Objective     To study the expression of granzyme B and perforin and the effect of cytotoxin on apoptosis of epithelial cells in oral lichen planus（OLP）with lymphocyte infiltration by detecting the apoptosis of epithelial cells.      Methods     Apoptosis of epithelial cells in OLP with lymphocyte infiltration was detected with the terminal deoxymuleotigyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) technique. Expression of granzym

e B and perfoin in lymphocytes and CD8

+

cells was detected with the immunohistochemcial method. Normal oral mucosa（NOM）was used as a control.      Results     The apoptosis level of epithelial cells and the expression level of granzyme B and perforin were significantly higher in epithelium of OLP than in control（P0.05）. Some positive cells were observed in the basal lamina of epithelium. The double positive expression levels of CD8

+

/granzyme B

+

and CD8

+

/perfoin

+

were significantly higher in OLP than in control（P0.05）. The apoptosis of epithelial cells in OLP was positively correlated with the expression of granzyme B and perfoin in OLP with lymphocyte infiltration（r=0.56

r=0.42

P0.05）.       Conclusion     Increased expression of granzyme B and perfoin in OLP with lymphocyte infiltration

including CD8

+

T cells

suggests that lymphocytes in OLP may attack oral epithelial cells as a cytotoxin of granzyme B and perfoin

thus leading to apoptosis of oral epithelial cells.