T-lymphocyte subsets and their cytotoxic capacity in patients with type I and type II diabetes mellitus.

: Distribution and cytotoxic function of lymphocyte subpopulations were studied in 20 patients with type I, in 20 patients with type II diabetes mellitus and in 40 control subjects. The percentage, the absolute number of (EA), (E Thr), (TM) subsets and the rate of (E Thr) (E Ths) and (TM/) (TG) cells were found to be higher in type I and lower in type II diabetic patients than in controls. This opposite tendency in the distribution of T-lymphocyte subsets may be related to the duration of diabetes. Simultaneously a significant cytotoxic capacity of U, null, T, (TG)-lymphocytes was observed against human pancreas extract-coated targets in almost all 18 out of 20 of type I, but only in a few cases (5 out of 20) of type II diabetic patients. These five patients needed insulin therapy six months later. The T and (TG)-lymphocytes had the largest killer activity in both diabetic groups. Lymphocyte-mediated cytotoxicity seems to be a specific method which is suitable for the study of in vitro sensitization against pancreas tissue, and it might predict insulin dependency in type II diabetic patients.