For instance, in rheumatoid arthritis (RA), S100A8/A9 has been reported to mediate chondrocyte activation, osteoclast differentiation, leukocyte infiltration in joints, proinflammatory cytokine production by monocytes, and synovial fibroblast proliferation, contributing to cartilage degradation and bone resorption [99,100]. Here, S100A8 is linked to rheumatoid arthritis.