IL-8 is expressed by human peripheral blood eosinophils. Evidence for increased secretion in asthma.
Eosinophils possess the capacity to synthesize various cytokines. We demonstrate that IL-8 mRNA and protein are constitutively expressed by freshly isolated resting human eosinophils. Most of the patients with bronchial asthma or atopic dermatitis show evidence for up-regulated IL-8 protein expression in eosinophils but not in neutrophils, suggesting that an eosinophil-specific cytokine may act in these patients. To investigate whether the intracellular IL-8 can be released, eosinophils were stimulated by different cytokines and platelet-activating factor. Priming with granulocyte-macrophage CSF and a subsequent 25-min stimulation with RANTES or platelet-activating factor resulted in release of IL-8 from highly purified human eosinophils in vitro. As the eosinophil is the predominant cell in asthmatic inflammation, we determined IL-8 concentrations in bronchoalveolar lavage fluids from normal individuals and asthmatic patients. Bronchoalveolar lavage fluids from patients with bronchial asthma consistently demonstrated high IL-8 concentration compared with the controls. This suggests that IL-8 is released in vivo by inflammatory bronchial cells in asthma.
Yousefi
S
S
Swiss Institute of Allergy and Asthma Research, Davos.
Hemmann
S
S
Weber
M
M
Hölzer
C
C
Hartung
K
K
Blaser
K
K
Simon
H U
HU
D001249:Asthma / Q000276:immunology*; D001483:Base Sequence; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D004804:Eosinophils / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000378:metabolism; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000276:immunology; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000096:biosynthesis
D016209:Interleukin-8; D012333:RNA, Messenger