Connective tissue macromolecules as markers for tissue processes in joint disease.

An early event in joint disease is a progressive destruction of the articular cartilage following degradation of matrix macromolecular constituents. The fragments thus formed are released into surrounding fluids by diffusion and can be detected and quantified by immunoassay. By using assays for macromolecules/fragments specific for cartilage, it is possible to monitor processes in a given articular cartilage. An example of such a molecule is the large aggregating proteoglycan, being a major constituent of cartilage. Fragmented proteoglycans are present at increased concentrations in synovial fluid of patients with early rheumatoid arthritis, reactive arthritis, crystal arthropathies and osteoarthritis. There are a number of other matrix proteins, where fragmentation and release is increased in joint disease. Since it is likely that the organisation of the cartilage is gradually destroyed in the degenerative process, it is likely that the pattern of fragments released varies with time. This can be verified by using a cartilage specific matrix protein, distinct from the proteoglycans. It may thus become possible to determine the prognosis of the disease process, the stage of the process and effects of therapy by the use of marker technology