Influx of neutrophils into the airway lumen at 4 h after segmental allergen challenge in asthma.
BACKGROUND
Segmental allergen challenge is a powerful tool to study inflammatory reactions in asthmatic airways. There is little information on the early events at 5 min and 4 h after allergen challenge with respect to the cell influx and the chemokine interleukin-8 (IL-8).


METHODS
Seven mild to moderate allergic asthmatics (AA group), 5 allergic nonasthmatics (ANA group) and 5 nonallergic controls underwent segmental allergen challenge, with allergen doses based upon skin reactivity. Bronchoalveolar lavage (BAL) samples were obtained before, 5 min and 4 h postchallenge, and were analyzed for cell numbers and differential counts, eosinophil and neutrophil chemotactic activity, and levels of IL-8.


RESULTS
At 5 min postchallenge, no changes were observed compared to baseline. At 4 h postchallenge, an increase was found in the number of neutrophils and the levels of IL-8, which was dependent on the dose of allergen in the AA and ANA group. At the same allergen dose, the increases in neutrophils and levels of IL-8 were calculated to be 91 and 67 times higher, respectively, in AA than in ANA. Levels of IL-8 correlated with the number of neutrophils and with the in vitro neutrophil chemotactic activities in BAL fluid.


CONCLUSIONS
Neutrophil chemotactic activity is increased in BAL fluid at 4 h after segmental allergen challenge. We suggest that apart from IgE-mediated mast cell degranulation, additional local factors in the airways determine the degree of IL-8 increase and neutrophil influx.
Nocker
R E
RE
Department of Pulmonology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Out
T A
TA
Weller
F R
FR
Mul
E P
EP
Jansen
H M
HM
van der Zee
J S
JS
D000328:Adult; D000485:Allergens / Q000276:immunology*; D001249:Asthma / Q000276:immunology*; D001980:Bronchi / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002452:Cell Count; D002634:Chemotaxis, Leukocyte; D004804:Eosinophils / Q000276:immunology; D005260:Female; D006801:Humans; D006967:Hypersensitivity; D016209:Interleukin-8 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000032:analysis; D008297:Male; D009504:Neutrophils / Q000276:immunology*; D012882:Skin Tests
D000485:Allergens; D016209:Interleukin-8; D008070:Lipopolysaccharides