title: Hematopoietic transplant-associated thrombotic microangiopathy: case report and review of diagnosis and treatments.
abstract: Transplant-associated thrombotic microangiopathy (TA-TMA) refers to inflammatory and thrombotic diseases of the microvasculature characterized by hemolytic anemia, thrombocytopenia, and evidence of organ damage, particularly acute renal failure. This syndrome occurs in 10% to 20% of patients with allogeneic hematopoietic stem cell transplants (HSCTs). It is much less frequent in the autologous setting. TA-TMAs present diagnostic challenges because they may not clearly fall into one of the categories of the 2 major TMAs: atypical hemolytic uremic syndrome (aHUS) and thrombotic thrombocytopenic purpura (TTP). In addition, complications of the transplant itself, including infection, graft-versus-host disease, and disseminated intravascular coagulation, as well as the side effects of immunosuppressive drugs, can mimic a TMA. Because the pathophysiology of TA-TMA is poorly understood, current treatment options are suboptimal, and the condition carries a very high mortality rate. In 3 recent case summaries, the median acute response rate to plasma exchange was as high as 55%, but this therapy failed to alter underlying disease pathology and had little impact on overall mortality, which was approximately 80%. Indeed, the vast majority of TA-TMA patients lack suppression of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity to less than 5% to 10% of normal and do not have a complete response to plasma exchange, characteristics indicating that a TTP-like disorder is not involved. Recent advances in the treatment of aHUS may offer a therapeutic option in the aHUS-like TMAs associated with HSCTs. These issues are discussed in the context of a patient recently evaluated and treated at our institution; the case serves to illustrate the difficulties associated with the diagnosis and treatment of TA-TMA.
authors: Weill Cornell Medical College, New York, New York.
authors: John
authors: J
authors: Chapin
authors: Weill Cornell Medical College, New York, New York.
authors: Tsiporah
authors: T
authors: Shore
authors: Weill Cornell Medical College, New York, New York.
authors: Peter
authors: P
authors: Forsberg
authors: Weill Cornell Medical College, New York, New York.
authors: Garrett
authors: G
authors: Desman
authors: Weill Cornell Medical College, New York, New York.
authors: Koen
authors: K
authors: Van Besien
authors: Weill Cornell Medical College, New York, New York.
authors: Jeffrey
authors: J
authors: Laurence
mesh_terms: D000328:Adult; D006086:Graft vs Host Disease / Q000473:pathology; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D057049:Thrombotic Microangiopathies / Q000175:diagnosis / Q000209:etiology / Q000628:therapy