Deposits of complement in synovial vessels in Reiter's syndrome. A role for hydatid antigen?

We present a patient diagnosed as having Reiter's syndrome in whom the presence of hydatid cysts are in temporal relation to bouts of the arthritic disease. We set up an immunologic study in order to explore the possible pathogenetic relationship between the hydatid and arthritic diseases. Special antibodies for hydatid antigen in synovial fluid were shown by ELISA and the presence of vasculitic changes and complement deposition were demonstrated by direct immunofluorescence of synovial tissue. We believe this data may add some weight to the immunologic pathogenesis of some cases of arthritis associated with HLA B27.