CD4 and chronic kidney disease: In the present study, we first evaluated the phenotype of Tregs in peripheral blood from CKD patients and healthy controls, showing similar frequencies of CD4+CD25hiCD127− (Figure S3B) and CD4+CD25hiCD127−FOXP3+ T cells (Figure S3C) and no difference in FOXP3 expression (MFI values) within the CD4+CD25hiCD127− T-cell population (Figure S3D).