title: Polymorphisms in innate immunity genes predispose to bacteremia and death in the medical intensive care unit.
abstract: OBJECTIVE
  Critically ill patients are at risk of sepsis, organ failure, and death. Studying the impact of genetic determinants may improve our understanding of the pathophysiology and allow identification of patients who would benefit from specific treatments. Our aim was to study the influence of single nucleotide polymorphisms in selected genes involved in innate immunity on the development of bacteremia or risk of death in patients admitted to a medical intensive care unit.
  
  
  METHODS
  DNA was available from 774 medical intensive care unit patients. We selected 31 single nucleotide polymorphisms in 14 genes involved in host innate immune defense. Serum levels of MASP2 and chemotactic capacity, phagocytosis, and killing capacity of monocytes at admission were quantified. Univariate Kaplan-Meier estimates with log-rank analysis and multivariate logistic regression were performed. Bootstrap resampling technique and ten-fold cross-validation were used to assess replication stability, prognostic importance of the variables, and repeatability of the final regression model.
  
  
  RESULTS
  Patients with at least one NOD2 variant were shown to have a reduced phagocytosis by monocytes (p = 0.03) and a higher risk of bacteremia than wild-type patients (p = 0.02). The NOD2/TLR4 combination was associated with bacteremia using survival analyses (time to bacteremia development, log-rank p < 0.0001), univariate regression (p = 0.0003), and multivariate regression analysis (odds ratio [OR] 4.26, 95% confidence interval [CI] 1.85-9.81; p = 0.0006). Similarly, the same combination was associated with hospital mortality using survival analysis (log-rank p = 0.03), univariate regression (p = 0.02), and multivariate regression analysis (OR 2.27, 95% CI 1.09-4.74; p = 0.03). Also variants in the MASP2 gene were significantly associated with hospital mortality (survival analysis log-rank-p = 0.003; univariate regression p = 0.02; multivariate regression analysis OR 2.35, 95% CI 1.38-3.99; p = 0.002).
  
  
  CONCLUSIONS
  Functional polymorphisms in genes involved in innate immunity predispose to severe infections and death, and may become part of a risk model, allowing identification of patients at risk, who could benefit from early introduction of specific preventive or therapeutic interventions.
authors.affiliation: Department of Medicine, Catholic University of Leuven, Leuven, Belgium.
authors.forename: Liesbet
authors.initials: L
authors.lastname: Henckaerts
authors.forename: Kaspar R
authors.initials: KR
authors.lastname: Nielsen
authors.forename: Rudi
authors.initials: R
authors.lastname: Steffensen
authors.forename: Kristel
authors.initials: K
authors.lastname: Van Steen
authors.forename: Chantal
authors.initials: C
authors.lastname: Mathieu
authors.forename: Annapaula
authors.initials: A
authors.lastname: Giulietti
authors.forename: Pieter J
authors.initials: PJ
authors.lastname: Wouters
authors.forename: Ilse
authors.initials: I
authors.lastname: Milants
authors.forename: Ilse
authors.initials: I
authors.lastname: Vanhorebeek
authors.forename: Lies
authors.initials: L
authors.lastname: Langouche
authors.forename: Séverine
authors.initials: S
authors.lastname: Vermeire
authors.forename: Paul
authors.initials: P
authors.lastname: Rutgeerts
authors.forename: Steffen
authors.initials: S
authors.lastname: Thiel
authors.forename: Alexander
authors.initials: A
authors.lastname: Wilmer
authors.forename: Troels Krarup
authors.initials: TK
authors.lastname: Hansen
authors.forename: Greet
authors.initials: G
authors.lastname: Van den Berghe
mesh_terms: D016470:Bacteremia / Q000235:genetics* / Q000401:mortality*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics*; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide