Figure 1. C1 Inhibition blocks APC-mediated Hemolysis in PNH Erythrocytes.
A. The erythrocytes of patient 1 were incubated for 1 hour at 37° C with acidified (pH 6.4) normal human serum(aNHS) (1:3) and acidified heat-inactivated serum (aNHS[H])(1:3) containing increasing concentrations of C1INH (0-12 Units/mL). Hemolysis was measured using the concentration of supernatant hemoglobin (determined by spectrophotometry at 415 nm).
B. The erythrocytes of patients 2-5 (treated with eculizumab) were incubated as above with increasing concentrations of C1INH (0-6 Units/mL). Hemolysis was measured again by spectrophotometry at 415 nm.
C. The erythrocytes of patient 6 (not treated with eculizumab) were incubated as above at increasing concentrations of C1INH (0-12 Units/mL) and hemolysis measured.