Flow cytometry for the analysis of T cells expressing CD69 after stimulation with glutamic acid decarboxylase.

Type 1 diabetes mellitus is a T-cell mediated autoimmune disease in which the insulin-producing pancreatic beta cells are selectively destroyed. We recently found that the detection of cell-mediated immune response to glutamic acid decarboxylase (GAD) was more useful than the detection of specific autoantibodies for the diagnosis of type 1 diabetes mellitus. In this study, we established a flow cytometric analysis for the detection of activated T cells in whole venous blood, obtained from diabetic patients and normal controls after stimulation by GAD. Two millitiers of peripheral venous blood and 6 hours incubation time were used for performing the test. It was found that 33% (3/9) type 1 diabetic patients, 7.7% (1/13) type 2 diabetic patients and neither patients with fibrocalculous pancreatopathy nor normal controls had > or = 20% CD8+ T cells expressing CD69. The results suggest that flow cytometry may be a useful tool for the detection of surrogate markers of type 1 diabetes mellitus.