Effect of streptokinase, epinephrine and plasmin on the paroxysmal nocturnal hemoglobinuria serum hemolytic system

¹ Hematology Service, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee

pH-lysis curves have been constructed from data obtained from incubating the erythrocytes of five cases of paroxysmal nocturnal hemoglobinuria (PNH) with autologous and normal acidified sera. The effect of streptokinase, epinephrine and plasmin (bovine and human) on these pH-lysis curves has been investigated. Streptokinase, human plasmin and epinephrine had little or no effect on these pH-lysis curves when added to the acid serum-PNH red cell suspenson just prior to incubation at 37°C. A period of preliminary incubation was necessary to demonstrate the inhibitory effect of these substances on the PNH serum hemolytic system. This suggests that these reagents react with something in the serum. No inhibition could be demonstrated after preliminary incubation of PNH erythrocytes with streptokinase, plasmin and epinephrine. Small concentrations of bovine plasmin added directly to the acid serum-PNH red cell suspension enhanced the PNH hemolytic activity; high concentrations completely inactivated the PNH hemolytic system. Bovine plasmin by itself in small concentrations was not hemolytic. Thrombin failed to reactivate the PNH hemolytic mechanism of the streptokinase-, and plasmin-treated sera. The addition of thrombin restored completely the hemolytic activity of epinephrine-treated sera.