CD1a+ dendritic cells in oral lichen planus and amalgam lichenoid reaction

To evaluate and compare the number of CD1a+ dendritic cells (DCs) in oral lichen planus (OLP), amalgam lichenoid reaction (ALR), and normal oral mucosa (NOM).

Fourteen cases of OLP and ALR, diagnosed both clinically and histologically, were obtained from an archive of an oral pathology service. Seven specimens of NOM were collected and served as controls. Immunohistochemistry was used to identify CD1a+ DCs. Densities were calculated using specimens of epithelium and lamina propria. For OLP and ALR, specimens of lamina propria included cells from inflammatory infiltrate (region A), and from below inflammatory infiltrate (region B). Comparisons and statistical analyses were performed among OLP, ALR, and NOM.

A higher density of CD1a+ DCs was observed in OLP compared to ALR in region A (P < .05) and regions A+B (P < .05). A higher density of CD1a+ DCs was also observed in OLP compared with NOM in the regions A+B (P < .05). Statistically significant differences were not observed for analyses involving epithelial tissue.

The observation that there is a lower quantity of DCs in ALR specimens compared with specimens from individuals with OLP suggests that the role for DCs in the 2 diseases may be different. The difference in cell density could be used in the differential diagnosis of these 2 diseases, but the overlapping intervals in the statistical analysis may limit the application of this approach in surgical practice.