The association of the disease activity of rheumatoid factor positive vasculitis and the level of rheumatoid factor

Abstract

Rheumatoid factor (RF), an autoantibody against the Fc portion of denatured IgG, has long been recognized as an important biologic marker not only for rheumatoid arthritis but also for other auto-immune diseases.
In this study, we measured the level of serum RF in four patients with RF positive systemic vasculitis using laser nephelometry. Three patients were diagnosed as polyarteritis nodosa and the other patient was diagnosed as systemic vasculitis without the finding of typical necrotizing vasculitis from biopsies. In the result, we found that the level of RF paralleled the disease activity in these cases. When active phase of the disease, the level of RF showed very high, and after the treatment combined with plasmapheresis, corticosteroid and immunosuppressive agent, the level of RF decreased in acorrdance with CRP, ESR and clinical features. These suggested that RF was the disease specific marker for RF positive vasculitis and benefical informations for proper diagnosis and better treatment could be provided by measurement of the level of RF in patients with RF positive systemic vasculitis.