CD4 and oral lichen planus: Since epithelial cells and T cells play a major role in the pathogenic mechanisms currently known for OLP, and given the observed shifts in cell type of T cells and epithelial cells with specific differential states, we further performed the ligand-receptor analyses on the specific subcluster of SFRP2+ fibroblasts (subcluster1-5), epithelial cells (basal, spinous, supraspinous) and T cells (cytotoxic CD8+ T cells, exhausted CD8+ T cells, naïve CD4+ T cells, naïve CD8+ T cells, Treg).