RANKL: A therapeutic target for bone destruction in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic inflammatory disorder characterized by progressive joint destruction. Recent studies have indicated the critical involvement of osteoclasts in bone destruction in RA. The osteoclast differentiation factor receptor activator of NF-κB ligand (RANKL), which belongs to the tumor necrosis factor superfamily, plays a critical role in osteoclast differentiation and bone destruction in RA. Denosumab, an antibody against human RANKL, efficiently suppressed the progression of bone erosion in RA patients in randomized controlled studies, and is considered as a putative therapeutic option for preventing bone destruction in RA.