Purification of C1 Esterase Inhibitor from Human Plasma

Background Plasma-derived human C1-esterase inhibitor (C1-INH) concentrates are indicated for the treatment of acute episodes of hereditary angioedema. Intravenous C1-INH concentrate provides rapid relief to patients with acute hereditary angioedema symptoms. Objective To develop a safe and efficient purification process for C1-INH from human plasma. Design A combination of anion exchange and hydrophobic interaction chromatography was used to purify C1-INH from human plasma. Method The cold insoluble fraction (cryoprecipitate) was separated via centrifugation; then, the cryoprecipitate-poor plasma was subjected to different separation techniques to purify C1-INH. First, separation was performed using diethylaminoethyl (DEAE) anion exchange chromatography to capture coagulation factors. Then, C1-INH was purified from the remaining plasma using quaternary amine (a strong anion exchanger) chromatography, followed by DEAE (a weak anion exchanger) chromatography. The final product was purified via hydrophobic interaction chromatography, followed by ultrafiltration to concentrate the purified C1-INH. This process is cost-effective because coagulation factors were captured before C1-INH purification and the waste fraction after the capture stage was diverted to Cohn fractionation to isolate other potential plasma products. Results The final C1-INH preparation had a specific activity of >12 IU/mg protein, which is sufficient for its intended purpose. The purified preparation was characterized via sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and coagulation factors were measured in the purified preparation. Furthermore, viral activity decreased via solvent detergent treatment and virus filtration. Conclusion We successfully developed a purification process for C1-INH from human plasma. This process is easily adaptable and has been successfully scaled up to approximately 15-fold. It can be further scaled up for the large-scale production of C1-INH.