ABERRANT EXPRESSION PATTERN OF THE SS-B LA ANTIGEN IN THE LABIAL SALIVARY-GLANDS OF PATIENTS WITH SJOGRENS-SYNDROME/

Objective. Salivary glands of patients with Sjogren's syndrome (SS) ha ve been shown to be a site of anti-SS-B/La antibody production. The pr esent study investigated differences in the localization of the SS-B/L a antigen in labial salivary gland (LSG) tissue between SS and non-SS patients, which may explain the local antigen-driven anti-SS-B/La resp onse. Methods. Distribution of SS-B/La was studied immunohistologicall y in the LSG biopsy samples of 9 SS patients, 10 non-SS patients, and in normal tissues obtained at autopsy within 2 hours after death, usin g a mouse monoclonal antibody directed to SS-B/La. In 3 SS and 3 non-S S patients, LSGs were also studied with affinity-purified biotinylated human antibodies directed against SS-B/La. Results. In the non-SS pat ients, SS-B/La was primarily observed in the nucleoli of acinic cells of the LSGs. Patients with either primary SS or secondary SS showed an accumulation of SS-B/La in the nucleoplasm of acinic cells, In the SS patients, SS-B/La was also detected in the cytoplasm as a diffuse or perinuclear staining. Sometimes, SS-B/La was found along the membrane of acinic cells as well. This aberrant nuclear and cytoplasmic distrib ution of SS-B/La in SS patients correlated well with abnormalities in the composition of the plasma cell population in the LSGs, but not wit h a lymphocytic focus score >1. Conclusion. The accumulation and redis tribution of SS-B/La in the LSGs may play an important role in the loc al antigen-driven anti-SS-B/La response in SS, and can also be used to improve the diagnostic possibilities of the LSG biopsy.