Which autoantibodies are commonly present in rheumatoid arthritis?

• A. Anti-dsDNA antibodies
• B. Rheumatoid factor and anti-CCP antibodies
• C. Anti-RNP antibodies
• D. Anti-centromere antibodies

Answer: (B)

Rheumatoid arthritis is typically diagnosed with serologic markers that include rheumatoid factor and anti-CCP antibodies. Rheumatoid factor is an autoantibody (usually IgM) directed against the Fc portion of IgG and can be positive in RA but also in other diseases and in some healthy individuals. Anti-CCP antibodies target citrullinated proteins and are highly specific for RA, often appearing early and indicating a greater risk of joint damage. Other antibodies listed are associated with different autoimmune diseases (anti-dsDNA with lupus, anti-RNP with mixed connective tissue disease/SLE, anti-centromere with limited scleroderma), not RA. Therefore, the combination of rheumatoid factor and anti-CCP antibodies best matches the frequent serologic findings in rheumatoid arthritis.