Infiltrating CD4+ T helper (Th) cells enhance expression of adhesion molecules and secrete cytokines depending on signals from the local microenvironment, which induce more Th cells to migrate, altering the balance toward pathology.2 Furthermore, we previously reported that Th cells are involved in the pathogenesis of OLP; in particular, we reported that the potential antigen recognized by these Th cells was derived from basal epithelial cells.3 Identification of the specificity of Th cells is one of the most important steps to reveal the pathogenesis and etiology of OLP. The gene discussed is CD4; the disease is oral lichen planus.