[Immune molecules and the mechanism of joint destruction]

Inflammation and joint destruction are the major symptom of rheumatoid arthritis(RA).Inflammation leads to osteoclast differentiation, resulting in bone destruction. Immune-related molecules such as inflammatory cytokines not only exacerbate inflammation but also bone destruction in RA. In vivo analysis using animal models of RA has contributed to the identification of synovial fibroblasts as a major osteoclastogenic cell type and a synergy between a novel Th17 subset and synovial fibroblasts as one of the primary axes in the joint destruction. Increasing numbers of immune-regulating factors including immune-complexes have been identified as new bone-regulating factors and are attractive therapeutic targets for bone destruction in RA.