Viral arthritis.

Viral infections are important in rheumatic disease not only because of the acute and subacute syndromes they cause but also because of their potential importance as etiologic factors in common chronic diseases such as rheumatoid arthritis. During 1996, the clinical spectrum of the acute polyarthritis caused by parvovirus B19 was further delineated and was shown to include carpal tunnel syndrome, hepatic dysfunction, and possibly angioedema. B19 infection can be studied using the salivary antibody response. No convincing additional data were reported regarding B19 in chronic syndromes such as rheumatoid arthritis or Behçet's syndrome. Regarding rubella as a possible cause of chronic arthropathy, more negative evidence accumulated with two additional studies in vaccinees and chronic arthritis using epidemiologic and virologic methods including the polymerase chain reaction. To define a possible link between rubella and autoimmunity in vitro, interactions of rubella RNA, ribonucleoprotein complexes including Ro and La, and calreticulin were explored. There was an avalanche of new information about hepatitis C virus infection, particularly its relationship to mixed cryoglobulinemia and related clinical syndromes. These syndromes have become much more commonly recognized, particularly in areas of high prevalence of hepatitis C virus infection such as Italy. The lymphotrophic nature of the virus is probably ultimately responsible for the rheumatic disease manifestations. Treatment is still problematic, but immunosuppressive drugs should be avoided. Epstein-Barr virus appears to have an etiologic role in the lymphomas occurring in immunosuppressed patients, including those who have had methotrexate therapy. Significant new studies regarding other viruses did not appear during the past year.