Detection of Epstein-Barr virus in salivary gland specimens from Sjogren's syndrome patients

The cause of Sjogren's syndrome remains unclear, but several environmental and genetic factors have been implicated. The Epstein-Barr virus (EBV), among others (e.g., cytomegalovirus, human herpesvirus 6, and retroviruses), has been widely studied in connection with Sjogren's syndrome without conclusive results. To determine the role of EBV infection in patients with Sjogren's syndrome, the presence of EBV deoxyribonucleic acid (DNA) in major and minor salivary gland biopsy specimens was investigated by means of sulfur 35 in situ hybridization and polymerase chain reaction. Additionally, the presence of latent virus proteins EBV latent membrane protein and Epstein-Barr nuclear antigen 2 was analyzed by immunohistochemical methods. Viral DNA, detected by in situ hybridization, was found in 19% of patients with a diagnosis of Sjogren's syndrome and in 3% of controls. AU tissues studied were found to be negative for EBV DNA by polymerase chain reaction. EBV latent membrane protein-positive staining was seen in 17% of patients and 22% of control subjects, while Epstein-Barr-positive staining was found in 25% of patients and 39% of controls. The low frequency of EBV DNA detected in the biopsy specimens does not indicate that the virus itself is the cause of Sjogren's syndrome. However, the possibility that the virus acts as a cofactor cannot be ruled out.