Corticosteroids seem to have no eff ect on many important
neutrophil antimicrobial functions, including phagocytosis
and oxidative burst,84,85 production of proteases,85 neutrophil
adhesion,86 and formation of neutrophil extracellular
traps.87 This fi nding might be because of the fact that the
glucocorticoid receptor is expressed at very low levels in
airway neutrophils compared with macrophages and
lymphocytes.88 Moreover, inhaled corticosteroids prolong
neutrophil survival and this eff ect is enhanced by
concomitant treatment with long-acting β2 agonists.89,90
Therefore, although there is some evidence for an eff ect of
corticosteroids on macrophage function, neutrophil
function does not seem to be compromised by inhaled
corticosteroids.