The effect of segmental bronchoprovocation with allergen on airway lymphocyte function.
We hypothesized that allergen-induced airway eosinophilia is linked to activation or recruitment of T cells in the airway and generation of interleukin-5 (IL-5). To evaluate this hypothesis, we performed bronchoscopy with segmental antigen bronchoprovocation in 12 atopic subjects. Bronchoalveolar lavage (BAL) was done 5 min and 48 h after challenge with saline or antigen. Airway cells were isolated and then stimulated ex vivo with a T-cell mitogen, phytohemagglutinin (PHA), and cytokine release was determined. Cells retrieved from the saline-challenged segment secreted principally interferon-gamma (IFN-gamma) and IL-2. In contrast, cells obtained 48 h after allergen challenge secreted high levels of IL-5 and small but increased amounts of IL-4, IL-10, and granulocyte-macrophage colony-stimulating factor (GM-CSF). Although CD4+ T cells were a major source of IL-5, there were no significant changes in the relative proportion of CD4+ cells in response to bronchoprovocation. Additionally, ex vivo secretion of IL-5 by airway cells correlated closely with amounts of IL-5 and eosinophils present in the bronchoalveolar lavage fluid (BALF). These observations suggest that following exposure to allergen, airway T cells are functionally but not phenotypically different from resident airway T cells, and that T cells within the airway contribute to eosinophilic airway inflammation through the secretion of IL-5.
Kelly
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EA
Department of Medicine, University Wisconsin School of Medicine, Madison 53972, USA.
Rodriguez
R R
RR
Busse
W W
WW
Jarjour
N N
NN
D000328:Adult; D000485:Allergens; D001980:Bronchi / Q000166:cytology / Q000276:immunology*; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D018791:CD4 Lymphocyte Count; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D006636:Histamine Release; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D010835:Phytohemagglutinins; D016176:T-Lymphocyte Subsets; D013601:T-Lymphocytes / Q000276:immunology*
D000485:Allergens; D015848:Interleukin-5; D007378:Interleukins; D010835:Phytohemagglutinins; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor