HMOX1 and vitiligo: Furthermore, in human studies, tacrolimus, miR-155, and HO-1 increase the IL-10 expression in vitiligo lesions, whereas narrow band-UVB phototherapy, miR-21-5p, and miR-155 enhance the Tregs' frequency and FOXP3 levels, thereby suppressing the melanocyte destruction caused by unregulated Th1 pathways [19, 21, 48, 49, 52].