Allogeneic mesenchymal stem cell treatment alleviates experimental and clinical Sjögren syndrome

Sjögren syndrome (SS) is a systemic autoimmune disease characterized by dry mouth and eyes, and the cellular and molecular mechanisms for its pathogenesis are complex. Here we reveal, for the first time, that bone marrow mesenchymal stem cells in SS-like NOD/Ltj mice and human patients were defective in immunoregulatory functions. Importantly, treatment with mesenchymal stem cells (MSCs) suppressed autoimmunity and restored salivary gland secretory function in both mouse models and SS patients. MSC treatment directed T cells toward Treg and Th2, while suppressing Th17 and Tfh responses, and alleviated disease symptoms. Infused MSCs migrated toward the inflammatory regions in a stromal cell-derived factor-1-dependent manner, as neutralization of stromal cell-derived factor-1 ligand CXCR4 abolished the effectiveness of bone marrow mesenchymal stem cell treatment. Collectively, our study suggests that immunologic regulatory functions of MSCs play an important role in SS pathogenesis, and allogeneic MSC treatment may provide a novel, effective, and safe therapy for patients with SS.