rheumatoid factor
Quick Summary
Rheumatoid factor (RF) is an autoantibody, meaning it's an antibody that attacks the body's own tissues. Specifically, RF reacts against IgG immunoglobulins, which are a type of protein in the blood.123
RF is often present in individuals with rheumatoid arthritis, a chronic inflammatory disease that primarily affects the joints. In rheumatoid arthritis, inflammation and thickening of the synovial membranes, which lubricate the joints, can lead to irreversible damage to the joint capsule and cartilage. While RF is a key diagnostic marker for rheumatoid arthritis, its presence doesn't automatically mean someone has the disease, as some individuals may have RF without symptoms. The exact cause of rheumatoid arthritis and the trigger for RF production are not fully understood, but an autoimmune mechanism is implicated.23
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
- rheumatoid arthritis
…against IgG, are collectively called rheumatoid factor.
Read More…against IgG, are collectively called rheumatoid factor.
Read More 
immune system disorderRheumatoid arthritis…autoantibodies, referred to collectively as rheumatoid factor. The autoantibodies react with the tail region of the Y-shaped IgG molecule—in other words, rheumatoid factor is anti-IgG antibodies. Immune complexes form between rheumatoid factor and IgG and apparently are deposited in the synovial membrane of joints. The deposition triggers a type III…
Read More…autoantibodies, referred to collectively as rheumatoid factor. The autoantibodies react with the tail region of the Y-shaped IgG molecule—in other words, rheumatoid factor is anti-IgG antibodies. Immune complexes form between rheumatoid factor and IgG and apparently are deposited in the synovial membrane of joints. The deposition triggers a type III…
Read More