FOXP3 and colitis: This finding is in line with a recent study by Shaw et al which showed that FOXP3+ Treg-cell frequencies gradually increase with colitis severity in intestinal biopsies of people with PSC-IBD.46 Nevertheless, potential differences in the suppressive capabilities of colonic FOXP3+ Treg cells from people with IBD and PSC-IBD have not been assessed in this study and by Shaw et al. 46 Thus further studies will be essential to decipher the mechanism how PSC influences Foxp3+ Treg-cell expression and function in the setting of intestinal inflammation.