title: Interleukin-1 receptor antagonist reverses stroke-associated peripheral immune suppression.
abstract: BACKGROUND
  Infections are common following stroke and adversely affect outcome. Cellular immune suppression associated with acute stroke may increase susceptibility to infection. Cytokines are important contributors to both stroke pathology and the response to infection. Since interleukin (IL)-1 blockade is a candidate treatment for cerebral ischemia, we examined whether administration of interleukin-1 receptor antagonist (IL-1Ra) to patients with acute stroke affected innate cellular immune responses in a phase II placebo-controlled trial.
  
  
  METHODS
  Venous blood samples were taken prior to treatment initiation, at 24h and 5 to 7d. Blood was also drawn from stroke-free controls. Lipopolysaccharide (LPS) stimulation of whole-blood cultures assessed the potential of leukocytes to produce cytokines.
  
  
  RESULTS
  Induction of tumor necrosis factor (TNF)-α, IL-1β, IL-6, IL-8 and IL-10 by LPS was significantly reduced in patients at admission, compared to controls. At 24h, cytokine induction remained suppressed in the placebo group. In contrast, for patients treated with IL-1Ra, induction of TNF-α, IL-6 and IL-10 was similar to controls and IL-1β induction was significantly greater than in the placebo group. At 5 to 7d, TNF-α and IL-1β induction remained suppressed only in the placebo group (p<0.05). Plasma cortisol concentrations, elevated at admission in patients compared to controls, were substantially reduced at 24h in the patients receiving IL-1Ra (p<0.05) and inversely correlated (p<0.001) with either TNF-α (r=-0.71) or IL-1β induction (r=-0.67) at admission.
  
  
  CONCLUSIONS
  Treatment with IL-1Ra reverses peripheral innate immune suppression in the acute phase of stroke, which is associated with attenuated cortisol production. The mechanisms underlying these observations, including the potential impact of IL-1Ra on stroke severity and the clinical significance of immune suppression, require further evaluation in larger studies.
authors.affiliation: Brain Injury Research Group, School of Biomedicine, University of Manchester, Manchester Academic Health Science Centre, Salford Royal Foundation Trust, Salford M6 8HD, UK. Craig.Smith-2@manchester.ac.uk
authors.forename: Craig J
authors.initials: CJ
authors.lastname: Smith
authors.forename: Hedley C
authors.initials: HC
authors.lastname: Emsley
authors.forename: Chinedu T
authors.initials: CT
authors.lastname: Udeh
authors.forename: Andy
authors.initials: A
authors.lastname: Vail
authors.forename: Margaret E
authors.initials: ME
authors.lastname: Hoadley
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Rothwell
authors.forename: Pippa J
authors.initials: PJ
authors.lastname: Tyrrell
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Hopkins
mesh_terms: D016022:Case-Control Studies; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood; D004311:Double-Blind Method; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007111:Immunity, Cellular / Q000187:drug effects*; D053590:Interleukin 1 Receptor Antagonist Protein / Q000494:pharmacology*; D010919:Placebos; D020521:Stroke / Q000276:immunology*
chemical_list: D016207:Cytokines; D053590:Interleukin 1 Receptor Antagonist Protein; D010919:Placebos; D006854:Hydrocortisone