Photodynamic treatment of oral lichen planus

Abstract

Objectives: The aim of this study was to examine the clinical behavior and response to topical methyl 5-aminolevulinate (MAL) photodynamic therapy (PDT) of oral lichen planus and to describe the buildup and biodistribution of photoactive porphyrins in normal and lichen planus-affected oral mucosa after MAL application.

Study design: The difference in clinical expression in 14 patients with buccal oral lichen planus was compared before and after treatment. MAL-induced photoactive porphyrins were monitored using noninvasive in situ fluorescence measurements. Microfluorometry was used to study the biodistribution.

Results: The absorption and conversion of protoporphyrin IX (PpIX) in epithelial and subepithelial T cells was demonstrated in histologic sections. As a result of 1 treatment session, there was a significant improvement of oral lichen planus after 6 months (P = 0.02) and during a 4-year follow-up period.

Conclusions: MAL is absorbed and converted to PpIX in T cells. Oral lichen planus treated with MAL-PDT showed lasting improvement after a single treatment.