Activated lymphocytes in patients with newly diagnosed type 1 (insulin-dependent) diabetes mellitus.

The expression of activation antigens (transferrin receptor, IL-2 receptor and Ia antigen) on circulating T lymphocytes from Japanese children with Type 1 diabetes was studied using five monoclonal antibodies (Ab), OKT9, anti-Tac Ab, OKIa1, anti-human HLA-DR Ab and OKT3. For detecting Ia positive T cells, the dual staining technique using OKT3 and anti-Ia antibody was employed. Four out of six patients (67%) with newly diagnosed Type 1 diabetes showed a raised level of either OKT9 or Tac positive cells when examined at diagnosis. These patients, however, rapidly lost these activation antigens after the insulin therapy was started. In contrast, in 32 long-standing patients, only 2 (6%) had a high percentage of OKT9 positive cells and none of them demonstrated Tac positive cells. One out of six newly diagnosed patients or three out of 21 long-standing patients had a significantly high percentage of Ia-positive T cells compared with normal subjects. In poorly controlled long-standing patients whose HbA1 value was higher than 14%, none of them had an increased number of activated lymphocytes. Therefore, it is unlikely that insulin deficiency and hyperglycemia were responsible for the changes observed in these studies. Activated lymphocytes might be related to activation of the immune system involved in pathogenesis of Type 1 diabetes.