Severe deficiency of the specific von Willebrand factor-cleaving protease (ADAMTS 13) activity in a subgroup of children with atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is an orphan disease caused by hyperactivation of the alternative complement pathway. Objective of the study: to assess the state of the «ADAMTS13 – von Willebrand factor (vWF) – platelets» system in children with aHUS. Materials and methods of research: [by the FRET method (fluorescence resonance energy transfer) for the FRETSVWF73 (Peptide Institude, Inc., Japan)] hydrolysis of the fluorescent substrate and ADAMTS13 antigen [by ELISA using TECHNOZYM® ADAMTS13 5450551 ELISA (Technoclone GmbH, Austria)], vWF activity [for platelet agglutination (aggregation) in the presence of ristomycin (NPO Renam reagent kit for the ALAT-230LA-2 aggregometer, Russia)] and vWF antigen [by ELISA using the TECHNOZYM® vWF kit: Ag 5450201 ELISA (Technoclone GmbH , Austria)]. Results: there was a decrease in the activity and concentration of ADAMTS13 in 63% and 62% of patients, respectively. A decrease in vWF activity was noted in 44% of cases, an increase in its concentration – in 54% of children. Thrombocytopenia was diagnosed in 99% of children. Conclusion: the imbalance in the «ADAMTS13 – vWF – platelets» system supports the process of thrombus formation with the development of organ ischemia in aHUS under conditions of endothelial dysfunction. Reduced ADAMTS13 activity predicts the severity of the disease.

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Factor H Binds to Von Willebrand Factor (VWF) and Regulates Its Cleavage by ADAMTS-13

Blood ◽

10.1182/blood.v112.11.3935.3935 ◽

2008 ◽

Vol 112 (11) ◽

pp. 3935-3935

Author(s):

Miguel A. Cruz ◽

Francisca C. Gushiken ◽

Rolando Rumbaut ◽

Kavita N Patel ◽

Nancy Turner ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Thrombotic Thrombocytopenic Purpura ◽

Von Willebrand Factor ◽

Atypical Hemolytic Uremic Syndrome ◽

Factor H ◽

Thrombocytopenic Purpura ◽

Uremic Syndrome ◽

Wall Injury ◽

Von Willebrand ◽

Willebrand Factor

Abstract Factor H is a plasma protein that regulates activation of the alternative complement system. Mutations in the factor H gene are associated with a rare form of thrombotic microangiopathy, known as atypical hemolytic uremic syndrome. Hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are characterized by systemic (TTP) or renal (HUS) microvascular thrombosis. The clinical presentations of TTP and HUS have some common clinical features, including the presence of thrombocytopenia, intravascular hemolysis, and mechanical injury to red cells. We investigated whether factor H has any interaction with proteins involved in the pathogenesis of thrombotic thrombocytopenic purpura, namely von Willebrand Factor (VWF) and ADAMTS-13. We found that factor H binds to the A1 and A2 domains of VWF, and inhibits cleavage of VWF by ADAMTS-13 under static and flowing conditions. Factor H deficient mice had a delayed thrombous formation after vessel wall injury, and showed a lower mortality rate and a higher platelet count after Shiga toxin/lipopolysaccharide challenge compared to their wild-type littermates. We concluded that factor H, in addition to its complement regulatory activity, might regulates cleavage of VWF by ADAMTS-13. Presence of an abnormal factor H that is unable to control complement activity on cell surfaces but still capable of inhibiting cleavage of VWF might contribute to the pathogenesis of thrombotic microangiopathies.

