title: Correlation between transcranial interleukin-6 gradient and outcome in patients with acute brain injury.
abstract: OBJECTIVE
  This study was performed to examine both brain and systemic interleukin-6 (IL-6) release in patients with an acute brain injury (ABI), to study whether a correlation exists between the transcranial IL-6 gradient during the first days after injury and prognosis, and finally, to investigate the relationship between a nucleotide polymorphism at position -174 in the promoter of the gene encoding IL-6, IL-6 responsiveness, and clinical evolution.
  
  
  METHODS
  Prospective clinical investigation.
  
  
  METHODS
  A 19-bed intensive care unit in a university hospital.
  
  
  METHODS
  A total of 62 patients were followed up for 3 days after acute brain injury, and both their arterial and jugular IL-6 levels were measured serially and at the moment of brain death diagnosis. Genetic polymorphism of IL-6 was also determined in all patients. Data were correlated with those from score procedures for clinical severity. Neurologic outcome was graded according to the Glasgow Outcome Scale 6 months after injury. IL-6 levels and IL-6 genotyping was performed in control healthy individuals.
  
  
  RESULTS
  There is a significant transcranial IL-6 gradient at admission and at the moment of brain death. The gradient is higher in those patients who evolved toward a fatal outcome during the first 6 months after injury (p <.001). There is significant correlation between the transcranial IL-6 gradient and the acute brain injury severity.
  
  
  CONCLUSIONS
  IL-6 is elevated in patients with acute brain injury, and a significant relationship exits between the severity of acute brain injury and the transcranial IL-6 gradient at admission. It can be considered to be a prognosis marker at admission. When data at the moment of brain death are considered, venous IL-6 (p <.01) and the transcranial IL-6 gradient (p <.005) are significantly higher than at the time of admission. Although the IL-6 C allele is associated with significantly lower concentrations of IL-6, there was no correlation between low or high IL-6 responders and patient outcome.
authors.affiliation: Departamento de Medicina Intensiva, Hospital Universitario Marqués de Valdecilla, Instituto Nacional de la Salud, Santander, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Miñambres
authors.forename: Arantxa
authors.initials: A
authors.lastname: Cemborain
authors.forename: Pablo
authors.initials: P
authors.lastname: Sánchez-Velasco
authors.forename: Marco
authors.initials: M
authors.lastname: Gandarillas
authors.forename: Genaro
authors.initials: G
authors.lastname: Díaz-Regañón
authors.forename: Ubaldo
authors.initials: U
authors.lastname: Sánchez-González
authors.forename: Francisco
authors.initials: F
authors.lastname: Leyva-Cobián
mesh_terms: D018806:APACHE; D000208:Acute Disease; D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000032:analysis* / Q000097:blood*; D001923:Brain Chemistry; D001926:Brain Death / Q000097:blood / Q000473:pathology; D001930:Brain Injuries / Q000097:blood* / Q000150:complications / Q000276:immunology / Q000401:mortality / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D005838:Genotype; D023261:Glasgow Outcome Scale; D006801:Humans; D007249:Inflammation; D015601:Injury Severity Score; D015850:Interleukin-6 / Q000032:analysis* / Q000097:blood* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011379:Prognosis; D011401:Promoter Regions, Genetic / Q000235:genetics; D011446:Prospective Studies; D016019:Survival Analysis
chemical_list: D015415:Biomarkers; D015850:Interleukin-6