Activation marker analysis of mononuclear cell infiltrates of oral lichen planus in situ.

Monoclonal activation markers (Ia, Tac, T9, and 4F2) were used to detect the degree of activation of mononuclear cells in the inflammatory infiltrates of oral lichen planus in situ. In addition the specimens were stained with the following monoclonal antibodies: T4, T8, T11, M1, and pan-B. T-lymphocyte was the predominant cell type in the inflammatory infiltrates. According to the results of the activation marker analysis, the majority of the T-lymphocytes were resting. However, activated cytotoxic T8 and 4F2 T-cells were located close to damaged basal cells; this finding may suggest that they are responsible for the damage and supports the claim that a cell-mediated immune response participates actively in local pathogenetic mechanisms in oral lichen planus.