutaminase autoantibodies were detected in 90.3% of group 1, 9% of group 2, 78.6% of group 3, and in none of the control subjects. I F-EMA were detected in 95.2% of group 1, 11.5% of group 2, 92.3% of group 3 , and 1.8% of the controls. CONCLUSIONS: Our results demonstrate a very high sensitivity and specificit y of the RIA method to detect antitransglutaminase autoantibodies in compar ison to ELISA and IF-EMA assays. We can explain this finding with the use o f human recombinant antigen and the increased capacity of the RIA method to detect low titers of autoantibodies. If our data are confirmed by studies on larger series, tissue transglutaminase RIA could be proposed as the best screening method for celiac patients. (C) 2001 by Am. Cell. of Gastroenter ology.