CD4 and colitis: To investigate the effect of hUC-MSCs treatment on Treg cells and Th17 cells in colitis MLNs, the frequency of Treg (CD25+ FOXP3+/CD4+) cells and Th17 (RORγt+/CD4+) cells in MLNs and spleen were evaluated at 3 days after intraperitoneal injection of hUC-MSCs.