[Analysis of Fas and bcl-2 expression on peripheral blood lymphocytes from primary Sjögren's syndrome].

The Fas antigen is the major trigger for apoptosis. In MRL/lpr mice, defects in Fas expression lead to autoimmunity and lymphoid accumulation, same as in the Sjögren's syndrome (SS). Bcl-2 protein is able to repress a number of apoptotic death. Therefore, we examined both Fas antigen and bcl-2 expression in peripheral blood lymphocyte (PBL) from SS patients. The rate of Fas+CD4+ PBL was significantly elevated (p < 0.01) in SS patients (n = 11) compared to normal controls (n = 15). Both Fas+CD3+ and Fas+CD8+ cells from SS patients showed a tendency to increase, whereas Fas+B cell was not different between each group. The percentages of bcl-2+ lymphocytes in SS patients were no different compared to the normal control. This study suggests that the increased expression of Fas may result in enhanced susceptibility to apoptosis.