IL6 and rheumatoid arthritis: To determine the possible correlation of these altered miRNAs with secreted cytokines in RA patients, we measured the levels of IL-2, IL-4, IL-6, IL-10, IFN-γ and TNF-α in both SF and serum of RA patients and healthy donors [Supplemental figure S1 in Additional file 1], among which the levels of TNF-α were found to be significantly higher in SF and serum of RA patients than healthy donors.