Therefore, a second, very sensitive method such as immunodetection on 2D-PAGE, was chosen to confirm the results of the broad range proteome approach and to investigate whether known antigens in RA (e.g. fibrinogenβ (Fibβ), fibrinogenγ (Fibγ), fibronectin and vimentin) are present in these complexes. The gene discussed is FN1; the disease is rheumatoid arthritis.