CD4 and peeling skin syndrome: Furthermore, UCMSC-Exos regulated CD4<sup>+</sup> T cell proliferation and early apoptosis, inhibited Th17 cell differentiation, promoted Treg cell differentiation, and restored the Th17/Treg balance in pSS patients through the autophagy pathway.<h4>Conclusions</h4>The study indicated that UCMSC-Exos exerts an immunomodulatory effect on the CD4<sup>+</sup> T cells, and maybe as a new treatment for pSS.