IL6 and rheumatoid arthritis: The serum level of IL-6 was 21.5 ± 30.3, 43.3 ± 55.6, 102.6 ± 82.8, 26.7 ± 29.9, and 1.2 ± 2.6 pg/mL in DM, SLE, RA, SS patients, and healthy controls, respectively.