Association between sputum natural killer T cells and eosinophilic airway inflammation in human asthma.
BACKGROUND
Natural killer T (NKT) cells play an essential role in the development of airway hyperresponsiveness (AHR) in murine asthma. However, their role in the pathogenesis of human asthma has not been defined. The present study investigated whether NKT cells were associated with AHR or airway inflammation in human asthma.


METHODS
We measured the number of NKT cells in peripheral blood and induced sputum obtained from 61 asthmatics, 10 patients with eosinophilic bronchitis (EB) and 17 controls. EB was used as a disease control model to investigate the mechanisms of AHR in asthma outside the influence of eosinophilic airway inflammation. The quantities of CD3+CD56+ NKT cells, 6B11+ NKT cells and Vα24+ NKT cells were measured by flow cytometry.


RESULTS
The measurement of NKT cells did not differ among the 3 groups in peripheral blood. However, in sputum, CD3+CD56+ NKT cells and Vα24+ NKT cells were significantly increased in patients with asthma and EB compared to controls, and 6B11+ NKT cells were also increased in patients with asthma and EB, although not significantly. There was no difference in the measurements of sputum NKT cells between asthmatics and patients with EB. Sputum Vα24+ NKT cells were inversely associated with the degree of AHR in asthmatics.


CONCLUSIONS
Sputum NKT cells might play an important role in the pathogenesis of eosinophilic airway inflammation in human chronic stable asthma. However, functional studies on airway NKT cells are needed to elucidate the association between NKT cells and AHR.
Koh
Young-Il
YI
Department of Allergy, Asthma and Clinical Immunology and Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju, South Korea. yikoh@chonnam.ac.kr
Shim
Jae-Uoong
JU
D000328:Adult; D001249:Asthma / Q000276:immunology*; D016535:Bronchial Hyperreactivity / Q000276:immunology*; D004802:Eosinophilia / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007249:Inflammation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D055611:Natural Killer T-Cells / Q000166:cytology* / Q000276:immunology*; D013183:Sputum / Q000166:cytology / Q000276:immunology*