Action of alpha-tocopherol phosphate on hemolysis in paroxysmal nocturnal hemoglobinuria.

T AROXYSMAL NOCTURNAL HEMOGLOBINURIA (PNH) is a relaI tively rare chronic hemolytic anemia, but its clinical and laboratory characteristics have been well covered in the recent literature. Crosby’ has published a comprehensive review of the literature on this subject, and Dacie2 has summarized much of the information available on the mechanism of hemolysis in this disea se. It is recognized that the erythrocytes are abnormal in PNH.2-4 The disease is characterized by the in vitro lysis of PNH cells by fresh serum, either PNH or normal, particularly at an acid pH.47 On the other hand, PNH serum will not lyse normal cells. How’ever, PNH cells are not susceptible to lysis by serum which has been heated at 56 C. for 30 minutes, and the addition of fresh guinea pig complement will not restore the activity. Ham has utilized these phenomena to devise the diagnostic laboratory test, w’hich bears his 6 The factor in serum, which is necessary for lysis of PNH erythrocytes, has not been fully identified at this time. There is a marked parallel between the characteristics of this serum factor and complement, and there is evidence both for and against their identity.2’ 4 6, S We have advanced evidence that at least two serum factors are concerned in PNH hemolysis and have suggested that they may prove to be components of complement.#{176} Recently, Crosby and Dameshek’#{176}observed that the PNH hemolytic activity of serum increases with the elapse of time after coagulation of the blood. They also noted the high incidence of thrombosis in report-ed cases of PNH. These two observations led them to investigate a possible relationship between PNH hemolysis and the normal coagulation of blood. They demonstrated that the addition of either thrombin or thromboplastin to mixtures of PNH cells with fresh acidified serum enhanced