Paroxysmal nocturnal hemoglobinuria: Plasma factors of the hemolytic system

(PNH) was shown by Hijmans van den Bergh9 to involve a defective red cell which could be lysed by normal serum made mildly acid with carbon di-oxide. He found that- normal cells were not injured by the patient’s serum under similar conditions. The factor in serum that is responsible for hemolysis of PNH cells has been studied by several investigators during the past fifteen years. Ham and Dingle6 found that when serum was so treated as to inactivate corn-plernent PNH hernolytic activity was also destroyed. However, they were not always able to reactivate the PXH system by adding guinea pig complement and described the system as “complement-like”. It is unfortunate that Ham and Dingle did IlOt adsorb the a,itihuma,i red cell heterohernolysins from the guinea pig serum that they used in this work. Dacie has shown that PNH red cells are readily lysed by this complement-antibody system.4 Normal human red cells are relatively insensitive. From the work of Ham and Dingle it is not possible to determine whether the hemolytic activity that they sometimes observed in the presence of guinea pig complement was due to restoration of the PNH system o