GLANDULAR AND EXTRAGLANDULAR EXPRESSION OF THE FAS-FAS LIGAND AND APOPTOSIS IN PATIENTS WITH SJOGRENS-SYNDROME

Objective To evaluate the role of Fas-Fas ligand system-mediated apopt osis in the sialoadenitis and interstitial nephritis of Sjogren's synd rome. Methods The expression of Fas antigen and Fas ligand in sialoade nitis and interstitial nephritis was examined by immunoperoxidase stai ning and the revel-se transcriptase-polymerase reaction (RT-PCR) in pa tients with Sjogren's syndrome and in normal subjects. The appearance of DNA str and breaks during apoptosis was detected in the tissue by D NA nick end labeling methods. Results In patients with severe sialoade nitis, Fas antigen was strongly expressed on the ductal epithelial cel ls. in contrast, Fas antigen was not seen in the minor salivary glands of nor-mal subjects nor in patients with mild sialoadenitis. In patie nts with massive mononuclear cell infiltration some of the infiltratin g cells showed the Fas ligand. In patients with interstitial nephritis associated with Sjogren's syndrome, Fas was expressed on the tubular epithelial cells, while such expression was not observed in control su bjects without interstitial nephritis. In the patients with interstiti al nephritis, some of the infiltrating cells showed the Fas ligand. Ap optotic changes were observed in the ductal epithelial cells, tubular epithelial cells and some infiltrating cells by DNA nick end labeling methods. mRNA for the Fas antigen and Fas ligand was found to be expre ssed in the labial salivary glands from all SS patients by RT-PCR. Con clusion The findings of this study suggest that the Fas-Fas ligand sys tem may play a role in the pathogenesis of the sialoadenitis and inter stitial nephritis of Sjogren's syndrome.