Biomarkers in blood, sputum and exhaled air
Severe nonsmoking asthma | Smokers and ex-smokers with severe asthma | Mild/moderate nonsmoking asthma | Healthy nonsmoking controls | p-value | p-value# | |
Subjects n | 311 | 110 | 88 | 101 | ||
Exhaled NO ppb | 26.5 (16−47) (n=290) | 23.5 (12−42) (n=104) | 25 (18−54) (n=87) | 19.25 (13−29) (n=96) | <0.001 | 0.438 |
Sputum | ||||||
Sputum eosinophils % | 2.75 (0−19) (n=128) | 4.13 (1−14) (n=53) | 1.05 (0−3) (n=43) | 0 (0−0) (n=41) | <0.001 | 0.004 |
Sputum neutrophils % | 53.69 (34−75) (n=128) | 55.15 (35−65) (n=53) | 44.5 (26−62) (n=43) | 39.56 (21−56) (n=41) | 0.002 | 0.042 |
Sputum differential eosinophil count >1.9% | 74 (57.81%) (n=128) | 32 (60.38%) (n=53) | 17 (39.53%) (n=43) | 1 (2.44%) (n=41) | <0.001 | 0.026 |
Blood | ||||||
Blood eosinophils % | 2.94 (1−6) (n=302) | 2.88 (1−5) (n=106) | 3.00 (2−5) (n=88) | 2.10 (1−3) (n=101) | 0.001 | 0.295 |
Blood eosinophils absolute | 0.2 (0.3) (n=302) | 0.22 (0.29) (n=106) | 0.23 (0.2) (n=88) | 0.1 (0.11) (n=101) | 0.001 | 0.295 |
Blood neutrophils % | 62 (55−70) (n=302) | 61.75 (55−69) (n=106) | 56.83 (52−63) (n=88) | 57.34 (51−64) (n=101) | <0.001 | <0.001 |
Blood neutrophils absolute | 4.73 (3.1) (n=302) | 4.97 (2.87) (n=106) | 3.64 (1.75) (n=88) | 3.03 (1.6) (n=101) | <0.001 | <0.001 |
Data are presented as median (interquartile range), unless otherwise stated. #: severe asthma (nonsmoking asthma group and smokers and ex-smokers with severe asthma group combined) versus mild/moderate nonsmoking asthma group.