PRESENCE OR ABSENCE OF MELANOCYTES IN VITILIGO LESIONS - AN IMMUNOHISTOCHEMICAL INVESTIGATION

There is a long-standing controversy over whether melanocytes in vitil igo lesions are actually lost or are still present but inactivated. Re solving this matter is essential for understanding the underlying path ology and for the development of treatment. Standard methods of detect ing melanocytes are based on active melanin synthesis. However, it is possible that inactive melanocytes remain in the lesions. There are no methods presently available to detect such dormant melanocytes. Using a panel of one polyclonal and 17 monoclonal antibodies directed again st melanocytic cells (largely selected by the European Organisation fo r Research and Treatment of Cancer Melanoma Group for diagnostic and t herapeutic purposes), we investigated the absence or inactivation of m elanocytes in vitiligo by immunohistochemistry. Results using this pan el of antibodies on frozen skin sections suggest that melanocytes are indeed absent in the lesions. However, in epidermal split-skin prepara tions, residual staining was occasionally observed. To determine wheth er the staining obtained was due to degenerated melanocytes, confocal laser scanning microscopy was used. Immunofluorescent staining using t he antibody NKI-beteb confirmed this to be the case. The results prese nted here strongly suggest that melanocytes are indeed lost in vitilig o lesions.