Dermatitis herpetiformis and gluten sensitive enteropathy (including celiac disease)--increased subepithelial extracellular matrix viscosity due to gliadin.

It is now firmly established that dermatitis herpetiformis (DH) is associated with gluten sensitive enteropathy (GSE), although the GSE of DH is generally milder than that form which occurs in celiac disease. The toxic fraction of gluten is in the gliadin, a protein fraction. Gliadin is absorbed in GSE and antigliadin antibodies are present in both DH and celiac disease. There is a question of a cross reactivity between reticulin and gliadin. Gliadin is reported to bind to reticulin. Reticulin has a glycosaminoglycan component. Fibronectin, another component of ground substance, also binds to reticulin. Reticulin and fibronectin are important in basement membrane areas and play a role in basement membrane attachment. Gluten may also exert a lectin effect on gastrointestinal mucosa which contributes to the underlying extracellular matrix. DH and GSE have different pathologies because of their different anatomical sites. The pathomechanisms of both diseases can be explained by one mechanism. Gliadin, or a peptide fraction from it, enters or combines with the extracellular matrix and increases tissue viscosity. The protein fraction of glycosaminoglycans in the extracellular matrix is known to control viscosity. In DH the increased extracellular matrix viscosity would interfere with the diffusion of tissue fluid in the dermal papillae and leads to vesicle formation. The intestinal villi serve a very different function. In GSE the increased extracellular matrix viscosity would decrease adsorption from the intestinal tract producing villi with less volume (shortened or atrophic). The shortened villi decrease the production of digestive enzymes and the absorptive surface. The decreased movement of nutrient tissue fluid supplied to the intestinal epithelial cells also eliminates the microvilli.(ABSTRACT TRUNCATED AT 250 WORDS)