Evaluation of fecal gluten immunogenic peptide in a follow-up of adherence to a gluten-free diet in children with newly diagnosed celiac disease: A prospective study

Abstract

Background: Celiac disease is a chronic autoimmune disorder of the small intestine for which the sole effective treatment is a lifelong gluten-free diet (GFD). Gluten immunogenic peptides (GIP) serve as biomarkers for recent gluten intake and can be utilized to assess gluten consumption levels. The aim of this study was to compare levels of fecal GIP with levels of tissue transglutaminase IgA (tTG-IgA), as well as dietary compliance, during follow-up.

Methods: This prospective, non-randomized, single-center study took place between August 2019 and August 2021 at Pediatric Gastroenterology Clinic at Gazi University Hospital in Ankara with the participation of 24 newly diagnosed celiac patients between 2 and 18 years (17 females, 7 males). Participants received GFD training from an expert dietitian, while any dietary transgressions were determined and assessed at 3 and 6 months. Levels of fecal GIP and blood tTG-IgA were analyzed at diagnosis, and again in follow-ups, using a sandwich enzyme-linked immunosorbent assay kit. Compliance with GFD was evaluated using a structured approach in terms of levels of GIP, tissue transglutaminase (tTG), Biagi score, as well as 24-hour food consumption records kept for 3 days (2 weekdays and 1 weekend).

Results: The mean age of participants was 8.3 ± 4.70 years. 23 patients (95.8%) initially had detectable GIP levels, while serum tTG-IgA was determined to be positive for all. After starting the GFD, GIP detection rates were measured as being 37.5% at 3 months, and 25% at 6 months, while tTG-IgA positivity rates were determined as being 41.7% and 37.5% respectively. While no significant correlation was found between GIP and tTG-IgA positivity. GIP detection at 3 months was moderately associated with dietitian assessments and Biagi scores (P < 0.05) but with no association at 6 months.

Conclusions: Expert dietitian training with regular monitoring increases celiac disease patients complying with GFD. Repeated fecal GIP analysis demonstrated any dietary nonadherence or unintentional gluten exposure that had occurred during the previous 2 to 7 days. It is suggested that a combination of these two tools can improve assessment of dietary compliance in celiac patients.

Keywords: Celiac disease; Children; Gluten immunogenic peptide; Gluten-free diet.