CDSN and rheumatoid arthritis: As shown in Fig. 1a, mean levels of calprotectin were significantly higher in patients with AOSD (55.26 ± 18.0 ng/ml), RA (39.17 ± 18.90 ng/ml), pSS (35.31 ± 19.47 ng/ml), SLE (32.21 ± 25.01 ng/ml), OA (19.24 ± 10.67 ng/ml), compared to HCs (8.46 ± 5.17 ng/ml); all the differences were statistically significant (p < 0.001).