…and IgM complexes known as rheumatoid factors can help confirm the diagnosis of certain conditions, including Sjögren syndrome, rheumatoid arthritis, and chronic hepatitis.

…arthritis contains an immunoglobulin called rheumatoid factor that behaves as an antibody and reacts with another class of immunoglobulin. This immunoglobulin is produced by plasma cells that are present in sites of tissue injury. There is evidence that suggests that this agent may be one or more viruses or viral…

…against IgG, are collectively called rheumatoid factor.

…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…