Possible involvement of Epstein-Barr virus in polyclonal B cell activation in Sjögren's syndrome.

We sought evidence of Epstein-Barr virus (EBV) involvement in the mechanism of polyclonal B cell activation in 29 patients with Sjögren's syndrome (SS). Serum levels of anti-viral capsid antigen antibodies of both the IgG and the IgM class were significantly elevated in these patients. Excretion of EBV from the oropharynx was frequently observed, as well. Spontaneously transformed B cell lines that produced a large amount of transforming EBV were established preferentially from SS patients. We also found that an EBV-specific regulatory mechanism was impaired in these patients. Our findings thus provide evidence of the involvement of EBV in patients with SS.