CD4 and oral lichen planus: The FOXP3/miR-146a/NF-κB axis was previously reported to modulate the induction and function of CD4+ Treg cells to alleviate oral lichen planus, while other signaling pathways including microRNA-155-IFN-γ loop and FOXP3/miR-146a/TRAF6 pathways are involved in the pathogenesis of oral lichen planus (Wang et al. 2018, 2019; Hu et al. 2015).