1. The action of alpha-tocopherol phosphate (αTPO4), an anticoagulant, on PNH hemolysis was studied by both in vitro and in vivo means. It was found that the addition of αTPO4 to the modified Ham test inhibited lysis of PNH erythrocytes. During the intramuscular administration of αTPO4, the susceptibility of the erythrocytes to lysis by fresh acidified serum progressively decreased. These cells, after incubation with the serum, gave a positive Coombs test.
2. The possible significance of these findings is briefly discussed.
3. It is concluded that αTPO4 has no therapeutic value in PNH.