scholarly journals Residual plasmatic activity of ADAMTS13 is correlated with phenotype severity in congenital thrombotic thrombocytopenic purpura

Blood ◽  
2012 ◽  
Vol 120 (2) ◽  
pp. 440-448 ◽  
Author(s):  
Luca A. Lotta ◽  
Haifeng M. Wu ◽  
Ian J. Mackie ◽  
Marina Noris ◽  
Agnes Veyradier ◽  
...  

Abstract The quantification of residual plasmatic ADAMTS13 activity in congenital thrombotic thrombocytopenic purpura (TTP) patients is constrained by limitations in sensitivity and reproducibility of commonly used assays at low levels of ADAMTS13 activity, blunting efforts to establish genotype-phenotype correlations. In the present study, the residual plasmatic activity of ADAMTS13 was measured centrally by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (limit of detection = 0.5%) in 29 congenital TTP patients. The results were used to study correlations among ADAMTS13 genotype, residual plasmatic activity, and clinical phenotype severity. An ADAMTS13 activity above 0.5% was measured in 26 (90%) patients and lower levels of activity were associated with earlier age at first TTP episode requiring plasma infusion, more frequent recurrences, and prescription of fresh-frozen plasma prophylaxis. Receiver operating characteristic curve analysis showed that activity levels of less than 2.74% and 1.61% were discriminative of age at first TTP episode requiring plasma infusion < 18 years, annual rate of TTP episodes > 1, and use of prophylaxis. Mutations affecting the highly conserved N-terminal domains of the protein were associated with lower residual ADAMTS13 activity and a more severe phenotype in an allelic-dose dependent manner. The results of the present study show that residual ADAMTS13 activity is associated with the severity of clinical phenotype in congenital TTP and provide insights into genotype-phenotype correlations.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2219-2219
Author(s):  
Luca A Lotta ◽  
Haifeng M Wu ◽  
Marie A Scully ◽  
Marina Noris ◽  
Agnes Veyradier ◽  
...  

Abstract Abstract 2219 ABSTRACT Congenital thrombotic thrombocytopenic purpura (TTP) (OMIM #274150) is a rare, recessively inherited thrombotic microangiopathy characterized by the congenital deficiency of ADAMTS13 due to mutations in the corresponding gene. The clinical phenotype of congenital TTP is variable, encompassing neonatal-onset disease and adult-onset disease, forms with a single disease episode and chronic-relapsing forms. A review of the ∼100 published cases of congenital TTP showed similar age of first disease episode in patients carrying the same ADAMTS13 gene suggesting that different ADAMTS13 mutations might influence the severity of clinical phenotype, conceivably by determining different patterns of residual plasmatic activity of ADAMTS13. However, the quantification of residual ADAMTS13 activity in severely deficient patients was blunted by the relatively high limit of detection (LOD) of commonly used ADAMTS13 activity assays (varying between 3% and 6%). We report 29 cases of congenital TTP from 4 European cohorts, with 32 mutations of ADAMTS13 including 8 not previously published. To assess if residual ADAMTS13 activity was detectable in these patients and correlated with their clinical history, ADAMTS13 activity was measured by SELDI-TOF mass spectrometry (LOD=0.5%). ADAMTS13 activity above 0.5% was measurable in 26 (90%) patients, and lower levels of activity correlated with an earlier age of disease onset (r=0.51; p=0.006) and with the need for regular fresh frozen plasma prophylaxis (2.24% vs 3.88%; p=0.03). Mutations at the highly conserved N-terminal domains of the protein were associated with lower residual ADAMTS13 activity (1.48% vs 4.89%, p=0.02) and earlier disease onset (3.2 years vs 24.2 years, p=0.003). Our results show that residual ADAMTS13 activity correlates with the severity of clinical phenotype in congenital TTP and provide insights into genotype-phenotype correlations. Disclosures: No relevant conflicts of interest to declare.


2021 ◽  
Vol 29 (3) ◽  
pp. 270-273
Author(s):  
Başak Ergin ◽  
Berna Buse Kobal ◽  
Zeynep Yazıcı ◽  
Ali Hakan Kaya ◽  
Sezin Canbek ◽  
...  

