TGFB1 and vitiligo: We found that the expressions of foxp3 is significantly up‐regulated(Figure S1), and correspondingly, LAP and IL‐10 were significantly up‐regulated in Hemin‐treated Tregs compared with that in untreated Tregs (Figure 5A‐D), although CTLA‐4 expression showed no alteration in both groups (Figure 5E,F), demonstrating that Hemin could promote the production of immunosuppressive cytokines including LAP and IL‐10 in vitiligo Tregs.