title: Low-dose endotoxin in allergic asthmatics: effect on bronchial and inflammatory response to cat allergen.
abstract: BACKGROUND
  Endotoxin was proposed to increase the severity of asthma. Endotoxin levels greatly differ according to settings. In domestic environments, airborne concentrations may be dramatically low compared with levels reported in occupational settings.
  
  
  OBJECTIVE
  Our first objective was therefore to assess the effect of inhalation of low-level lipopolysaccharide (LPS) on the immediate and late-phase asthmatic bronchial response. Our second objective was to evaluate the effect of exposure to LPS on the local and systemic inflammatory response.
  
  
  METHODS
  Nineteen asthmatics sensitized to cat underwent on two separate occasions a bronchial challenge test to cat allergen (cat BCT) preceded randomly by a pre-exposure to either saline or LPS (2 microg). Methacholine challenge test was performed 24 h before exposure to LPS or saline. The Borg scale for dyspnoea and lung function were recorded before and after exposure to LPS or saline, and before and after cat BCT. Induced sputum and blood samples were collected before and after cat BCT, and analysed for cell counts and eosinophil cationic protein (ECP) levels.
  
  
  RESULTS
  Inhalation of 2 microg LPS did not induce any changes in forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), FEF 25-75 and Borg scale of dyspnoea. It neither modified Fel d 1 PD20 (45.03 ng as compared with 87.03; P=0.42). As well, there was no significant difference in late-phase reaction. Pre-exposure to LPS did not influence eosinophil counts or ECP levels in blood and sputum.
  
  
  CONCLUSIONS
  Our study demonstrated that pre-exposure to LPS at low levels, which may be encountered in domestic environment, had no significant effect on the immediate and late-phase bronchial response to cat allergen. It neither modified local and systemic eosinophilic inflammation.
authors.affiliation: Service de Pneumologie, Hôpital Lyautey, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
authors.forename: C
authors.initials: C
authors.lastname: Sohy
authors.forename: F
authors.initials: F
authors.lastname: Pons
authors.forename: A
authors.initials: A
authors.lastname: Casset
authors.forename: M-P
authors.initials: MP
authors.lastname: Chesnard
authors.forename: F
authors.initials: F
authors.lastname: Lieutier-Colas
authors.forename: P
authors.initials: P
authors.lastname: Meyer
authors.forename: G
authors.initials: G
authors.lastname: Pauli
authors.forename: F
authors.initials: F
authors.lastname: de Blay
mesh_terms: D000328:Adult; D000485:Allergens / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001249:Asthma / Q000276:immunology* / Q000503:physiopathology*; D001980:Bronchi / Q000187:drug effects / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D002415:Cats; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D047150:Eosinophil Cationic Protein / Q000032:analysis / Q000097:blood; D004804:Eosinophils / Q000276:immunology; D005260:Female; D006801:Humans; D008070:Lipopolysaccharides; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D013183:Sputum / Q000737:chemistry / Q000276:immunology; D013997:Time Factors
chemical_list: D000485:Allergens; D008070:Lipopolysaccharides; D016210:Methacholine Chloride; D047150:Eosinophil Cationic Protein