Depressed serum IgM levels in SLE are restricted to defined subgroups

Clin Immunol. 2017 Oct:183:304-315. doi: 10.1016/j.clim.2017.09.013. Epub 2017 Sep 15.


Natural IgM autoantibodies have been proposed to convey protection from autoimmune pathogenesis. Herein, we investigated the IgM responses in 396 systemic lupus erythematosus (SLE) patients, divided into subgroups based on distinct autoantibody profiles. Depressed IgM levels were more common in SLE than in matched population controls. Strikingly, an autoreactivity profile defined by IgG anti-Ro/La was associated with reduced levels of specific natural IgM targeting phosphorylcholine (PC) antigens and malondialdehyde (MDA) modified-protein, as well as total IgM, while no differences were detected in SLE patients with an autoreactivity profile defined by anti-cardiolipin/β2glycoprotein-I. We also observed an association of reduced IgM levels with the HLA-DRB1*03 allelic variant among SLE patients and controls. Associations of low IgM anti-PC with cardiovascular disease were primarily found in patients without antiphospholipid antibodies. These studies further highlight the clinical relevance of depressed IgM. Our results suggest that low IgM levels in SLE patients reflect immunological and genetic differences between SLE subgroups.

Keywords: APS; Antiphospholipid syndrome; Autoantibodies; IgM anti-CWPS; IgM anti-MDA; IgM anti-PC; Natural IgM; SLE; SS; Sjögren's syndrome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Case-Control Studies
  • Female
  • HLA-DRB1 Chains
  • Humans
  • Immunoglobulin M / blood*
  • Immunoglobulin M / immunology*
  • Lupus Erythematosus, Systemic / immunology*
  • Male
  • Middle Aged


  • HLA-DRB1 Chains
  • Immunoglobulin M