Rheumatoid factors.

Rheumatoid factors (RFs) have been studied for over 50 years and are probably the most written about of any antibody. Nevertheless, the etiology of these RFs and the precise role they play in the pathogenesis of rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA) remain a major interest. When RFs participate in the generation of inflammation in RA and JRA, they probably do so by forming immune complexes (IC) or are themselves able to bring about the inflammatory response. Their presence has been associated with more severe disease, vasculitis, and systemic symptoms. The present review summarises the literature over the last few years on new and interesting findings on RF. This review covers an update on RF assays, RF cross-reactivity, specificity studies, immune complex formation, RF lymphocyte studies, and RF binding.