IL17A and oral lichen planus: In this study, we thus investigated the expression of infiltrating lymphocyte subsets (CD3, CD20, CD4, and CD8) and T helper (Th) cytokines including interferon (IFN)-γ (Th1 type), interleukin (IL)-4 (Th2 type), IL-17 (Th17 type), and IL-10 (regulatory T cell type) by immunohistochemistry in buccal mucosa specimens from 2 GS patients compared with 15 OLP patients.