[Demonstration of increased influenza-A-antibody levels in the serum of patients with chronic polyarthritis].

Patients with rheumatoid arthritis show increased levels of anti-influenza-A antibodies in their sera compared to healthy controls and patients with other inflammatory rheumatic diseases (systemic lupus erythematosus, ankylosing spondylitis and psoriatic arthritis). These antibody levels are dependent on the activity of rheumatoid arthritis.