Reprograming of peripheral Foxp3+ regulatory T cell towards Th17-like cell in patients with active systemic lupus erythematosus.

Treg is essential to limit the extend and duration of the immune response, but its stability is still under debate. Here we demonstrate that IL-17-producing Treg cells (Th17-like cells) increased in peripheral blood of patients with Systemic Lupus Erythematosus (SLE). Notably, the Th17-like cells from patient with active SLE were characterized with some phenotype and function of Th17 cells. Upon stimulation, Helios-Foxp3 + CD4+ T cells decrease Foxp3 expression but increase expression of IL-17 and RORγt. Damage associated molecule pattern and inflammatory cytokines are important for induction of IL-17 expression in Treg cells. The Th17-like cells from patients with active SLE lose suppressive function and have robust response to stimulation of autoantigens. We also observed that the level of Th17-like cells in peripheral blood is closely associated with the clinical index of SLE. These findings suggest that instability of Treg plays a critical role in pathogenesis of autoimmune diseases.