Ultrastructural changes suggestive of immune reactions in the jejunal mucosa of coeliac children following gluten challenge.

The jejunal mucosa of eight coeliac children on a gluten-free diet and two non-coeliac children was studied by light and electron microscopy two to 98 hours after a single challenge dose of gluten. In all coeliac patients the early cytopathological reactions were principally confined to the structures within the subepithelial connective tissue. Changes were observed in the connective tissue fibrils, the basement membranes of epithelial and endothelial cells, the endothelium of small blood vessels, and the type and degree of inflammatory cell infiltration. The timing of these reactions was compatible with the concept that gluten acts as an antigen and combines with antibody in the form of immune complexes in the connective tissue close to the epithelium and to small blood vessels. These changes appeared to precede epithelial cell damage. No subepithelial tissue changes were seen in the non-coeliac patients after gluten challenge.