CD8⁺ and CD8⁺Foxp3⁺ cells in duodenal biopsies in the first and second cohorts. Number of CD8⁺ and CD8⁺Foxp3⁺ cells in GVHD patients with grade less than 2 or 2 or more. Although Foxp3 has a central role in Treg development, it is also clear that Foxp3 up-regulation occurs with T-cell activation. Thus, as a control of the specificity, CD8/Foxp3 double staining was performed on the 2 first cohorts. Counts showed that most of the CD8⁺ cells are not activated in the 2 independent cohorts of patients who underwent duodenal biopsies.