Potential Different Immune Phenotypes of Macrophages in Oral Lichen Planus by Integrating Immunofluorescence Double Staining and Single-Cell RNA Sequencing

Background/purposeOral lichen planus (OLP) is a chronic inflammatory disease with obscure etiopathogenesis. Macrophages play an important role in interaction between innate and adaptive immunity. This study aimed to investigate the macrophage phenotypes and obtain more comprehensive gene characteristics of macrophages in OLP.Materials and methodsDouble cluster of differentiation (CD) 68/CD86 and CD68/CD206 immunofluorescence staining was conducted in 11 biopsy-proven OLP tissue samples and 5 health control (HC) to represent M1 and M2 macrophages, respectively. The number of positively stained cells was manually counted, and the density was calculated. Furtherly, OLP single-cell dataset GSE211630 was downloaded from Gene Expression Omnibus. Gene characteristics and functional analysis of the macrophages were elucidated.ResultsIn the OLP group, the densities of M1 (P < 0.001), M2 macrophages (P < 0.001) and M1/M2 ratio (P = 0.001) were significantly higher than those in HC group. Single-cell RNA sequencing revealed that proportions of CXCL10 macrophages (P = 0.003), IL1B/MMP19 macrophages (P < 0.001) were increased in OLP tissues compared with those in HC. Macrophages in OLP tissues had a stronger ability to cell chemotaxis, positive regulation of cell adhesion and antigen processing and presentation. Functional analysis revealed macrophages in OLP tissues could interact with multiple immune cells, and multiple signaling pathways were associated with macrophages in OLP.ConclusionA pro-inflammatory status of macrophages with different gene characteristics was found in the microenvironment of OLP by integrating immunofluorescence double staining and single-cell RNA sequencing, which provided a potential target for clinical treatment of OLP.