Beyond Anti-Ttg Antibodies: Diagnostic Value Of Antibodies Against Deamidated Gliadin Peptides In Celiac Disease

Celiac disease is an autoimmune enteropathy whose diagnosis primarily relies on serological testing, with IgA anti-tissue transglutaminase (anti-tTG) antibodies serving as the first-line biomarker.However, their diagnostic performance may be limited in certain situations, particularly in cases of selective IgA deficiency or atypical clinical presentations.Antibodies directed against deamidated gliadin peptides (anti-DGP) represent a promising alternative, but their role in diagnostic strategies remains controversial.This study aimed to evaluate the diagnostic performance of anti-tTG and anti-DGP antibodies, used alone or in combination, in Moroccan patients with celiac disease.This retrospective single-center study included 96 serum samples from 49 patients with confirmed celiac disease and 47 healthy controls.IgA and IgG anti-tTG antibodies, as well as IgA and IgG anti-DGP antibodies, were detected using the immunodot technique.Serological profiles were compared between the two groups using Pearson's χ² test.A total of 96 participants were included, comprising 49 patients with confirmed celiac disease and 47 healthy controls.Among the patients, 65% were children and 35% were adults, with a female predominance (63%; sex-ratio = 0.58).In contrast, the control group consisted predominantly of adults (59%) and showed a balanced sex distribution (51% male).All controls were seronegative for the four biomarkers investigated.Among patients, positivity rates were 59.2% for IgA anti-tTG, 46.9% for IgA anti-DGP, 40.8% for IgG anti-tTG, and 49.0% for IgG anti-DGP (p < 0.0001).Combined analysis of serological profiles showed that 87.8% of patients had at least one IgA autoantibody, compared with 61.2% for IgG autoantibodies.Isolated anti-DGP positivity was observed in 28.6% of patients for IgA and 20.4% for IgG, highlighting the complementary value of these biomarkers relative to anti-tTG antibodies and suggesting that a multi-marker serological approach could improve the detection of celiac disease cases with heterogeneous immunological profiles.The combined use of anti-tTG and anti-DGP antibodies improves the serological detection of celiac disease compared with an approach based on a single biomarker.Although IgA anti-tTG remains the first-line reference test, IgG anti-DGP provides additional diagnostic value, particularly in atypical cases or when clinical suspicion persists.These findings, obtained from a Moroccan population, support the value of a multi-marker serological strategy adapted to settings where diagnostic resources are limited and warrant confirmation through prospective multicenter studies.