B-cell activation and development within chronically inflamed synovium in rheumatoid and reactive arthritis.

In autoimmune diseases, B cells often accumulate in the affected tissue. In patients with rheumatoid arthritis or reactive arthritis, germinal center-like structures may develop in the inflamed synovial tissue. B cells from these structures were isolated and their V-gene repertoire determined. The majority of synovial B cells are long-term memory cells and thus are part of the chronic inflammatory reaction. In the synovium a micro-environment is built up which allows the activation of naive and memory B cells and the diversification of their V-gene repertoire. The analysis of plasma cells suggests that these cells are long lived and hence accumulate in the synovial tissue under chronic activation.