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Background: Platelet (PLT) transfusions are probably harmful in patients with acquired idiopathic thrombotic thrombocytopenic purpura (aTTP). Introduction of a rapid assay for ADAMTS13 activity should reduce the time to definite diagnosis of aTTP, reduce the amount of inappropriately transfused PLT concentrates, and improve mortality and morbidity.Study Design and Methods: We selected 265 aTTP patients with severe ADAMTS13 deficiency. Of these, 91 patients were diagnosed by March 2005 (Period 1), when ADAMTS13 activity was measured by von Willebrand factor multimer assay, which took 4 to 7 days until the result was reported. An additional 174 patients were diagnosed after April 2005 (Period 2), when the activity was measured by a chromogenic enzyme-linked immunosorbent assay, which took 1 to 2 days.Results: We found no significant differences in 30-day survival rate between the two periods. Overall, 48 patients received PLT transfusions. Mortality was slightly greater between patients with (22.9%) versus without PLT transfusion (17.7%), but not significant. In Period 1, Cox proportional hazards regression analysis showed that older age (≥60 years) and PLT transfusion administration were independent factors associated with higher risks of 30-day mortality. In contrast, in Period 2, lower Rose-Eldor TTP severity score and use of plasma exchange and corticosteroid therapy were independent factors associated with higher survival rates while nonadministration of PLT transfusions was not.Conclusion: Our results indicate that PLT transfusions are harmful for aTTP patients when the definite diagnosis of severe ADAMTS13 deficiency is delayed. If it can be done as soon as possible, PLT transfusions for severe bleeding or surgical interventions might be allowed with subsequent plasmapheresis. [ABSTRACT FROM AUTHOR]

Background: Plasma exchange (PE) is the first-line treatment for primary acquired thrombotic thrombocytopenic purpura (aTTP) with severe deficiency of ADAMTS13 activity (ADAMTS13:AC). Some patients are poor responders to PE, raising concern over multiple pathogenetic pathways. Study Design and Methods: Based on 52 aTTP patients in our national cohort study, we monitored plasma levels of ADAMTS13, clinical and laboratory findings, and outcomes. In a representative poor responder to PE, we examined an ADAMTS13 inhibitor (ADAMTS13:INH) complex in plasma milieu, by means of a large-pore isoelectric focusing (IEF) analysis. Results: Of 52 aTTP patients, 20 were good responders and 32 were poor responders. In the latter group, plasma ADAMTS13:AC levels never increased to more than 10% of normal during 14 days after PE initiation. Mean (±SD) plasma ADAMTS13:INH titers (Bethesda unit/mL) were 5.7 (±4.5) before PE, but decreased to 1.4 (±0.8) on the fourth PE day and then remarkably increased to 14.8 (±10.0) on the 10th PE day, termed "inhibitor boosting," and then slowly decreased to undetectable level over 1 month. On admission, none of the routinely available clinical and laboratory markers differentiated these two groups. However, elevated pre-PE levels of ADAMTS13:INH were correlated with a poor response. We visualized an ADAMTS13:INH (immunoglobulin G) complex in a patient plasma by an IEF analysis and found proteolytic fragment of ADAMTS13 antigen by a two-dimensional IEF and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Conclusion: Findings from this cohort of aTTP patients demonstrated that inhibitor boosting often occurs in aTTP patients in Japan. Poor responders could be predicted by elevated pre-PE ADAMTS13:INH levels on admission, but not by routinely collected clinical or laboratory data. [ABSTRACT FROM AUTHOR]

