Involvement of T cells in early evolving segmental vitiligo.

Recent studies have suggested an overlapping autoimmune mechanism between segmental vitiligo (SV) and nonsegmental vitiligo (NSV). Although T-cell infiltration is observed in the margins of active lesions in NSV, the histopathological characteristics of the active margin of SV are not well known. To determine if T-cell inflammatory responses are present in the active margin of SV lesions, biopsies were taken from the active margin of a lesion in 12 patients with early or actively spreading SV and compared with a normal control sample (on the symmetrical, opposite site of the same dermatome). The samples were stained for CD4, CD8, CD25 and interferon-γ. Lymphocytic infiltration was seen in 70% of patients. CD4+ T cells infiltrated the dermis, while CD8+ T cells were present in the epidermis or attached to the basal layer. The increase in the number of CD8+ T cells was significant (P < 0.04), while CD4+ or CD25+ T cells also appeared to be increased in number, but this was not significant. These results suggest that SV also has an autoimmune mechanism in the early evolving stage.