CTSG and asthma: Particularly, recent evidence indicates the persistence of neutrophilic and eosinophilic inflammation in patients' airways with severe asthma, and the activation by neutrophil proteinases (i.e. elastase, cathepsin G and proteinase-3) of peripheral blood leukocytes in order to produce superoxide and proinflammatory cytokines, which can further aggravate airway inflammation [79].