T lymphocytes in asthma: bronchial versus peripheral responses.
Recent evidence points to the recruitment of T(H)2 cells, phenotype T lymphocytes, their activation, and the generation of T(H)2 cytokines, particularly IL-4 and IL-5, in both peripheral blood and bronchial mucosa of asthmatic patients, leading to local tissue eosinophilia and IgE-dependent mast-cell activation. Activation of T(H)2 T lymphocytes appears to be specific for asthma (as opposed to airway obstructive disease) and was shown to correlate with asthma severity as evidenced by the inverse correlation between CD25(+)/CD4(+) cells and peak expiratory flow rates. These findings support the fundamental importance of T-lymphocyte responses in bronchial asthma and delineate potential therapeutic strategies, such as broad-based immunosuppression versus a more selective approach targeted against CD4(+) T lymphocytes. The high efficacy of topical treatments (ie, inhalation) supports the notion that changes that are detectable in peripheral blood merely reflect a "spill-over" of local T-lymphocyte responses in the target organ. Conversely, the multiple systemic manifestations of allergy (such as allergic rhinitis and atopic dermatitis in atopic patients) support systemic therapeutic approaches.
Durham
S R
SR
Imperial College School of Medicine, London, United Kingom.
Till
S J
SJ
Corrigan
C J
CJ
D000818:Animals; D001249:Asthma / Q000097:blood / Q000473:pathology*; D001980:Bronchi / Q000473:pathology; D006801:Humans; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism; D007376:Interleukin-2 / Q000097:blood / Q000378:metabolism; D015847:Interleukin-4 / Q000097:blood / Q000378:metabolism; D015848:Interleukin-5 / Q000097:blood / Q000378:metabolism; D009092:Mucous Membrane / Q000276:immunology; D010641:Phenotype; D013601:T-Lymphocytes / Q000276:immunology*; D018417:Th1 Cells / Q000378:metabolism; D018418:Th2 Cells / Q000378:metabolism
D007376:Interleukin-2; D015848:Interleukin-5; D015847:Interleukin-4; D007371:Interferon-gamma