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Copyright of Lijecnicki Vjesnik is the property of Croatian Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Osmangazi Journal of Medicine / Osmangazi Tip Dergisi is the property of Eskisehir Osmangazi University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Transplant-associated thrombotic microangiopathy (TA-TMA) is a fatal complication of hematopoietic stem cell transplantation and is characterized by severe thrombocytopenia, hemolytic anemia, and organ dysfunction. In response to several possible triggers, dynamic multimetric change in von Willebrand factor (VWF) may contribute to inducing microthrombi in circulation in TA-TMA. Objectives: By performing VWF multimer analysis and measuring VWF-degradation product (DP), we unraveled the relationship between multimeric changes in circulating VWF and the pathogenesis of TA-TMA. Methods: This study analyzed 135 plasma samples from 14 patients who underwent allogeneic hematopoietic stem cell transplantation at a single institute. VWF-associated markers, namely VWF:antigen (VWF:Ag), VWF-DP/VWF:Ag ratio, VWF:ristocetin cofactor activity, VWF:ristocetin cofactor activity/VWF:Ag ratio, and ADAMTS13 activity, were analyzed in these samples collected every 7 days. Results: There were 2 patients with definite thrombotic microangiopathy (TMA) and 6 patients who presented with probable TMA that did not progress to definite TMA. Each plasma sample was classified into 3 groups: definite TMA, probable TMA, and non-TMA. VWF multimer analysis showed the absence of high-molecular-weight VWF multimers in probable TMA, whereas the appearance of unusually large VWF multimers was observed in definite TMA. The median value of the VWF-DP/VWF:Ag ratio in probable TMA was elevated to 4.17, suggesting that excessive cleavage of VWF multimers by VWF cleaving enzyme, ADAMTS13, resulted in the loss of high-molecular-weight VWF multimers. Conclusion: During the transition from probable to definite TMA, drastic VWF multimer changes imply a switch from bleeding to thrombotic tendencies. Extensive VWF-DP and VWF multimer analyses provided novel insights.

Microangiopathic Hemolytic Anemia (MAHA); Congenital Thrombotic thrombocytopenic purpura (TTP), Acquired (Immune) TTP, Shiga toxin associated Endemic hemolytic uremic syndrome (HUS) and Complement-Mediated TMA (CM-TMA), which may present with different clinical findings, Thrombocytopenia is a severe condition that affects multiple organ systems with anemia. In the congenital form, ADAMTS13 (von Willebrand Factor-Cleaving Protease or a metalloprotease that belongs to the "a disintegrin and metalloprotease with a thrombospondin type I motif) is diagnosed by the deficiency of the enzyme and the absence of antibodies. While in autoimmune TTP, the enzyme deficiency is associated with antibodies, endemic HUS associated with Shiga toxin is characterized by decreased ADAMTS13 levels due to endothelial damage. CM-TMA is associated with complement factor H (CFH) inhibitory dysfunction and increased complement levels due to a genetic mutation. On March 27, 2023, the patient with complaints of shortness of breath, headache, dizziness, weakness, and numbness in the hands and arms was admitted to the internal medicine clinic. The patient, presenting with Thrombocytopenia, reduced haptoglobin levels, elevated reticulocyte count, increased LDH, indirect hyperbilirubinemia, and a PLASMIC score of 6 in peripheral blood smear, was hospitalized and treated with the prediagnosis of TTP. Later, ADAMTS13 level was found to be 73% (normal range: 40-130), and the diagnosis of CM-TMA was considered. In addition, we discussed the clinical distinction and treatment of TTP by reviewing the literature. [ABSTRACT FROM AUTHOR]

