title: Sialadenitis in patients with chronic hepatitis C is not directly related to hepatitis C virus.
abstract: Sjogren's syndrome has been suspected to be an extrahepatic manifestation of chronic hepatitis C virus (HCV) infection. To evaluate the association of sialadenitis with HCV infection, serum levels of salivary amylase (s-isoamylase) and antibodies to Ro (SS-A) and La (SS-B) were analyzed in 114 patients with chronic hepatitis C. Serum s-isoamylase levels were monitored before and after HCV was eradicated by interferon therapy. Immunohistochemistry and Western blotting using anti-HCV antibodies, and in situ hybridization of HCV-RNA were performed in the salivary gland. Serum s-isoamylase levels were elevated in patients with chronic hepatitis C (P<0.0001). The s-isoamylase remained high even after HCV was eradicated. The in situ hybridization did not show the presence of HCV-RNA in the salivary gland from patients with chronic hepatitis C. A protein reacting with anti-HCV-E2 antibodies was found in the cytosol fraction of normal salivary gland from HCV-negative cases. Latent sialadenitis is frequently observed in chronic hepatitis C, which is not directly related to HCV per se. The presence of a common epitope between antigenic protein in the salivary gland and the HCV-derived protein may be a possible pathogenetic mechanisms such as molecular mimicry.
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan
authors.forename: Shinya
authors.initials: S
authors.lastname: Ohoka
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Amako
authors.forename: Michinori
authors.initials: M
authors.lastname: Kohara
authors.forename: Kozo
authors.initials: K
authors.lastname: Ishidate
authors.forename: Mamoru
authors.initials: M
authors.lastname: Watanabe
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Chifumi
authors.initials: C
authors.lastname: Sato