[Interepithelial lymphocytes of the gastric mucosa in peptic ulcer].

Unlike intestinal interepithelial lymphocytes (IEL), gastric IEL have not been studied. Gastric mucosa from 27 stomachs resected for peptic ulcer was examined. The intact high prismatic superficial epithelium contained 51.38 +/- 4.39 IEL per 1000 epitheliocytes, foveolar epithelium 56.31 +/- 5.77. In chronic gastritis, in both superficial and foveolar epithelium the number of IEL was increased nearly 3-fold and was 161.3 +/- 21.08 and 154.81 +/- 15.03, respectively. In these cases the number of lymphocytes in lamina propria did not increase. The increase in the number of IEL correlated with a marked increase of plasma cells in lamina propria and with rapid epithelial proliferation. The epithelium lining of the stomach as well as that of the small intestine is the site of differentiation of the immunological activity of lymphoid cells as indicated by mitosis figures in IEL as well as the presence in superficial epithelium of plasma cells the appearance of which may be explained by disorders in differentiation of B-lymphocytes and maturation of plasma cells in the epithelial sheet. Infiltration of proliferating epithelium with IEL suggests that they take part in stimulation of cell renewal in gastric mucosa.