Epithelial HLA-DR expression and lymphocyte subsets in gastric mucosa in type B chronic gastritis.

Lymphocyte subpopulations (B, T4, T8), monocytes/macrophages (LeuM5, KiM5) and HLA-DR antigen expression were studied immunohistochemically in frozen sections from 32 antral and 37 fundal biopsies of type-B chronic gastritis. Aberrant HLA-DR antigen expression in epithelial cells of gastric mucosa was found in all cases closely related to mononuclear infiltrates. Epithelial HLA-DR expression and mononuclear infiltrates were practically absent in foci of intestinal metaplasia. These findings suggest that an immunopathologic mechanism probably plays a role in initiation or perpetuation of type-B chronic gastritis.