SERPINA4 and acute respiratory distress syndrome: Our previous reports also showed that lower plasma kallistatin levels were associated with increased mortality and disease severity in patients with community-acquired pneumonia (CAP) [20]; a lower ratio of kallistatin to total protein in the bronchoalveolar lavage fluid was associated with higher neutrophil counts in the bronchoalveolar lavage fluid and increased mortality in patients with sepsis-induced acute respiratory distress syndrome (ARDS) [17].