Index of IFN-a Ab’s in different patients groups. Anti-IFN a autoantibodies showed significant specificity in APS1 patients. Serum was diluted in 1:10 and measured by europium-based fluorescence. Each point presents the mean index of the duplicated well for that individual sample. The bar indicates the mean value for each cohort. APS1, n=7; non-APS1, n=6; normal controls, n=100; Addison’s Disease, n =71; Type 1 diabetes, n=141.