Binding of rhCD59-P to PNH erythrocytes. (A-E) Washed whole blood from PNH patients was incubated with rhCD59-P at 15 500 nM (A), 1938 nM (B), 969 nM (C), 484 nM (D), or 121 nM (E). Cells were washed and surface levels of human CD59 were determined by flow cytometry, using a fluorescent anti–human CD59 antibody. Untreated PNH cells are shown in panel F; normal human erythrocytes are shown in panel G.