An immunohistological study of cutaneous lymphocytes in vitiligo

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Abstract
In a study of 49 biopsies from the margins of depigmented cutaneous lesions in 18 patients with vitiligo, highly significant overall increases were found in CD3+, CD4+, and CD8+ T cells, though cell numbers in individual cases were often within the normal range. Many of the T cells were activated (MHC class II+, interferon gamma+), of CD45RO (UCHL1+) memory subset, and many expressed the cutaneous lymphocyte‐associated antigen (HECA‐452+) typical of skin‐homing T cells. Immunohistologically, the most intense epidermal T‐cell infiltration was present within 0.6 mm of the edge of the lesion in 10 of 13 double‐stained sections with a clearly defined zone of melanocyte depletion. In 40 lesions from 17 patients seen 11–64 weeks after biopsy, no apparent association was found between T‐cell numbers and disease activity as assessed by Köbnerization of biopsy wounds or spread of depigmentation. These findings are consistent with the hypothesis that lesional T cells rather than circulating antimelanocytic antibody may be responsible for the supposedly autoimmune but characteristically patchy destruction of cutaneous melanocytes in vitiligo. Nevertheless, many of the infiltrating T cells are probably innocent bystanders attracted by upregulated cell adhesion molecules near sites of melanocyte damage.