Suppressor cell activity and beta-cell function in insulin-dependent diabetics

Immunological mechanisms may play a role in the pathogenesis of insulin-dependent diabetes mellitus (IDDM), and suppressor cell activity (SCA) has been found depressed at diagnosis. The aim of the present study was to elucidate whether patients with preserved beta-cell function display a different SCA than other patients. Sixteen patients without and 12 patients with beta-cell function after averagely 9 years' duration of IDDM were examined. The suppressive effect of lymphocytes was investigated after incubation with concanavalin A followed by inactivation. Suppression was measured as the ability of the lymphocytes to inhibit 3H-thymidine incorporation in concanavalin A stimulated normal donor lymphocytes. The main findings were: (1) No significant differences in SCA between patients with and without beta-cell function, and one of these patient groups had SCA significantly different from normal controls. (2) A correlation between SCA and administered dose of insulin among patients without beta-cell function. It is concluded that the actual SCA several years after diagnosis is not connected with the beta-cell function in patients with IDDM.