Chloroquine Autophagic Inhibition Rebalances Th17/Treg-Mediated Immunity and Ameliorates Systemic Lupus Erythematosus

Abstract

Background: Imbalanced cellular immunity is critical to the pathogenesis of systemic lupus erythematosus (SLE). Recently, autophagy has emerged as a key homeostatic mechanism in T lymphocytes. This study was conducted to explore the impact of autophagy on the Th17/regulatory T (Treg) immune imbalance in SLE. Methods: Peripheral Th17 and Treg cells from newly diagnosed patients with SLE and healthy controls were detected by flow cytometry. Additionally, the effects of chloroquine (CQ) autophagic inhibition on the Th17/Treg immune response were investigated in vitro. In addition, hydroxychloroquine (HCQ) treatment of the Th17/Treg immune response and the disease progression of lupus MRL/lpr mice were studied in vivo. Results: Compared with healthy controls, both peripheral Th17 and Treg cells of patients with SLE exhibited activated autophagy, resulting in a heightened Th17 proinflammatory response and diminished Treg immunosuppression. Furthermore, in vitro experiments indicated that CQ autophagic inhibition effectively rebalanced the Th17/Treg immune responses in patients with SLE. In vivo studies of MRL/lpr mice similarly confirmed that HCQ treatment decisively inhibited the autophagy of Th17/Treg cellular subsets, restoring the immune balance, lowering the serum levels of inflammatory cytokines and autoantibodies, and improving renal histopathology. Conclusion: Activated autophagy contributed to the Th17/Treg immune imbalance in SLE, and chloroquine autophagic inhibition rebalanced Th17/Treg-mediated immunity and ameliorated SLE.