Molecular analysis of vitiligo lesions reveals sporadic melanocyte survival

Vitiligo is a depigmenting disease of uncertain aetio-pathogenesis. Although accepted as dogma, the question of whether melanocytes survive in vitiligo lesions has not been adequately resolved. Defining with greater accuracy the melanocyte status of lesions would contribute greatly towards the understanding of the etiology, progression and treatment of this disorder. We have therefore revisited this issue by carrying out a molecular screen for melanocytes in lesional skin using the sensitive and specific technique of reverse transcription PCR (RT-PCR) followed by Southern blotting. Biopsies from vitiligo lesions and normal skin were obtained from 15 patients. The RT-PCR was carried out using primers for tyrosinase and dopa-chrome tautomerase (DCT). To increase the sensitivity of detection, Southern-blot analysis of all PCR products was conducted. Southern-blot analysis indicated that three lesional samples were positive: one for tyrosinase, one for DCT, and one for both. Lesions yielding positive results had been present for between 2-5 years and were inactive, as defined by no disease progression within the last 3 months. Some vitiligo lesions showed evidence of melanocyte survival, even after some years. These results open the way for the possibility of using a range of melanocyte-specific markers for molecular staging of lesional status by quantitative RT-PCR. Such information would be extremely valuable for the appropriate selection and potential success of medical therapies.