IgA anti-endomysial antibodies in dermatitis herpetiformis: correlation with jejunal morphology, gluten-free diet and anti-gliadin antibodies.

Circulating IgA-class anti-endomysium antibodies (EmA) can be detected by indirect immunofluorescence on monkey oesophagus sections. We found EmA in 22 (76%) of 29 patients with dermatitis herpetiformis (DH) on a normal, gluten-containing diet. The highest frequency (100%) of EmA was observed in patients with sub-total villous atrophy. IgA-class antigliadin antibodies (AGA) were found using an ELISA method in 59% of 29 DH patients and in 86% of those with sub-total villous atrophy. There was a significant correlation between EmA titres and AGA levels in individual patients. Gluten-free diet (GFD) treatment caused a rapid decrease in EmA titres; only three of the 12 patients still showed raised EmA after 6-12 months on a GFD and two of these three had failed to adhere to a strict diet. In contrast, no decrease in EmA titres occurred in four patients maintained on a normal diet, and two of the three patients with initially negative EmA developed positive titres when continuing on a normal diet. These results show that both IgA-class EmA and AGA are good indicators of jejunal damage in DH. The rapid fall of EmA titres after gluten withdrawal indicates that this test is also useful for monitoring a patient's adherence to a GFD.