Cellular Inhibitors of Complement Decay accelerating factor(DAF)and CD59 are proteins present on mammalian cells,inhibit the assembly of the MAC on host cells. Deficiencies of DAF and CD59 occur in the disease Paroxysmal Nocturnal Hemoglobinuria (PNH)-intermittent hemolysis of RBCs due to unregulated deposition of activated complement components on the cell surface.Cellular Inhibitors of Complement Decay accelerating factor (DAF) and CD59 are proteins present on mammalian cells, inhibit the assembly of the MAC on host cells. Deficiencies of DAF and CD59 occur in the disease Paroxysmal Nocturnal Hemoglobinuria (PNH) - intermittent hemolysis of RBCs due to unregulated deposition of activated complement components on the cell surface