Aberrant autoantibody production is characteristic of systemic lupus erythematosus (SLE), but follicular regulatory T (TFR) cells potentially can suppress this abnormality. We investigate functional changes in TFR cells from SLE patients. Circulating TFR cells were collected from 19 SLE patients and 14 healthy controls (HC) to compare molecular expression and in vitro suppressive capacity of follicular helper T (TFH) cell proliferation. To reveal the stability of Foxp3 in TFR, pyrosequencing of conserved non-coding sequence (CNS) 2 at the Foxp3 gene locus was performed. We then tested IL-2 in SLE-TFR cells to check restoration of suppressor function. Programmed death-1 (PD-1) expression in SLE-TFR cells was positively correlated with anti-DNA antibody levels and disease activity. These cells had impaired suppressive function for TFH cells with decreased expression of suppression mediators forkhead box p3 (Foxp3), cytotoxic T-lymphocyte antigen 4 (CTLA4), and IL-2 receptor alpha (IL2Rα). Pyrosequencing identified hyper-methylation in CNS2 region of SLE-TFR cells comparing to HC. With In vitro IL-2 stimulation, PD-1 expression of TFR cells significantly decreased along with increased expression of Foxp3 and CTLA-4, especially in low-dose. Thus, SLE-TFR cells have functionally defective to TFH suppression, but low-dose IL-2 therapy might be useful to restore this ability.

RORγt+Foxp3+ regulatory T (Treg) cells, known as T regulatory 17 cells (Tr17 cells), are a novel subset of Treg cells, which have the potential to regulate the development of experimental autoimmune encephalomyelitis (EAE) thorough a specific repression of T helper 17 (Th17) cell mediated inflammation. However, the function of Tr17 cells the development of other autoimmune diseases such as autoimmune arthritis remains unclear. Collagen induced arthritis (CIA) was found to be prolonged in Foxp3creRORγtfl/fl mice, in which Tr17 cells were deleted, compared with Foxp3wtRORγtfl/fl mice. Tr17 cells were significantly increased in ankle joints compared with draining lymph nodes after the onset of arthritis. CC chemokine receptor 6 (CCR6) was up-regulated on Tr17 cells compared to RORγt negative Treg cells. CD25, cytotoxic T-lymphocyte antigen 4 (CTLA-4), glucocorticoid-induced TNF-receptor (GITR), and inducible T-cell co-stimulator (ICOS) expression was also up-regulated on Tr17 cells compared to RORγt negative Treg cells. IL-10-producing cells and Blimp-1+ cells were increased in Tr17 cells compared to RORγt-Treg cells. Tr17-enriched Treg cells significantly suppressed proliferation of conventional T cells compared with CCR6-Treg cells. Tr17 cells increased during the clinical course of CIA and accumulated in inflamed joints. These cells expressed CD25, CTLA4, GITR, and ICOS molecules and up-regulated Blimp-1 and over-produced IL-10. Moreover, CCR6+ Treg cells significantly suppressed cell proliferation. Taken together, it appears that Tr17 cells play a crucial role in the regulation of autoimmune arthritis.