An immunohistological study of cutaneous lymphocytes in vitiligo.

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.