Immunophenotypic analysis reveals differences in circulating immune cells in peripheral blood of segmental and non-segmental vitiligo patients.

Abstract

Accumulating studies have indicated immune-based destruction of melanocytes in both segmental vitiligo (SV) and non-segmental vitiligo (NSV). Whereas SV often occurs unilaterally during childhood and stabilizes after an initial period of activity, the disease course of NSV is usually slowly progressive, with new lesions occurring bilaterally during life. This suggests involvement of distinct pathophysiology pathways, specifically increased systemic immune activation in NSV patients, but not in SV patients. This research aimed to identify differences in immune cells in blood of patients with SV and NSV, through immunophenotyping of circulating cells. Regulatory T cells (Tregs) were unaffected in patients with SV compared to healthy controls, but decreased in NSV patients. In NSV patients, the reduction in Tregs was associated with presence of other systemic autoimmune comorbidities, which were less present in SV. Likewise, absence of a melanocyte-specific antibody response in patients with SV, suggests less involvement of B cell immunity in SV. These data show that, in contrast to NSV, no increased systemic immunity is found in SV patients, indicating that SV pathogenesis is associated with a localized cytotoxic reaction targeting epidermal melanocytes.