The occurrence of gastric and duodenal auto-antibodies in peptic ulcer disease.

The possible relationship between peptic ulcer and the occurrence of auto-antibodies was investigated by means of an enzyme-linked immunosorbent assay (ELISA). Sera from 24 patients with active duodenal ulcer were analysed using cells and subcellular fractions from pig gastric acid duodenal mucosa for binding of immunoglobulins. Four sera (17%) reacted with a homogenate from duodenal mucosa. Nine sera (38%) were found to contain auto-antibodies against gastric mucosal cells. The cell-reactive auto-antibodies were shown to bind preferentially to parietal cells and chief cells. In these cells the antigens were identified as H, K-ATPase and pepsinogen respectively. Six sera were positive against purified H,K-ATPase; 12 sera were positive against pepsinogen, and only one of these sera reacted with both H,K-ATPase and pepsinogen. The results show that auto-antibodies are formed in a large fraction of patients (18/24; 75%) with peptic ulcer disease. The present study further demonstrates that enrichment of antigenic structures is required for obtaining a satisfactory sensitivity in the assay.