title: Immune stimulatory effects of neutrophil extracellular traps in granulomatosis with polyangiitis.
abstract: OBJECTIVE
  The aim of this study was to analyse the role of netting neutrophils in the pathogenesis of granulomatosis with polyangiitis (GPA), especially their interplay with peripheral blood mononuclear cells (PBMCs).
  
  
  METHODS
  The amount of cell-free DNA (cfDNA) was determined in sera from GPA patients (pairs active/inactive state of disease, n=18) and from healthy controls (HCs, n=10). Furthermore, we performed in vitro incubation experiments using PBMCs and NETs from patients and HCs for accessing the effect of NETs on PBMC behaviour. We determined proliferation of T- and B-cells (CSFE assay), B-cell maturation (CD38 staining and flow cytometry), production of IgG (ELISpot, ELISA), and secretion of the cytokines IFN-γ, IL-4, IL-10, IL-17A (ELISA).
  
  
  RESULTS
  We detected a significant increase in serum cfDNA levels of GPA patients compared to HCs. The concentration of cfDNA was associated with disease activity. NETs of patients and HCs induced proliferation of CD4+ T- cells and CD19+ B-cells and maturation of B-cells. Furthermore, we detected an increase in IL-17A secretion after stimulating PBMCs with NETs. A significant difference between PBMCs from GPA patients and HCs was not detectable.
  
  
  CONCLUSIONS
  NETs activate PBMCs of HCs and GPA patients. Our findings give supportive evidence that NETosis plays a role in the pathogenesis of GPA.
authors.affiliation: Christian Albrecht University of Kiel, Institute of Anatomy, Kiel, Germany. dr.christinalange@gmail.com.
authors.forename: Christina
authors.initials: C
authors.lastname: Lange
authors.affiliation: Klinikum Bad Bramstedt, Rheumatology and Immunology, Bad Bramstedt, Germany.
authors.forename: Elena
authors.initials: E
authors.lastname: Csernok
authors.affiliation: Klinikum Bad Bramstedt, Rheumatology and Immunology, Bad Bramstedt; and Rheumazentrum Schleswig-Holstein Mitte, Neumünster, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Moosig
authors.affiliation: Klinikum Bad Bramstedt, Rheumatology and Immunology, Bad Bramstedt; and Rheumazentrum Schleswig-Holstein Mitte, Neumünster, Germany.
authors.forename: Julia U
authors.initials: JU
authors.lastname: Holle
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D049109:Cell Proliferation; D002478:Cells, Cultured; D004247:DNA / Q000097:blood; D065206:Extracellular Traps / Q000276:immunology* / Q000378:metabolism; D005260:Female; D014890:Granulomatosis with Polyangiitis / Q000097:blood / Q000175:diagnosis / Q000276:immunology*; D006801:Humans; D020381:Interleukin-17 / Q000097:blood; D008213:Lymphocyte Activation; D008297:Male; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D019899:Paracrine Communication; D010641:Phenotype; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D058504:Th17 Cells / Q000276:immunology / Q000378:metabolism
chemical_list: D015415:Biomarkers; C508717:IL17A protein, human; D020381:Interleukin-17; D004247:DNA