Possible participation of IgG4 in the activation of complement in IgG4-related disease with hypocomplementemia

  • Mitsuru Sugimoto
    Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University, Fukushima, Japan
  • Hiroshi Watanabe
    Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University, Fukushima, Japan
  • Tomoyuki Asano
    Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University, Fukushima, Japan
  • Shuzo Sato
    Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University, Fukushima, Japan
  • Tadayuki Takagi
    Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University, Fukushima, Japan
  • Hiroko Kobayashi
    Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University, Fukushima, Japan
  • Hiromasa Ohira
    Department of Gastroenterology and Rheumatology, School of Medicine, Fukushima Medical University, Fukushima, Japan

Search this article

Description

To investigate which IgG subclasses contribute to the activation of the complement pathway in IgG4-related disease (IgG4RD) patients with hypocomplementemia.Sera of IgG4RD patients were analyzed for the binding ability of IgG subclasses to complement component 1q (C1q). Polyethylene glycol (PEG) precipitates containing immune complexes (ICs) in sera of IgG4RD patients were analyzed for IgG subclass composition by Western blotting. PEG precipitates containing ICs (PEG-ICs) in sera of patients were also analyzed for their ability to consume complement in normal human serum (NHS) using a total complement hemolytic (CH50) assay and a commercial kit to measure the complement capacity of all three individual complement pathways.The C1q binding assay revealed high serum levels of C1q-binding IgG4 in IgG4RD patients with hypocomplementemia. ICs in PEG precipitates were formed with IgG4 in IgG4RD patients, regardless of the presence or absence of hypocomplementemia. We observed a marked reduction of CH50 and reduced complement activity in the classical complement pathway as well as the mannan-binding lectin complement pathway in NHS incubated with PEG-IC isolated from IgG4RD patients with hypocomplementemia.Our results suggest that IgG4 may participate in the activation of complement in IgG4RD patients with hypocomplementemia.

Journal

  • Modern Rheumatology

    Modern Rheumatology 26 (2), 251-258, 2015-09-10

    Oxford University Press (OUP)

Citations (7)*help

See more

Details 詳細情報について

Report a problem

Back to top