Anti-Neutrophil-Elastase Defenses of the Lower Respiratory Tract in α1-Antitrypsin Deficiency Directly Augmented with an Aerosol of α1-Antitrypsin

Abstract

To determine if aerosolization of purified human plasma alpha 1-antitrypsin is an effective means for increasing lower respiratory anti-neutrophil-elastase defenses in alpha 1-antitrypsin deficiency. Nonrandomized, before-and-after trial with a 7-day treatment period. Companion studies in animals to determine lung epithelial permeability to alpha 1-antitrypsin. Twelve patients with homozygous Z-type alpha 1-antitrypsin deficiency and mild to moderate emphysema. Aerosol administration of human plasma alpha 1-antitrypsin, 100 mg every 12 hours for 7 days. Single, 100-mg aerosol dose to anesthetized sheep with indwelling thoracic lymph duct catheters for direct assessment of lung permeability. Treatment resulted in increased alpha 1-antitrypsin levels in the lung epithelial lining fluid (0.28 +/- 0.07 microM before therapy to 5.86 +/- 1.03 microM after therapy) and increased anti-neutrophil-elastase capacity (0.78 +/- 0.38 microM before therapy to 4.16 +/- 0.95 microM after therapy). Aerosolized alpha 1-antitrypsin diffused across the respiratory epithelium and entered lung interstitial lymph (in sheep) and reached the systemic circulation (in sheep and humans). No side effects were noted. Short-term aerosol administration of human plasma alpha 1-antitrypsin to patients with alpha 1-antitrypsin deficiency is safe and feasible, resulting in a return to normal of anti-neutrophil-elastase defenses in the lower respiratory tract. The aerosol approach, therefore, merits serious long-term evaluation as an alternative to other parenteral forms of administering therapeutic proteins.