title: The role of natural killer T cells in the pathogenesis of acute exacerbation of human asthma.
abstract: BACKGROUND
  Natural killer T (NKT) cells have been reported to play a crucial role in the pathogenesis of asthma in a mouse model of acute asthma. The present study aimed to investigate the role of NKT cells in the immune pathogenesis of acute exacerbation of human asthma.
  
  
  METHODS
  Blood and sputum were obtained at baseline and 8 h after a challenge in 20 asthmatics who underwent allergen bronchial provocation testing and during exacerbation and convalescence in 9 asthmatics who were admitted to hospital with an acute exacerbation after an upper respiratory tract infection. 6B11+ or Vα24+ NKT cells were measured with flow cytometry. Inflammatory cells, cytokines and chemokines were determined in sputum.
  
  
  RESULTS
  The number of blood NKT cells did not change after a positive allergen challenge compared to the baseline. However, blood CD4+Vα24+ NKT cells decreased during infection-associated asthma exacerbations compared to the convalescence measurements of the same patients (p < 0.05) or the baseline measurements of asthmatics who underwent allergen challenges (p < 0.01). The number of sputum NKT cells did not change after a positive allergen challenge or during infection-associated asthma exacerbations. Eosinophils and various cytokines and chemokines increased in sputum during infection-associated asthma exacerbations. Blood CD4+Vα24+ NKT cells were inversely related to sputum eosinophils (Spearman's correlation coefficient = -0.62; p < 0.01).
  
  
  CONCLUSIONS
  Blood NKT cells decreased during infection-associated asthma exacerbation and were inversely associated with eosinophilic airway inflammation, suggesting that blood NKT cells might be mobilized to the airways and lungs during asthma exacerbation in humans.
authors.affiliation: Department of Allergy, Asthma and Clinical Immunology and Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju, Korea. yikoh@chonnam.ac.kr
authors.forename: Young-Il
authors.initials: YI
authors.lastname: Koh
authors.forename: Jae-Uoong
authors.initials: JU
authors.lastname: Shim
authors.forename: Jeongook
authors.initials: J
authors.lastname: Wi
authors.forename: Yong Eun
authors.initials: YE
authors.lastname: Kwon
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000276:immunology*; D001985:Bronchial Provocation Tests; D018925:Chemokines / Q000097:blood; D016207:Cytokines / Q000097:blood; D004804:Eosinophils / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D055611:Natural Killer T-Cells / Q000276:immunology*; D012141:Respiratory Tract Infections / Q000150:complications; D013183:Sputum / Q000737:chemistry / Q000166:cytology / Q000276:immunology*; D055815:Young Adult
chemical_list: D018925:Chemokines; D016207:Cytokines