Deamidated gliadin peptide antibodies as a routine test for celiac disease: a prospective analysis

This study was designed to establish whether deamidated gliadin peptide antibodies (DGP-AGA) could improve the serologic workup for celiac disease (CD).

The best serologic approach for CD screening is currently based on the combined detection of tissue transglutaminase (tTGA), endomysial (EmA), and gliadin antibodies (AGA).

One hundred forty-four consecutive patients with gastrointestinal and extraintestinal signs suggestive for CD were investigated using serologic tests, that is, IgG and IgA DGP-AGA, IgA tTGA, IgA EmA, and duodenal biopsy.

Forty-eight out of 144 patients (33%) had CD with different severity of villous atrophy. IgA tTGA showed 93.7% sensitivity compared with 91.6% for IgA EmA, 84.3% for IgA DGP-AGA, and 82.3% for IgG DGP-AGA. Of the 3 cases negative for IgA tTGA, IgA EmA, and IgA DGP-AGA, 2 had total IgA deficiency, although both were positive for IgG DGP-AGA. IgG DGP-AGA showed a very high specificity for CD (98.9%), not only superior to IgA DGP-AGA (79.8%), but also to IgA tTGA (96.6%) and very close to IgA EmA (100%).

Our prospective study shows that the combined search for IgA tTGA and IgG DGP-AGA provides the best diagnostic accuracy for CD, allowing the identification of all CD cases---except one---with a very high specificity. The serologic workup for CD screening could be significantly improved by the routine introduction of IgG DGP-AGA together with IgA tTGA, thus reducing the number of tests and with an obvious advantage in terms of cost-efficacy.