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Vitiligo: characterization of melanocytes in repigmented skin after punch grafting
Author(s) -
Kovacs D.,
AbdelRaouf H.,
AlKhayyat M.,
AbdelAzeem E.,
Hanna M.R.,
Cota C.,
Picardo M.,
Anbar T.S.
Publication year - 2015
Publication title -
journal of the european academy of dermatology and venereology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.655
H-Index - 107
eISSN - 1468-3083
pISSN - 0926-9959
DOI - 10.1111/jdv.12647
Subject(s) - vitiligo , melanocyte , medicine , immunohistochemistry , pathology , microphthalmia associated transcription factor , ex vivo , in vivo , dermatology , biology , melanoma , cancer research , tyrosinase , microbiology and biotechnology , enzyme , biochemistry
Background Punch grafting is a surgical technique mainly applied in therapy‐resistant, stable and circumscribed vitiligo. Objective (i) To characterize in detail the features of the repigmented skin among punch grafts; and (ii) to correlate the ex vivo results with clinical data and punch grafting outcome. Methods We evaluated by immunohistochemistry and image analysis the expression of a panel of specific melanocyte markers including HMB 45, MITF , c‐kit, MART ‐1 and TRP 1, the proliferation marker Ki67 and the cell–cell adhesion molecule E‐cadherin in tissue samples collected from nine patients after punch grafting. Results Cells positive for MITF , c‐kit, MART ‐1 and TRP 1 were detected in the repigmented skin of all biopsies, whereas no reactivity was observed for HMB 45. Melanocytes were identified along the entire length of the sections, and their mature state was assessed by the immuno‐reactivity for the differentiation marker MART ‐1, the absence of cells positively stained for Ki67 and by the co‐expression of c‐kit and TRP 1, a marker of a differentiated and pigmented state. Clinically, smaller punch grafts aimed at repigmenting lesional areas on the face gave the faster clinical results with no side‐effects. Patients subjected to bigger punch grafts on the knee exhibited a longer repigmentation time and presented cobble stoning. Conclusion Our results suggest that the repigmentation observed in the areas between the grafts is due to the activation of the melanocytes located in the donor sites. These cells start to horizontally migrate towards the lesional skin thanks to successively the enlargement of intercellular spaces in relation to a decrease of E‐cadherin reactivity and the up‐modulation of pro‐melanogenic mediators. Production and transfer of melanin in the surrounding keratinocytes and their persistence were assessed by the reactivity for MITF , c‐kit, MART ‐1 and TRP 1 but not for the pre‐melanosome marker ( HMB 45).