Objective: To investigate the rate and extent of infection by Epstein-Barr virus (EBV), cytomegalovirus, and herpesvirus 6 in families (affected and nonaffected members) with multiple cases of rheumatoid arthritis (RA).
Methods: Viral DNA was detected by polymerase chain amplification in cells from saliva and peripheral blood. Human leukocyte antigen pedigrees were characterized.
Results: Viral DNA, particularly EBV, was detected in increased frequency (p = 0.029) in the patients with RA compare to their nonaffected relatives.
Conclusion: We suggest that in RA multicase families, increased frequency of viral infection is likely a consequence of the disease state and/or due to gene(s) as yet unidentified.