TNF and rheumatoid arthritis: To explore the role of Tan IIA on the expression of key pro-inflammatory cytokines induced by TNF-α, the mRNA expression levels of IL-6, IL-8, IL-17, and IL-1β stimulated by TNF-α in RA-FLSs treated with 10 μM and 20 μM Tan IIA for 24 h were assessed with qPCR.