Vitiligo Skin Is Imprinted with Resident Memory CD8 T Cells Expressing CXCR3

Vitiligo is a chronic autoimmune depigmenting skin disorder that results from a loss of melanocytes. Multiple combinatorial factors have been involved in disease development, with a prominent role of the immune system, in particular T cells. After repigmentation, vitiligo frequently recurs in the same area, suggesting that vitiligo could involve the presence of resident memory T cells (T_RM). We sought to perform a thorough characterization of the phenotype and function of skin memory T cells in vitiligo. We show that stable and active vitiligo perilesional skin is enriched with a population of CD8 T_RM expressing both CD69 and CD103 compared with psoriasis and control unaffected skin. CD8 T_RM expressing CD103 are mainly localized in the epidermis. Expression of CXCR3 is observed on most CD8 T_RM in vitiligo, including the population of melanocyte-specific CD8 T cells. CD8 T_RM displayed increased production of IFN-γ and tumor necrosis factor-α with moderate cytotoxic activity. Our study highlights the presence of functional CD8 T_RM in both stable and active vitiligo, reinforcing the concept of vitiligo as an immune memory skin disease. The CD8 T_RM that remain in stable disease could play a role during disease flares, emphasizing the interest in targeting this cell subset in vitiligo.