RESUMO
Objective:To investigate the expression of Mucosal-associated invariant T (MAIT) cells in the salivary gland of primary Sj?gren′s syndrome (pSS) patients, and to analyze its clinical significance.Methods:Thirty-two pSS patients and 27 non-pSS controls who had salivary gland biopsies were enrolled. The expression of MAIT cells was detected by immunofluorescence and then analyzed based on clinical data. T test, variance analysis and Spearman correlation analysis were used for statistical analysis. Results:The expression of MAIT cells in the salivary gland of pSS patients was significantly higher than in controls [(2.40±0.33)/gland and (0.79±0.13)/gland respectively, t=4.24, P<0.01]. In pSS patients with mouth dryness ( n=26), MAIT cells in the sali-vary gland were significantly increased compared with those without [(2.73±0.38)/gland vs (0.95±0.15)/gland, t=2.24, P=0.03]. In patients with dental caries ( n=17), MAIT cells in the salivary gland were also significantly increased [(3.13±0.54)/gland vs (1.57±0.20)/gland, t=2.57, P=0.02]. The expression of MAIT cells in the salivary gland of pSS patients was positively correlated with erythrocyte sedimentation rate (ESR) and European League Against Rheumatism Sj?gren′s Syndrome Disease Activity Index (ESSDAI) scores ( r=0.37, P=0.04 and r=0.65, P<0.01 respectively). In pSS patients with positive SSA antibody ( n=23), the amount of MAIT cells was more than controls [(2.89±0.40)/gland vs (1.13±0.32)/gland, t=2.61, P=0.01]. The level of MAIT cells in the salivary gland was higher in pSS patients with more lymphocytic foci [one foci: (1.50±0.49)/gland, two foci: (2.29±0.52)/gland, three foci(3.66±0.59)/gland; F=4.22, P=0.02]. Conclusion:The expression of MAIT cells in the salivary gland of pSS patients is significantly higher than non-pSS controls, and is correlated with oral symptoms, disease activity and the production of autoantibodies. This may suggest that MAIT cells may participate in the local inflammation response and play a role in the pathogenesis of pSS.