Detection and Characterisation of Anti-Endomysial Antibody in Coeliac Disease Using Human Umbilical Cord

Abstract

Objectives: To verify the effectiveness of human umbilical cord (HUC) in the detection of anti-endomysial antibodies (AEA) in coeliac disease and to characterize further these antibodies by studying tissue adsorption characteristics and antibody inhibition studies. Methods: AEA were detected on HUC and primate oesophagus in a blind study, using sera from 46 patients with untreated coeliac disease and 108 controls. Tissue adsorption studies were performed using homogenized tissue from rodent liver, HUC, primate oesophagus and human liver. Sera were adsorbed with each of these homogenates and antibody was detected using HUC, primate oesophagus and rat kidney. In the inhibition experiments AEA was detected on HUC, and inhibition of binding was attempted by pre-incubating the sections with antibodies against collagen types I, III and IV. Results: The sensitivity of AEA was 91% when detected on HUC, 89% when detected on primate oesophagus (93% and 91%, respectively, after exclusion of 1 patient with IgA deficiency). Specificity was 100% for both assays. Tissue adsorption studies showed identical results for AEA detected on both HUC or primate oesophagus, whereas antireticulin antibody was adsorbed only by rodent tissue. Blocking of the HUC with anticollagen antibodies did not prevent binding of AEA. Conclusions: HUC is an effective substrate for the detection of AEA and may be superior to primate oesophagus. The antibody detected by HUC shows identical tissue adsorption specificities to that detected on primate oesophagus.

A genome‐wide family‐based linkage study of coeliac disease

“…IgA and IgG AGA were measured by ELISA, while EmA were detected by immunofluorescence using human umbilical cord. Both assays were performed within our laboratory, and have been previously shown to have sensitivities and specificities in excess of 90 % (Yiannakou et al 1997). Five individuals tested positive and were asked to have a duodenal biopsy.…”

Determination of Anti-?-Gliadin Antibodies in Serologic Tests for Coeliac Disease

“…EMA determination, using either monkey oesophagus or human umbilical cord, is the most specific test available so far (3,21). However, these immunofluorescence tests are not easy to apply as a screening method for the general population.…”

“…Consequently, it is not easy to apply on a wide scale. Partly, these problems can be solved by using human umbilical cord as an alternative substrate to determine EMA (3). Besides, some reports have warned about a considerable number of false-negative results in EMA determination (4).…”

Recent advances in coeliac disease

“…They include anti-gliadin antibodies (both IgG and IgA class), and the antiendomysial (EMA) IgA test. The latter has excellent specificity, approaching 100%, 11,12 although other groups have reported a lower sensitivity, if the test is used alone (74-93%). [12][13][14] Sensitivity partly reflects the problem of selective IgA deficiency among patients with coeliac disease, which affects 2-3% of sufferers, as this can cause false negative EMA IgA testing.…”

“…The latter has excellent specificity, approaching 100%, 11,12 although other groups have reported a lower sensitivity, if the test is used alone (74-93%). [12][13][14] Sensitivity partly reflects the problem of selective IgA deficiency among patients with coeliac disease, which affects 2-3% of sufferers, as this can cause false negative EMA IgA testing. Untreated coeliac disease patients with selective IgA deficiency commonly have positive IgG1 EMA and IgG tissue transglutaminase (tTG) antibodies (tissue transglutaminase being the antigen for endomysial antibodies).…”