title: Epstein-Barr virus lytic infection promotes activation of Toll-like receptor 8 innate immune response in systemic sclerosis monocytes.
abstract: Monocytes/macrophages are activated in several autoimmune diseases, including systemic sclerosis (scleroderma; SSc), with increased expression of interferon (IFN)-regulatory genes and inflammatory cytokines, suggesting dysregulation of the innate immune response in autoimmunity. In this study, we investigated whether the lytic form of Epstein-Barr virus (EBV) infection (infectious EBV) is present in scleroderma monocytes and contributes to their activation in SSc.
  
  
  
  Monocytes were isolated from peripheral blood mononuclear cells (PBMCs) depleted of the CD19+ cell fraction, using CD14/CD16 negative-depletion. Circulating monocytes from SSc and healthy donors (HDs) were infected with EBV. Gene expression of innate immune mediators were evaluated in EBV-infected monocytes from SSc and HDs. Involvement of Toll-like receptor (TLR)8 in viral-mediated TLR8 response was investigated by comparing the TLR8 expression induced by infectious EBV to the expression stimulated by CL075/TLR8/agonist-ligand in the presence of TLR8 inhibitor in THP-1 cells.
  
  
  
  Infectious EBV strongly induced TLR8 expression in infected SSc and HD monocytes in vitro. Markers of activated monocytes, such as IFN-regulated genes and chemokines, were upregulated in SSc- and HD-EBV-infected monocytes. Inhibiting TLR8 expression reduced virally induced TLR8 in THP-1 infected cells, demonstrating that innate immune activation by infectious EBV is partially dependent on TLR8. Viral mRNA and proteins were detected in freshly isolated SSc monocytes. Microarray analysis substantiated the evidence of an increased IFN signature and altered level of TLR8 expression in SSc monocytes carrying infectious EBV compared to HD monocytes.
  
  
  
  This study provides the first evidence of infectious EBV in monocytes from patients with SSc and links EBV to the activation of TLR8 and IFN innate immune response in freshly isolated SSc monocytes. This study provides the first evidence of EBV replication activating the TLR8 molecular pathway in primary monocytes. Immunogenicity of infectious EBV suggests a novel mechanism mediating monocyte inflammation in SSc, by which EBV triggers the innate immune response in infected cells.
authors.affiliation: Rheumatology, Boston University School of Medicine, Arthritis Center, 72 E. Concord Street, E-5, Boston, MA, 02118, USA.|Department of Experimental Medicine, Sapienza University, Rome, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Farina
authors.affiliation: Istituto Italiano di Tecnologia, CLNS@Sapienza, Rome, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Peruzzi
authors.affiliation: Rheumatology, Boston University School of Medicine, Arthritis Center, 72 E. Concord Street, E-5, Boston, MA, 02118, USA.
authors.forename: Valentina
authors.initials: V
authors.lastname: Lacconi
authors.affiliation: Rheumatology, Boston University School of Medicine, Arthritis Center, 72 E. Concord Street, E-5, Boston, MA, 02118, USA.
authors.forename: Stefania
authors.initials: S
authors.lastname: Lenna
authors.affiliation: Department of Clinical Medicine, Sapienza University, Rome, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Quarta
authors.affiliation: Department of Clinical Medicine, Sapienza University, Rome, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Rosato
authors.affiliation: Department of Public Health, Sapienza University, Rome, Italy.
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Vestri
authors.affiliation: Rheumatology, Boston University School of Medicine, Arthritis Center, 72 E. Concord Street, E-5, Boston, MA, 02118, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: York
authors.affiliation: Department of Pediatrics, Yale, New Haven, CT, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Dreyfus
authors.affiliation: Department of Experimental Medicine, Sapienza University, Rome, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Faggioni
authors.affiliation: Department of Experimental Medicine, Sapienza University, Rome, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Morrone
authors.affiliation: Rheumatology, Boston University School of Medicine, Arthritis Center, 72 E. Concord Street, E-5, Boston, MA, 02118, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Trojanowska
authors.affiliation: Rheumatology, Boston University School of Medicine, Arthritis Center, 72 E. Concord Street, E-5, Boston, MA, 02118, USA. farina@bu.edu.
authors.forename: G Alessandra
authors.identifier: 0000-0002-3948-6920
authors.initials: GA
authors.lastname: Farina
mesh_terms: D000328:Adult; D000368:Aged; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D020031:Epstein-Barr Virus Infections / Q000235:genetics / Q000276:immunology* / Q000821:virology; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000276:immunology; D020869:Gene Expression Profiling / Q000379:methods; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D054884:Host-Pathogen Interactions / Q000235:genetics / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D011804:Quinolines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012595:Scleroderma, Systemic / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology; D051200:Toll-Like Receptor 8 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D014779:Virus Replication / Q000235:genetics / Q000276:immunology / Q000502:physiology; D055815:Young Adult
chemical_list: C551788:CL 075; D011804:Quinolines; C495349:TLR8 protein, human; D013844:Thiazoles; D051200:Toll-Like Receptor 8
keywords: EBV reactivation; IFN inducible genes; Innate immune response; Monocytes; Systemic sclerosis; Toll-like receptor 8