Recruitment of circulating allergen-specific T lymphocytes to the lung on allergen challenge in asthma.
BACKGROUND
In allergic subjects with asthma, the migration of CD4+ T cells to the lungs in the hours after allergen exposure may contribute to allergic inflammation in the target organ.


OBJECTIVE
We studied allergen-specific T cells from the peripheral blood and lungs of allergic subjects with asthma at baseline and after allergen challenge.


METHODS
In each patient, blood samples were taken 10 minutes before and 24 hours after the inhalation of a major sensitizing allergen. In vitro proliferation of peripheral blood CD4+ T cells specific for the same allergen used in the in vivo challenge was assessed. In one patient two Dermatophagoides pteronyssinus-specific T-cell clones (TCCs) were derived from peripheral blood, and their T-cell receptors were sequenced to determine their clonotypic determinants on the beta chains. The T-cell receptor determinants of the allergen-specific TCCs were sought in blood and bronchoalveolar lavage samples taken from this patient.


RESULTS
We found that allergen inhalation is followed by a decrement in the specific proliferation of peripheral CD4+ T cells to the same allergen used for bronchial provocation. In one patient the clonotypic determinants of two allergen-specific TCCs diminished in the peripheral blood, whereas they were simultaneously expanded in the lower respiratory tract.


CONCLUSIONS
Our data suggest that allergen-specific T cells are recruited from the peripheral blood to the bronchial lumen after allergen challenge.
Borgonovo
B
B
Department of Biotechnology, San Raffaele Scientific Institute, Milan, Italy.
Casorati
G
G
Frittoli
E
E
Gaffi
D
D
Crimi
E
E
Burastero
S E
SE
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D001249:Asthma / Q000276:immunology* / Q000473:pathology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D002999:Clone Cells; D005260:Female; D006801:Humans; D008168:Lung / Q000166:cytology*; D008212:Lymphocyte Depletion; D008297:Male; D008925:Mites; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry; D013601:T-Lymphocytes / Q000166:cytology
D000485:Allergens; D016693:Receptors, Antigen, T-Cell, alpha-beta