The Overlap between Type 1 Diabetes and Celiac Disease in Children and the Role of Tissue Transglutaminase-IgA Positivity in Endoscopy Decision.

Abstract

Introduction: Celiac disease (CD)-related antibody positivity in children with type 1 diabetes (T1D) may fluctuate and become negative spontaneously. There are uncertainties about the optimal tissue transglutaminase IgA (tTG-IgA) titre and timing of endoscopy in the diagnosis of CD, and this study aimed to contribute to the debate on the tTG-IgA threshold titre for endoscopy decisions in children with T1D.

Methods: The data of 991 children with T1D who had undergone serologic evaluation for CD were analysed retrospectively. The tTG-IgA positivity rate and the upper limit of normal (ULN) tTG-IgA positivity were assessed. Participants were grouped according to the frequency, course, and test results of tTG-IgA tests. Those with and without histopathologic diagnosis of CD by endoscopic biopsy were compared in terms of tTG-IgA screening time and tTG-IgA predictive values.

Results: In 10.2% (n:101) of all cases, tTG-IgA antibody was positive and endoscopic biopsy was performed in 68.3% (n:69) of these cases. Of all cases, 4.3% (n:43) were diagnosed with CD by endoscopic biopsy. A tTG-IgA titre of 7×ULN and above was found to be the best predictive value for the diagnosis of CD with 79.1% sensitivity, 80.8% specificity 87.2% positive predictive value, and 70% negative predictive value.

Conclusions: Approximately 10% of antibody positive cases showed fluctuating and low-titre positivity, and no CD was detected by endoscopic biopsy in the group with fluctuating antibody course. The results of our study suggest that endoscopy in children with tTG-IgA levels 7×ULN or above may prevent both false-positive results and missed cases.