Mucosal mast cells in reflux gastritis and chronic (type B) gastritis.

The histological features that characterize alkaline reflux gastritis are typical of the histamine-mediated response to tissue injury. We have investigated this in nine patients with symptomatic reflux gastritis following partial gastrectomy for duodenal ulcer by determining the gastric mucosal mast cell count before and after Roux-en-Y biliary diversion. Following diversion, the histological picture changed from that of reflux gastritis to type B chronic gastritis in all cases. The mean mucosal mast cell count in all patients was 47.57/mm2 before diversion and 123.33/mm2 after diversion (P less than 0.05). Analysis of the paired data, in which eight out of nine patients showed a rise in mucosal mast cell numbers following bile diversion, also showed a significant difference before and after surgery (P less than 0.01). The gastric mucosal mast cell count is significantly less in reflux gastritis than in type B chronic gastritis. This is most likely to be due to increased degranulation, which would explain why striking vascular changes occur in the absence of inflammatory cell infiltration in reflux gastritis.