[Biologic agents for the treatment of rheumatic diseases]

Rheumatoid arthritis (RA) is a systemic inflammatory disease characterized by chronic synovitis and bone damage. Bone homeostasis is maintained by a balance between bone resorption and bone formation. It is also involved by immune systems and imbalance in immune system often results in pathological processes such as joint destruction as well as secondary osteoporosis. Proinflammatory cytokines such as TNF and IL-6 cause an imbalance in bone metabolism via direct and/or indirect effects on osteoclasts. However, the combination of methotrexate and biologic DMARDs targeting TNF and IL-6 have revolutionized the treatment of RA, producing significant improvements in clinical, radiographic, and functional outcomes that were not previously observed. Such progress in the treatment of RA has been expanded to other joint diseases including psoriatic arthritis, spodylarthritis and so on.