title: Serum levels of BAFF and APRIL in myeloperoxidase anti-neutrophil cytoplasmic autoantibody-associated renal vasculitis: association with disease activity.
abstract: BACKGROUND
  A proliferation-inducing ligand (APRIL) and the B cell activation factor belonging to the tumor necrosis factor family (BAFF) have proven to be key factors in the selection and survival of B cells, and a higher concentration of BAFF has been shown to contribute to autoreactive B cell survival and elevated autoantibody production. Here, serum BAFF and APRIL levels were investigated to analyze their association with disease activity in myeloperoxidase anti-neutrophil cytoplasmic autoantibody (MPO-ANCA)-associated renal vasculitis.
  
  
  METHODS
  APRIL and BAFF levels in serum obtained from 37 patients with MPO-ANCA-associated vasculitis were measured by ELISA. Samples were taken from active vasculitis patients, inactive vasculitis patients and inactive vasculitis patients with infectious complications.
  
  
  RESULTS
  Although there was no difference in serum APRIL among the active vasculitis, inactive vasculitis and infectious complication patients, serum BAFF was higher in active vasculitis patients than in inactive vasculitis, infectious complication and control patients (for all, p < 0.001). There was no significant correlation between serum APRIL and ANCA titers, but there was a significant correlation between serum BAFF and ANCA titers (r = 0.465, p < 0.001).
  
  
  CONCLUSIONS
  Excessive BAFF production in MPO-ANCA-associated vasculitis may be one of the factors for autoimmune B cell tolerance, resulting in MPO-ANCA production.
authors.affiliation: Department of Nephrology, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, Ami, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Nagai
authors.forename: Kouichi
authors.initials: K
authors.lastname: Hirayama
authors.forename: Itaru
authors.initials: I
authors.lastname: Ebihara
authors.forename: Homare
authors.initials: H
authors.lastname: Shimohata
authors.forename: Masaki
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Akio
authors.initials: A
authors.lastname: Koyama
mesh_terms: D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000097:blood* / Q000201:enzymology / Q000276:immunology; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D001323:Autoantibodies / Q000096:biosynthesis / Q000097:blood; D053264:B-Cell Activating Factor / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D006801:Humans; D007239:Infections / Q000097:blood / Q000201:enzymology / Q000276:immunology; D007674:Kidney Diseases / Q000097:blood* / Q000201:enzymology / Q000276:immunology; D009195:Peroxidase / Q000097:blood / Q000276:immunology*; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13 / Q000097:blood*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D001323:Autoantibodies; D053264:B-Cell Activating Factor; D015415:Biomarkers; C505719:TNFSF13B protein, human; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13; D009195:Peroxidase