TH2 cytokine expression in bronchoalveolar lavage fluid T lymphocytes and bronchial submucosa is a feature of asthma and eosinophilic bronchitis.
BACKGROUND
Asthma is characterized by variable airflow obstruction and airway hyperresponsiveness in association with airway inflammation under the influence of T(H)2 cytokines. Eosinophilic bronchitis has similar immunopathology to asthma but without disordered airway physiology. Whether eosinophilic bronchitis is associated with increased expression of T(H)2 cytokines is unknown.


OBJECTIVE
We sought to assess the expression of T(H)2 cytokines in eosinophilic bronchitis.


METHODS
Expression of activation markers and chemokine receptors from blood and bronchoalveolar lavage (BAL) fluid T cells and the T(H)2 cytokine expression from these T cells and bronchial mucosa biopsy specimens were assessed from subjects with eosinophilic bronchitis, subjects with asthma, and healthy control subjects.


RESULTS
The proportion of resting (stimulated) CD4 BAL fluid T cells expressing intracellular IL-4 was significantly higher in the subjects with eosinophilic bronchitis 7.2% (11.4%) and subjects with asthma 5.3% (5.5%) than in healthy control subjects 2.8% (3.9%) (P =.03). The number of IL-4(+) (P <.001) and IL-5(+) (P =.003) cells per square millimeter of bronchial submucosa was significantly higher in the disease groups than in the healthy control subjects. Expression of intracellular IFN-gamma was significantly higher in stimulated blood CD8 T cells from subjects with eosinophilic bronchitis (24%) and asthma (17%) than in the healthy control subjects (5%; P =.003). There were no between-group differences in expression of IFN-gamma in the BAL fluid T cells or in the bronchial submucosa and no differences in expression of activation markers or chemokine receptors.


CONCLUSIONS
These findings support the concept of asthma as a disease associated with activation of T(H)2 lymphocytes in the airway and provide evidence that these cytokines play a role in the development of airway inflammation in eosinophilic bronchitis but suggest that the release of T(H)2 cytokines is not sufficient for the elaboration of disordered airway physiology in asthma.
Brightling
Christopher E
CE
Division of Respiratory Medicine, Institute for Lung Health, Leicester-Warwick Medical School and University Hospitals of Leicester, Leicester, United Kingdom.
Symon
Fiona A
FA
Birring
Surinder S
SS
Bradding
Peter
P
Pavord
Ian D
ID
Wardlaw
Andrew J
AJ
D000328:Adult; D001249:Asthma / Q000276:immunology*; D001980:Bronchi / Q000378:metabolism*; D001991:Bronchitis / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis*; D004802:Eosinophilia / Q000276:immunology*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000378:metabolism*; D018418:Th2 Cells / Q000276:immunology*
D016207:Cytokines; D015848:Interleukin-5; D015847:Interleukin-4; D007371:Interferon-gamma