As shown in Fig. 1, flow cytometry analysis that the percentage of CD4+GranzB+CTLs were significantly upregulated in pSS patients than in healthy controls (7.1% ± 4.9% vs 3.1% ± 1.9%, p < 0.0001; Fig. 1A), and the CD4+GranzB+CTLs frequency was positively correlated with European League Against Rheumatism (EULAR) SS Disease Activity Index ( ESSDAI) (r = 0.6332, p < 0.0001), indicating that CD4+GranzB+CTLs is probably involved in the pathogenesis of pSS, while the CD4+GranzB+CTLs frequency had no correlation with European League Against Rheumatism SS Patient Report Index (ESSPRI) (p > 0.05). This evidence concerns the gene CD4 and synovial sarcoma.