MMP9 and chronic obstructive pulmonary disease: In human airway-relevant systems, corticosteroids suppress macrophage MMP-9 release (together with CXCL8 and TNF-α) in both healthy individuals and smokers, though this effect is attenuated in glucocorticoid-refractory diseases such as chronic obstructive pulmonary disease, underscoring both the on-target nature of the response and its dependence on disease type [97].