Background: Hereditary thrombotic thrombocytopenia purpura (hTTP) is an ultra‐rare disorder resulting from an inherited deficiency of ADAMTS13, a von Willebrand factor (VWF)‐cleaving metalloprotease. The plasma‐derived factor VIII/VWF Koate (FVIII/VWFKoate) has been shown to contain ADAMTS13, allowing for its use to treat hTTP at home by the patient/caregiver. Aim: Based on prior demonstration of safe and effective use of FVIII/VWFKoate in eight patients with hTTP, we conducted a retrospective study to gather additional data regarding the use of FVIII/VWFKoate for hTTP. Methods: This was a multicentre, retrospective, noninterventional chart review of patients who had received FVIII/VWFKoate for the management of hTTP. Data collected included demographics, medical history, relevant family history, past use and tolerability of fresh frozen plasma, and details regarding FVIII/VWFKoate therapy. Results: The cohort included 11 patients (seven males, four females) with hTTP, ranging in age at study entry from 2 to 28 years. The average duration of FVIII/VWFKoate therapy was 4.8 years (range, 0.5–6.5 years). Among nine patients using FVIII/VWFKoate as prophylaxis, the normalized annual rate of breakthrough TTP episodes ranged from 0.2 to 1.1 episodes/year. All nine patients who received FVIII/VWFKoate prophylaxis had thrombocytopenia recorded at baseline, while eight (88.9%) did not have thrombocytopenia after using FVIII/VWFKoate. There was one AE (unspecified) attributed to FVIII/VWFKoate. Conclusion: These data suggest that FVIII/VWFKoate is a safe and well‐tolerated source of the missing ADAMTS13 enzyme in patients with hTTP, producing a marked reduction in thrombocytopenia prevalence, low frequency of TTP episodes, and with the added benefit of self‐ or caregiver‐administration. [ABSTRACT FROM AUTHOR]

Objective: To determine and compare plasma thrombomodulin, von Willebrand factor and von Willebrand factor-cleaving protease levels between pre-eclamptic and healthy pregnant females. Method: The cross-sectional, comparative study was conducted at the Department of Haematology, University of Health Sciences, Lahore, Pakistan, from November 2019 to December 2020, and comprised pregnant females who were divided into healthy pregnant group A and pre-eclamptic group B. Plasma thrombomodulin and von Willebrand factor-cleaving protease levels were determined by using commercially available enzyme-linked immunosorbent assay kit, and von Willebrand factor level was determined by using immuno-turbidimetric assay kit. Data was analysed using SPSS 25. Results: Of the 88 participants, there were 44(50%) females with mean age 25.5±6 years in group A and 44(50%) in group B with mean age 26±5 years. Median thrombomodulin level in group B was significantly higher than group A (p=0.003). Median von Willebrand factor-cleaving protease levels were lower in group B compared to group A (p=0.838). A significant difference in von Willebrand factor level was observed between the groups (p=0.038). Conclusion: Females with pre-eclampsia had significantly higher plasma levels of von Willebrand factor and thrombomodulin than healthy pregnant subjects. Key Words: Thrombomodulin, vWF, ADAMTS13 protein, Pre-eclampsia.

Copyright of Acta Medica Colombiana is the property of Acta Medica Colombiana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening thrombotic microangiopathy (TMA) related to a severe ADAMTS13 deficiency, the specific von Willebrand factor (VWF)-cleaving protease. This deficiency is often immune-mediated (iTTP) and related to the presence of anti-ADAMTS13 autoantibodies that enhance its clearance or inhibit its VWF processing activity. iTTP management may be challenging at extreme ages of life. International cohorts of people with TTP report delayed diagnoses and misdiagnoses in children and elderly people. Child-onset iTTP shares many features with adult-onset iTTP: a female predominance, an idiopathic presentation, and the presence of neurological disorders and therapeutic strategies. Long-term follow-ups and a transition from childhood to adulthood are crucial to preventing iTTP relapses, in order to identify the occurrence of other autoimmune disorders and psychosocial sequelae. In contrast, older iTTP patients have an atypical clinical presentation, with delirium, an atypical neurological presentation, and severe renal and cardiac damages. They also have a poorer response to treatment and prognosis. Long-term sequelae are highly prevalent in older patients. Prediction scores for iTTP diagnoses are not used for children and have a lower sensitivity and specificity in patients over 60 years old. ADAMTS13 remains the unique biological marker that is able to definitely confirm or rule out the diagnosis of iTTP and predict relapses during follow-ups. [ABSTRACT FROM AUTHOR]

The endothelial exocytosis of high-molecular-weight multimeric von Willebrand factor (vWF) may occur in critical illness states, including trauma and sepsis, leading to the sustained elevation and altered composition of plasma vWF. These critical illnesses involve the common process of sympathoadrenal activation and loss of the endothelial glycocalyx. As a prothrombotic and proinflammatory molecule that interacts with the endothelium, the alterations exhibited by vWF in critical illness have been implicated in the development and damaging effects of downstream pathologies, such as disseminated intravascular coagulation and systemic inflammatory response syndrome. Given the role of vWF in these pathologies, there has been a recent push to further understand how the molecule may be involved in the pathophysiology of related diseases, such as trauma-induced coagulopathy and acute renal injury, which are also known to develop secondarily to critical illness states. Elucidation of the role of vWF across the broader spectrum of generalized pathologies may provide a basis for the development of novel preventative and restorative measures, while also bolstering the scaffold of more widely used treatments, such as the administration of plasma-containing blood products.

