To determine whether Epstein-Barr virus (EBV) could be involved in the pathogenesis of Sjögren's syndrome (SS).
In situ hybridization using the BamH1-W fragment of EBV DNA was performed using labial salivary gland biopsy specimens from 14 patients with SS (eight with primary SS and six with secondary SS) and 39 control subjects. Furthermore, labial salivary gland biopsy specimens from 12 patients with SS (seven with primary SS and five with secondary SS) and 24 control subjects were submitted to the polymerase chain reaction to detect EBV DNA.
In situ hybridization detected EBV DNA in epithelial cells of labial salivary gland biopsy specimens from four of eight (50%) patients with primary SS, zero of six patients with secondary SS, and three of 39 (8%) control subjects. The difference between patients with primary SS and control subjects was statistically significant (p less than 0.02). The polymerase chain reaction detected EBV DNA in six of seven (86%) patients with primary SS, three of five (60%) patients with secondary SS, and seven of 24 (29%) control subjects. The difference between patients with primary SS and control subjects was statistically significant (p less than 0.01).
Both newly developed techniques showed that the presence of EBV DNA was significantly increased in patients with primary SS in comparison with control subjects. In all the positive SS patients who underwent in situ hybridization, epithelial cells of the labial salivary gland were the target of EBV infection. Our results suggest that this virus may play a role in the pathogenesis of SS. We cannot yet determine whether EBV is directly responsible for the destruction of the gland, or if its presence is a secondary event following gland injury.