The Preliminary Study Of The Expression Of PD-1 And Tim-3 In Oral Lichen Planus

BackgroundOral lichen planus(OLP)is a common chronic inflammatory disease of oral mucosa.It has a high prevalence rate,about 0.5%~4.0%.Although the pathogenesis of OLP is unclear,most studies suggest that OLP is a T cell-mediated autoimmune disease.Programmed death-1(PD-1)and T cell immunoglobulin and mucin domain-containing molecule-3(Tim-3)are two important regulatory molecules expressed on T cells.When PD-1/Tim-3 expressed on T cell,the function of T cells is suppressed.Many studies suggest that the expression of PD-1 and Tim-3 is abnormal in autoimmune diseases.We explore the expression of PD-1/Tim-3 in OLP so that we can further understand the role of them in the pathogenesis of OLP.ObjectiveThis study was designed to detect the expression of PD-1 and Tim-3 in oral lichen plaus(OLP)and normal oral mucosal tissues,we analyze the role of PD-1/Tim-3 in the occurrence and development of OLP in order to further understand the pathogenesis of OLP.And finally our results may make a contribution to the new immune targeted therapy of OLP.MethodsWe selected 60 surgical OLP specimens which had whole clinical pathological note between October 2014 and October 2016 from Pathology Department,First Affiliated Hospital of Zhengzhou Univerisity.All of the lesions were diagnosed as OLP both clinically and pathologically.30 cases with normal oral mucosal tissues were collected from Maxillofacial Surgery Department,Stomotology Hospital of Henan Province.The expression of PD-1 and Tim-3 in OLP and normal oral mucosal tissues were examined by immunohistochemistry.We analyze PD-1 and Tim-3 expression in OLP and their correlation with OLP progression and other clinical characteristics.All data were analyzed by SPSS 23.0 software package.The statistical methods contain the Chi-square test and Spearman correlation analysis.P value<0.05 is considered statistically significant.Results1.PD-1 is mainly expressed on subepithelial infiltrating lymphocytes,and Tim-3 is mainly expressed on subepithelial infiltrating lymphocytes and intraepithelial cells.PD-1 and Tim-3 were observed in the cytoplasm and cytomembrane of OLP,and mainly in the cytoplasm.2.The positive rate of PD-1 and Tim-3 in OLP tissues(65%,85%)is much higher than normal oral mucosal tissues(26.7%,20%),and the difference is statistically significant(P<0.05).3.The positive rate of PD-1 in erosion OLP is 41.0%(9/22),while in non-erosion OLP is 78.9%(30/38),and the difference has a statistical significance(χ~2=8.862,P=0.003).The positive rate of Tim-3 in erosion OLP is 68.2%(15/22),while in non-erosion OLP is 94.7%(36/38),and the difference is statistically significant(χ~2=5.764,P=0.016).4.There is a strong positive correlation between PD-1 and Tim-3 expression in OLP tissues(r=0.279,P=0.031).conclusions1.The expression of PD-1 and Tim-3 is elevated in OLP tissues compared to normal oral mucosal tissues which suggests that the fuction of T cells are inhibited in the local lesion of OLP.2.The expression of PD-1 and Tim-3 are negatively correlated with the activity of OLP which suggests that the expression of PD-1 and Tim-3 are closely related to the function of T cells.3.There is a strong positive correlation between PD-1 and Tim-3 expression in OLP tissues which suggests that PD-1 and Tim-3 can coexpression in OLP.4.Maybe PD-1 and Tim-3 are biomarkers of OLP,and they will be the immune therapeutic targets of OLP.