TGFB1 and vitiligo: Although the previous studies strongly suggest the key role of Treg cells in vitiligo pathogenesis [8, 14, 17–21], the role of Tregs in vitiligo patients' peripheral immunological tolerance is still being contested, as few findings suggest increased or unaltered Treg cells' frequency [33–35], Tregs' suppressive function [14], FOXP3 [14, 33], and TGF-β [24, 36, 37] expression in vitiligo patients.