Description
Hyaline cartilage is composed of an extracellular matrix containing mainly type II collagen and a large aggregating proteoglycan called aggrecan. In arthritic joints, the collagen matrix is disrupted and the proteoglycan content is decreased. This change in matrix composition appears to be due to abnormal matrix degradation and synthesis, although the exact sequence of events during the development of arthritis remains unknown. The CS846 epitope is an indicator of large or fetal-like aggrecan synthesis. This epitope is only present on the largest aggrecan molecules and was originally identified in human fetal cartilage; its content decreases considerably with cessation of growth (Glant et al, 1986). In osteoarthritis (OA), where synthesis is increased, content is elevated, both in articular cartilage (Rizkalla et al., 1992) and in synovial fluid and serum (Lohmander et al., 1999; Poole et al, 1994; Otterness et al, 2001). In rheumatoid arthritis (RA) it is elevated in serum in chronic disease although depressed in rapid progressive disease (Mansson et al., 1999). Similar increases are seen in hemophilic arthropathy (Jansen et al, 2009). Synovial fluid concentrations are much higher in OA and RA than in serum (Poole et al, 1984). Increased serum and synovial fluid concentrations of epitope CS846 are associated with osteochondral fragmentation (OC) in (Frisbie et al., 1999). Concentrations are decreased in the joint fluids of young horses with osteochondrosis (Laverty et al., 2000). In a dog preclinical model of OA, serum CS846 is elevated within 3 weeks following anterior cruciate section and remains elevated at 3 months (Matyas et al, 2004).
This assay uses a mouse IgM monoclonal antibody to measure an epitope on chondroitin sulfate chains of the cartilage proteoglycan aggrecan which is increased in content in arthritis. In arthritis, articular cartilage is progressively destroyed. This is characterized by degradation of key molecules such as type II collagen and the proteoglycan aggrecan. It is accompanied by attempts at repair with an increase in synthesis of these molecules. This assay is for in vitro research use only and has been optimized for analyzing human serum. It has also been used to analyze various types of samples and species. It has been designed to be used for comparative analysis only, and is not to be used for absolute diagnostic purposes. All samples must be treated the same way and in the recommended manner.