Table 1

 Characteristics of study patients

NValue*Reference range¶
EBC, exhaled breath condensate; Feno, fractional exhaled nitric oxide concentration; FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; LTB4, leukotriene B4; NA, not applicable or available; PD20, provocative dose of methacholine that caused a 20% fall in FEV1; MDC, macrophage derived chemokine; TARC, thymus and activation regulated chemokine; SD, standard deviation.
*Results expressed as mean (SD) or median (IQR) unless stated otherwise.
†Only 80 and 68 patients could successfully perform spirometric tests and methacholine bronchial challenge, respectively.
‡Mean (SD) volume of EBC collected was 1.26 (0.44) ml.
¶Reference ranges for “inflammatory markers” were established in-house from non-atopic and non-allergic children.
Clinical characteristics
    Age (years)9212.7 (3.4)NA
    Male gender, n (%)9264 (70)NA
    Body mass index (kg/m2)9219.0 (3.5)NA
    Disease severity score (range 6–30)9211 (9–14)NA
Atopic features
    Plasma total IgE concentration (kU/l)92611 (271–1256)⩽160 for 7 years; ⩽180 for ⩾8 years
    Specific IgE to D pteronyssinus (kU/l)92105 (39–145)<0.35
    Peripheral blood eosinophil (%)928 (5–10)⩽3
    Absolute eosinophil count (109/l)920.52 (0.35–0.77)⩽0.25
Lung function†
    FEV1 predicted (%)8092.1 (15.9)⩾80
    FVC predicted (%)80104.8 (17.3)⩾80
    FEV1/FVC (%)8080.0 (9.6)⩾80
    PD20 (μmol)681.95 (0.58–6.00)>7.8
Inflammatory markers‡
    Feno (ppb)9272.4 (39.5–117.8)⩽30
    Plasma TARC concentration (pg/ml)9245.0 (26.8–85.3)⩽70
    Plasma MDC concentration (pg/ml)92540 (411–702)⩽480
    Plasma eotaxin concentration (pg/ml)9239.0 (33.5–47.5)⩽45
    EBC MDC concentration (pg/ml)92113 (93–126)⩽105
    EBC eotaxin concentration (pg/ml)9237.0 (33.0–43.3)⩽35
    EBC LTB4 concentration (pg/ml)9239.9 (31.4–47.7)⩽35