Objective Thrombotic thrombocytopenic purpura is a thrombotic microangiopathic condition characterized by hemolytic anemia, thrombocytopenia, neurologic abnormalities, fever and renal dysfunction. Thrombotic microangiopathies such as preeclampsia and HELLP syndrome are pregnancy-specific, whereas others such as thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome are not. In this report, we present a case at which we identified a novel mutation which led to a significant reduction of ADAMTS13 activity. Case(s) A nulliparous pregnant woman of 32-year-old presenting with epigastric pain, hypertension and low platelet count was first suspected of HELLP syndrome, but was diagnosed with congenital TTP after delivery. Conclusion HELLP syndrome co-existed with undiagnosed TTP in this case. We strive to have sufficient awareness in order to distinguish these two pathologies from each other on an antenatal basis, because the causes of the managements are entirely different.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3556-3556
Author(s):  
Nathan T. Connell ◽  
Joseph D. Sweeney

Abstract Introduction While the activity level of ADAMTS13 can be helpful in diagnosing patients with thrombotic thrombocytopenic purpura (TTP), the current long turnaround time of this test for most institutions limits its role in early clinical decision-making about the initiation of plasma exchange. Levels of ADAMTS13<10% are pathognomonic of TTP and levels in excess of 10% indicate an alternate cause of thrombotic microangiopathy. The aim of the study was to look at recent practice in the State of Rhode Island regarding the criteria for initiation of plasma exchange with a subsequent categorization of those patients based on ADAMTS13 activity levels. Methods Patients with a diagnosis of TTP were identified from hospital records of the major hospitals in Rhode Island which perform therapeutic apheresis in calendar years 2011 and 2012. From a chart review and blood bank records, baseline clinical parameters were collected, the number of therapeutic plasma exchanges (TPE) performed and the volume of plasma utilized. Pre-treatment ADAMTS13 activity was recorded if available in addition to the number of days from the initiation of TPE to test result availability. An analysis was performed to examine if patients who had a pre-treatment ADAMTS13 activity level ≤10% differed in baseline characteristics or response to TPE from those with activity levels >10%. Based on the normality of the distribution of the data, independent t-tests or Wilcoxon rank-sum tests were performed using SAS version 9.3. Results During this two year period, 24 patients received plasma exchange in Rhode Island for a presumptive diagnosis of TTP. The mean age was 47 years (range 20-89 years) and 38% were male. ADAMTS13 activity was available for 20 patients and 7 (30% of those exchanged) had documented pre-treatment activity levels ≤10% consistent with TTP. The median turnaround time for the ADAMTS13 assay was 10 days (range 2-52). Mean baseline parameters at the time of presentation are shown in the table. As expected, creatinine levels were lower in those patients with true TTP (p=0.0410). ADAMTS13 activity level was predictive of the number of days to a platelet count ≥150 x 109/L (Pearson correlation 0.56; p-value 0.0458). Overall, 4238 units of plasma were utilized for exchange. Of these 4238 units, 1886 were transfused to patients who were subsequently shown to have an ADAMTS13 activity >10%, and 813 of the 1886 units (20% of all plasma exchanged) were transfused after the results of enzyme activity were available in this population. Conclusions Based on an ADAMTS13 >10%, a significant volume of plasma was unnecessarily transfused. Reducing the turnaround time for the ADAMTS13 assay in tertiary care centers could help clinicians better determine which patients will benefit from plasma exchange, avoiding the morbidity and expense associated with large volume plasma exchange. Disclosures: No relevant conflicts of interest to declare.


2004 ◽  
Vol 91 (04) ◽  
pp. 806-811 ◽  
Author(s):  
Wenhua Zhou ◽  
Han-Mou Tsai

