CD8A and oral lichen planus: Oral lichen planus (OLP) is a chronic inflammatory immune mediated disease of unknown cause, in which T lymphocytes attack multi-layer flat epithelial cells.1,2 Most infiltrating lymphocytes seen in OLP are CD8+, so the condition probably results from a cytotoxic autoimmune response.3 Furthermore, CD4+ T lymphocytes increase the cytotoxicity of CD8+ lymphocytes by infiltrating OLP lesions.