Human umbilical vein endothelial cells: A new easily available source of endomysial antigens

Objective: To evaluate human umbilical vein endothelial cells (HUVEC) as an alternative source of endomysial antigen (EmAg) and to assess their suitability for the detection of endomysial antibodies (EmA) in coeliac disease (CD). Methods: HUVEC were reacted on glass slides with patient sera and examined by fluorescent microscopy. Flow cytometry was used to determine whether the EmAg was expressed on the surface of the cells or was intracellular. Absorption studies were used to confirm the specificity of results. Results: The data presented here show that HUVEC contain an intracellular antigen that binds to immunoglobulin A (IgA) from patients with active CD. Correlation studies showed that HUVEC antibodies were present in the sera of all patients that contained EmA and reticulin IgA antibodies whereas reticulin antibodies were only present in 24 of the 31 patients who were either EmA or HUVEC positive. All of the sera tested which were negative for EmA were also negative for HUVEC antibodies. Ten patients with Crohn's disease and 10 patients with ulcerative colitis were negative for HUVEC or EmA reactivity, as were 16 control subjects attending the gastroenterology clinic with non-specific symptoms and normal small intestinal biopsies. Conclusions: These findings suggest that the antigen found in HUVEC is antigenically similar to that found in reticulin and endomysium and that all three antigens may be the same. In contrast to the monkey oesophagus, HUVEC offer an easily available antigen for the serological diagnosis of coeliac disease.