IL4 and oral lichen planus: In OLP, several inflammatory cytokines, such as interleukin (IL)‐2, IL‐4, IL‐6, IL‐8, IL‐10, IL‐12, IL‐17, interferon (IFN)‐γ, and tumor necrosis factor (TNF)‐α, have been shown to have abnormal expression patterns.7, 8, 9 However, the production and regulation of cytokines is complex.