Health Questions and Answers

Question: Which conditions rheumatoid factors (RFs) associated with their presence in the circulation?

Answer:

The presence of RF is not specific for RA. Patients with other conditions that have rheumatic features, including sarcoidosis, interstitial lung disease, cryoglobulinemia, SLE, and Sjögren’s syndrome, may have circulating RFs. Viral, parasitic, and other infectious diseases, including mononucleosis, hepatitis, malaria, tuberculosis, and bacterial endocarditis, may be associated with RFs. Up to 70% of patients with active hepatitis C infection have RFs in the circulation, probably because of the cross-reactivity between cryoglobulins (produced commonly in hepatitis C) and RF. Since chronic hepatitis can also produce achiness and occasionally a mild synovitis, careful attention should be paid to excluding hepatitis C (even if the patient has normal serum transaminase levels) before establishing a diagnosis of RA. Finally, human parvovirus B19 infection (fifth disease or slapped-cheek syndrome) may produce a symmetric polyarthropathy that can mimic RA, at times with modest titers of RFs in the circulation.

Reference: Harris ED, Budd RC, Firestein GS, et al (eds): Kelley’s Textbook of Rheumatology, 7th ed. Philadelphia, W.B. Saunders, 2005

Leave a Reply