Autoantibodies in osteoarthritis
© The Author(s) 2003
Received: 14 January 2003
Published: 24 February 2003
We have previously shown that inflammatory cytokines are up-regulated in chondrocytes of osteoarthritis (OA) patients. However, the inflammatory responses associated with OA are still ill defined. To investigate in more detail the involvement of the immune system in the pathogenesis of OA, we here analyzed patients for the presence of autoantibodies.
Both sera and synovial fluids obtained from 85 OA patients at the time of joint replacement were tested for autoreactivity. Autoantibodies reacting against synovial membranes were detected performing immunofluorescence on cryosections. Autoantibodies recognizing lysate components of various cell lines (B-cell, T-cell, monocyte, fibroblast and chondrosarcoma) were shown by the use of Western blot analyses. In preparation for the identification of the respective autoantigens, we started to immunoprecipitate the proteins of interest.
Our results demonstrate the presence of autoantibodies in sera and synovial fluid in about half the OA patients. The specificities of these autoantibodies are not restricted to the joints, as reactivity was detected towards any cell line tested. Hoping to design new diagnostic tools and to shed light on the role of autoantibodies in the development and progression of OA, we are in the process of identifying the corresponding autoantigens.