HEPATITIS-C VIRUS-INFECTION OF SALIVARY-GLAND EPITHELIAL-CELLS - LACKOF EVIDENCE

Background: Hepatitis C virus genome (HCV-RNA) has been detected in wh ole salivary gland tissue of chronically infected patients, However, c ontamination of the tissue by plasma or blood cells,vas not excluded b y the previous reports, Aims: To assess whether HCV infects the saliva ry gland epithelial cells in patients with chronic HCV liver disease. Methods: Twenty unselected patients with chronic active hepatitis (11 cases) or active cirrhosis (nine cases) were examined. Serum and saliv a samples were obtained from all patients, 12 of whom (seven, chronic active hepatitis; five, active cirrhosis) underwent salivary gland bio psy, PCR for HCV-RNA was performed on RNA extracted from serum, saliva and salivary gland epithelial cells collected by isokinetic gradient separation after trypsin digestion of whole salivary gland tissue. Sal iva samples were also examined for the presence of secretory IgA anti- HCV by gel chromatography and ELISA testing. Results: HCV-RNA was dete cted in all sera with titers ranging from 5.42 x 10(5) genome equivale nts/ml to 123.2 x 10(5) genome equivalents/ml. Thirteen patients were infected with genotype 1b, four patients had genotype la, two patients had genotype 2a and one patient was unclassifiable, Low titer HCV-RNA (<2 x 10(5) genome equivalents/ml) was detected in 3 20 saliva sample s (15%) from highly viremic patients infected with Ib genotype. RNA ex tracted from salivary gland epithelial cells consistently tested negat ive for HCV-RNA. In addition, all saliva specimens tested negative for secretory-IgA (S-IgA) anti-HCV, even after a 10-fold concentration of the samples. Conclusions: There was no evidence that HCV infects the salivary gland epithelial cells in our viremic patients with HCV chron ic liver disease, Low level HCV-RNA in saliva is most probably due to virus spillover from blood.