Assessment of tissue FoxP3+, CD4+ and CD8+ T-cells in active and stable nonsegmental vitiligo

The exact etiology of vitiligo remains obscure. Studies have indicated a role for cellular immunity in the pathogenesis of vitiligo. The aim of this study is to assess tissue FoxP3+ natural regulatory T-cells (Tregs), as well as CD4+ and CD8+ T-cells in active vs. stable nonsegmental vitiligo.

Immunohistochemical double-staining for expression of CD4+ and CD8+ T-cells with immunostaining for expression of FoxP3 in lesional, marginal, and nonlesional skin of nonsegmental vitiligo was used to evaluate the abundance of Tregs among CD4+ and CD8+ T-cells in active and stable cases of vitiligo.

A significant increase in the number of CD4+ and CD8+ T-cells and a highly significant reduction in the number of FoxP3-expressing Tregs were detected in marginal skin in both stable and active vitiligo cases. FoxP3+ cells were decreased in tissue of patients with vitiligo compared with healthy controls. The number of CD8+ T-cells was increased in the epidermis and dermoepidermal junction (DEJ) in comparison with the number of CD4+ T-cells. Tregs were mostly present at the DEJ.

The reduction in the number of FoxP3+ cells in the marginal skin suggests that this is the site where regulatory activity is needed to suppress the activity of helper and cytotoxic T-cells that are actively contributing to depigmentation.