Identification of galectin-3 as an autoantigen in patients with IgG 4-related disease

J Allergy Clin Immunol. 2019 Feb;143(2):736-745.e6. doi: 10.1016/j.jaci.2018.05.011. Epub 2018 May 29.

Abstract

Background: The antigenic trigger that drives expansion of circulating plasmablasts and CD4+ cytotoxic T cells in patients with IgG4-related disease (IgG4-RD) is presently unknown.

Objective: We sought to sequence immunoglobulin genes from single-cell clones of dominantly expanded plasmablasts and generate recombinant human mAbs to identify relevant antigens in patients with IgG4-RD by using mass spectrometry.

Methods: Paired heavy and light chain cDNAs from dominant plasmablast clones were expressed as mAbs and used to purify antigens by using immunoaffinity chromatography. Affinity-purified antigens were identified by using mass spectrometry and validated by means of ELISA. Plasma levels of the antigen of interest were also determined by using ELISA.

Results: mAbs expressed from the 2 dominant plasmablast clones of a patient with multiorgan IgG4-RD stained human pancreatic tissue sections. Galectin-3 was identified as the antigen specifically recognized by both mAbs. Anti-galectin-3 autoantibody responses were predominantly of the IgG4 isotype (28% of the IgG4-RD cohort, P = .0001) and IgE isotype (11% of the IgG4-RD cohort, P = .009). No significant responses were seen from the IgG1, IgG2, or IgG3 isotypes. IgG4 anti-galectin-3 autoantibodies correlated with increased plasma galectin-3 levels (P = .001), lymphadenopathy (P = .04), total IgG level increase (P = .05), and IgG4 level increase (P = .03).

Conclusion: Affinity chromatography using patient-derived mAbs identifies relevant autoantigens in patients with IgG4-RD. IgG4 galectin-3 autoantibodies are present in a subset of patients with IgG4-RD and correlate with galectin-3 plasma levels. The marked increases in levels of circulating IgG4 and IgE observed clinically are, at least in part, caused by the development of IgG4- and IgE-specific autoantibody responses.

Keywords: IgG(4)-related disease; autoantibody; autoantigen; galectin-3; plasmablast.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantibodies / metabolism
  • Autoantigens / immunology
  • Autoantigens / isolation & purification*
  • CD4-Positive T-Lymphocytes / immunology*
  • Cell Proliferation
  • Female
  • Galectin 3 / immunology
  • Galectin 3 / isolation & purification*
  • Humans
  • Immunoglobulin E / metabolism
  • Immunoglobulin G / metabolism
  • Immunoglobulin G4-Related Disease / immunology*
  • Immunoglobulins / genetics
  • Immunosorbent Techniques
  • Lymphocyte Activation
  • Male
  • Mass Spectrometry
  • Middle Aged
  • Plasma Cells / immunology*
  • Recombinant Proteins / genetics

Substances

  • Autoantibodies
  • Autoantigens
  • Galectin 3
  • Immunoglobulin G
  • Immunoglobulins
  • Recombinant Proteins
  • Immunoglobulin E