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal acquired thrombotic microangiopathy syndrome that frequently develops in the context of infectious diseases or systemic autoimmune conditions including connective tissue diseases. We report the case of a 42-year-old female suffering from severe iTTP associated with anti-Jo-1 positive antisynthetase syndrome, which was successfully treated with combination therapy of intravenous immune globulin, rituximab and plasma exchange. Based on a systematic review of the literature, two additional cases of idiopathic inflammatory myopathy-associated iTTP (secondary iTTP) were identified. In conclusion, iTTP may be a rare complication of IIM that clinicians should consider in cases of marked thrombocytopenia. Further work-up of this finding should include a peripheral blood smear (schistocyte count) and ADAMTS13 activity. The concomitant manifestation of these autoimmune conditions may require intensive immunosuppressive therapy. [ABSTRACT FROM AUTHOR]

Thrombotic thrombocytopenic purpura (TTP) is a fatal disease in which platelet-rich microthrombi cause end-organ ischemia and damage. TTP is caused by markedly reduced ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity. Hereditary or congenital TTP (cTTP) is caused by ADAMTS13 gene mutations. In acquired or immune TTP (iTTP), ADAMTS13 activity is reduced by anti-ADAMTS13 autoantibodies. TTP is characterized by thrombocytopenia, hemolytic anemia, fever, renal dysfunction, and neuropsychiatric symptoms. Therapeutic plasma exchange (TPE) and immunosuppressive therapy are the mainstays of treatment. As untreated TTP has a high mortality rate, immediate initiation of TPE is recommended when TTP is suspected. Conventionally, corticosteroids have been used for immunosuppressive therapy. Current drug therapies include rituximab, an anti-CD20 antibody that is effective in newly diagnosed cases and refractory cases, as well as for relapse prevention, and caplacizumab, an anti- von Willebrand factor (VWF) nanobody that inhibits the binding of platelets to VWF and prevents microthrombi formation. Recombinant human ADAMTS13 is a promising treatment for cTTP. Although these therapeutic advances have improved the outcomes of TTP, early diagnosis and prompt initiation of appropriate therapy are necessary to achieve these outcomes. [ABSTRACT FROM AUTHOR]

Background: Thrombotic thrombocytopenic purpura (TTP) considers a rare cause of ischemic stroke (IS). We reported a case of a newly diagnosed patient with acquired immune-mediated TTP (iTTP), in whom two IS events developed during 48 h. Case presentation: A 59-year-old diabetic male was presented to the hospital 24 h after symptoms onset, including left hemiparesis, dysarthria, and decreased consciousness. A brain CT scan was performed with the suspicion of acute IS, indicating infarct lesions in the right middle cerebral artery (MCA) territory. The patient was not eligible for thrombolytic therapy due to admission delay. Over the next 24 h, the patient's neurological condition deteriorated, and the second brain CT scan showed new ischemic lesions in the left MCA territory. Initial laboratory evaluation indicated thrombocytopenia without evidence of anemia. However, in the following days, thrombocytopenia progressed, and microangiopathic hemolytic anemia (MAHA) developed. The ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity and inhibitors assay confirmed the diagnosis of iTTP. The patient underwent plasma exchange activity and inhibitors assay confirmed the diagnosis of iTTP. The patient underwent and pulse IV methylprednisolone. Rituximab was also added due to the refractory course of the disease. After a prolonged hospital course, he had considerable neurologic recovery and was discharged. Conclusions: Clinicians should consider two points. First, TTP should be considered in any patient presenting with IS and having thrombocytopenia or anemia without other symptoms of TTP. Second, worsening the patient's condition during hospitalization may indicate a new stroke and should be investigated immediately. [ABSTRACT FROM AUTHOR]