SummaryRecent studies demonstrate that assay of ADAMTS13, a circulating zinc metalloprotease that cleaves von Willebrand factor (VWF) at the Y1605-M1606 bond, is an important tool in the diagnosis of thrombotic thrombocytopenic purpura (TTP). In order to develop a method that could be adapted for general use, we describe an enzyme immunoassay (EIA)-based method for measuring the activity of ADAMTS13 in patient plasma samples. A monomeric peptide consisting of the amino acid residues D1596-R1668 of VWF was produced that spanned the ADAMTS13 cleavage site and was franked by glutathione s-transferase (GST) and a 6His sequences at the amino and carboxyl termini respectively. When probed with either anti-GST or anti-6His, the VWF fragment appeared as a 38.1-kDa band. After incubation with normal plasma, the VWF fragment was replaced by a 30.4-kDa band, which was recognized by antiGST but not by anti-6His, consistent with the expected cleavage at the Y1605-M1606 bond. EDTA or plasma samples from patients with TTP inhibited this cleavage. After incubation with normal plasma, the VWF fusion protein immobilized onto antiGST coated microtiter plate wells lost its anti-6His binding activity in a timeand plasma concentration-dependent manner. By using this EIA, the ADAMTS13 activity level was less than 0.12 U/mL in patients with acquired or hereditary TTP, distinguishing these patients from normal individuals or carriers of one copy of mutant ADAMTS13 allele. These results suggest the EIA method based on the VWF fusion protein is a simple but promising alternative for measuring ADAMTS13 activity.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2660-2660
Author(s):  
Haifeng Wu ◽  
Spero Cataland ◽  
Michael Bissell ◽  
Ming Jin

Abstract Thrombotic Thrombocytopenic Purpura (TTP), a life-threatening microangiopathic thrombotic disorder, requires immediate diagnosis and plasma exchange therapy. Development of TTP is related to functional deficiency of a metalloprotease, ADAMTS13, that leads to accumulation of ultra large von Willebrand factor (vWF) and subsequent platelet thrombosis. Currently no clinical test is available for a rapid detection of functional ADAMTS13 activity. In this study, a recombinant vWF peptide containing the ADAMTS13 cleavage site and a 6 X Histidine tag was used as a substrate for ADAMTS13. ADAMTS13 cleaved the substrate in a dose-dependent manner, generating a ~7739 Dalton peptide containing a 6 X Histidine tag. This cleaved peptide, bound to an IMAC/Nickel ProteinChip, was quantified using Surface Enhanced Laser Desorption/Ionization Time-of-flight Mass Spectrometry (SELDI-TOF-MS). The assay is capable of quantifying ADAMTS13 activity as low as 2.5 % in plasma within 3–4 hours. When the cleaved peptide was quantified as a ratio of an internal control peptide, the test displayed excellent reproducibility, with an average inter-assay CV of &lt; 33 %. Further validation of the test in healthy donors (n=39) revealed normal ADAMTS13 activity with a mean of 92.5% + 16.6. Sixteen patients with idiopathic TTP displayed mean ADAMTS13 activity of 1.73% + 3.62 at presentation, prior to any therapy. Further utility of this novel method includes functional determination of ADAMTS13 antibody titers in cases of acquired TTP. In summary, we have devised a novel SELDI-TOF-MS assay that offers a rapid, cost-effective, and functionally relevant test for timely diagnosis and management of TTP patients.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2088-2088 ◽  
Author(s):  
Charles L. Bennett ◽  
Thanh Ha Luu ◽  
Anaadriana Zakarija ◽  
Hau C. Kwaan ◽  
Nicholas Bandarenko ◽  
...  

