Racial Differences in Paroxysmal Nocturnal Hemoglobinuria Thrombosis and Glycosylphosphatidylinositol-Deficient Granulocytes

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired glycosylphosphatidylinositol (GPI)-deficient hematopoietic stem cell disorder that is characterized by complement-mediated hemolytic anemia, thrombosis, and bone marrow failure. Eculizumab, an inhibitor of terminal complement C5, provides patients with PNH with a good quality of life by ameliorating hemolysis and thrombosis, and promotes a better understanding of the complement-mediated molecular pathophysiology of PNH [1-3]. However, the underlying reasons for distinct differences in the incidences of thrombosis and bone marrow failure between Caucasian and Asian patients with PNH are still unknown (West vs. Japan, 32% vs. 4%) [4]. Racial differences are more evident in PNH thrombosis than in other conventional arterial thromboses (PNH vs. others, 2.4 to 9.8 vs. 1.7 to 3.9-fold increase) [4,5], suggesting that the presence of thrombus formation is characteristic of PNH. Progression to thrombosis is generally attributable to synergistic interactions between hypercoagulation and hypofibrinolysis.