IL6 and rheumatoid arthritis: In the process of RA, effector cells and immune cells, such as fibroblast-like synoviocytes (RAFLS), helper T cell 17 (Th17), and M1-type macrophages, release inflammatory cytokines including TNF-α, IL-1β, IL-6, and IL-17, which then lead to the secretion of RANKL (Danks et al., 2016; Muñoz et al., 2020; Nygaard and Firestein, 2020; Chen et al., 2021).