title: Fab glycosylation of immunoglobulin G does not associate with improvement of rheumatoid arthritis during pregnancy.
abstract: Changes in immunoglobulin G (IgG) constant domain (Fc) glycosylation are associated with changes in rheumatoid arthritis (RA) disease activity in response to pregnancy. Here, we sought to determine whether the same holds true for variable domain (Fab) glycosylation.
  
  
  
  IgGs were captured from RA and control sera obtained before (RA only), during and after pregnancy, followed by Fc and Fab separation, glycan release, and mass spectrometric detection. In parallel, glycans from intact IgG were analysed. The data was used to calculate glycosylation traits, and to estimate the level of Fab glycosylation.
  
  
  
  The overall level of Fab glycosylation was increased in RA patients compared to controls, while no differences in Fab glycosylation patterns were found. For the Fc and intact IgG (Total) previously observed differences in galactosylation and bisection were confirmed. Furthermore, increased galactosylation of Fc and Total were associated with lower disease activity and autoantibody positivity. In addition, the change in Fc galactosylation associated with the change in disease activity during pregnancy and after delivery, while this was not the case for Fab.
  
  
  
  In contrast to changes in Fc glycosylation, changes in Fab glycosylation are not associated with improvement of RA during pregnancy and arthritis flare after delivery.
authors.affiliation: Department of Rheumatology, Erasmus University Medical Center, PO Box 2400, 3000, CA, Rotterdam, The Netherlands.|Center for Proteomics and Metabolomics, Leiden University Medical Center, 2300, RC, Leiden, The Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: Bondt
authors.affiliation: Center for Proteomics and Metabolomics, Leiden University Medical Center, 2300, RC, Leiden, The Netherlands.
authors.forename: Manfred
authors.initials: M
authors.lastname: Wuhrer
authors.affiliation: Department of Rheumatology, Erasmus University Medical Center, PO Box 2400, 3000, CA, Rotterdam, The Netherlands.
authors.forename: T Martijn
authors.initials: TM
authors.lastname: Kuijper
authors.affiliation: Department of Rheumatology, Erasmus University Medical Center, PO Box 2400, 3000, CA, Rotterdam, The Netherlands.
authors.forename: Johanna M W
authors.initials: JM
authors.lastname: Hazes
authors.affiliation: Department of Rheumatology, Erasmus University Medical Center, PO Box 2400, 3000, CA, Rotterdam, The Netherlands. r.dolhain@erasmusmc.nl.
authors.forename: Radboud J E M
authors.initials: RJ
authors.lastname: Dolhain
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006031:Glycosylation; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism*; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000276:immunology* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G
keywords: Disease activity; Inflammation; Pregnancy; Rheumatoid arthritis