TNF and rheumatoid arthritis: In vitro, levels were higher in RA compared to OA FLS at both 7 and 14 days, for both IL-6 (9.4-fold with TNF-α + IL-17A vs. 0.6-fold without cytokines for OA FLS, **p < 0.005; 17-fold with TNF-α + IL-17A vs. 2.5-fold without cytokines for RA FLS, **p < 0.005), and IL-8 (3-fold with TNF-α + IL-17A vs. 0.4-fold without cytokines OA, **p < 0.005; 13.8-fold with TNF-α + IL-17A vs. 2.2-fold without cytokines RA, ***p < 0.0005) (Figures 4A,B).