Association of measles virus with rheumatoid arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic inflammatory polyarthritis; while the cause is unknown, it has been speculated that an infectious agent could be the trigger for the disease. Numerous attempts at isolating an agent have been unsuccessful. Our purpose was to identify a virus from diseased tissue from a patient with RA. METHODS: Diseased tissue taken at the time of knee replacement surgery from a patient with RA was inoculated into several cell lines and observed for cytopathic effect. Cells from the tissue were also grown as explants and were examined for viruses. Synovial fluid drawn 4 years prior to the surgery and frozen at -70 degrees C was also inoculated into cell lines. Following the development of a cytopathic effect and identification of the agent, sera from 50 patients with rheumatoid factor (RF)-negative RA were examined for IgM antibodies to the agent. RESULTS: After many inoculations and numerous subpassages, measles virus was identified in 6 cell lines inoculated with either the minced tissue or synovial fluid. Six cell lines co-cultivated with one or more of 9 explants also showed the presence of measles virus. Measles virus was confirmed by immunofluorescence and by neutralization. Eleven of 50 (22%) sera samples from patients with RF-negative RA had IgM antibodies to measles virus recombinant nucleoprotein. CONCLUSION: There is an association between measles virus and RA.