Current concepts in the diagnosis and management of thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura is a multisystem disease characterized by thrombocytopenia, hemolytic anemia, renal failure, fever, and neurologic abnormalities. Plasma exchange has revolutionized the outcome of this entity from a once fatal disease to a disease that potentially is cured or has prolonged remission. The understanding of the pathophysiology of TTP continues to evolve. Recently, investigators showed that a deficiency in a specific plasma protease responsible for cleaving vWf plays a crucial role in the familial form of TTP. This explains in part why patients usually respond to plasma exchange therapy. The identification of a mutation in a specific gene that belongs to the metalloproteinase family located at chromosome 9q34 could have important therapeutic implications. TTP can be induced by certain drugs, especially immunosuppressants, in the setting of bone marrow and solid organ transplantation. This disease also has been described in association with HIV, pregnancy, cancer, and chemotherapy. TTP remains an ideal example of how knowledge about the etiology of a disease can improve therapeutic interventions.