Alterations of Peripheral T-lymphocyte Subpopulations in Patients with Insulin-dependent (type 1) Diabetes Mellitus

Subpopulations of peripheral T-lymphocytes were studied in two groups of patients with insulin-dependent diabetes mellitus (IDDM): eleven newly diagnosed diabetics and twenty-one patients having diabetes of long duration (13 +/- 1 yr). Monoclonal antibodies to the surface antigens of helper (OKT 4) and suppressor (OKT 8) T-cell subsets and to a common T-cell antigen (OKT 3) were used. The percentage of suppressor T-lymphocytes were found reduced in both the newly diagnosed patients (p less than 0.001) and the patients with long-term IDDM (p less than 0.05) in comparison with 16 age-matched healthy control persons. Furthermore, the newly diagnosed diabetics showed a lower percentage of suppressor T-cells (p less than 0.05) and a higher amount of helper T-cells (p less than 0.01) than the patients with long-term diabetes. Concerning the percentage of the total number of T-cells and the absolute number of lymphocytes, there were no significant differences between the patient groups and the controls. As earlier studies have pointed to the significance of immune reactions in diabetogenesis, a pathogenetic importance of the observed imbalance of subpopulations of T-lymphocytes in IDDM should be considered.