Abstract Background: Thrombotic thrombocytopenic purpura (TTP) is a rare disorder that presents with microangiopathic hemolytic anemia and thrombocytopenia, fevers, renal insufficiency and neurologic features. We reviewed clinical, laboratory, and outcome data for TTP cases with severely deficient versus non-severely deficient ADAMTS13 activity levels. Methods: Mean and median data were from the Surveillance, Epidemiology and Risk Factors for TTP (SERF-TTP) study group for idiopathic TTP cases, the Canadian Apheresis Group (CAG), and five published series (Zheng 2004, Raife 2004, Vesely 2003 (Oklahoma TTP-HUS Registry), Matsumoto 2004 (Japan Referral Center), Bennett 2007). Results: Compared to TTP cases with near-normal ADAMTS13 activity levels (n= 282), TTP cases with severe ADAMTS13-deficiency (n=185) were more likely to have severe thrombocytopenia, normal renal function and neutralizing ADAMTS13 antibodies. Severe ADAMTS13 deficient TTP cases have better overall survival after therapeutic plasma exchange (TPE) but are more likely to relapse. TTP patients with severe ADAMTS13 deficiency were primarily categorized as idiopathic or ticlopidine-associated, while TTP patients with non-severely deficient ADAMTS13 activity levels were frequently categorized as idiopathic, secondary to drugs (clopidogrel, quinine), stem cell transplantation, or cancer. Conclusions: Severe ADAMTS13 deficiency is most commonly idiopathic, has better survival following TPE, and a 35–40% spontaneous relapse rate. By contrast, non-ADAMTS13 deficient TTP cases are usually associated with an underlying disorder or external insults. Amongst this cohort, four series have 47–62% survival rates and three series, which contain mostly idiopathic cases, have 83–90% survival rates following TPE. From this, we propose that TTP may occur by three possible mechanism; ADAMTS13-deficient (antibody-mediated), an immunologic mediated pathway independent of ADAMTS13 (i.e. quinine) that is responsive to TPE, and endothelial injury related TTP that is unresponsive to TPE. Platelet count mean (x10^9/L) Creatinine mean (mg/dl) ADAMTS13 neutralizing antibodies (%) Survival % Relapse % * &lt;15% ADAMTS13 activity cutoff Severe ADAMTS13 Deficiency (&lt;10–15%) SERF-TTP (n=30) 19 1.3 83 97 41 Zheng (n=16) 19 1.6 44 81 38 Bennett (n=26) 15 85 Oklahoma (n=18) 12 1.8 94 81 38 Raife (n=50) * 13 1.2 92 35 Japan (n=34) 35 91 Canada (n=11) 16 2.4 82 Not Severely Deficient ADAMTS13 Activity (&gt; 15%) SERF-TTP (n=22) 57 3.9 35 90 0 Raife (n=57) * 44 2.7 83 9 Canada (n=17) 57 4.1 88 Zheng (n=13) 40 3.0 0 54 Bennett (n=13) 62 Japan (n=66) 9 62 Oklahoma (n=94 ) 23 47 3


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 599-599 ◽  
Author(s):  
Jialing Bao ◽  
Khalil Bdeir ◽  
Don L. Siegel ◽  
Douglas B. Cines ◽  
X. Long Zheng

Abstract Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal syndrome associated with severe deficiency of plasma ADAMTS13 activity resulting from either mutations or autoantibodies. However, patients with severe ADAMTS13 deficiency do not always develop TTP. Rather, a trigger, such as infection or inflammation, often precedes the onset of the TTP syndrome. We hypothesized that antimicrobial human neutrophil peptides 1-3 (HNPα1-3) or α-defensins, the most abundant proteins in the granules of neutrophils, which are released at site of inflammation, activate platelets, and inhibit fibrinolysis, might help to initiate TTP. This question arose because we noted that the amino acid sequences of HNPα1-3, which are nearly identical except for one residue at the N-terminus, all contain a motif (RRY) similar to exosite 3 (659RRYGEEY665) in the spacer domain of ADAMTS13 (Fig. 1) that was shown to be critical for recognition of von Willebrand factor (VWF). Here, we found that both purified and synthetic HNPα1 bind to FRETS-VWF73 and plasma-derived VWF and inhibit proteolytic cleavage of these substrates in a concentration-dependent manner. At the final concentrations of 10 micro mol/L and 150 micro mol/L, HNPα1 completely abolished the cleavage of FRETS-VWF73 (IC50=3.5 micro mol/L) (Fig. 2) and VWF (IC50=75 micro mol/L) (not shown), respectively. Such concentrations are readily attained locally after systemic infection. Deletion or alanine substitution within the RRY motif of HNPα1 completely abolished its ability to inhibit ADAMTS13 activity assessed by FRETS-VWF73 and VWF multimer analysis. This suggests that an interaction of the RRY motif in HNPα1 with the central A2 domain of VWF is required to mediate its inhibition. In support of this hypothesis, HNPα1 interacts with a human monoclonal antibody against ADAMTS13 scFv (the single chain fragment of variable region) designated 4-20, but not scFv3-1, both isolated by phage display from patients with acquired autoimmune TTP. Hydrogen-deuterium exchange mass spectrometry has shown that the binding site for scFv4-20, but not scFv3-1, contains the RRY sequence. These results suggest that HNPα1-3 released from neutrophils following infection or inflammation may inhibit residual plasma ADAMTS13 activity in vivo similar to anti-ADAMTS13 autoantibodies by interfering with its interaction with VWF, thereby triggering the onset of hereditary and acquired autoimmune TTP. Our findings suggest a potential novel link between systemic inflammation and the pathogenesis of TTP and possibility other thrombotic sequelae. Figure 2 Figure 2. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


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