Distinct mutations in IRAK-4 confer hyporesponsiveness to lipopolysaccharide and interleukin-1 in a patient with recurrent bacterial infections

J Exp Med. 2003 Aug 18;198(4):521-31. doi: 10.1084/jem.20030701.

Abstract

We identified previously a patient with recurrent bacterial infections who failed to respond to gram-negative LPS in vivo, and whose leukocytes were profoundly hyporesponsive to LPS and IL-1 in vitro. We now demonstrate that this patient also exhibits deficient responses in a skin blister model of aseptic inflammation. A lack of IL-18 responsiveness, coupled with diminished LPS and/or IL-1-induced nuclear factor-kappaB and activator protein-1 translocation, p38 phosphorylation, gene expression, and dysregulated IL-1R-associated kinase (IRAK)-1 activity in vitro support the hypothesis that the defect lies within the signaling pathway common to toll-like receptor 4, IL-1R, and IL-18R. This patient expresses a "compound heterozygous" genotype, with a point mutation (C877T in cDNA) and a two-nucleotide, AC deletion (620-621del in cDNA) encoded by distinct alleles of the IRAK-4 gene (GenBank/EMBL/DDBJ accession nos. AF445802 and AY186092). Both mutations encode proteins with an intact death domain, but a truncated kinase domain, thereby precluding expression of full-length IRAK-4 (i.e., a recessive phenotype). When overexpressed in HEK293T cells, neither truncated form augmented endogenous IRAK-1 kinase activity, and both inhibited endogenous IRAK-1 activity modestly. Thus, IRAK-4 is pivotal in the development of a normal inflammatory response initiated by bacterial or nonbacterial insults.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Bacterial Infections / immunology
  • Bacterial Infections / metabolism*
  • Cell Line
  • Female
  • Humans
  • Inflammation / immunology
  • Inflammation / metabolism
  • Interleukin-1 / immunology*
  • Interleukin-1 / metabolism
  • Interleukin-1 Receptor-Associated Kinases
  • Interleukin-18 / immunology
  • Interleukin-18 / metabolism
  • Leukocytes, Mononuclear / metabolism
  • Lipopolysaccharides / immunology*
  • Lipopolysaccharides / metabolism
  • Molecular Sequence Data
  • NF-kappa B / metabolism
  • Neutrophils / immunology
  • Neutrophils / metabolism
  • Phosphotransferases (Alcohol Group Acceptor) / genetics*
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Point Mutation*
  • Signal Transduction / physiology
  • Transcription Factor AP-1 / metabolism

Substances

  • Interleukin-1
  • Interleukin-18
  • Lipopolysaccharides
  • NF-kappa B
  • Transcription Factor AP-1
  • Phosphotransferases (Alcohol Group Acceptor)
  • Interleukin-1 Receptor-Associated Kinases

Associated data

  • GENBANK/AF445802
  • GENBANK/AY186092