CTSS and rheumatoid arthritis: Most importantly, cathepsin S expression significantly correlated with the pro-inflammatory inducible ADAR1p150 isoform (r = 0.623, P = 0.004), as well as with the RNA editing rate of 12 individual adenosines within cathepsin S AluSx+ (r = range 0.461–0.716, P ≤ 0.05 for all; Supplementary Table 1) and mean RNA editing rate (r = 0.589, P = 0.008, Fig. 4C) in active RA.