title: Screening for IgG4-type anti-nuclear antibodies in IgG4-related disease.
abstract: BACKGROUND
  Immunoglobulin (Ig) G4-related disease (IgG4-RD) is characterized by elevated serum IgG4 and infiltration of IgG4(+) plasma cells into multiple organs. It is not known whether serum IgG4 is autoreactive in IgG4-RD.
  
  
  METHODS
  We measured anti-nuclear antibody (ANA) in 19 IgG4-RD cases, determined IgG subclasses of the ANA, and compared them with those of other systemic autoimmune diseases (systemic lupus erythematosus, Sjögren's syndrome, systemic sclerosis, and polymyositis), using subclass-based ANA test (indirect immunofluorescence).
  
  
  RESULTS
  58 % of IgG4-RD cases were ANA-positive (cut-off: 1:40). Whereas their subclass of ANA was predominantly IgG2, we observed no IgG4-type ANA. In systemic autoimmune diseases, subclasses of ANA were mostly IgG1, 2, or 3, but IgG4-type ANA was very rarely detected. We also found several patients in whose serum ANA patterns differed among IgG subclasses, probably due to the difference of corresponding autoantigens.
  
  
  CONCLUSIONS
  Although IgG4 is highly elevated in sera of IgG4-RD patients, their ANA do not include IgG4 subclass. These results offer new insight into the role of IgG4 and the pathogenesis of IgG4-RD, implying that each IgG subclass tends to cover its own spectrum of antigens, and IgG4 is not preferentially used to make ANA.
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. rheum@kuhp.kyoto-u.ac.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kiyama
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. yossii@kuhp.kyoto-u.ac.jp.
authors.forename: Hajime
authors.initials: H
authors.lastname: Yoshifuji
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. kandou.tsugumitsu.35m@st.kyoto-u.ac.jp.
authors.forename: Tsugumitsu
authors.initials: T
authors.lastname: Kandou
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. hosono25@kuhp.kyoto-u.ac.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hosono
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. kitagori@kuhp.kyoto-u.ac.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Kitagori
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. ranran@kuhp.kyoto-u.ac.jp.
authors.forename: Ran
authors.initials: R
authors.lastname: Nakashima
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. imuray@kuhp.kyoto-u.ac.jp.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Imura
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. naoichiy@kuhp.kyoto-u.ac.jp.
authors.forename: Naoichiro
authors.initials: N
authors.lastname: Yukawa
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. ohmurako@kuhp.kyoto-u.ac.jp.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ohmura
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. takfujii@kuhp.kyoto-u.ac.jp.
authors.forename: Takao
authors.initials: T
authors.lastname: Fujii
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. daisuke@kuhp.kyoto-u.ac.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kawabata
authors.affiliation: Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. mimorit@kuhp.kyoto-u.ac.jp.
authors.forename: Tsuneyo
authors.initials: T
authors.lastname: Mimori
mesh_terms: D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000097:blood*; D001327:Autoimmune Diseases / Q000097:blood* / Q000175:diagnosis / Q000276:immunology; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015854:Up-Regulation
chemical_list: D000974:Antibodies, Antinuclear; D015415:Biomarkers; D007074:Immunoglobulin G