IL-13 expression at the sites of allergen challenge in patients with asthma.
Atopic asthma is characterized by inflammatory responses of the airway and is associated with up-regulation of Th2 cytokines, notably IL-4 and IL-5. A recently described human cytokine, IL-13, is a potent in vitro modulator of various cell types, including monocytes, B cells, and endothelial cells. Similar to IL-4, it is also involved in the induction of IgE synthesis. However, the in vivo expression and function of IL-13 and its relation to disease remain to be defined. Using a segmental allergen challenge model, we have examined the in vivo expression of IL-13 in the bronchoalveolar lavage (BAL) cells of atopic patients. We found a significant enhancement of both IL-13 transcripts and secreted proteins in the allergen-challenged BAL compared with the saline-challenged control sites of asthmatic and rhinitic patients. In contrast, the expression of IL-13 transcripts was not detected in the BAL of two normal subjects challenged with the same dose of ragweed allergen. The cellular source of IL-13 mRNA was identified in the mononuclear cell fraction of the allergen-challenged BAL. The allergen-induced quantitative differences in the level of transcripts were confirmed by competitive PCR assays. These results suggest that the significant increase in IL-13 in the allergen-challenged BAL is primarily from the mononuclear cells and is involved in the regulation of allergen-induced late phase inflammatory responses.
Huang
S K
SK
Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA.
Xiao
H Q
HQ
Kleine-Tebbe
J
J
Paciotti
G
G
Marsh
D G
DG
Lichtenstein
L M
LM
Liu
M C
MC
D000328:Adult; D000485:Allergens / Q000008:administration & dosage*; D001249:Asthma / Q000175:diagnosis / Q000276:immunology*; D001483:Base Sequence; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D004804:Eosinophils / Q000378:metabolism; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology; D018793:Interleukin-13 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology*; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology; D015854:Up-Regulation / Q000235:genetics
D000485:Allergens; D018793:Interleukin-13; D012333:RNA, Messenger