Langerin-expressing and CD83-expressing cells in oral lichen planus lesions

Objective. Dendritic Langerhans cells (LCs) have been attributed a role in the pathogenesis of lichen planus as autoantigen- presenting cells initiating expansion of autoreactive T cells. Langerin and CD83, which are cell molecules expressed on LCs, are associated with antigen presentation. The present study examined expression of Langerin and CD83 molecules on LCs in patients with oral lichen planus (OLP). Material and methods. Biopsies were obtained from seven patients with OLP. Oral mucosa from seven healthy subjects served as controls. Monoclonal antibodies (mAbs) were used in standard immunohistochemical procedures to visualize CD1a-, Langerin-, and CD83-molecule- expressing cells. Results. CD1a + and Langerin + cells were found in significantly higher frequencies in OLP epithelium compared with healthy oral epithelium (p < 0.01 and p < 0.05, respectively); however, the frequency of CD83+ cells did not differ (p < 0.05). The connective tissue in OLP lesions showed significantly higher frequencies of CD1a +, Langerin +, and CD83+ cells compared with healthy connective tissue (p < 0.01, p < 0.01, and pB/ 0.05). CD1a + and Langerin + cells in OLP and healthy epithelium had a dendritic morphology. Conclusions. The study shows increased numbers of CD1a- and Langerin- expressing LCs in OLP compared with healthy controls. In the connective tissue, CD83+ cells with dendritic morphology were localized to regions of lymphocyte clusters. The presence of CD83+ dendritic cells in areas of lymphocyte clusters in the connective tissue of OLP lesions indicates the possibility of ongoing autoantigen presentation.