Data_Sheet_2_Chronic Immune Activation in Systemic Lupus Erythematosus and the Autoimmune PTPN22 Trp620 Risk Allele Drive the Expansion of FOXP3+ Regulatory T Cells and PD-1 Expression.xlsx Ricardo C. Ferreira Xaquin Castro Dopico João J. Oliveira Daniel B. Rainbow Jennie H. Yang Dominik Trzupek Sarah A. Todd Mhairi McNeill Maristella Steri Valeria Orrù Edoardo Fiorillo Daniel J. M. Crouch Marcin L. Pekalski Francesco Cucca Tim I. Tree Tim J. Vyse Linda S. Wicker John A. Todd 10.3389/fimmu.2019.02606.s002 https://frontiersin.figshare.com/articles/dataset/Data_Sheet_2_Chronic_Immune_Activation_in_Systemic_Lupus_Erythematosus_and_the_Autoimmune_PTPN22_Trp620_Risk_Allele_Drive_the_Expansion_of_FOXP3_Regulatory_T_Cells_and_PD-1_Expression_xlsx/10274084 <p>In systemic lupus erythematosus (SLE), perturbed immunoregulation underpins a pathogenic imbalance between regulatory and effector CD4<sup>+</sup> T-cell activity. However, to date, the characterization of the CD4<sup>+</sup> regulatory T cell (Treg) compartment in SLE has yielded conflicting results. Here we show that patients have an increased frequency of CD4<sup>+</sup>FOXP3<sup>+</sup> cells in circulation owing to a specific expansion of thymically-derived FOXP3<sup>+</sup>HELIOS<sup>+</sup> Tregs with a demethylated FOXP3 Treg-specific demethylated region. We found that the Treg expansion was strongly associated with markers of recent immune activation, including PD-1, plasma concentrations of IL-2 and the type I interferon biomarker soluble SIGLEC-1. Since the expression of the negative T-cell signaling molecule PTPN22 is increased and a marker of poor prognosis in SLE, we tested the influence of its missense risk allele Trp<sup>620</sup> (rs2476601C>T) on Treg frequency. Trp<sup>620</sup> was reproducibly associated with increased frequencies of thymically-derived Tregs in blood, and increased PD-1 expression on both Tregs and effector T cells (Teffs). Our results support the hypothesis that FOXP3<sup>+</sup> Tregs are increased in SLE patients as a consequence of a compensatory mechanism in an attempt to regulate pathogenic autoreactive Teff activity. We suggest that restoration of IL-2-mediated homeostatic regulation of FOXP3<sup>+</sup> Tregs by IL-2 administration could prevent disease flares rather than treating at the height of a disease flare. Moreover, stimulation of PD-1 with specific agonists, perhaps in combination with low-dose IL-2, could be an effective therapeutic strategy in autoimmune disease and in other immune disorders.</p> 2019-11-08 14:16:52 regulatory T cells (Tregs) systemic lupus erythematosus (SLE) autoimmunity FOXP3 PTPN22 Arg620Trp PD-1 type I interferon immunotherapy