Macrophages in oral lichen planus

The presence and distribution of macrophages within 15 non-ulcerated lesions of oral lichen planus was investigated using an immunoperoxidase technique for the detection of the macrophage markers lysozyme and alpha 1 antitrypsin. All specimens contained mononuclear lysozyme and alpha 1 antitrypsin positive cells which were concentrated in a band immediately beneath the epithelium and often associated with areas of damaged basal cells. Cell counts revealed that 11% of the positive cells were in the epithelium and 89% in the lamina propria. Approximately 61% of all positive cells were found within a 125 micron wide zone centred on the basement membrane. These results suggest that in oral lichen planus macrophages are in close proximity to the epithelial basal cells, where cell damage occurs, and play a role in the pathogenesis of this condition.