title: Immune complexome analysis of antigens in circulating immune complexes isolated from patients with IgG4-related dacryoadenitis and/or sialadenitis.
abstract: OBJECTIVE
  IgG4-related disease (IgG4-RD) is characterized by various serological abnormalities. Some patients with IgG4-RD present with hypergammaglobulinemia, hypocomplementemia, and autoantibodies recognizing rheumatoid factors and nuclear factors. However, whether IgG4-RD is an autoimmune disease remains unclear.
  
  
  METHODS
  Here, we used immune complexome analysis to comprehensively identify constituent antigens of circulating immune complexes isolated from 10 patients with IgG4-related dacryoadenitis and/or sialadenitis (IgG4-RDS) which is one condition associated with IgG4-RD.
  
  
  RESULTS
  We detected each of 125 distinct antigens in independent samples from two or more patients with IgG4-RDS. Of them, 17 antigens were found to be specific to patients with IgG4-RDS by comparing 125 antigens with all the antigens found in other connective tissue diseases (antineutrophil cytoplasmic antibody-associated vasculitis, Takayasu's arteritis, mixed connective tissue disease, dermatomyositis, Sjögren's syndrome, systemic scleroderma, and systemic lupus erythematosus) or healthy donors. The number of disease-specific antigens associated with IgG4-RDS was comparable to those autoimmune diseases.
  
  
  CONCLUSIONS
  Studies of the 17 IgG4-RDS-specific antigens might lead to a better understanding of the pathogenesis of IgG4-RD, but further study of the prevalence of these CIC-associated antigens that involves a selective and sensitive assay will be needed to determine their potential as diagnostic or pathogenic biomarkers.
authors.affiliation: a Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.|b Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC) , Nagasaki , Japan.
authors.forename: Kaname
authors.initials: K
authors.lastname: Ohyama
authors.affiliation: a Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Baba
authors.affiliation: c Unit of Translational Medicine, Department of Immunology and Rheumatology , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Tamai
authors.affiliation: d Department of Gastroenterology , Rheumatology and Clinical Immunology, Sapporo Medical University School of Medicine , Sapporo , Japan.
authors.forename: Motohisa
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: c Unit of Translational Medicine, Department of Immunology and Rheumatology , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Ichinose
authors.affiliation: a Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kishikawa
authors.affiliation: d Department of Gastroenterology , Rheumatology and Clinical Immunology, Sapporo Medical University School of Medicine , Sapporo , Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: c Unit of Translational Medicine, Department of Immunology and Rheumatology , Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawakami
authors.affiliation: a Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University , Nagasaki , Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Kuroda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000936:Antigen-Antibody Complex / Q000276:immunology*; D015415:Biomarkers; D003607:Dacryocystitis / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012793:Sialadenitis / Q000276:immunology*
chemical_list: D000936:Antigen-Antibody Complex; D015415:Biomarkers; D007074:Immunoglobulin G
keywords: Autoimmune disease; IgG4-related disease; Immune complex; Immune complexome analysis; Tandem mass spectrometry