title: The association between bacterial colonization and inflammatory pattern in Chinese chronic rhinosinusitis patients with nasal polyps.
abstract: BACKGROUND
  Chronic rhinosinusitis with nasal polyps (CRSwNP) can be subdivided according to the mucosal inflammatory patterns. In mainland China, apart from interleukin (IL)-5-positive and IL-17-positive polyps, a large group of patients with IL-5/IL-17/interferon-gamma (IFNγ)-negative nasal polyps (referred to as key cytokine-negative (KCN) polyps) can be found.
  
  
  OBJECTIVE
  To further study the KCN polyps and evaluate the associations between bacterial colonization and mucosal inflammatory pattern in KCN vs IL-5-positive nasal polyps.
  
  
  METHODS
  Nasal polyp or nasal turbinate tissue was obtained from 89 Chinese CRSwNP patients and 36 nonatopic control subjects during surgery. Samples without and after SEB exposure were processed for the assessment of pro-inflammatory cytokines and mediators by immunoassay. Prior to surgery, nasal swabs were taken from each patient for microbiological evaluation.
  
  
  RESULTS
  Overall, 80% polyp tissue did not express IL-5, with about 70% (49/71) of these being KCN. Key cytokine-negative nasal polyps were characterized by the synthesis of mediators promoting neutrophilic inflammation (myeloperoxidase (MPO), IL-1β, IL-6 and IL-8), whereas IL-5-positive nasal polyps were characterized by the synthesis of mediators promoting eosinophilic inflammation (IL-5, ECP, total IgE and SE-IgE). Key cytokine-negative nasal polyps were associated with greater Gram-negative bacterial load compared with controls, while IL-5-positive nasal polyps were associated with greater Gram-positive bacterial colonization vs controls and KCN polyps.
  
  
  CONCLUSIONS
  Our findings suggest that the bacteria colonizing nasal polyps of CRSwNP patients may impact on or be determined by the presence/absence of IL-5.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery of West China Hospital, Chengdu, Sichuan, China.
authors.forename: L
authors.initials: L
authors.lastname: Ba
authors.forename: N
authors.initials: N
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Meng
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: P
authors.initials: P
authors.lastname: Lin
authors.forename: P
authors.initials: P
authors.lastname: Zhou
authors.forename: S
authors.initials: S
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Bachert
mesh_terms: D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000302:isolation & purification*; D002908:Chronic Disease; D016207:Cytokines / Q000378:metabolism; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007249:Inflammation / Q000209:etiology / Q000276:immunology; D018836:Inflammation Mediators / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000150:complications / Q000276:immunology* / Q000382:microbiology*; D012220:Rhinitis / Q000150:complications* / Q000276:immunology / Q000382:microbiology*; D012852:Sinusitis / Q000150:complications* / Q000276:immunology / Q000382:microbiology*; D055815:Young Adult
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D007073:Immunoglobulin E