New Antibody Test Improves Celiac Disease Diagnosis in T1D

TOPLINE:

An IgA anti-transglutaminase 2 (TGA-IgA) antibody cut-off of approximately 6.1 times the upper limit of normal optimised celiac disease diagnosis in children and adolescents with type 1 diabetes (T1D). Adding IgG antibodies against deamidated gliadin peptides (GLA-IgG) to TGA-IgA further improved diagnostic accuracy.

METHODOLOGY:

• The diagnosis of celiac disease in patients with T1D is challenging due to the common asymptomatic or oligosymptomatic presentation and fluctuating antibody levels.
• Researchers conducted this study to evaluate the effectiveness of TGA-IgA antibody levels in diagnosing celiac disease and to establish optimal criteria for performing diagnostic biopsies.
• They included 588 children and adolescents with T1D (age, < 18 years; 44% girls), resulting in a total of 2944 TGA-IgA measurements. During the follow-up, 34 (5.8%) patients developed celiac disease, of whom 50% had celiac disease–associated symptoms at diagnosis.
• Multiple celiac disease antibodies were documented, including TGA-IgA, endomysial antibodies, and GLA-IgG, with their respective upper limits of normal calculated according to the assays used.
• Receiver operating characteristic (ROC) analysis was used to determine the optimal TGA-IgA cut-off for recommending a biopsy; performance was assessed using the area under the ROC curve (AUC).

TAKEAWAY:

• Balancing sensitivity and specificity, the optimal TGA-IgA cut-off for performing biopsies to confirm the diagnosis of celiac disease was approximately 6.1 times the upper limit of normal, resulting in an accuracy of 80.4% and a sensitivity of 90.3%.
• Compared with TGA-IgA alone, the combination of GLA-IgG and TGA-IgA improved diagnostic accuracy, yielding a higher AUC of 0.79.
• Celiac disease was more frequently diagnosed within 2 years of T1D diagnosis, with about two thirds of individuals showing elevated TGA-IgA levels at the time of T1D diagnosis.
• Late diagnosis of celiac disease (≥ 2 years after T1D diagnosis) was associated with a more gradual increase in TGA-IgA levels.

IN PRACTICE:

“Our data let us propose a screening strategy for biopsy indication with TGA-IgA and GLA-IgG determination with a TGA-IgA cut-off around 6.1x ULN [upper limit of normal]. TGA-IgA determination at T1D diagnosis may predict CD [celiac disease] diagnosis within 2 years of T1D diagnosis,” the authors wrote.

SOURCE:

The study was led by Nadja Zoe Müller, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland, and was published online on March 8, 2025, in The Journal of Clinical Endocrinology & Metabolism.

LIMITATIONS:

The study’s retrospective nature, limited sample size, and data unavailability may have influenced the overall findings. The small sample size prevented the separation of the two centres into training and validation cohorts, a step that could have strengthened the results. Additionally, potential selection bias in performing endoscopies with biopsies could not be excluded, possibly influencing diagnostic outcomes.

DISCLOSURES:

The study did not receive any funding. Two authors reported being consultants for or receiving honoraria or research support from various pharmaceutical companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.