Eotaxin level in induced sputum is increased in patients with bronchial asthma and in smokers.
BACKGROUND
Airway eosinophilia is one of the hallmarks of asthma. Eotaxin may play an important role in eosinophil recruitment.


OBJECTIVE
To examine the relationship between eotaxin levels in the sputum and eosinophilic inflammation.


METHODS
The sputum was obtained from 11 non-smokers, 14 smokers and 13 asthmatic patients using a sputum induction method. Eotaxin and interleukin (IL)-5 levels in the sputum were determined by ELISA and immunocytochemical analysis.


RESULTS
Asthmatic patients had eosinophilia and smokers showed neutrophilia in their sputum. The eotaxin level in the sputum was significantly higher in smokers (median 412.5, range 91.1-872.2 pg/ml) and asthmatic patients (351.0, 185.0-928.0 pg/ml) compared with non-smokers (123.2, 0-369.0 pg/ml; both p < 0.05). IL-5 was detected in the sputum of 1 non-smoker, none of the smokers and 4 asthmatic patients. The percentage of eotaxin-positive cells was higher in smokers and asthmatic patients than in non-smokers, but the percentage of IL-5-positive cells was significantly higher only in asthmatic patients (p < 0.05).


CONCLUSIONS
These findings suggest that the elevated eotaxin level in the sputum does not always accompany the increase in eosinophils, and cooperation with another cytokine such as IL-5 may be required for the recruitment of eosinophils.
Yamamoto
Katsumaru
K
Second Department of Internal Medicine, Hirosaki University School of Medicine, 5 Zaifu-cho, 036-8562, Japan.
Takanashi
Shingo
S
Hasegawa
Yukihiro
Y
Kanehira
Yutaka
Y
Kaizuka
Mitsuaki
M
Okumura
Ken
K
D000328:Adult; D000368:Aged; D001249:Asthma / Q000276:immunology* / Q000378:metabolism; D054413:Chemokine CCL11; D019742:Chemokines, CC / Q000032:analysis*; D002631:Chemotactic Factors, Eosinophil / Q000032:analysis*; D004802:Eosinophilia / Q000378:metabolism; D005260:Female; D006801:Humans; D015848:Interleukin-5 / Q000032:analysis; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D012907:Smoking / Q000276:immunology* / Q000378:metabolism; D013183:Sputum / Q000737:chemistry* / Q000166:cytology / Q000276:immunology
C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil; D015848:Interleukin-5