Eosinophil traffic in the circulation following allergen challenge.
BACKGROUND
Eosinophils contribute to the pathogenesis of asthma and localize to the lung after allergen exposure by uncertain mechanisms.


METHODS
We used intrabronchial instillation of allergen to model the interaction between inhaled allergen and the lung. We measured the number of peripheral blood leukocytes and the expression of VLA-4 (CD49d), Mac-1 (CD11b) and PSGL-1 (CD162) up to 4 h after instillation of allergen into a bronchus of eight atopic asthmatics. For controls, we instilled normal saline into a subset of the asthmatic subjects, and allergen into nonatopic, nonasthmatic subjects.


RESULTS
There were changes of total leukocyte number, number of polymorphonuclear leukocytes, lymphocytes, monocytes and eosinophils in all three groups (atopic asthmatics instilled with allergen, atopic asthmatics instilled with saline, nonatopic nonasthmatic subjects instilled with allergen), which were likely related to bronchoscopy. However, the decrease of eosinophils was significant only in the atopic asthmatics instilled with allergen. The remaining eosinophils in the allergen challenged asthmatics were not activated as defined by cell density or change of expression of VLA-4, Mac-1 and PSGL-1.


CONCLUSIONS
While eosinophils rapidly and specifically leave the circulation after allergen challenge of atopic asthmatics, the remaining circulating eosinophils are not activated.
Sklar
L A
LA
Department of Pathology and Cancer Research, Treatment Center, University of New Mexico, Albuquerque, NM 87131, USA.
Tsuji
H
H
Edwards
B S
BS
Larson
R S
RS
Schuyler
M
M
D000280:Administration, Inhalation; D000328:Adult; D000485:Allergens / Q000008:administration & dosage* / Q000276:immunology; D001249:Asthma / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000276:immunology; D039481:CD11b Antigen / Q000032:analysis / Q000276:immunology; D002465:Cell Movement / Q000276:immunology*; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D006801:Humans; D039441:Integrin alpha4 / Q000032:analysis / Q000276:immunology; D015848:Interleukin-5 / Q000032:analysis / Q000276:immunology; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis / Q000276:immunology; D020545:Respiratory Mucosa / Q000276:immunology
D000485:Allergens; D039481:CD11b Antigen; D015848:Interleukin-5; D008562:Membrane Glycoproteins; C084882:P-selectin ligand protein; D039441:Integrin alpha4