IL6 and rheumatoid arthritis: Mounting data of evidence have shown that the degree of macrophage infiltration into the synovium is correlated with the degree of bone erosion in the affected joints in RA (Soler Palacios et al., 2015; Udalova et al., 2016), since pro-inflammatory cytokines from activated macrophage, such as tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6), contribute to synovial inflammation in early stages of RA (Arthur and Ley, 2013).