Direct immunofluorescence in oral lichen planus.

Direct immunofluorescent staining (DIF) was performed on biopsy specimens from thirty-five patients with oral lichen planus. The results showed fibrin deposition in all cases at the mucosal-submucosal interface, within colloid bodies (fourteen of thirty-five) and within vascular walls (five of thirty-five). Deposition of IgG, IgA and IgM was detected to a lesser extent, while complement (C3) could not be identified in any case. The significance of these findings was assessed by comparison with the IF results obtained in thirty-five biopsies from various oral diseases other than lichen planus and ten healty persons. Although the presence of fibrin deposition at the mucosal-submucosal junction, within vessels and cytoid bodies, was found to be highly characteristic of lichen planus, these findings were not specifically diagnostic. Morphologically identical deposits were also seen in lupus erythematosus. It is known at present whether immunologic reactions may play a role in the pathogenesis of lichen planus. However, the immunopathologic findings may occasionally be additional suggestive markers in the diagnosis of the disease.