RANKL as a therapeutic target of rheumatoid arthritis.

Rheumatoid arthritis (RA) is an inflammatory disorder characterized by progressive joint destruction. Recent studies have demonstrated that osteoclasts are responsible for bone destruction in RA. Receptor activator of nuclear factor kappa B ligand (RANKL), an osteoclast differentiation factor, belongs to the tumor necrosis factor superfamily and plays a critical role in osteoclast differentiation. RANKL is highly expressed in the synovial tissues in patients with RA and is involved in osteoclast development and thus bone destruction in RA. Denosumab, a specific antibody to human RANKL, efficiently suppressed the progression of bone destruction in patients with RA in a randomized controlled study and is considered a putative therapeutic option for RA.