It has been reported that the expression of Hsp70 is higher in both tissue and cultured RA FLSs than in the FLSs of osteoarthritis and that inflammatory cytokines, such as TNF-α and IL-1β, that exist abundantly in RA joint fluid further increase Hsp70 expression in cultured RA FLSs [13]. Here, IL1B is linked to rheumatoid arthritis.