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Total deficiency of specific von Willebrand factor-cleaving protease and recovery following plasma therapy in one patient with hemolytic-uremic syndrome

The Hematology Journal ◽

10.1038/sj.thj.6200126 ◽

2001 ◽

Vol 2 (5) ◽

pp. 352-354 ◽

Cited By ~ 8

Author(s):

Agnès Veyradier ◽

François Brivet ◽

Martine Wolf ◽

Catherine Boyer-Neumann ◽

Bernadette Obert ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Von Willebrand Factor ◽

Plasma Therapy ◽

Uremic Syndrome ◽

Von Willebrand ◽

Willebrand Factor

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Von Willebrand Factor and Von Willebrand Factor-Cleaving Metalloprotease Activity in Escherichia coli O157:H7-Associated Hemolytic Uremic Syndrome

Pediatric Research ◽

10.1203/00006450-200105000-00008 ◽

2001 ◽

Vol 49 (5) ◽

pp. 653-659 ◽

Cited By ~ 111

Author(s):

Han-Mou Tsai ◽

Wayne L Chandler ◽

Ravindra Sarode ◽

Robert Hoffman ◽

Srdjan Jelacic ◽

...

Keyword(s):

Escherichia Coli ◽

Hemolytic Uremic Syndrome ◽

Von Willebrand Factor ◽

Escherichia Coli O157 ◽

Uremic Syndrome ◽

Metalloprotease Activity ◽

Von Willebrand ◽

Willebrand Factor

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von Willebrand factor cleaving protease (ADAMTS13) is deficient in recurrent and familial thrombotic thrombocytopenic purpura and hemolytic uremic syndrome

Blood ◽

10.1182/blood-2001-12-0166 ◽

2002 ◽

Vol 100 (3) ◽

pp. 778-785 ◽

Cited By ~ 144

Author(s):

Giuseppe Remuzzi ◽

Miriam Galbusera ◽

Marina Noris ◽

Maria Teresa Canciani ◽

Erica Daina ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Thrombotic Thrombocytopenic Purpura ◽

Acute Phase ◽

Von Willebrand Factor ◽

Adamts13 Activity ◽

Thrombocytopenic Purpura ◽

Uremic Syndrome ◽

Adamts13 Deficiency ◽

Von Willebrand ◽

Willebrand Factor

Abstract Whether measurement of ADAMTS13 activity may enable physicians to distinguish thrombotic thrombocytopenic purpura (TTP) from hemolytic uremic syndrome (HUS) is still a controversial issue. Our aim was to clarify whether patients with normal or deficient ADAMTS13 activity could be distinguished in terms of disease manifestations and multimeric patterns of plasma von Willebrand factor (VWF). ADAMTS13 activity, VWF antigen, and multimeric pattern were evaluated in patients with recurrent and familial TTP (n = 20) and HUS (n = 29). Results of the collagen-binding assay of ADAMTS13 activity were confirmed in selected samples by testing the capacity of plasma to cleave recombinant VWF A1-A2-A3. Most patients with TTP had complete or partial deficiency of ADAMTS13 activity during the acute phase, and in some the defect persisted at remission. However, complete ADAMTS13 deficiency was also found in 5 of 9 patients with HUS during the acute phase and in 5 patients during remission. HUS patients with ADAMTS13 deficiency could not be distinguished clinically from those with normal ADAMTS13. In a subgroup of patients with TTP or HUS, the ADAMTS13 defect was inherited, as documented by half-normal levels of ADAMTS13 in their asymptomatic parents, consistent with the heterozygous carrier state. In patients with TTP and HUS there was indirect evidence of increased VWF fragmentation, and this occurred also in patients with ADAMTS13 deficiency. In conclusion, deficient ADAMTS13 activity does not distinguish TTP from HUS, at least in the recurrent and familial forms, and it is not the only determinant of VWF abnormalities in these conditions.

