Glycaemic control and suppressor cell activity in patients with insulin-dependent diabetes mellitus.

Suppressor cell activity (SCA) in patients with insulin-dependent diabetes mellitus (IDDM), has been found depressed at diagnosis and normal in the remission period. To investigate whether poor metabolic control as seen at diagnosis influences SCA, two groups of patients in poor glycaemic control were examined. Group 1 consisted of nine patients with IDDM of 27±4 months, with a mean glucosuria of 84±19 (s.e.m.) g/24 hr. Group 2 comprised eight patients with newly diagnosed IDDM, examined for the first time 4±1 days after diagnosis, when having a mean glucosuria of 43±14 g/24 hr. After 1 week of hospitalization with strict glycaemic control resulting in a massive reduction of the glucosuria (group 1 now showing 0±0 g/24 hr, group 2, 16±5 g/24 hr), the patients were re-examined. SCA was investigated for the third time after approximately 4 weeks (group 1) and after 5 months (group 2), when the patients were outpatients (glucosuria: group 1, 61±20 g/24 hr; group 2, 17±6 g/24 hr). 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 H-thymidine incorporation in concanavalin A-stimulated normal donor lymphocytes. There were no significant differences in SCA between the first (group 1,25±7; group 2, 22±11) and the second (group 1, 22±8; group 2, 15±5) examination. At the third examination, group 1 patients displayed 35±5, and group 2 patients, now being in the remission period, 44±4. Only the third value of group 2 patients was significantly higher than the second value (<0·01). SCA of healthy controls were 35±3. It is concluded that short-term effects on SCA of improvement of the glycaemic control are unlikely, at least in patients without severe ketoacidosis. On the other hand, late effects on SCA of good metabolic control, after weeks or months, could not be excluded.