HLA-associated cellular response to GAD in type 2 diabetes with antibodies to GAD

Proliferative response of peripheral blood mononuclear cells (PBMC) to glutamic acid decarboxylase (GAD), which has been reported in patients with type 1 diabetes, was measured in type 2 diabetes, especially in patients with antibodies to GAD initially diagnosed as having type 2 diabetes (anti-GAD+ type 2 diabetes). We studied 12 patients with type 1 diabetes, 22 with anti-GAD+ type 2 diabetes, 31 with type 2 diabetes who were negative for anti-GAD (anti-GAD+ type 2 diabetes), and 30 healthy control subjects for cellular responses in vitro to GAD. The mean stimulation index (SI) in response to GAD was significantly higher in type 1 diabetes than in anti-GAD+ type 2 diabetes or healthy controls (1.47+/-0.35 vs. 1.11+/-0.35, P<0.05, and 1.06+/-0.07, P<0.05, respectively). The mean