Poster presentation, P59

Official XXIst International Pigment Cell Conference website - 21-24 Sept 2011, Bordeaux - France | updated: September 04 2011

New in vivo vitiligo induction and therapy model: proof of concept

SPEAKER R. Speeckaert #whois submiter ?
AUTHOR(s) N. Van Geel, R. Speeckaert, I. Mollet, S. De Schepper, E. Tjin, R. Luiten, L. Brochez, J. Lambert

BACKGROUND AND OBJECTIVES: Tissue damage can cause new lesions in vitiligo (= Koebner’s phenomenon). The aim of our study was to develop an in vivo vitiligo induction model to explore the underlying mechanisms leading to Koebner’s phenomenon and to evaluate the effect of therapeutic strategies on this process. METHODS: Twelve pigmented test regions (2.5x2.5cm) on the back of 3 generalized vitiligo patients were exposed to 3 different Koebner induction methods: cryotherapy, 755nm laser therapy and CO2-laser abrasion. In addition, 4 cream treatments (pimecrolimus, tacrolimus, local steroid and placebo) were randomly applied (day 0, 3 and 6). Surface measurement of skin depigmentation per test region was performed at different time points using ImageJ software. Skin biopsies were taken for immunohistochemical stainings (CD3, CD4, CD8, CD1a, Foxp3). In 1 patient lesional lymphocytes were isolated and stained with HLA-A2 tetramers for MART-1, gp100 and tyrosinase. RESULTS: Koebnerisation was efficiently induced in all 3 patients, resulting in patterns of depigmentation which differed between the patients according to the induction method. Strong significantly higher percentages of depigmentation were observed at placebo treated sites compared to therapeutic test regions (p<0.001). The therapeutic methods showed in all patients reproducible results and pointed to tacrolimus and local steroids as significantly better inhibitors of Koebner’s process (p<0.05) compared to pimecrolimus. The most pronounced lymphocytic infiltrate and the highest percentage of gp100 and MART-1 CD8 cells were observed at placebo treated sites. CONCLUSION: This is a very informative model to investigate vitiligo induction. This proof of concept confirms the efficient comparison of head to head therapeutic strategies intra-individually in a standardized, specific and better timed way.



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