IL15 and rheumatoid arthritis: At the UA stage, IL-15 levels differentiated future RA patients from those who did not develop RA (non-RA patients) more accurately (AUC = 0.814, SE = 0.067, 95% CI:0.682–0.947; p < 0.001) than RF (AUC = 0.750, SE = 0.076, 95% CI:0.602–0.898; p = 0.001) or anti-CCP Abs (AUC = 0.684, SE = 0.075, 95% CI:0.538–0.830; p = 0.014) (Figure 3).