Original article—alimentary tract
Comparative Usefulness of Deamidated Gliadin Antibodies in the Diagnosis of Celiac Disease

https://doi.org/10.1016/j.cgh.2007.12.030Get rights and content

Background & Aims: Serologic tests are used frequently in celiac disease diagnosis. Gliadin antibodies generally lack the accuracy required for proper diagnosis. We evaluated the value of deamidated gliadin antibody measurements in the diagnosis and follow-up evaluation of celiac disease and compared their potential usefulness with that of gliadin and tissue-transglutaminase antibodies. Methods: We tested deamidated gliadin, gliadin, and tissue-transglutaminase–immunoglobulin (Ig)A and -IgG in 216 biopsy-selected subjects including 92 biopsy-proven untreated celiac patients (46% with total villous atrophy and 54% with partial villous atrophy) and 124 biopsy-proven nonceliac controls. Fifty-nine celiac patients also were tested after treatment with a gluten-free diet. Antibodies were measured by commercial enzyme-linked immunosorbent assays. Deamidated gliadin–IgA+G was detected using a conjugate reactive to both isotypes, which gives a positive if either isotype is present. Results: The sensitivity, specificity, and accuracy of deamidated gliadin–IgA (74%, 95%, and 86%), deamidated gliadin–IgG (65%, 98%, and 84%), and deamidated gliadin–IgA+G (75%, 94%, and 86%) were superior to gliadin-IgA (63%, 90%, and 79%) (P < .05) and gliadin–IgG (42%, 90%, and 69%) (P < .01), and were similar to tissue-transglutaminase–IgA (78%, 98%, and 90%) before treatment. The sensitivity of IgA isotype for all tests was significantly greater in celiac patients with total villous atrophy compared with those with partial villous atrophy (P < .05). The proportion of positive test results for all tests decreased significantly after treatment (P < .0001). Conclusions: Deamidated gliadin antibody is a better diagnostic test for celiac disease than the conventional gliadin antibody testing; although histopathology remains the gold standard test for diagnosis of celiac patients.

Section snippets

Study Design

Serum samples were collected from patients referred to the Division of Gastroenterology and Hepatology at the Mayo Clinic (Rochester, MN) for the assessment of gastrointestinal symptoms, unexplained weight loss/anemia, or to rule out CD. All patients underwent small intestinal biopsy between January 1999 and December 2006. All serum samples were stored at or below −20°C. The study was approved by the Institutional Review Board of the Mayo Clinic (Rochester, MN).

Patients

Subjects whose serum samples were

Subject Characteristics

We evaluated serum antibodies from 92 biopsy-proven celiac patients and 124 biopsy-proven nonceliac controls. Patients and controls were similar regarding age and sex. Of 92 celiac patients, 50 had PVA, 4 had subtotal villous atrophy, and 38 had TVA. For simplicity, patients with mild or a partial degree of villous atrophy were categorized into a PVA group (54%), and patients with subtotal villous atrophy or TVA were categorized into a TVA group (46%). The demographic characteristics of

Discussion

The present study reports the diagnostic accuracy of a new deamidated gliadin antibody assay in a population of mainly adult patients who were selected only on the basis of histopathology. This represents a major difference from previous studies wherein a positive serologic test was the inclusion criterion for patient recruitment.16, 17 Our results showing the superiority of AGA II over AGA were consistent with previous studies;16, 17, 18 however, the sensitivity of AGA II antibodies in our

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    Supported by a National Institutes of Health grant (DK-057892) and the Mayo Foundation.

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