CXCL8 and rheumatoid arthritis: Mong et al. (2008) suggested that ROCK is involved in the endothelial response to TNF-α by increasing IL-6 production. In the treatment of rheumatoid arthritis, TNF-α and IL-17 have shown a synergistic effect in promoting the production of IL-6 and IL-8 (Fischer et al., 2015).