Comparison of Radioimmunoprecipitation With Luciferase Immunoprecipitation for Autoantibodies to GAD65 and IA-2β

OBJECTIVE: To compare the sensitivity and specificity of luciferase immunoprecipitation (LIPS) with radioimmunoprecipitation (RIP) for the measurement of autoantibodies to the type 1 diabetes autoantigens glutamic acid decarboxylase 65 (GAD65) and insulinoma-associated protein (IA)-2β. RESEARCH DESIGN AND METHODS: Sera from 49 type 1 diabetic patients and 100 nondiabetic control subjects from Diabetes Antibody Standardization Program 2007 were used to screen for autoantibodies to GAD65. An additional 200 type 1 diabetic patients and 200 nondiabetic control subjects were used to validate the GAD65 results and screen for autoantibodies to IA-2β. RESULTS: LIPS showed equal sensitivity and specificity to RIP for detecting autoantibodies to GAD65 and IA-2β. Receiver-operating characteristic analysis revealed that the detection of autoantibodies to GAD65 and IA-2β by LIPS and RIP were not statistically different. CONCLUSIONS: The LIPS assay does not require the use of radioisotopes or in vitro transcription/translation and is a practical alternative at the clinical level for the RIP assay.