HO‐1 has been proved to modulate the function of Tregs.12 For instance, enhanced HO‐1 is necessary for the regulation of Tregs on the balance of Th1/Th2 response in Spesis,13 while the blockage of HO‐1 abrogates the protective effect of Treg on immune homoeostasis during murine pregnancy.14 Given that the level of HO‐1 is significantly decreased in vitiligo,15 we hypothesized the deficiency of HO‐1 may be a key reason for the impaired function of Tregs in vitiligo. The gene discussed is HMOX1; the disease is vitiligo.