CD59 and paroxysmal nocturnal hemoglobinuria: PNH is caused by the development of a genetic mutation of the X-linked gene phosphatidylinositol glycan class A (PIGA), which produces a deficiency in the glycosylphosphatidylinositol (GPI)-anchored terminal inhibitors (e.g. CD55, CD59), in haematopoietic stem cells [3, 4].