Increased expression of interleukin-16 in bronchial mucosa of subjects with atopic asthma.

Abstract

Asthma is characterized by the presence of activated CD4+ cells in the airways. We hypothesized that the newly characterized cytokine interleukin (IL)-16 is involved in the pathogenesis of asthma through its ability to selectively induce CD4+ cell recruitment within the inflamed bronchial wall. We investigated the expression of IL-16 in bronchial biopsies obtained from subjects with mild asthma (n = 10), atopic nonasthmatic individuals (n = 6), and normal control subjects (n = 10). Cryostat sections from 4% paraformaldehyde-fixed fiberoptic bronchial biopsies were immunostained using a specific antibody that recognizes human IL-16. IL-16 mRNA expression was determined by in situ hybridization. IL-16 immunoreactivity and mRNA were demonstrated mainly in bronchial epithelial cells in all subjects. IL-16 immunoreactivity and IL-16 mRNA expression within the epithelium were significantly higher in bronchial biopsies obtained from asthmatic subjects as compared to both atopic nonasthmatic and normal controls (P < 0.001). The numbers of subepithelial IL-16 immunoreactive cells and IL-16 mRNA-positive cells were also greater in the bronchial biopsies obtained from asthmatic subjects as compared to both atopic nonasthmatic and normal controls (P < 0.001). Epithelial expression of IL-16 immunoreactivity and mRNA correlated with the CD4+ cell infiltration (r2 = 0.70, P < 0.001). There were significant associations between epithelial and subepithelial IL-16 immunoreactivity and airway responsiveness to methacholine. This study demonstates that IL-16 is expressed in airway tissues, particularly in the epithelial cells, and that up-regulation of its expression is a feature of allergic asthma. These results suggest an in vivo role for IL-16 in the pathogenesis of asthma, possibly through the recruitment of CD4+ cells, and support the increasing evidence for the participation of epithelial cells in regulating inflammatory responses.

• Authors: S Laberge, P Ernst, O Ghaffar, W W Cruikshank, H Kornfeld, D M Center, Q Hamid
• Journal: American journal of respiratory cell and molecular biology (Am J Respir Cell Mol Biol) Vol. 17 Issue 2 Pg. 193-202 (Aug 1997) ISSN: 1044-1549 [Print] United States
• PMID: 9271307 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Interleukin-16
• RNA, Messenger

Topics

• Adult
• Asthma (metabolism, pathology)
• Biopsy
• Bronchi (metabolism, pathology)
• Bronchoscopy
• CD4-Positive T-Lymphocytes (cytology)
• Female
• Humans
• Interleukin-16 (genetics)
• Male
• Mucous Membrane (metabolism, pathology)
• RNA, Messenger (genetics)