Slow Decrease of Antitissue Transglutaminase Antibody Positivity in Children With Celiac Disease After Starting the Gluten-free Diet

The use of urine peptidomics to define dietary gluten peptides from patients with celiac disease and the clinical relevance

INTRODUCTION

Determination of urinary gluten immunogenic peptides (GIP) has emerged as one of the most attractive test to monitor the adherence to the gluten-free diet (GFD) of patients with celiac disease (CD), being a simple, noninvasive and direct method to detect gluten contamination of the GFD.

AREAS COVERED

We conducted a scoping review in Medline (PubMed) of articles published up to April 2023 that analyzed any aspect of the clinical relevance of the use of urinary GIP measurement in patients with CD. A total of 17 articles reporting the clinical use of urinary peptidomics for the follow-up of CD patients were finally included.

EXPERT OPINION

Available data suggest that a negative urinary GIP result is a reliable noninvasive predictor of intestinal mucosa healing in CD patients treated with the GFD, especially if testing three urine samples on different days including the weekend. Due to conflicting results about the sensitivity and the specificity of the urinary GIP determination, additional in-depth information is needed, particularly related to (1) the relationship between the amount of ingested gluten and the quantity of urinary GIP excreted in treated CD patients, (2) the GIP kinetics and best timing for sample collection.

Time to normalisation of tissue transglutaminase in paediatric coeliac disease is dependent on initial titre and half of patients will normalise within 12 months

BACKGROUND

Coeliac disease (CD) is common. Response to a gluten-free diet is assessed through serial measurement of tissue transglutaminase (TTG) antibody titre. However, the relationship of TTG titres to symptoms and the speed of normalisation is poorly understood.

METHODS

Patients seen in 2020, and under follow-up in the Southampton CD clinic, had blood results, growth measures and symptom data collated. Time to normalisation, predictors of normalisation and relationship of TTG to growth/symptoms were assessed.

RESULTS

57 patients were included. All had TTG results from the time of diagnosis and follow-up. All families reported dietary compliance.Median TTG at diagnosis was 100 μ/L (range 0.3-4360), 94.7% of the patients had symptoms compatible with CD. At 6-12 months after diagnosis, the median TTG was 3.8 μ/mL (range 0.3-133). In terms of response, 29 of the 57 patients (50.9%) had a TTG below 4 μ/mL (upper normal limit). A further 25 patients (43.9%) had a TTG<10 times the upper limit of normal. Ten patients (17.5%) had a persistently high TTG (median=8.55 μ/mL, range 4.1-303) after >12 months.TTG at diagnosis was correlated with TTG at 6-12 months, β=0.542, p=0.000016. Patients with TTG<10 times the upper limit of normal at diagnosis group were more likely to have normalised at 6-12 months compared with >10 times normal (85% vs 32.4%, p=0.0015). TTG titres did not correlate with growth measures (Z-scores) at diagnosis or at follow-up.

CONCLUSIONS

Normalisation of TTG levels occurs within 6-12 months for around half of patients. Higher TTG levels at diagnosis take longer to normalise. The role of compliance is unclear.

Clinical Value of Tissue Transglutaminase Antibodies in Celiac Patients over a Long Term Follow-Up

Introduction & Aim: Anti-tissue transglutaminase antibody (tTGA) titer is used during the follow-up of celiac patients to evaluate gluten-free diet (GFD) responsiveness. However, no clear data are available on this issue. The aim of this study was to evaluate tTGA significance during celiac disease (CD) monitoring. Methods: From January 2017 to January 2020, consecutive CD patients on a GFD with persistent positive tTGA were enrolled. Antibody titres were evaluated on a yearly basis from CD diagnosis to the last follow-up. Urinary gluten detection tests, duodenal histology and capsule enteroscopy (CE) were performed. A tTGA-positive cohort was compared with a control group composed of 212 treated CD patients with negative tTGA. Results: 65 patients (12% males, median age at enrollment and CD diagnosis, 37 (14–86) and 31 (1–76), respectively, median follow up 4 (1–26) years) presented with positive tTGA during follow-up. Overall, the tTGA titres were 3 (1–79) fold increased (ULN). Three different tTGA trends were recognized: (I) 36 (55%) patients with a progressive titres decrease; (II) 16 (25%) patients with a fluctuating behavior; (III) 13 (20%) patients with a steady state or increased titres. tTGA+ patients did not present with different clinical and demographic parameters. Duodenal atrophy was present in 10% vs. 36% of the tTGA positive vs. negative group (p < 0.005), respectively. Gluten detection results were positive in 3 (8%) cases, all in the III group. In tTGA+ patients, CE did not identify any CD-related complications. Conclusions: tTGA positivity during CD follow up did not present a relevant clinical significance without association with autoimmune comorbidities and mucosal damage.