Background: This study aimed to assess the declared benefits of the new test using antibodies against tissue transglutaminase in complex with gliadin representing a neo-epitope in the IgA and IgG class of immunoglobulins compared with currently used tissue transglutaminase antibodies in the IgA class of immunoglobulins among children. Methods: In the cross-sectional study (P1 study, n = 406) and two small-size prospective observational studies (P2 study, n = 59 and P3 study, n = 12), serum samples from all children were simultaneously tested for endomysial antibodies, IgA tissue transglutaminase antibodies, and antibodies against tissue transglutaminase in complex with gliadin in the IgA and IgG class of immunoglobulins. The exact McNemar test, Wilcoxon test, and Spearman’s correlation coefficient were used to analyze the data.
Results: We found a significant asymmetry of the tissue transglutaminase antibodies test compared with the antibodies against tissue transglutaminase neo-epitope test (P1). More patients (1.5%) had tissue transglutaminase an¬tibodies positive and antibodies against tissue transglutaminase neo-epitope negative results, whereas no patients had tissue transglutaminase antibodies negative and antibodies against tissue transglutaminase neo-epitope positive results. Of 59 children with tissue transglutaminase antibodies and/or endomysial antibodies positive results (P2), one (1.7%) did not have celiac disease. In agreement with the P1 study, four patients (6.8%) with confirmed celiac disease were tissue transglutaminase antibodies positive and antibodies against tissue transglutaminase neo-epitope negative. In this group, the sensitivity of the antibodies against tissue transglutaminase neo-epitope test for diagnosis of celiac disease was 91.4% (95% confidence interval, 81.0 - 97.1%). Among children diagnosed with functional gastrointestinal disorder (P3), all had negative serological test results, and none was diagnosed with celiac disease.
Conclusions: The results do not indicate that antibodies against tissue transglutaminase neo-epitope test would be an unambiguously better test than the currently used tissue transglutaminase antibodies.