Reliability of Autoantibodies Against a Tissue Transglutaminase Neo-Epitope for the Diagnosis of Pediatric Celiac Disease.

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.

Symptom positivity is essential for omitting biopsy in children with suspected celiac disease according to the new ESPGHAN guidelines.

The aim of this study was to assess the accuracy of serological tests in combination with clinical symptoms for diagnosing celiac disease (CD) according to the new proposed European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) criteria. We retrospectively assessed children and adolescents aged 16 months -19 years who were examined for suspicion of CD (n = 345). Evaluation of clinical symptoms and the presence of tissue transglutaminase (anti-TG-IgA) and endomysial antibodies (EMA-IgA) as well as intestinal biopsies was performed in all patients. Human leukocyte antigens (HLAs) were not included. Among 345 biopsied children, 213 (62 %) children had anti-TG titers >10 times the upper limit of normal (ULN) and positive EMA antibodies. Ninety-nine (29 %) children also had symptoms suggestive of CD in addition to EMA positivity and elevated titers of anti-TG >10 times the ULN. In patients who were asymptomatic, but positive for EMA, and had anti-TG antibodies >10 times the ULN, the specificity of tests for Marsh 2-3 was only 85 %, while in symptomatic patients with the same antibodies levels, the specificity was 99 %. Conclusion: Our results reveal that intestinal biopsies could be omitted in 28 % of patients when the new ESPGHAN guidelines are applied. Due to high accuracy of serological tests in combination with clinical symptoms for diagnosis of CD, the new guideline seems to be applicable even without the use of HLA testing.