Immune-Dysregulation of T Helper Cells in Vitiligo
The numbers of circulating Th1 and Th17 cells are increased in vitiligo compared to controls [90]. A mouse model of vitiligo shows a predominantly Th1-mediated pattern with a dominant role of CXCL10 [73]. Serum levels of interleukin 17 (IL-17), the effector molecule of Th17 cells, are raised in vitiligo patients, and IL-17 mRNA is elevated in their skin, implying a role for Th17 cells in driving the inflammatory response [91]. Recently, decreased frequencies of circulating Th1/Tc1, Th17/Tc17 and Th1/Th17-Tc1/Tc17 cells were shown in patients with vitiligo, suggesting possible migration of these cells into the skin [92]. Indeed, Th1/Th17, Tc1/Tc17 and Th17 cells have been touted as potential targets for therapy [93].