Immunohistochemical analysis of melanocyte content in different zones of vitiligo lesions using the Melan-A marker.

INTRODUCTION: Occurence of vitiligo lesions is caused by the destruction of melanocytes in a ected skin and therefore by the re- duction of pigment melanin content. Questions remain about the presence of residual melanocytes in the depigmented skin and optimal methods of their identi cation. METHODS: Skin biopsy samples from 16 patients with non-segmental vitiligo and from 10 healthy volunteers were investigated for Melan-A (A103 clone)+ melanocytes expression by immunohistochemical analysis and for melanin by histochemical studies with section staining by Fontana-Masson method. RESULTS: For some patients including those with long-standing disease (up to 40 years) Melan-A+ cells and melanin granules were detected in depigmented skin as indication that the residual melanocytes are preserved in vitiligo lesions. More than three-fold decrease of Melan-A+ melanocytes amount was revealed in perilesional normally pigmented skin of vitiligo patients (P < 0.001) compared with the skin of healthy volunteers. Clinically intact skin involvement in the pathological process should be taken into consideration if local treatment methods are prescribed. CONCLUSION: In some vitiligo patients the residual melanocytes are preserved in depigmented skin. Melan-A marker is useful for identi cation of melanocytes in vitiligo patients' skin.

Characterization of lymphocyte surface markers in patients with vitiligo.

It was demonstrated that all vitiligo patients, independently of the disease stage, have a significant decrease in the total number of T cells and an elevated level of peripheral blood lymphocytes and activated natural killers (CD56). The low level of T lymphocytes is associated with the increase in the number of CD3(+)4(+)8(+) cells, which are characterized by a faster apoptosis induction. The elevated level of B lymphocytes in peripheral blood in vitiligo is due to the significant increase in the number of B cells of all the stages of differentiation, suggesting a general activation of the whole B-cell immunity. Perhaps, it is associated with the continuous stimulations of B cells by the type 2 helper lymphocytes. The Th2 lymphocyte mediators, including IL-4, do not only stimulate of B-cell immunity, but also regulate maturation of NK cells. It is typical for vitiligo that the level of mature B cells responsible for Ig synthesis (CD38(+), mIgM(+), mIgG(+)) stays elevated even in remission. Moreover, a considerable increase in the number of peripheral blood lymphocytes expressing the adhesion receptor CD54 is observed, which most likely reflects that the blood lymphocytes are highly prepared for tissue migration.