Copyright ©ERS Journals Ltd 2006 Reduced bronchial CD4+ T-cell density in smokers with occupational asthma1 Laboratory for Mucosal Immunology (LMI), Dept of Oral Biology, University of Oslo, 2 Dept of Respiratory Medicine, Rikshospitalet, Oslo, 3 Health Dept, Hydro Aluminium, Karmøy, Håvik, and 4 Health Dept, Elkem Aluminium, Lista, Farsund, Norway. CORRESPONDENCE: T. Sjåheim, Rikshospitalet, 0027 Oslo, Norway. Fax: 47 23073917. E-mail: tonebs{at}odont.uio.no Keywords: Asthma, inflammation, smoking, T-lymphocyte subsets
Received: March 7, 2006
Cigarette smoking may alter bronchial inflammation in asthma. Multicolour immunohistofluorescent examination on bronchial cryosections was used to examine bronchial inflammatory cell infiltrate in patients with occupational asthma. Monoclonal antibodies to CD3, CD4, CD8, T-cell receptor-
The increased subepithelial CD4+ T-cell density in nonsmoking asthmatics was not present in smoking asthmatics, who had the lowest CD4+ T-cell density of all groups. The decreased subepithelial CD4+ and CD8+ T-cell density correlated with a reduction in lung function, as measured by percentage predicted forced expiratory volume in one second, in smoking asthmatics only. Although smoking asthmatics had a significantly increased number of intraepithelial CD8+ T-cells and macrophages compared with nonsmoking asthmatics, the proportion of
Smoking asthmatics had a distinctly different distribution of T-cell subsets compared with nonsmoking asthmatics. The accumulation of subepithelial CD4+ T-cells, which was observed in nonsmoking asthmatics, appeared to be inhibited in smoking asthmatics, suggesting a smoking-induced bronchial immune modulation, at least in occupational asthma in the aluminium industry.
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