Epithelial cell proliferation of oral lichen planus in patients treated with an aromatic retinoid

In 4 patients with lichen planus mucosae (l.p.m.) biopsies were taken from the involved and uninvolved buccal sides before treatment and from the affected side after a 3-week systemic therapy with aromatic retinoid (Ro 10-9359; 50 mg/die). After in vitro labelling with 3H-thymidine the epithelial cell proliferation was determined histo-autoradiographically. In atrophic lesions of l.p.m., increased 3H-thymidine labelling indices were observed during retinoid therapy. After 3 weeks of treatment the augmented relative portion of labelled basal cells (quotient LIbas/LIsuprabas) was found to be lowered, indicating a tendency of proliferating cells to regain normal distribution in the progenitor compartment of the mucosa epithelium.