TNF and rheumatoid arthritis: Additionally, in the setting of TNF-α-induced RA-FLSs, the treatment markedly downregulated the mRNA expression of IL-1β (no dose-dependency observed in the expression levels), IL-6, IL-8 (dose-dependent fold change was reported for both IL-6 and IL-8) and IL-17A (greater fold changed in the expression levels observed at the higher doses of 5 and 10 μΜ).