T-cell mediated inflammatory pathway in osteoarthritis

Osteoarthritis (OA) is not caused by a simple consequence of aging and cartilage degradation. Based on the conventional paradigm, OA has been considered a degenerative joint disorder. However, the dominant clinical symptom has been characterized by a non-infectious chronic inflammatory condition with infiltration of inflammatory cells in the synovial tissue or synovial fluid, especially in the early stage of the disease. The inflammatory process appeared to develop degeneration of chondrocytes and/or formation of osteophytes. Immunohistochemical staining of synovial tissue with OA in the early stage, suggests the presence of T-cell infiltration in the perivascular area, some of which were CD4 positive T cells. Among the T cells, we identified the clonality of restricted TCR usage of Vbeta chain by single strand conformation polymorphism (SSCP) method on T-cell repertoire. Therefore we address the immune response in primary OA.