IL6 and rheumatoid arthritis: Significantly elevated serum IL-6 levels were observed in patients with RA compared with the control group (1.7 (1.6–2.6) pg/ml, P < 0.001), and the difference in levels in the two RA groups (active RA group, 27.6 (12.0–51.4) pg/ml; inactive RA group, 7.7 (3.2–15.0) pg/ml) was also significant (P < 0.01) (Fig. 3, IL-6 levels are shown on a logarithmic scale).