Identification of cartilage matrix glycoprotein in synovial fluid in human osteoarthritis.

Cartilage matrix glycoprotein (CMGP) is a high molecular weight protein found in hyaline cartilage and fibrocartilage. It consists of disulfide-bonded subunits, each with an apparent molecular weight of 116,000. Fragmentation of CMGP is noted in extracts of osteoarthritic canine cartilage. CMGP has been identified in the serum and synovial fluid of dogs with experimentally induced osteoarthritis. It has now been identified in synovial fluid from osteoarthritic human joints but not in synovial fluid from joints of patients with other arthritides or joint abnormalities. The possible significance of CMGP in synovial fluid in human osteoarthritis is discussed.