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Enhanced proteolysis of plasma von Willebrand factor in thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome

Blood ◽

10.1182/blood.v74.3.978.bloodjournal743978 ◽

1989 ◽

Vol 74 (3) ◽

pp. 978-983 ◽

Cited By ~ 57

Author(s):

PM Mannucci ◽

R Lombardi ◽

A Lattuada ◽

P Ruggenenti ◽

GL Vigano ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Thrombotic Thrombocytopenic Purpura ◽

Von Willebrand Factor ◽

Relative Increase ◽

Thrombocytopenic Purpura ◽

Uremic Syndrome ◽

Von Willebrand ◽

Willebrand Factor

To examine whether enhanced in vivo proteolysis of von Willebrand factor (vWF) would account for the reported loss of larger multimers in acute thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), we studied eight patients with acute TTP/HUS whose blood samples were collected into an anticoagulant containing a cocktail of protease inhibitors to impede in vitro proteolysis. In all, enhanced proteolytic degradation of vWF was expressed as a relative decrease in the intact 225-Kd subunit of vWF and a relative increase in the 176-Kd fragment. However, instead of the loss of larger forms of normal multimers reported by other investigators, the plasma of all but one of our patients (whether they had TTP or HUS) contained a set of larger than normal (supranormal) multimers. Hence, although proteolytic fragmentation of vWF was enhanced during acute TTP/HUS, this phenomenon was not associated with the loss of larger multimers. In the five patients who survived the acute disease and underwent plasma exchange (three with HUS and two with chronic relapsing TTP), subunits and fragments returned to normal values, and supranormal multimers were no longer detected in plasma. In conclusion, even though vWF proteolysis is enhanced in acute TTP/HUS, it does not lead to loss of larger multimers.

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Increased Fragmentation of von Willebrand Factor, Due to Abnormal Cleavage of the Subunit, Parallels Disease Activity in Recurrent Hemolytic Uremic Syndrome and Thrombotic Thrombocytopenic Purpura and Discloses Predisposition in Families

Blood ◽

10.1182/blood.v94.2.610 ◽

1999 ◽

Vol 94 (2) ◽

pp. 610-620 ◽

Cited By ~ 36

Author(s):

Miriam Galbusera ◽

Marina Noris ◽

Chiara Rossi ◽

Silvia Orisio ◽

Jessica Caprioli ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Thrombotic Thrombocytopenic Purpura ◽

Acute Phase ◽

Von Willebrand Factor ◽

Thrombocytopenic Purpura ◽

Uremic Syndrome ◽

Sporadic Cases ◽

Von Willebrand ◽

Willebrand Factor

Abstract We investigated here the changes in von Willebrand factor (vWF) multimers in recurrent, sporadic and familial forms of hemolytic uremic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) to see whether they are actually proteolyzed in vivo in these patients. Molecular determinants of fragments in vWF were also characterized to identify possible sites of cleavage of the subunit. Unusually large vWF multimers were found in blood of 8 of 10 patients with recurrent HUS/TTP, both in the acute phase and in remission, but never in familial and sporadic cases. Instead, all of the groups showed evidence of enhanced fragmentation of vWF multimers during the acute phase. Increased fragmentation was also shown by decrease in native 225-kD vWF subunit. In recurrent and sporadic HUS/TTP, enhanced fragmentation normalized at remission, but the abnormality persisted in familial HUS/TTP patients. The latter findings suggest that patients with familial HUS/TTP may have a congenital abnormality in vWF processing. Analysis with specific monoclonal antibodies showed the presence of the normal vWF fragments with apparent molecular mass of 189, 176, and 140 kD in all patients; however, in 6 recurrent and in 5 familial cases, novel fragments that differed in size from normal ones were found. The size of these abnormal fragments differed from one patient to another and none of them was ever found in normal plasma. These results documented, for the first time in HUS/TTP, an abnormal cleavage of the vWF subunit that might account for the increased fragmentation observed in these patients.

