title: Proteomic profiling of antigens in circulating immune complexes associated with each of seven autoimmune diseases.
abstract: OBJECTIVE
  Immune complexes (ICs) trigger humoral immune responses. Therefore, the identification of constituent antigens within ICs would have very different clinical significance than identification of free antigens.
  
  
  METHODS
  Here, we applied immune complexome analysis of serum to the study of seven major autoimmune diseases-anti-neutrophil cytoplasmic antibody-associated vasculitis, Takayasu's arteritis, mixed connective tissue disease, dermatomyositis, Sjögren's syndrome, systemic scleroderma, and systemic lupus erythematosus-and healthy donors to comprehensively identify antigens incorporated into circulating ICs and to find disease-specific antigens.
  
  
  RESULTS
  We identified 468 distinct IC-associated antigens using this method. Importantly, 62 of those antigens were disease-specific antigens, and there were at least three disease-specific antigens for each of the seven autoimmune diseases. Of the disease-specific antigens identified, coiled-coil domain-containing protein 158 and spectrin were identified as potential autoantigens important to SSc and SS pathogenesis, respectively; notable titin and spectrin autoantibodies are reportedly found in SSc and SS patients, respectively.
  
  
  CONCLUSIONS
  Immune complexome analysis may be generally applicable to the study of the relationship between ICs and autoimmune diseases in animals and humans.
authors.affiliation: Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan; Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Japan.
authors.forename: Kaname
authors.initials: K
authors.lastname: Ohyama
authors.affiliation: Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Miyako
authors.initials: M
authors.lastname: Baba
authors.affiliation: 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: Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Aibara
authors.affiliation: 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: Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kishikawa
authors.affiliation: 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: Course of Pharmaceutical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan. Electronic address: n-kuro@nagasaki-u.ac.jp.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Kuroda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000936:Antigen-Antibody Complex / Q000097:blood*; D001324:Autoantigens / Q000097:blood* / Q000276:immunology; D001327:Autoimmune Diseases / Q000097:blood* / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D040901:Proteomics / Q000379:methods*; D055815:Young Adult
chemical_list: D000936:Antigen-Antibody Complex; D001324:Autoantigens
keywords: Autoimmune disease; Immune complex; Immune complexome analysis; Tandem mass spectrometry