No abstract

Objective. T helper cells develop into discrete Th1, Th2 or Th17 lineages that selectively express IFN-gamma, IL-4/IL-5/IL-13, or IL-17, respectively and actively silence signature cytokines expressed by opposing lineages. Our objective was to compare Th1, Th2 and Th17 polarization in cell culture models using JIA patient samples. Methods. Peripheral blood mononuclear cells were isolated from JIA or healthy prepubescent children. T cell naive and memory phenotypes were assessed by flow cytometry. T cell proliferation was measured using a fluorescence-based assay. Th cell cultures were generated in vitro and IFN-gamma, IL-17, and TNF-alpha measured by ELISA and flow cytometry. Results. JIA Th1 cells produced increased IFN-gamma and inappropriately produced IL-17. JIA Th17 cells produced increased IL-17. JIA Th1 cell cultures develop dual producers of IFN-gamma and IL-17, which are Th1.17 cells. JIA Th1 cultures expressed elevated levels of both T-bet and ROR-gamma-T. RNA sequencing confirmed activation of immune responses and inappropriate activation of IL-17 signaling pathways in Th1 cultures. A subset of JIA patient samples was disproportionally responsible for the enhanced IFN-gamma and IL-17 phenotype and Th1.17 phenotype. Conclusions. This study reveals that JIA patient uncommitted T cell precursors, but not healthy children, inappropriately develop into inflammatory effector Th1.17 and Th17 cells under Th1 polarizing conditions.

Hypertension, vascular inflammation and renal inflammation are characteristic of systemic lupus erythematosus (SLE), a multisystem autoimmune disease that is complex and poorly understood. Oxidation products of arachidonic and other fatty acids, termed isolevuglandins (isoLG) lead to formation of post-translational protein modifications that are immunogenic. We demonstrate isoLG enrichment in dendritic cells (DCs), B cells, and plasma cells from juvenile female B6.SLE123 mice. In adult B6.SLE123 and NZBWF1 mice, isoLG adducts are enriched in plasma cells and splenic DCs compared to C57Bl/6 and NZW mice respectively. Treatment with the isoLG-scavenger 2-hydroxybenzylamine (2-HOBA) reduced blood pressure, improved renal function, and attenuated renal injury. Moreover, 2-HOBA reduced bone marrow plasma cells, total IgG levels, and anti-dsDNA antibody titers. We also demonstrate that mice with SLE generate specific IgG antibodies against isoLG adducted protein, confirming the immunogenicity of isoLG adducts. Finally, we found that isoLG adducted peptides are markedly enriched in monocytes from patients with SLE which was accompanied by an increase in superoxide production. These findings support a role of isoLG adducts in the genesis and maintenance of systemic autoimmunity and its associated hypertension in SLE. Scavenging of isoLGs promises to be a novel therapy for this disease.