Trend of Anti-Tissue Transglutaminase Antibody Normalization in Children with Celiac Disease Started on Gluten Free Diet: A Comparative Study between Chemiluminescence and ELISA Serum Assays.

Abstract

BACKGROUND The aim of this study is to compare the performance of anti-tissue Transglutaminase (atTG) Chemiluminescence Immuno-Assay (CLIA) versus the standard ELISA methods in monitoring celiac children after the start of gluten free diet (GFD). METHODS Celiac children diagnosed between 2005 and 2016 at our centre were classified into 2 groups based on serum assay (ELISA versus CLIA) used for atTG monitoring, and were compared on percentage of decrease and time to normalisation of atTG on GFD. RESULTS Among 260 included children, the rate of normalisation of atTG levels at 30 months' follow-up was 86% and 70% in ELISA and CLIA group respectively (p < 0.01). Median time to normalisation was 11.7 and 14.7 months in ELISA and CLIA group respectively (p = 0.003). Marsh score at diagnosis was not associated with time to atTG normalisation (p = 0.770), while older age at diagnosis and higher baseline atTG predicted longer time to atTG normalisation (p = 0.01, p < 0.01). CONCLUSION The percentage and the time of the atTG normalisation in celiac children on GFD should be interpreted according to the utilised assay: at 30 months' follow up children tested by CLIA are less likely to normalize atTG levels compared to those tested by ELISA. Younger age at diagnosis and lower baseline atTG are predictors of earlier atTG normalisation, regardless of the adopted assay.