Suppressor cell activity in patients with newly diagnosed insulin-dependent diabetes mellitus: a prospective study

Suppressor cell activity (SCA) was investigated longitudinally, at the time of diagnosis and during the remission period, in 17 patients with insulin-dependent diabetes mellitus (IDDM). The suppressive effect of lymphocytes from patients 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: I. SCA was reduced, on the average, at diagnosis but normal during the remission period. II. Patients with the lowest SCA at diagnosis showed significantly lower C-peptide values during the remission period than other patients. III. No relationship was found between on the one side various tissue types and on the other SCA, C-peptide values, insulin dose, and degree of glucaemic control, neither at diagnosis nor during remission. Previous studies have pointed to the significance of immune reactions in diabetogenesis. The findings in the present study may associate SCA with the development of IDDM.