In addition, we identified prominent apoptosis of epithelial cells represented by ductal and acinar cells, the accumulation of CD8+CTLs expressing FasL in the vicinity of the epithelial cells and the upregulation of Fas by apoptotic cells in tissues affected by pSS, suggesting that CD8+CTLs may be of pathogenic relevance in directing tissue damage in SS. This evidence concerns the gene CD8A and synovial sarcoma.