DERMATITIS-HERPETIFORMIS - AN AUTOIMMUNE-DISEASE DUE TO CROSS-REACTION BETWEEN DIETARY GLUTENIN AND DERMAL ELASTIN

Dermatitis herpetiformis (DH), is associated with skin eruptions and g ranular depositions of IgA in the papillary dermis, but this is not a feature of coeliac disease (CD). The specificity of the IgA in the ski n is unknown. High molecular weight glutenin (HMW-g), a component of g luten, has been shown to have structural similarities to human elastin . This paper reports immunoadsorption studies which suggest that human serum may contain antibodies which cross-react with HMW-g and elastin . DH patients had significantly lower levels of IgA antibodies to HMW- g and to elastin than both CD patients and healthy controls. Furthermo re, introduction of a gluten-free diet (GFD) was associated with a fur ther reduction in the amount of IgA antibodies to elastin in the DH pa tients. This diet-associated decrease of elastin antibodies was restri cted to the IgA isotype. A significant correlation was observed betwee n IgA antibodies to HMW-g and elastin in healthy controls and CD patie nts, while no such correlation was found in patients with DH. These fi ndings could indicate that HMW-g induces production of antibodies to e lastin, which are deposited in the skin, and that when the antigenic s timulus is removed, these antibodies are further reduced due to contin uous dermal deposition. It is postulated that DH may be an autoimmune disease due to cross-reactivity between dietary glutenin and dermal el astin.