Tissue transglutaminase autoantibody enzyme-linked immunosorbent assay in detecting celiac disease

Background & Aims: Tissue transglutaminase has been reported to be the targ et for endomysial antibodies in celiac disease. We sought to establish whet her immunoglobulin (Ig) A class tissue transglutaminase autoantibodies can be considered specific for celiac disease. Methods: Serum samples from 136 patients with untreated celiac disease (diagnosed according to the criteria of the European Society for Pediatric Gastroenterology, Hepatology and Nut rition) and 207 disease controls were studied. Enzyme-linked immunosorbent assay (ELISA) and Western blots were performed using calcium-treated and un treated tissue transglutaminase as antigen. Reticulin, endomysial, and mous e monoclonal tissue transglutaminase antibodies were studied by an indirect immunofluorescence method and gliadin antibodies with ELISA. Results: The calcium-activated tissue transglutaminase autoantibody ELISA was highly sen sitive (129 of 136) and specific (194 of 207) in detecting celiac disease. The new autoantibody ELISA test correlated well with the endomysial antibod y test. Tissue transglutaminase autoantibody ELISA showed a clearly better predictive potential than the IgA class gliadin antibody ELISA. Immunoblots and ELISA blocking studies showed that calcium is needed for the specific antigen-antibody reaction to occur. Double immunofluorescence staining in h uman umbilical cord with sera from patients with celiac disease and with mo noclonal tissue transglutaminase antibodies showed complete overlap. Conclu sions: Calcium-activated tissue transglutaminase autoantibody ELISA is high ly accurate in detecting untreated celiac disease. Tissue transglutaminase seems to be the target self-antigen for endomysial antibodies.