Rheumatoid factor is an antibody that usually signals an autoimmune attack in the body. Although useful in diagnosing rheumatoid arthritis and monitoring disease activity, this marker may also be produced in other inflammatory diseases and certain infections. We break down all the possible causes and effects of high levels.What Is Rheumatoid Factor?Rheumatoid factor (RF) is an autoantibody produced by the immune system. Autoantibodies trigger autoimmunity and inflammation responses by mistakenly mounting an attack against the body’s own tissues.This marker got its name from its initial discovery in people with rheumatoid arthritis. Since then, it became evident that other conditions can also trigger its production. Detectable levels of the rheumatoid factor were uncovered in people with other autoimmune diseases, chronic infections, cancer, liver disease, and parasites [1, 2].The rheumatoid factor is a curious autoantibody that attacks other antibodies. It mostly takes the form of an I...
