IL17A and oral lichen planus: For refractory cases, biologics (adalimumab, alefacept, etanercept, guselkumab, rituximab, secukinumab, tildrakizumab, and ustekinumab) have been used to control OLP by regulating the expression of cluster of differentiation 2 (CD2), tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL2), interleukin-17 (IL17), interleukin-12/23 (IL12/23), etc [11, 24, 25].