Relation between HLA-DR-like antigens and secretory component (SC) in jejunal epithelium of patients with coeliac disease or dermatitis herpetiformis.

HLA-DR-like antigens and secretory component (SC) were localized immunohistochemically in adjacent tissue sections of ethanol-fixed paraffin-embedded jejunal mucosa from control subjects and patients with coeliac disease (CD) or dermatitis herpetiformis (DH). HLA-DR-like antigens were found in a patchy distribution apically in the columnar epithelial cells facing the gut lumen and in the upper part of the crypt epithelium. The staining pattern was similar in controls and patients with CD or DH. SC was normally most abundant in the crypt epithelium but the concentration of SC in the surface epithelium increased with increasing villous atrophy both in CD and DH patients. Despite this sign of immaturity, the surface cells retained their capacity to express HLA-DR-like antigens in the pathological mucosa.