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What role does rheumatoid factor play in rheumatoid arthritis?

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immune system disorder False-color scanning electron micrograph of a T cell infected with HIV (human immunodeficiency virus), the agent that causes AIDS (acquired immunodeficiency syndrome).

In the context of rheumatoid arthritis, rheumatoid factor acts as an autoantibody that targets IgG immunoglobulins.12

The inflammatory process is believed to be initiated when these autoantibodies bind to IgG, forming immune complexes that deposit within the synovial membranes of the joints. This deposition triggers a type III hypersensitivity reaction, which activates the complement system and attracts granulocytes. These cells release enzymes that degrade cartilage and collagen, leading to the inflammation, pain, and eventual joint destruction characteristic of the disease.12

While the presence of these autoantibodies is a key diagnostic marker, it is important to note that the disease can still manifest in patients without detectable rheumatoid factor, indicating that other immune mechanisms also contribute to the development of this immune system disorder.1