Secretory leukocyte proteinase inhibitor is preferentially increased in patients with acute respiratory distress syndrome

Inappropriate release of proteases from inflammatory and stromal cells can lead to destruction of the lung parenchyma, Antiproteinases such as alpha-l -proteinase inhibitor (alpha(1)-Pi), secretory leukocyte proteinase inhibit or (SLPI) and elastase-specific inhibitor (elafin) control excess productio n of human neutrophil elastase, In the present study, the concentrations of alpha(1)-Pi, SLPI and elafin fo und in bronchoalveolar lavage (BAL) fluid from control subjects, patients a t risk of developing acute respiratory distress syndrome (ARDS) and patient s with established ARDS were determined, Levels of all three inhibitors were raised in patients compared with normal subjects. SLPI was increased in the group of patients who were at risk of ARDS and went on to develop the condition, compared with the "at-risk" grou p who did not progress to ARDS (p=0.0083), alpha(1)-Pi and elafin levels we re similar in these two populations. In patients with established ARDS, bot h alpha(1)-Pi and SLPI levels were significantly increased, compared to pat ients at risk of ARDS who did (p=0.0089) or did not (p=0.0003) progress to ARDS, The finding of increased antiproteinases shortly before the development of acute respiratory distress syndrome provide further evidence for enhanced i nflammation prior to clinical disease.