Table 1

 Subject details presented for the whole study group and for each separate study group

TNFα study and patient groups‡Subject numbersSex (M/F)Mean (range) age(years)Mean (SE) FEV1(% predicted)
Differences between the groups and the healthy control subjects with respect to FEV1% predicted are designated by *p<0.01, **p<0.001 and ***p<0.0001, while differences for the same measure between the mild and severe asthmatic groups are indicated as †p<0.001 and ††p<0.0001.
‡The different subject groups were defined on the following basis:
(a) Healthy control subjects had no history or symptoms to suggest asthma, normal lung function and normal bronchial reactivity, as reflected by a PC20 methacholine of >16 mg/ml.
(b) Mild asthma was defined on the basis of a doctor diagnosis of asthma, current symptoms compatible with asthma, the need for the use of prn salbutamol for symptom relief but no other medication use for asthma.
(c) Severe asthma was defined on the basis of doctor diagnosed and treated asthma that remained symptomatic, despite treatment at stage 4/5 of the BTS/SIGN guidelines,2 together with historical data of airway reversibility and the need for oral steroid therapy, either as regular maintenance therapy or for the treatment of exacerbations. Thirty seven of the 51 severe asthmatics were on maintenance oral steroid therapy for their disease control in addition to high dose inhaled steroids, long acting β agonists, and additional treatment such as leukotriene receptor antagonists and theophyllines.
All subjects
    Healthy controls268/1830.2 (19–54)101.7 (2.0)
    Mild asthma6740/2730.0 (18–57)90.4 (1.4)**
    Severe asthma5115/3641.5 (18–67)61.4 (2.7)*** ††
Lavage studies
Comparator study
    Healthy controls268/1830.2 (19–54)101.7 (2.0)
    Mild asthma4224/1830.3 (18–50)94.2 (1.2)*
    Severe asthma205/1539.6 (18–67)55.8 (4.3)*** †
Biopsy studies
Gene expression
    Mild asthma147/728.8 (19–47)98.8 (2.0)
    Severe asthma146/844.5 (20–67)59.4 (6.0)†
    Mild asthma4225/1731.1 (20–52)87.2 (2.0)
    Severe asthma146/838.0 (18–67)48.8 (3.1)††
Etanercept study
    Severe asthma175/1243 (30–67)68.3 (5.0)