ABO (H) blood group antigen expression in gastric mucosa.

The A, B, O (H) blood group antigens (BGA) are glycolipids present in the plasma membranes of many different epithelial cells. Alterations in BGA expression have been described in malignant tumors and premalignant lesions. We have studied ABO (H) BGA expression in paraffin sections of gastric specimens using immunofluorescence techniques with monoclonal antibodies. 102 patients were studied. 15 with normal mucosa (NM); 16 with duodenal ulcer (DU); 23 with gastric ulcer (GU); 11 with pernicious anaemia (PA) and 37 with adenocarcinoma (AC). The expression of BGA in normal gastric mucosa is detected in surface epithelium, mucoid cell neck glands and parietal cells as well as 2/3 of antral glands. BGA expression in DU gastritis is very similar to that seen in NM. In atrophic chronic gastritis associated with GU and PA there is a significant decrease in BGA expression. In patients with PA, BGA expression is greater in antral mucosa than in fundic mucosa. Loss of BGA expression is more pronounced in atrophic chronic gastritis surrounding AC. Intestinal metaplasia shows variable BGA expression. Our results support the hypothesis that loss of BGA expression by epithelial gastric mucosal cells may be related to alterations in cellular differentiation and premalignant potential.