Objective To evaluate the expression of CD4+, CD8+T cells and cell apoptosis in oral lichen planus （OLP） and investigate the role and the relationship of immunological reaction and cell apoptosis in the pathogenesis of OLP. Methods Immunohistochemical technique was used to study the expression of CD4+, CD8+T cells in 27 OLP cases. TUNEL was used for detecting the cell apoptotic index（AI） in 17 OLP cases. Results The expression of CD4+, CD8+T cells were obviously elevated in lamina propria of OLP group compared with control group（P＜0.05）. There was a strong significance when compared the ration of CD4/CD8 in both group. AI was remarkably increased in epithelia cells and significantly decreased in lymphocytes in lamina propria in OLP cases compared with its expression in the control group respectively. Conclusion The increased amount of CD4+, CD8+T cells in lamina propria of OLP and the change ration of CD4/CD8 suggest that immune response is involved in the pathogenesis of OLP. The abnormal cell apoptosis plays an important role in the pathogenesis of OLP.
