The proportion of subjects with measurable GM-CSF in the sputum was raised in those with moderate (7/14) and severe (11/18) asthma, and in those with COPD GOLD stage II (7/16), III (8/17) and IV (7/14) compared with controls (1/18) and those with mild asthma (0/13) (p = 0.001). This evidence concerns the gene CSF2 and asthma.