DEFICIENT INTERLEUKIN-2 DEPENDENT PROLIFERATION PATHWAY IN T-LYMPHOCYTES FROM ACTIVE AND INACTIVE ULCERATIVE-COLITIS PATIENTS

There is increasing evidence that ulcerative colitis is associated wit h, an abnormality of the immune system. Although the aetiology remains unknown, it has been suggested that the immune system of these patien ts is implicated in the pathogenesis of their disease. T cell function was investigated in ulcerative colitis patients and defective phytoha emaglutinin induced T cell mitogenesis was found. The DNA synthesis in duced by stimulation with phorbol esters ionophore (ionomycin), howeve r, was normal. These changes cannot be ascribed to either decreased in terleukin 2 synthesis or to a defective interleukin 2 receptor express ion after cellular activation. Moreover, this defective proliferative response of the T lymphocytes was observed even in the presence of sat urated concentrations of exogenous interleukin 2. These results emphas ise that the interleukin 2 dependent proliferation pathway is deficien t in T lymphocytes from ulcerative colitis patients.