Background Thrombotic thrombocytopenic purpura ( TTP) is characterized by deficient ADAMTS13 activity. Treatment involves plasma exchange ( PE). Both fresh-frozen plasma ( FFP) and cryosupernatant ( CSP) are used, but it remains to be determined which is more effective. Study Design and Methods To analyze the interaction between von Willebrand factor ( VWF) and ADAMTS13, we used large-pore isoelectric focusing ( IEF) analysis followed by detection with anti- ADAMTS13 monoclonal antibody. FFP, CSP, cryoprecipitate ( CP), and purified ADAMTS13 were analyzed for their effects on high shear stress-induced platelet aggregation ( H- SIPA). Results IEF analysis of normal plasma revealed three groups of ADAMTS13 bands with pI of 4.9 to 5.6, 5.8 to 6.7, and 7.0 or 7.5. Two band groups ( pI 4.9-5.6 and 5.8-6.7) were found in plasma of a patient with Type 3 von Willebrand disease, in which VWF is absent, whereas no bands were found in plasma of a patient with congenital ADAMTS13 deficiency. Mixing these plasmas generated the bands at pI 7.0 or 7.5, representing the VWF- ADAMTS13 complex; these bands were absent in CSP. FFP and purified ADAMTS13 down regulated H- SIPA in a dose-dependent manner. However, CP did not inhibit H- SIPA in the initial phase, and the degree of inhibition at the endpoint was almost indistinguishable from those of the other two plasma products. Conclusion Both plasma products ( FFP and CSP) are effective for PE in TTP patients. However, CSP may be more favorable, because it has lower levels of VWF and almost normal ADAMTS13 activity, but lower levels of ADAMTS13 in complex with larger VWF multimers. [ABSTRACT FROM AUTHOR]

We encountered the case of a 4-year-old boy with thrombotic microangiopathy (TMA) of unknown etiology. Verotoxin-induced hemolytic uremic syndrome (HUS), Streptococcus-pneumoniae-related HUS, factor H deficiency, drug-induced thrombotic thrombocytopenic purpura (TTP), and ADAMTS13 (von Willebrand factor-cleaving protease; a disintegrin-like and metalloprotease with thrombospondin type 1 repeats)-related TTP were excluded. His condition was refractory to anticoagulants and plasma exchange, and his clinical course was catastrophic, with central nervous system symptoms and progressive renal failure. However, factual treatment of intravenous gamma globulin (IVIG) ended the hemolysis and resulted in a rise in platelet count. He fully recovered except for end-stage renal failure, but he underwent a successful renal transplant after peritoneal dialysis. He has not suffered a relapse of TMA or an allograft rejection for 4 years. IVIG might be an option for some patients with TMA of unknown etiology refractory to conventional treatment. [ABSTRACT FROM AUTHOR]

Upshaw- Schulman syndrome ( USS) involves a congenital deficiency of von Willebrand factor-cleaving metalloprotease ( ADAMTS13) activity due to gene mutations. Female patients develop overt thrombotic thrombocytopenic purpura ( TTP) caused by a decline of ADAMTS13 activity in pregnancy. A 23-year-old nulliparous Japanese woman died due to severe, rapid progression of TTP with intrauterine fetal death at 20 weeks of gestation after its onset, even though she underwent intensive treatment which included plasma exchange. She had a history of idiopathic thrombocytopenic purpura at the age of 3 years. The patient's ADAMTS13 activity was of very low level. It should be borne in mind that there is the possibility of rapidly progressive fulminant USS during pregnancy. [ABSTRACT FROM AUTHOR]

Abstract Upshaw-Schulman syndrome (USS) is an inherited type of thrombotic thrombocytopenic purpura (TTP) that is extremely rare, but often diagnosed during pregnancy. Reversible cerebral vasoconstriction syndrome (RCVS) is the transient stenosis of several cerebral arteries that is frequently diagnosed post-partum. We describe a 28-year-old woman with USS complicated by RCVS after delivery that was treated by plasma exchange with a good outcome. She was referred to our hospital with thunderclap headache, anemia and thrombocytopenia that occurred immediately postpartum. She was diagnosed with TTP and multiple cerebral infarctions. Plasma exchange promptly improved her symptoms on hospital day 3. Moreover, multiple stenoses of cerebral arteries indicating RCVS were resolved. Since her sister also had an episode of thrombocytopenia during pregnancy, inherited TTP was suspected and genetic analyses confirmed USS. Pregnancy is a risk for not only TTP, but also RCVS. Endothelial damage might be an underlining cause and vasospasm after delivery is a trigger of RCVS. Plasma exchange was effective against both TTP and RCVS. [ABSTRACT FROM AUTHOR]