Eculizumab therapy in adults with allogeneic hematopoietic cell transplant-associated thrombotic microangiopathy

Hematopoietic cell transplant-thrombotic microangiopathy (HCT-TMA) is a devastating syndrome associated with transplant-related morbidity and mortality, and has similar histomorphologic features to those seen in atypical hemolytic uremic syndrome (aHUS) and thrombotic thrombocytopenic purpura (TTP).1, 2, 3 These conditions share a common end point of microthrombotic vascular endothelial cell injury, but with differing underlying pathophysiologic mechanisms. The TMA in TTP is related to severely deficient ADAMTS13 activity and the resulting ultra-large Von Willebrand factor multimers that aggregate platelets in conditions of high shear forces.