[The demonstration and specificity of autoreactive T-lymphocytes in type-1 diabetes]

Type 1 diabetes is characterised by a chronic autoimmune process predominantly transmitted by T-cells. Yet current knowledge about autoimmune reactions in type 1 diabetes transmitted by antigen-specific T-cells is very limited. In this study we investigated T-cell reactivity to potential autoantigens and their immunodominant epitopes in patients with type 1 diabetes and in control groups.

Using 3H-thymidine incorporation in peripheral blood lymphocytes in patients with type 1 (group 1) or type 2 (group 2) diabetes, healthy controls (group 3) and healthy twins of type 1 diabetics (group 4), cell reactivity was measured to the proteins insulin and glutamate decarboxylase (GAD) 65 and against the peptides of insulin, GAD 65, heat shock protein (HSP) and bovine serum albumin (BSA).

Patients with type 1 diabetes had a significantly higher stimulation of peripheral T-lymphocytes by GAD 65 and a mixture of selected GAD 65 peptides than healthy controls. There was no significant difference between the groups with regard to the stimulation of peripheral blood lymphocytes by insulin, individual GAD peptides or insulin, HSP- and BSA-peptides.

Autoantigen-specific T-lymphocytes can be demonstrated in blood of type 1 diabetics. The necessary tests for this are at present relatively cumbersome and therefore limited to special research laboratories. But in the future their identification in autoimmune diseases, such as type 1 diabetes, will be a valuable addition to the demonstration of antibodies in which, even in the prediabetic phase, possibly protective and cytotoxic immune reactions can be distinguished.