Coordination between innate immune cells, type I IFNs and IRF5 drives SLE pathogenesis

• Published in: Cytokine (Philadelphia, Pa.) Vol. 132; p. 154731
• Main Authors: Matta, Bharati, Barnes, Betsy J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2020
• Subjects: Autoimmunity; NETosis; Neutrophils; Plasmacytoid dendritic cells; SLE; Autoimmunity; Plasmacytoid dendritic cells; NETosis; SLE; Neutrophils
• ISSN: 1043-4666; 1096-0023
• DOI: 10.1016/j.cyto.2019.05.018

•Direct/indirect exposure to IFN contributes to aberrant SLE immune deregulation.•pDCs, neutrophils and other immune cell types contribute to IFN production in SLE.•The contribution of IRF5 to SLE genetic risk is cell type-specific and pleiotropic. Systemic lupus erythematosus (SLE) is a complex autoimmune disease which affects multiple organs. The type I interferon (IFN) gene signature and circulating autoantibodies are hallmarks of SLE. Plasmacytoid dendritic cells (pDCs) are considered the main producers of type I IFN and production is modulated by multiple other immune cell types. In SLE, essentially every immune cell type is dysregulated and aberrant deregulation is thought to be due, in part, to direct or indirect exposure to IFN. Genetic variants within or around the transcription factor interferon regulatory factor 5 (IRF5) associate with SLE risk. Elevated IFNα activity was detected in the sera of SLE patients carrying IRF5 risk polymorphisms who were positive for either anti-RNA binding protein (anti-RBP) or anti-double-stranded DNA (anti-dsDNA) autoantibodies. Neutrophils are also an important source of type I IFNs and are found in abundance in human blood. Neutrophil extracellular traps (NETs) are considered a potential source of antigenic trigger in SLE that can lead to type I IFN gene induction, as well as increased autoantibody production. In this review, we will focus on immune cell types that produce type I IFNs and/or are affected by type I IFN in SLE. In addition, we will discuss potential inducers of endogenous type I IFN production in SLE. Last, we will postulate how the different immune cell populations may be affected by an IRF5-SLE risk haplotype.