Upshaw‐Schulman syndrome (USS)—rare autosomal recessive disease that affects <1/1 000 000 individuals. It is characterized by the massive formation of platelet thrombi in the microcirculation accompanied by haemolytic anaemia, thrombocytopenia and clinical and laboratory signs of renal and neurological failure. USS is caused by mutations in the ADAMTS13 gene. Mutations in the ADAM metallopeptidasewith thrombospondin type 1 motif 13 (ADAMTS13) gene can lead to disruption of secretion of this enzyme, or to decrease of enzyme proteinase activity without effect on ADAMTS13 secretion. The aim of this work is to describe a clinical case of USS caused by a new missense mutation in the ADAMTS13 gene. The diagnosis of thrombotic thrombocytopenic purpura was based on clinical signs and confirmed if plasma ADAMTS13 activity was <10%. ADAMTS13 gene sequencing was performed by the Sanger method using oligonucleotide primers of our own design. We found a new, undescribed mutation p.Trp387Ser in a TrpXXTrp motif. Previously, a pathogenic variation disrupting the 387TrpSerSerTrp390 motif of the ADAMTS13 protein was detected only once. Clinical picture of a patient with the combination of the p.Trp387Ser and p.Arg1060Trp variations is quite similar to that of the homozygous state of p.Arg1060Trp variant. [ABSTRACT FROM AUTHOR]

Abstract: Pediatric thrombotic thrombocytopenic purpura (TTP) is an ultrarare disease. Immune TTP (iTTP) is driven by anti-ADAMTS13 autoantibodies causing an imbalanced von Willebrand factor (VWF):ADAMTS13 axis, and rarer still in children, but potentially life-threatening. Caplacizumab is licensed for iTTP treatment in adults and adolescents aged ≥12 years who weigh ≥40 kg. There is a need to clarify whether caplacizumab can be used in younger children. We retrospectively described caplacizumab use in 16 patients under 18 years of age from the UK TTP Registry, including 4 children aged <12 years. For patients weighing <40 kg (n = 3), caplacizumab was dosed at 5 mg once dailyThe youngest patient was 33 months old at diagnosis. Plasma exchange (PEX) was used in 15 patients, with a median of 5 exchanges required before platelet count normalization (range, 2-9). One patient was managed without PEX. All patients achieved normalization of platelet count (median, 5.5 days; range, 3-28) and ADAMTS13 activity (median, 35 days; range, 8-149), with a median hospital admission of 11 days (range, 5-26). There were no refractory patients. One patient relapsed 9 months after presentation. Bleeding requiring VWF supplementation and reduction of caplacizumab use occurred in 1 patient with severe epistaxis, with no significant intracranial or gastrointestinal bleeding. We demonstrated the efficacy and safety of caplacizumab in the pediatric population, which is synonymous with the adult trial data: primarily, reduction of PEX compared with the precaplacizumab era. This has implications for the intensification and duration of admission, particularly relevant in pediatric care., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Thrombotic Thrombocytopenic Purpura (TTP) is rare and potentially life-threatening thrombotic microangiopathy (TMA) caused by acquired immune-mediated or congenital deficiency of the von Willebrand factor regulatory enzyme, a Disintegrin And Metalloproteinase with a Thrombospondin Type 1 motif, member 13 (ADAMTS13) which cause microthrombi to form and occlude the microvasculature. The occurrence of acute kidney injury (AKI) in TTP is rare and often underestimated due to confusion with hemolytic uremic syndrome (HUS). A 23-year-old Mestizo male patient presented with altered mental status, hemolytic anemia, thrombocytopenia, intermittent fever, laboratory tests suggestive of thrombotic microangiopathy, and clinical findings consistent with acute kidney injury. Predictive values of the platelet count, lactate dehydrogenase, absent active cancer, schistocytes, mean corpuscular volume, international normalized ratio, creatinine (PLASMIC) score, were used to assess the likelihood of ADAMTS13 deficiency, were employed, and enzymatic activity testing confirmed severe protein deficiency. Honduras' lack of advanced diagnostic capabilities is underscored, emphasizing the urgent need to invest in precision medical technology. ADAMTS13 testing allows for a more precise diagnosis of TTP, which is crucial for early diagnosis and timely treatment., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Escoto-Pineda et al.)

