Immunomodulation by α(1)-proteinase inhibitor: lack of chemotactic effects of recombinant human α(1)-proteinase inhibitor from yeast on human peripheral blood granulocytes

INTRODUCTION: Recombinant α(1)-proteinase inhibitor, clinically developed for inhalative augmentation therapy in patients with α(1)-proteinase inhibitor deficiency or cystic fibrosis, may directly contribute to leukocyte accumulation as it may function as a chemoattractant. The migratory effects of yeast-derived human recombinant α(1)-proteinase inhibitor on human peripheral blood neutrophils and eosinophils were therefore tested in vitro. MATERIALS AND METHODS: Human peripheral blood leukocytes were prepared from forearm venous blood and tested for migration toward various preparations of yeast-derived recombinant α(1)-proteinase inhibitor in modified Boyden-chamber micropore filter assays. RESULTS: No direct effects of yeast-derived recombinant human α(1)-proteinase inhibitor on in vitro migration of isolated neutrophils or eosinophils were seen. CONCLUSIONS: The lack of direct chemotactic effects of recombinant human α(1)-proteinase inhibitor despite anti-inflammatory effects in other biological activities of leukocytes may contribute to the preserved antibacterial defense mechanisms observed in patients under experimental augmentation therapy with inhaled α(1)-proteinase inhibitor.