First histopathological and immunophenotypic analysis of early dynamic events in a patient with segmental vitiligo associated with halo nevi.

Segmental vitiligo is often ascribed to the neurogenic theory of melanocyte destruction, although data about the initial etiopathological events are scarce. Clinical, histopathological and T-cell phenotypic analyses were performed during the early onset of a segmental vitiligo lesion in a patient with associated halo nevi. Histopathological analysis revealed a lymphocytic infiltrate, mainly composed of CD8+ T-cells and some CD4(+) T-cells around the dermo-epidermal junction. Flow cytometry analysis of resident T-cells revealed a clear enrichment of pro-inflammatory IFN-gamma producing CD8+ T-cells in lesional skin compared to the non-lesional skin. Using human leukocyte antigen-peptide tetramers (MART-1, tyrosinase, gp100), increased numbers of T cells, recognizing melanocyte antigens were found in segmental vitiligo lesional skin, as compared with the non-lesional skin and the blood. Our findings indicate that a CD8+ melanocyte specific T cell-mediated immune response, as observed in generalized vitiligo, also plays a role in segmental vitiligo with associated halo nevi.