IRAK-4 and MyD88 deficiencies impair IgM responses against T-independent bacterial antigens Academic Article uri icon


MeSH Major

  • Antibodies, Bacterial
  • Antigens, Bacterial
  • B-Lymphocytes
  • Bacterial Infections
  • Immunoglobulin M
  • Immunologic Deficiency Syndromes
  • Polysaccharides, Bacterial


  • IRAK-4 and MyD88 deficiencies impair interleukin 1 receptor and Toll-like receptor (TLR) signaling and lead to heightened susceptibility to invasive bacterial infections. Individuals with these primary immunodeficiencies have fewer immunoglobulin M (IgM)(+)IgD(+)CD27(+) B cells, a population that resembles murine splenic marginal zone B cells that mount T-independent antibody responses against bacterial antigens. However, the significance of this B-cell subset in humans is poorly understood. Using both a 610 carbohydrate array and enzyme-linked immunosorbent assay, we found that patients with IRAK-4 and MyD88 deficiencies have reduced serum IgM, but not IgG antibody, recognizing T-independent bacterial antigens. Moreover, the quantity of specific IgM correlated with IgM(+)IgD(+)CD27(+) B-cell frequencies. As with mouse marginal zone B cells, human IgM(+)CD27(+) B cells activated by TLR7 or TLR9 agonists produced phosphorylcholine-specific IgM. Further linking splenic IgM(+)IgD(+)CD27(+) B cells with production of T-independent IgM, serum from splenectomized subjects, who also have few IgM(+)IgD(+)CD27(+) B cells, had reduced antibacterial IgM. IRAK-4 and MyD88 deficiencies impaired TLR-induced proliferation of this B-cell subset, suggesting a means by which loss of this activation pathway leads to reduced cell numbers. Thus, by bolstering the IgM(+)IgD(+)CD27(+) B-cell subset, IRAK-4 and MyD88 promote optimal T-independent IgM antibody responses against bacteria in humans.

publication date

  • December 4, 2014



  • Academic Article



  • eng

PubMed Central ID

  • PMC4256908

Digital Object Identifier (DOI)

  • 10.1182/blood-2014-07-587824

PubMed ID

  • 25320238

Additional Document Info

start page

  • 3561

end page

  • 71


  • 124


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