IL6 and rheumatoid arthritis: TNF-α, IL-1β, and IL-6 are also osteolytic cytokines that are involved in the destruction of bone and joints in RA as implicated in promoting the expression of receptor activator of nuclear factor kappa-B ligand or RANKL in synovial fibroblasts, in the differentiation of osteoclasts and also in the induction of matrix metalloproteinase production [16, 17].