CD4 and Autoimmunity: As shown in Figure 5H, the proportion of CD4+CD25+Foxp3+ Treg cells was significantly higher in the MEXs (p<0.001) and MSCs groups (p<0.001) than in the PBS control group, indicating that, like MSCs, MEXs can also exert a critical role in encouraging T lymphocytes to differentiate into Treg cells, which play key roles in suppressing autoimmunity and in maintaining immune homeostasis (23, 24).