Recently, studies showed that TLR4 expression was up-regulated in synovial tissues and RA-FLSs [25], and that TLR4 promotes pathological progression of RA by increasing the secretion of matrix metalloproteinase3 as well as IL-6 and IL-8 in RA-FLSs [26]. This evidence concerns the gene CXCL8 and rheumatoid arthritis.