In vitro studies have confirmed that the TLR2 and TLR4 expression levels were upregulated in peripheral blood monocytes, ST macrophages, and fibroblasts of patients with RA (Radstake et al. 2004), suggesting that TLR2 and TLR4 are associated with the pathogenesis of RA. The gene discussed is TLR4; the disease is rheumatoid arthritis.