Background: Although anti-endomysial antibodies (EmA) have been found in the supernatants of cultured intestinal mucosa from patients with coeliac disease (CD), in no study has the clinical reliability of this new diagnostic tool been investigated. Our aims were to evaluate the clinical usefulness of the in vitro production of EmA in CD diagnosis in consecutive patients with suspected CD, and to evaluate the reliability of the in vitro challenge in CD patients on a gluten-free diet (GFD).
Methods: For the former aim, consecutive patients who were due to undergo intestinal biopsy for suspected diagnosis of CD were enrolled: according to the final diagnosis, these patients were divided into two groups: Group 1 comprised 91 newly diagnosed CD patients (40 males; age range 7 months to 84 years), Group 2 included 100 subjects with diseases other than CD (44 males; age range 9 months to 76 years). For the latter aim, we also studied 21 CD patients on a gluten-free diet after 16-123 months (8 males; age range 3-51 years), with normal intestinal architecture (Group 3) and 22 patients who served as controls (12 males; age range 4-60 years) with gastroesophageal reflux disease-like symptoms (Group 4). All patients underwent determination of serum anti-gliadin (AGA) and EmA antibodies, histology evaluation of the intestinal biopsies and EmA assay in the supernatants of in vitro gliadin-challenged duodenal mucosa.
Results: EmA assay in the supernatants showed a sensitivity and specificity of 96% and 100%, respectively; these were not significantly different from those observed for serum EmA (88% and 99%, respectively). However, EmA assay in the supernatants was useful in CD patients with mild intestinal histology lesions (infiltrative/hyperplastic type): in this subgroup it was positive in 9/12 of cases, but serum EmA was positive in only 2/12. As regards the reliability of the in vitro gliadin challenge, EmA production in supernatants was recorded only in 10/21 CD patients on a gluten-free diet. The patients with a positive in vitro challenge had a higher number of intra-epithelial lymphocytes than patients with a negative challenge.
Conclusions: 1) EmA assay in the medium of cultured intestinal biopsy can detect gluten-sensitive enteropathy, characterized by an infiltrative/hyperplastic histological pattern, which is often associated with negative serum EmA. 2) The in vitro challenge in CD patients on a gluten-free diet detects EmA production in the culture medium only in half of the cases and other studies must be performed to evaluate whether EmA production after in vitro challenge can be considered a reliable test for confirming CD diagnosis.