Past infections are associated with low levels of anti-citrullinated protein autoantibodies in rheumatoid arthritis.

Background : Rheumatoid arthritis (RA), an autoimmune disease of unknown etiology, is believed to occur as the result of actions of genetic and environmental factors. In this study, we examined the relation of past histories about infectious diseases with the levels anti-citrullinated protein autoantibodies (ACPA) in RA. Methods : Results of a questionnaire about histories of infectious diseases were obtained from 85 patients with RA, and were analyzed.