“…Moreover, Treg cell frequency was shown to be reduced by as much as 40% in the peripheral blood of allogeneic HSCT recipients that developed GVHD as compared to autologous or allogeneic HSCT recipients that displayed no signs of GVHD (Magenau et al, 2010). Similar results have also been observed in cGVHD, where the frequency of Treg cells negatively correlated with disease severity (Zorn et al, 2005; Li et al, 2010; McIver et al, 2012). Whereas most human studies have examined peripheral blood Treg cells; Rieger et al assessed mucosal Treg cell frequencies in intestinal biopsies, which are perhaps a more relevant marker of disease.…”