T cell and OKM1-positive monocyte populations in the intestinal lamina propria mucosae and in the peripheral venous blood in Crohn's disease.

Nineteen patients with Crohn's disease were examined prior to operation. Peripherally circulating mononuclear cells were examined for the presence of the cell surface markers recognized by monoclonal antibodies OKT3, OKT4, OKT8 and OKM1. After surgical treatment samples of the mucosal lesions were obtained from the resected bowel segments of these patients. The inflammatory infiltrate in the lamina propria mucosae was examined immunohistologically for the presence and distribution of the cell surface markers recognized by Dako T11, OKT4, OKT8 and OKM1. In comparison to normal controls, the patients with Crohn's disease had a relative peripheral lymphocytopenia with a relative monocytosis. The intestines afflicted by active Crohn's disease showed a significant increase in macrophages and T cells in the lamina propria mucosae; both T helper and T suppressor cell populations had equally increased without a significant change in the T helper/suppressor ratio. These findings suggest a change in the equilibrium state between intravascular and intestinal mucosal lymphocytes and monocytes in the active phase of the disease. The new equilibrium can be characterized as an intestinal lymphomonocytosis with a relative lymphocytopenia and monocytosis in the peripheral blood.