Sjögren's syndrome and hepatitis C virus.

Sjögren's Syndrome (SS) is an autoimmune disease that mainly affects exocrine glands and usually presents as a persistent dryness of the mouth and eyes. The spectrum of the disease extends from an organ-specific autoimmune disease to a systemic process. Viral infection has long been suspected as a potential cause of SS because several viruses have been incriminated in the aetiology of this disease, and a possible relationship between SS and hepatitis C virus (HCV) was postulated in 1992. In this paper, we review the literature concerning SS and HCV infection and summarise the current knowledge regarding their association and their pathogenic, clinical and immunological significances. The main conclusions of this review are that the prevalence of antibodies to HCV in patients with primary SS ranges between 14 and 19% using third-generation ELISA, chronic HCV infection may mimic the main clinical, histological and immunologic features of 'primary' SS and, finally, testing for HCV infection must be performed in patients with SS, especially in those patients with evidence of liver involvement or associated cryoglobulinaemia. HCV seems to be a rare cause of 'primary' SS in the absence of recognised liver disease or cryoglobulinaemia.