Detection of Epstein-Barr virus-associated antigens and DNA in salivary gland biopsies from patients with Sjogren's syndrome.

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Abstract
Sjogren's syndrome (SS) is an autoimmune disorder characterized by lymphocytic infiltration of salivary and lacrimal glands. To determine whether Epstein-Barr virus (EBV) might play a role in the pathogenesis of this disorder, we used monoclonal antibodies and DNA probes to detect evidence of viral gene products and genomes in these patients' tissue biopsies and saliva. Cytoplasmic staining of epithelial cells (i.e., ductal and/or acinar cells) with monoclonal antibody against the EBV-encoded early antigen (EA-D) was noted in 8/14 salivary gland biopsies from SS patients. This antibody did not react with normal salivary glands or salivary gland tumors, nor with other tissues from SS patients. The reactive antigen in SS biopsies had a m.w. of 52,000 on the basis of immunoblotting experiments, similar to the EA-D antigen found in lymphoblastoid cells lytically infected with EBV. EBV DNA was detected in parotid biopsies from two SS patients in amounts ranging from 0.1 to 3 pg per 20 micrograms of cellular DNA. Southern blotting was used to demonstrate the reactivity with Bam V, Eco D, and Bam M probes. Parotid saliva samples from 8/20 SS patients contained EBV DNA detectable by slot blot hybridization. EBV DNA was not detected in saliva of age-matched controls, rheumatoid arthritis patients lacking sicca symptoms, or patients with benign parotid tumors. The presence of EBV in salivary gland and saliva samples was associated with clinically more severe SS, as manifested by extraglandular symptoms such as vasculitis, occurrence of "pseudolymphoma", and marked abnormalities in immunoglobulin levels. These results demonstrate an elevated content of EBV in salivary glands of SS patients, and suggest that this virus may play a role in pathogenesis.