Mast cell - Melanocyte axis mediates pathogenesis in Oral Lichen Planus

• Main Authors: Komali Rajkumar, Venkatesh Vishwanath Kamath, Rangaswamy Meenakshisundaram Lavanya
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2014-01-01
• Series: Journal of Dental Research and Review
• Subjects: auto-immune disroder; mast cells; melanocytes; pathogensis; oral lichen planus
• Online Access: http://www.jdrr.org/article.asp?issn=2348-2915;year=2014;volume=1;issue=3;spage=143;epage=147;aulast=Rajkumar
• ISSN: 2348-2915; 2348-3172

Background: Oral Lichen Planus (OLP) is a cell-mediated inflammatory condition of the oral cavity with propensity for malignant transformation. Often classified as an autoimmune disorder, the pathogenesis of the lesion is still under debate. The presence of mast cells (MCs) and melanocytes (MNs) has been identified as an integral part of the cellular reaction in all stages of the disorder. Aims: The present study aims to qualify, localize and quantify MCs and MNs in OLP and normal oral mucosa (NOM) using special stains and image analysis software. Computations and correlations between the numbers and localization of the cells in different layers of the tissue were done.Materials and Methods: Thirty cases of OLP and 10 cases of NOM were included. MCs were identified by their metachromasia using Toluidine blue and the MNs by Masson′s Fontana stain. A localization and quantification of the numbers of the two cell groups was done by image analysis and statistically correlated by two sample t-test. Results: The total count of mast cells and melanocytes was more in OLP in comparison to that of NOM. The MCs were present in the deeper tissues in contrast to MNs which were localized only to the basal and sub-basal areas. MNs appeared to proliferate and migrate to the subepithelial areas in OLPs in contrast to their strong localization to the basal layer in NOM. The ratio of MCs/MNs was higher in OLP compared with NOM. Interestingly the toluidine blue stain showed cross-sensitivity in expression of both MCs and MNs in OLP. Conclusion: MCs and MNs are expressed in increased numbers in OLP and probably have a synergistic mode of action in the pathogenesis of the disorder. The spilling out of MNs in OLP to the sub-basal areas is consistent with the clinical observation of pigmentation in healed/under remission OLP cases.