Fig. 1

Levels of interferon (IFN)-induced gene expression in the participant subsets, stratified by diagnosis. a IFN-induced gene expression was quantified in whole peripheral blood RNA using NanoString technology and the normalized levels of five ubiquitously expressed IFN-induced genes summed to produce an IFN5 score. Results to the left of the figure are shown for healthy control subjects (Control), individuals who were asymptomatic anti-nuclear antibody–positive (ANA⁺), and patients who had undifferentiated connective tissue disease (UCTD) and early systemic autoimmune rheumatic disease (SARD). Significant differences from healthy control subjects are indicated as * p < 0.05, ** p < 0.01 and *** p < 0.001. Results to the right of the figure show the IFN5 scores for the different early SARD patient subsets with the significant differences between groups indicated. b IFN5 scores for different ANA⁺ subject subsets, stratified by ethic group. c Expression levels of two IFN-β-induced genes (EIF2AK2 and PLSCR1) and BAFF in whole peripheral blood. Significant differences from healthy control subjects are indicated. d Correlation between EIF2AK2 and BAFF levels and IFN5 score for the different ANA⁺ subsets. Solid lines indicate linear regression curves. For all panels, dashed lines represent 2 SD above the mean for healthy control subjects. e Correlation between serum IFN-α levels as measured by enzyme-linked immunosorbent assay and IFN5 scores for the different ANA⁺ subsets. Solid lines indicate linear regression curves. SSc Systemic sclerosis, SS Sjögren’s syndrome, SLE Systemic lupus erythematosus, DM Dermatomyositis, MCTD Mixed connective tissue disease