Fig 1: Epithelial cells expressing Fas are frequent targets of apoptosis in SS. (a) Representative multi-color immunofluorescence image showing GZMA (purple) expressing CD8+CTLs (white arrows) in close proximity to cCasp-3+ epithelial cells (arrow heads). (b) Relative proportions of cCasp-3+ cells in contact with CD4+ or CD8+ T cells. Paired t test was used to calculate p-value. (n = 5). (c) Multi-color immunofluorescence images of cCasp-3 (green), Fas (red) and DAPI (blue) staining. White arrows show cells co-expressing cCasp-3 (green) and Fas (red). (d) Relative proportions of cCasp-3-/+ cells expressing Fas (n = 5). Paired t test used to calculate p-value. (e) Multi-color immunofluorescence images show a CD8+ (purple) and FasL+ (orange) expressing cell in contact with a cCasp-3 (green) and Fas (red) expressing cell in a pSS tissue. Error bars represent mean ± SEM. **p < 0.01.