Anti-Endomysial Antibodies (Anti-EMA)

IgA anti-endomysial antibodies remain the most specific test for coeliac disease or dermatitis herpetiformis. IgA anti-tTg antibodies are the same as most IgA anti-endomysial antibodies. They are more sensitive but slightly less specific than anti-endomysial antibodies. Since anti-tTg can be readily automated, this test is used as a screening test.All sera positive for IgA anti-tTg antibodies are assayed for IgA anti-endomysial antibodies. Both assays are far more sensitive and specific than the anti-gliadin antibody tests that used to be used. The endomysium is the term given to the connective tissue surrounding the smooth muscle bundles of many tissues. Anti-endomysial antibodies are detected using monkey oesophageal tissue. The antigens are generated by the effect of tissue transglutaminase which modifies glutamine residues in proteins to glutamic acid. The same process occurs in wheat gluten and explains the link between antibodies to gluten and autoantibodies to the gut.