Indeed, we previously showed that Tcons isolated from inflamed Crohn's mucosa are relatively resistant to Treg-mediated suppression, due to overexpression of Smad7, an inhibitor of TGF-β signalling.35, 36 In this study, we utilised Tregs cultured in the presence of rapamycin, which has been shown to enhance the suppressive ability of in vitro expanded Tregs, compared with Tregs freshly isolated from the same donor26, 38 and show that in vitro expansion enhances the suppressive ability of Tregs obtained from CD PB. The gene discussed is TGFB1; the disease is Cowden disease.