[Native anti-DNA antibodies and the synovial fluid. A report of a problematic clinical case].

The authors report the unusual case of a 30-years-old woman affected by bilateral gonarthritis with anti-ds DNA antibodies at higher level in synovial fluid than in serum. This finding, and the presence of an intensive infiltration of polyclonal plasma cells in the synovial membrane, studied by biopsy, lead to suppose a local production of autoantibodies with a probable pathogenetic role.