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Increased Fragmentation of von Willebrand Factor, Due to Abnormal Cleavage of the Subunit, Parallels Disease Activity in Recurrent Hemolytic Uremic Syndrome and Thrombotic Thrombocytopenic Purpura and Discloses Predisposition in Families

Blood ◽

10.1182/blood.v94.2.610.414k22_610_620 ◽

1999 ◽

Vol 94 (2) ◽

pp. 610-620 ◽

Cited By ~ 1

Author(s):

Miriam Galbusera ◽

Marina Noris ◽

Chiara Rossi ◽

Silvia Orisio ◽

Jessica Caprioli ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Thrombotic Thrombocytopenic Purpura ◽

Acute Phase ◽

Von Willebrand Factor ◽

Thrombocytopenic Purpura ◽

Uremic Syndrome ◽

Sporadic Cases ◽

Von Willebrand ◽

Willebrand Factor

We investigated here the changes in von Willebrand factor (vWF) multimers in recurrent, sporadic and familial forms of hemolytic uremic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) to see whether they are actually proteolyzed in vivo in these patients. Molecular determinants of fragments in vWF were also characterized to identify possible sites of cleavage of the subunit. Unusually large vWF multimers were found in blood of 8 of 10 patients with recurrent HUS/TTP, both in the acute phase and in remission, but never in familial and sporadic cases. Instead, all of the groups showed evidence of enhanced fragmentation of vWF multimers during the acute phase. Increased fragmentation was also shown by decrease in native 225-kD vWF subunit. In recurrent and sporadic HUS/TTP, enhanced fragmentation normalized at remission, but the abnormality persisted in familial HUS/TTP patients. The latter findings suggest that patients with familial HUS/TTP may have a congenital abnormality in vWF processing. Analysis with specific monoclonal antibodies showed the presence of the normal vWF fragments with apparent molecular mass of 189, 176, and 140 kD in all patients; however, in 6 recurrent and in 5 familial cases, novel fragments that differed in size from normal ones were found. The size of these abnormal fragments differed from one patient to another and none of them was ever found in normal plasma. These results documented, for the first time in HUS/TTP, an abnormal cleavage of the vWF subunit that might account for the increased fragmentation observed in these patients.

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von Willebrand factor cleaving protease and ADAMTS13mutations in childhood TTP

Blood ◽

10.1182/blood-2002-08-2399 ◽

2003 ◽

Vol 101 (5) ◽

pp. 1845-1850 ◽

Cited By ~ 153

Author(s):

Reinhard Schneppenheim ◽

Ulrich Budde ◽

Florian Oyen ◽

Dorothea Angerhaus ◽

Volker Aumann ◽

...

Keyword(s):

Von Willebrand Factor ◽

Direct Sequencing ◽

Compound Heterozygous ◽

Evans Syndrome ◽

Thrombocytopenic Purpura ◽

Severe Deficiency ◽

Patients At Risk ◽

Uremic Syndrome ◽

Von Willebrand ◽

Willebrand Factor

Thrombotic thrombocytopenic purpura (TTP) is caused by the persistence of the highly reactive high-molecular-weight multimers of von Willebrand factor (VWF) due to deficiency of the specific VWF-cleaving protease (VWF-CP) ADAMTS13, resulting in microangiopathic disease. The acquired form is caused by autoantibodies against VWF-CP, whereas homozygous or compound heterozygous mutations of ADAMTS13 are responsible for recessively inherited TTP. We investigated 83 children with hemolytic or thrombocytopenic episodes with or without additional neurologic symptoms or renal failure. The presumed diagnosis was chronic idiopathic thrombocytopenic purpura (ITP; n = 50), TTP (n = 8), hemolytic uremic syndrome (HUS; n = 24), and Evans syndrome (n = 1). A severe deficiency of VWF-CP (≤ 5%) was found in all investigated patients with TTP and in none of those with HUS. Additionally, 2 of 50 patients with a prior diagnosis of ITP were deficient for VWF-CP. Antibodies against VWF-CP were found in 4 children. Mutation analysis of the ADAMTS13 gene in the patients deficient in VWF-CP by direct sequencing of all 29 exons identified 8 different mutations, suggesting the hereditary form of TTP in 1 patient with ITP, in the patient with Evans syndrome, and in 5 of the 8 patients with TTP. The phenotype of TTP in childhood can be rather variable. Besides the classical clinical picture, oligosymptomatic forms may occur that can delay the identification of patients at risk.

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