During agarose electrophoresis C4 in the normal human serum is converted into cleavage products of Beta 1 and Beta 2 mobility. By contrast in the serum of untreated patients with hereditary angiodema C4 gives only one Beta 2 peak on crossed immunoelectrophoresis. The normal C4 electrophoretic pattern is restored in serum of patients treated with stanazolol but not with danazol despite the same C1-esterase inhibitor (C1 INH) activities and C4 serum concentration. We suggest that stanazolol besides having specific effect on C1 INH activity can interfere with other protease inhibitors affecting C1 activation.
Available online at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC497765/