IFI16 and rheumatoid arthritis: With the cut-off value set to the 95th percentile of the control population (27 ng/ml), mean IFI16 levels were significantly increased in patients with SSc, SLE, RA, and SjS compared to the control group (4.7 ng/ml) (SSc: 25.4 ng/ml, p<0.001; SLE: 23.5 ng/ml, p<0.001; RA: 222 ng/ml, p<0.001; SjS: 88.2 ng/ml, p<0.001).