Increased Bronchial Density of CD25+Foxp3+ Regulatory T Cells in Occupational Asthma: Relationship to Current Smoking

• Published in: Scandinavian journal of immunology Vol. 77; no. 5; pp. 398 - 404
• Main Authors: Sjåheim, T. B., Bjørtuft, Ø., Drabløs, P. A., Kongerud, J., Halstensen, T. S.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.05.2013
• Subjects: Adult; Asthma, Occupational - immunology; Asthma, Occupational - metabolism; Bronchi - immunology; Bronchi - pathology; CD4-Positive T-Lymphocytes - immunology; CD4-Positive T-Lymphocytes - metabolism; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - metabolism; Cell Proliferation; Forkhead Transcription Factors - immunology; Forkhead Transcription Factors - metabolism; HLA-DR Antigens - immunology; HLA-DR Antigens - metabolism; Humans; Immunohistochemistry - methods; Interleukin-2 Receptor alpha Subunit - immunology; Interleukin-2 Receptor alpha Subunit - metabolism; Lymphocyte Activation - immunology; Lymphocyte Count; Microscopy, Fluorescence; Middle Aged; Smoking - immunology; T-Lymphocytes, Regulatory - immunology; T-Lymphocytes, Regulatory - metabolism; Young Adult
• ISSN: 0300-9475; 1365-3083
• DOI: 10.1111/sji.12035

To identify activated T cell subset in the asthmatic bronchia, we developed a triple‐colour immunohistofluorescence labelling technique on cryo‐section to discriminate activated CD4+CD25+ T cells, (effector T cells) from Foxp3+ regulatory T cells (Treg). Additional coexpression of activation and proliferation markers was also examined in situ. Bronchial biopsies were taken from 20 aluminium potroom workers (12 smokers) with asthma (>12% reversibility), 15 non‐asthmatic potroom workers (7 smokers) and 10 non‐smoking, non‐exposed controls. Non‐smoking asthmatics had significantly higher subepithelial density of both Tregs, effector T cells, activated (HLA‐DR+) CD8+ and activated CD4+ T cells. Moreover, both Tregs, effector T cells and CD8+ T cells proliferated in the non‐smoking asthmatics, only. Although smoking asthmatics had no asthma‐associated increase in bronchial T cell, both had a significantly increase in effector T cell to Treg ratios. The significantly increased bronchial density of Tregs, effector T cells, proliferative T cells and activated CD8+ T cells in non‐smoking asthmatics clearly showed that both the effector T cells and the inhibitory Treg system were activated in asthma.