CSF2 and chronic obstructive pulmonary disease: However, in culture, GM-CSF secretion by ex vivo sputum cells is increased in COPD.18 Similarly, whether GM-CSFR expression is increased in airways disease is contentious, with one study suggesting that GM-CSFR is increased in non-atopic, but not atopic asthma.19 Therefore, GM-CSF and GM-CSFR expression in airways disease needs to be further defined.