IMMUNOHISTOCHEMICAL ANALYSIS OF MELANOCYTE CONTENT IN LESIONAL, PERILESIONAL AND UNINVOLVED SKIN OF VITILIGO USING THE MELAN- A MARKER.

Background: Vitiligo is an acquired disease characterized by progressive skin depigmentation resulting from an autoimmune response targeting epidermal melanocytes. Few studies have shown specific cytotoxic T-lymphocyte response against Melan -- A which is the most specific marker of melanocytes. There are also other studies which have confirmed the presence of residual melanocytes even in the vitiliginous skin. Objectives: To evaluate the melanocyte content in lesional, perilesional [within 2 cm] and distant normal skin of non- segmental vitiligo patients. Materials and Methods: A total of 40 cases of non-segmental were enrolled in the study based on the prevelance of vitiligo in India. After taking informed consent, skin biopsy from the lesional, perilesional and normal skin was sent to pathology for immunohistochemical analysis of melanocyte content in the above zones using Melan -- A marker. Results: All 40 lesional sites were negative for Melan-A staining. The Melan-A positive melanocytes were reduced in immediate perilesional skin compared to distant normal skin. Paired t-test was applied between perilesional skin and normal skin and the result was statistically significant at p<0.001. Conclusion: Melan-A positive residual melanocytes were not present in the lesional skin in our study as opposed to very few studies which confirmed their presence in the vitiliginous skin even in the long standing cases. But there was significant difference between perilesional and normal skin. [ABSTRACT FROM AUTHOR]