A POSSIBLE ROLE OF MAST CELL TRYPTASE AND PROTEINASE-ACTIVATED RECEPTOR-2 IN THE PATHOGENESIS OF ORAL LICHEN PLANUS

Oral lichen planus (OLP) is a relatively common chronic inflammatory disease. In contrast to self-limiting and pruritic cutaneous lichen planus (LP), oral lesions in OLP are potentially premalignant and rarely undergo spontaneous remission. Several observations are in favour of an important role of serine proteases (such as MCT) in regulating of skin homeostasis, dermo-epidermal barrier function, cell differentiation, tumour growth and invasion. Moreover, they activate a novel subfamily of G protein-coupled, defined as proteinase-activated receptors (PARs). Both antigen-specific and non-specific mechanisms may be involved in the pathogenesis of OLP. However, the pathogenesis of OLP is not fully understood, therefore we investigated the expression and possible role of mast cell tryptase (MCT) and Proteinase-activated Receptor-2 (PAR-2) in both cutaneous and oral lesions of LP. The sudy is the first to examine MCT and PAR-2 expression in OLP. Mast cell de-granulation in OLP and releases of pro-inflammatory mediators, such as MCT, may be involved in non-specific mechanisms in the pathogenesis of OLP. PAR-2 may also play a role in the pathogenesis of the disease. However, more studies are required for full understanding of OLP pathogenesis.