title: Effect of allergen challenge on the percentage of natural killer T cells in patients with atopic asthma.
abstract: BACKGROUND
  Invariant natural killer T (iNKT) cells produce cytokines that can influence the immune response to infection or allergen. Controversy surrounds their role in exacerbations of human atopic asthma.
  
  
  OBJECTIVE
  To determine the effect of allergen challenge on iNKT cells' mobilization to the airways and blood and to establish the relationship between airway iNKT cells and bronchial sensitivity to methacholine and allergen in patients with atopic asthma.
  
  
  METHODS
  We performed flow cytometry analysis for the iNKT cell receptor Va24 and V311 on bronchoalveolar lavage (BAL) cells at baseline and 24 hours after segmental antigen challenge (SAC) (n = 8) and on peripheral blood mononuclear cells (PBMCs) at baseline and 6 to 7 hours after inhaled allergen (n = 10). Challenges were performed using standardized protein allergens to which the participants were sensitive.
  
  
  RESULTS
  The number of BAL eosinophils increased 24 hours after SAC. The low mean (SEM) baseline percentage of iNKT cells in the population of BAL CD4' T cells remained unchanged 24 hours after SAC (0.035% [0.01%] vs 0.049% [0.02%]; n = 8; P = .50). Likewise, the mean (SEM) percentage of iNKT cells in PBMCs was unchanged after inhaled allergen provocation (0.068% [0.033%] vs 0.057% [0.026%]; n = 10; P = .10). No correlation was found between iNKT cells in BAL and the sensitivity to inhaled methacholine or allergen.
  
  
  CONCLUSIONS
  The percentages of both BAL and peripheral blood iNKT cells did not increase during allergen provoked asthmatic responses. Determination of iNKT cells in airway biopsy specimens would allow conclusively ruling against mobilization of iNKT cells in allergen-induced asthma exacerbation in humans.
authors.affiliation: Program in Vaccine Sciences, Vanderbilt University, Nashville, Tennessee 37232-2650, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Rock
authors.forename: Sandra
authors.initials: S
authors.lastname: Yoder
authors.forename: Aimee
authors.initials: A
authors.lastname: Hoskins
authors.forename: Wilfred U
authors.initials: WU
authors.lastname: Ajayi
authors.forename: Wiktor
authors.initials: W
authors.lastname: Ajayi
authors.forename: James R
authors.initials: JR
authors.lastname: Sheller
authors.forename: Ryszard
authors.initials: R
authors.lastname: Dworski
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology*; D001249:Asthma / Q000276:immunology* / Q000503:physiopathology; D001773:Blood Cells / Q000166:cytology; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D004804:Eosinophils / Q000166:cytology; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects / Q000276:immunology; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D055611:Natural Killer T-Cells / Q000166:cytology* / Q000276:immunology*; D009504:Neutrophils / Q000166:cytology; D055815:Young Adult
chemical_list: D000485:Allergens; D016210:Methacholine Chloride