ABNORMALITY OF SUPPRESSOR T CELLS IN ULCERATIVE COLITIS AND ITS RELATIONSHIP TO INTERLEUKIN 2 (IL2)

Abstract

T cell subsets of peripheral blood lymphocytes (PBL) were examined in 30 patients with ulcerative colitis (UC) by a fluorescence activated cell sorter (FACS), using monoclonal antibodies to suppressor/cytotoxic (anti-Leu-2a) and helper/inducer (anti-Leu-3a) T cells. Leu-2a positive T cells were decreased in PBL from patients with active UC (9.1±5.6%, p<0.001) compared with normal controls (24.6±3.7%). Con A-induced suppressor T cell activity was decreased in patients with active UC whose Leu-2a positive cells in PBL were decreased. We examined the ability of PBL from patients with UC to produce and respond to exogenous interleukin 2 (IL2). IL2-production was normal in patients with active UC, while they had a decreased response to exogenous IL2. Moreover it was proven that the hyporesponsiveness was due to inadequate expression of IL2-receptors on the surface of Leu-2a positive T cells. These results suggest that decrease in the number and function of suppressor T cells demonstrated in patients with UC is caused by a disturbance in differentiation and prolieferation of suppressor T cells. The abnormality of suppressor T cell may play a role in the immunological disorders of patients with UC.