GAD2 and type 1 diabetes mellitus: The apparent association constants (AAC) indicate greater affinity of IgG from retinopathic T1D patients (1.90 × 10-6 M) followed by nephropathic (1.81 × 10-6 M) and uncomplicated (3.11 × 10-7 M) T1D patients for ROS-GAD65 compared to N-GAD65.