The results showed that TLR2, TLR3 and TLR4 mRNA were upregulated in a dose-dependent manner and a 8.5-, 3.7- and 2.1-fold increases in TLR2, TLR3 and TLR4 mRNA expression, respectively, were observed in RA-FLSs after incubation with 100 ng/ml IL-29 for 24 hours (Figure 4A). Here, TLR4 is linked to rheumatoid arthritis.