Lymphocytes in Control Ileum and Colon and in Inflammatory Bowel Disease

Using monoclonal antibodies to T and B lymphocytes, to natural killer cells, and to HLA-DR antigen, we characterized the lymphocyte population within the epithelial and lamina propria regions in control intestine and colon, and in grossly involved and in grossly uninvolved intestine and colon of patients with active inflammatory bowel disease. There were significantly more intraepithelial T cells in control ileum than in control colon. In comparison to control, there was a heterogeneity ofalterations in intraepithelial and lamina propria T lymphocyte subsets (Tll +, T8 +, T4 +) in inflammatory bowel disease. B lymphocyteS were not detected within the lamina propria, except when found in and adjacent o lymphoid aggregates. Leu 7 + cells were uncommon i the lamina propria of control ileum and colon and in diseased tissues. The majority of intraepithelial lympho-cytes did not express HLA-DR. Epithelial cells of control colon did not express HLA-DR w,hile epithelial cells of control ileal tissues and of diseased colonic and ileal specimens expressed HLA-DR antigen. Only small numbers of lamina propria T cells expressed HLA-DR in both control and disease tissues. There was intense xpression of HLA-DR by monocytes and modest expression of HLA-DR by capillary and lymphatic endothelia