Prolastin aerosol therapy and sputum taurine in cystic fibrosis.

BACKGROUND: Neutrophil elastase in the cystic fibrosis airways inhibits opsonophagocytosis and induces the expression of interleukin-8, a neutrophil chemoattractant. Prolastin is a therapeutic preparation of alpha-1 proteinase inhibitor (alpha1,-PI), a neutrophil elastase inhibitor. The objective of this study was to determine the effects of Prolastin aerosol therapy on airway inflammation in cystic fibrosis.
METHODS: The primary endpoint of this study was sputum taurine, an amino-acid present in high concentrations in neutrophils. Sputum taurine correlates with respiratory exacerbations of cystic fibrosis. Seventeen patients with cystic fibrosis were each assigned to three sequential 10-day periods including first, aerosol therapy of 5 ml saline solution bid; second, aerosol therapy of 250 mg Prolastin bid; third, no aerosol therapy. On days 8, 9 and 10 of each period, early morning sputum was collected for the quantification of alpha1-PI, neutrophil elastase activity, IL-8 and taurine.
RESULTS: During Prolastin therapy, a 3-fold increase in sputum alpha1-PI was observed (P = 0.002). Baseline values of sputum alpha1-PI correlated with the values obtained after Prolastin aerosol (R = 0.77, P < 0.01). Sputum neutrophil elastase activity remained unchanged but taurine decreased after Prolastin therapy (during therapy P = 0.052, after therapy P = 0.026). Prolastin aerosol therapy had no adverse effect on pulmonary function.
CONCLUSIONS: Aerosol therapy with Prolastin in patients with cystic fibrosis leads to a progressive decrease in sputum taurine. This suggests that even in the absence of sustained elastase inhibition, Prolastin aerosol therapy may have a beneficial effect on airway inflammation in patients with cystic fibrosis.