Anti‐protease levels in cystic fibrosis are associated with lung function, recovery from pulmonary exacerbations and may be gender‐related

Airway SLPI is deficient in CF, which appears more marked in P. aeruginosa-infected female patients. Importantly, a reduced anti-protease to protease ratio is associated with accelerated lung function decline. Treatment of an exacerbation is accompanied by partial recovery of anti-protease defences and significant improvement in lung function, an important clinical outcome.