Expression of eotaxin in induced sputum of atopic and nonatopic asthmatics.
BACKGROUND
The chemokine eotaxin has been implicated in airway eosinophilia in atopic asthma. We have compared airway eosinophils and eotaxin expression in induced sputum from well-matched atopic and nonatopic asthmatics.


METHODS
Eosinophil numbers, eosinophil cationic protein (ECP), and the expression of eotaxin were examined in induced sputum from atopic asthmatics (AA = 11), nonatopic asthmatics (NAA = 11), and atopic (AC = 12) and normal (NC = 10) controls. Slides were prepared for differential cell counts by Romanowsky stain, and ECP levels were measured by RIA. Eotaxin expression was detected by in situ hybridization, with 35S-labelled riboprobes and immunocytochemistry.


RESULTS
The numbers of eosinophils and ECP concentration were increased in the sputum of AA and NAA compared with AC and NC (P < 0.05). The numbers of eotaxin mRNA+ and immunoreactive cells were increased in NAA, but not AA, when compared with controls (P < 0.05). Eotaxin immunoreactive cells in NAA were significantly higher than in AA (P < 0.05). Eotaxin was expressed predominantly by macrophages, eosinophils, and epithelial cells. In NAA, but not AA, the numbers of eotaxin mRNA+ cells were correlated with histamine PC20 (r = -0.81, P < 0.01) and eosinophil numbers in sputum (r = 0.7, P < 0.05).


CONCLUSIONS
Eotaxin production by macrophages, eosinophils, and epithelial cells may play a more pronounced role in airway eosinophilia in nonatopic than in atopic asthma.
Zeibecoglou
K
K
Allergy and Clinical Immunology, Imperial College School of Medicine, National Heart and Lung Institute, London, UK.
Ying
S
S
Meng
Q
Q
Kay
A B
AB
Robinson
D S
DS
Papageorgiou
N
N
D000328:Adult; D001249:Asthma / Q000378:metabolism*; D001798:Blood Proteins / Q000032:analysis; D054413:Chemokine CCL11; D019742:Chemokines, CC; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000502:physiology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006967:Hypersensitivity / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D012260:Ribonucleases; D013183:Sputum / Q000166:cytology / Q000378:metabolism*
D001798:Blood Proteins; C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D016207:Cytokines; D047091:Eosinophil Granule Proteins; D012333:RNA, Messenger; D012260:Ribonucleases