title: Differences in RANTES and IL-6 levels among chronic rhinosinusitis patients with predominant gram-negative and gram-positive infection.
abstract: BACKGROUND
  Bacteria are suspected players in the pathogenesis of chronic rhinosinusitis (CRS), yet their exact role is not understood. We investigated the effect of planktonic and biofilm of staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA) on the mucosa of CRS patients with gram-positive and gram-negative infections by measuring the levels of IL-6 and RANTES, a chemokine with activity on eosinophils and T lymphocytes.
  
  
  METHODS
  Ethmoid mucosa of six CRS patients with gram-positive bacteria on culture and five with gram-negative bacteria were compared to ethmoid mucosa of 8 control patients. The tissue explants were stimulated with SA and PA extracts in planktonic and biofilm form for 6 hours, then RANTES levels were measured by ELISA.
  
  
  RESULTS
  Compared to the control group, CRS patients with gram-negative predominance demonstrated a significantly higher level of RANTES expression in response to all forms of bacterial stimuli (P-value <0.05). Patients with gram-positive predominance showed a higher level of RANTES compere to control group, however, this difference was not significant (P-value >0.05).
  
  
  CONCLUSIONS
  The mucosa of CRS patients with gram-negative infections has a heightened innate immune response compared to controls and patients with gram-positive infections. It is possible that this response leads to the pathological eosinophilic inflammation seen in CRS.
authors.affiliation: Department of Otolaryngology - Head and Neck Surgery, McGill University, Montreal, Canada.|Department of Otolaryngology - Head and Neck Surgery, King Abdul-Aziz University, Jeddah, Saudi Arabia.
authors.forename: Almoaidbellah
authors.initials: A
authors.lastname: Rammal
authors.affiliation: McGill University Health Centre, 1001 Decarie Blvd., Rm D05.5718, Montreal, QC, H4A 3 J1, Canada. marc.tewfik@mcgill.ca.
authors.forename: Marc
authors.initials: M
authors.lastname: Tewfik
authors.affiliation: Departments of Medicine, McGill University, Montreal, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Rousseau
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D018946:Chemokine CCL5 / Q000378:metabolism*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011552:Pseudomonas Infections / Q000378:metabolism*; D011550:Pseudomonas aeruginosa; D012220:Rhinitis / Q000378:metabolism* / Q000382:microbiology; D012852:Sinusitis / Q000378:metabolism* / Q000382:microbiology; D013203:Staphylococcal Infections / Q000378:metabolism*; D013211:Staphylococcus aureus
chemical_list: C483024:CCL5 protein, human; D018946:Chemokine CCL5; D015850:Interleukin-6
keywords: Chronic rhinosinusitis; Gram negative infection; Gram positive infection; IL-6; RANTES