Serum RANKL levels associate with anti- citrullinated protein antibodies in early untreated rheumatoid arthritis and are modulated following methotrexate

Introduction Receptor activator of nuclear factor kappa B ligand (RANKL) is a key regulator of bone metabolism. Anti-citrullinated protein antibodies (ACPA) have been suggested to cause bone destruction by osteoclast activation. We investigated the relationship between RANKL and ACPA in patients with early untreated rheumatoid arthritis (RA).