CCL5 and oral lichen planus: Once keratinocytes are activated, they can secrete a variety of inflammatory mediators, including C–C motif chemokine (CCL)5, tumor necrosis factor (TNF)‐α, and interleukin (IL)−1β; recruit inflammatory cells to mediate the development of OLP; amplify inflammatory signals; and promote the chronic progression of OLP.10, 11