IL1B and rheumatoid arthritis: As presented in Figure 4B, although TNF-α (20ng/mL) did upregulate, to a greater or lesser extent, the mRNA levels of IL-6, IL-1β, and IL-8 in RA-FLSs, 20 μM Tan IIA inhibited the IL-6, IL-1β, and IL- 8 mRNA upregulation stimulated by 20-ng/mL TNF-α, while 10 μM Tan IIA had no obvious effect except for on IL-1β.