Impairment of immunoregulatory activity of BMMSCs during SS pathogenesis. (A-B) BMMSCs from NOD/Ltj mice failed to effectively suppress the proliferation of stimulated T cells. Stimulated normal T cells cocultured with NOD BMMSCs showed higher proliferative response compared with those cocultured with control ICR BMMSCs (P = .0002, n = 12). (C-E) CD4⁺Foxp3⁺Treg cells from splenocytes cocultured with ICR BMMSCs or NOD BMMSCs. *CD4⁺ cells in splenocytes cocultured with NOD/Ltj BMMSCs were significantly higher than that with ICR BMMSCs (P = .0005); n = 12. *ICR BMMSCs had better regulatory potential for Treg cells compared with BMMSCs from NOD mice (P = .0001); n = 12. (F-G) Impairment of immunoregulatory capacity was observed in the BMMSCs of SS patients. Normal PBMCs cultured with BMMSCs obtained from SS patients showed higher proliferative response compared with those cocultured with normal BMMSCs (P = .01, n = 5).