Contributions to the Optimal Use of Human Blood

A C1 esterase inhibitor concentrate was prepared in large quantities from fresh human plasma. After removal of the cryoprecipitate and prothrombin complex, the inhibitor was adsorbed batchwise onto an anion‐exchanger. 2.5 g (dry weight) of DEAE‐Sephadex A‐50 was used per liter of ‘plasma’. After extensive washing with 0.15 M NaCl, the inhibitor was eluted from the anion‐exchanger with 2 m NaCl. The eluate was fractionated with ammonium sulphate. The fraction precipitating between 50 and 65% saturation with ammonium sulphate was collected, desalted, sterilized by filtration, and freeze‐dried. The yield of C1 esterase inhibitor was 35%. The method gave a 100‐ to 150‐fold purification on a protein basis. The final preparation contained 2 mg/ml albumin, 6 mg/ml ceruloplasmin and traces of other plasma proteins. The final product passed the test for general safety and was not pyrogenic. To test the effect of the concentrate, 20 ml portions equal in activity to 2 1 of fresh plasma were infused into 5 adults with hereditary angioedema during remission. The activity of C1 esterase inhibitor in the serum of a patient increased from zero to about 75% of normal serum and decreased to about 25% after 24 h. Preliminary observations concerning the risk of transmitting serum hepatitis by the C1 esterase inhibitor concentrate are described.