New aspects in the pathogenesis and treatment of thrombotic thrombocytopenic purpura and hemolytic uremic syndrome.

The thrombotic microangiopathy (TM) syndromes, thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome, are a rare and heterogeneous group of disorders characterized by widespread microvascular thrombosis and end organ injury. Decades of descriptive studies have defined clinical subsets of TM syndromes by clinical and laboratory features. Despite many advances, however, progress towards understanding of the etiology and pathogenesis of TM disorders remains limited. The rarity of occurrence and lack of natural animal models of TM syndromes have hampered progress in experimental and clinical studies. Treatment remains essentially empirical and options are limited. However, recent advances in the genetic and molecular understanding of subsets of TM disorders and the development of relevant animal models offer new resources to explore the pathogenic mechanisms. With these new advances more effective and individualized treatments for TM syndromes can be developed.