Diagnostic accuracy of anti-DGP (IgG) for celiac disease
Seyed Ali Jafari, Ali Alami, Niloofar Sedghi, Hamid Reza Kianifar, Mohammad Ali Kiani, Maryam Khalesi, Raheleh Derafshi
Abstract
Background: Celiac disease (CD) is an autoimmune enteropathy that is caused by the intake of gluten-containing grains in genetically susceptible humans. The gliadin and glutenin parts of wheat gluten are the essential factors that cause intestinal damage. Objectives: We analyzed the performance of a time-resolved immunofluorometric assay (TR-IFMA) in the diagnosis of CD in children. For this purpose, we compared the performance of IgA anti-tissue transglutaminase antibodies (IgA anti-TTG) and IgG antibodies against deamidated gliadin peptides (IgG anti-DGP) for the diagnosis of CD. Materials and Methods: In this cross-sectional study conducted in 2021 for a duration of about 6 months, 200 patients with suspected CD symptoms, children who needed screening due to Down syndrome or Turner syndrome, and the first-degree relatives of CD patients who underwent diagnostic evaluation were enrolled in a census study. Results: This study compares existing point-of-care anti-DGP Ab (IgG) and anti-TTG Ab (IgA) tests against each other using the gold standard of duodenal biopsy and pathology. Serology as a screening test was acceptable (93.6% for anti-DGP vs. 94.2% for anti-TTG) for both of them. This equivalent sensitivity of serum TTG and the DGP tests validates its potential as a basic tool for serological testing. Furthermore, endoscopy is carried out in patients positive for both. Conclusions: Our study showed that for the diagnosis of CD, anti-DGP antibodies had comparable characteristics with anti-TTG (IgA) in terms of diagnostic specificity and sensitivity. Specify of anti-DGP was higher than that of anti-TTG.