Atypical haemolytic uremic syndrome (aHUS) is a rare disorder characterised by complement-mediated thrombotic microangiopathy (TMA). Despite clinical guidelines, the diagnosis and treatment of aHUS in its early stages remains challenging. This study examined the annual trends in aHUS clinical practices in Japan and explored factors influencing early diagnosis and treatment. Using data from the 2011-2020 Diagnosis Procedure Combination database, 3096 cases with the HUS disease code were identified, of which 217 were confirmed as aHUS and treated with eculizumab or plasma exchange. Early initiation, defined as starting eculizumab or plasma exchange within 7 days of admission, was the focus of the study. Our study revealed no significant changes over time in the number of aHUS diagnoses, cases treated with eculizumab, or early initiation cases. Early initiation cases underwent haemodialysis earlier and had ADAMTS13 activity measured earlier, shorter hospital stays, and lower hospitalisation costs than late initiation cases. In conclusion, we found no increase in the number of newly diagnosed aHUS cases or early treatment initiation over time. Early recognition of TMA and differentiation of the causative disease are crucial for identifying potential aHUS cases, which may lead to better patient prognoses., (© 2024. The Author(s).)

Background: Transplant-associated thrombotic microangiopathy (TA-TMA) is a fatal complication of hematopoietic stem cell transplantation and is characterized by severe thrombocytopenia, hemolytic anemia, and organ dysfunction. In response to several possible triggers, dynamic multimetric change in von Willebrand factor (VWF) may contribute to inducing microthrombi in circulation in TA-TMA., Objectives: By performing VWF multimer analysis and measuring VWF-degradation product (DP), we unraveled the relationship between multimeric changes in circulating VWF and the pathogenesis of TA-TMA., Methods: This study analyzed 135 plasma samples from 14 patients who underwent allogeneic hematopoietic stem cell transplantation at a single institute. VWF-associated markers, namely VWF:antigen (VWF:Ag), VWF-DP/VWF:Ag ratio, VWF:ristocetin cofactor activity, VWF:ristocetin cofactor activity/VWF:Ag ratio, and ADAMTS13 activity, were analyzed in these samples collected every 7 days., Results: There were 2 patients with definite thrombotic microangiopathy (TMA) and 6 patients who presented with probable TMA that did not progress to definite TMA. Each plasma sample was classified into 3 groups: definite TMA, probable TMA, and non-TMA. VWF multimer analysis showed the absence of high-molecular-weight VWF multimers in probable TMA, whereas the appearance of unusually large VWF multimers was observed in definite TMA. The median value of the VWF-DP/VWF:Ag ratio in probable TMA was elevated to 4.17, suggesting that excessive cleavage of VWF multimers by VWF cleaving enzyme, ADAMTS13, resulted in the loss of high-molecular-weight VWF multimers., Conclusion: During the transition from probable to definite TMA, drastic VWF multimer changes imply a switch from bleeding to thrombotic tendencies. Extensive VWF-DP and VWF multimer analyses provided novel insights., (© 2024 The Author(s).)

Lupus nephritis (LN) is one of the most common organ-specific manifestations of systemic lupus erythematosus (SLE). Various clinical signs of LN develop in at least 50% of patients with SLE. In addition to LN, the spectrum of renal lesions associated with SLE also includes vascular pathology. One of the variants of renal microvascular injury is thrombotic microangiopathy (TMA), the mechanisms of which are diverse. The review focuses on the main forms of TMA, including antiphospholipid syndrome and nephropathy associated with antiphospholipid syndrome, TMA caused by complement system regulation disorders and deficiency of ADAMTS13. In most cases, these forms of TMA are combined with LN. However, they may also exist as a single form of kidney damage. This article discusses the TMA pathogenesis, the impact on kidney prognosis, and treatment options.

Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening thrombotic microangiopathy (TMA) related to a severe ADAMTS13 deficiency, the specific von Willebrand factor (VWF)-cleaving protease. This deficiency is often immune-mediated (iTTP) and related to the presence of anti-ADAMTS13 autoantibodies that enhance its clearance or inhibit its VWF processing activity. iTTP management may be challenging at extreme ages of life. International cohorts of people with TTP report delayed diagnoses and misdiagnoses in children and elderly people. Child-onset iTTP shares many features with adult-onset iTTP: a female predominance, an idiopathic presentation, and the presence of neurological disorders and therapeutic strategies. Long-term follow-ups and a transition from childhood to adulthood are crucial to preventing iTTP relapses, in order to identify the occurrence of other autoimmune disorders and psychosocial sequelae. In contrast, older iTTP patients have an atypical clinical presentation, with delirium, an atypical neurological presentation, and severe renal and cardiac damages. They also have a poorer response to treatment and prognosis. Long-term sequelae are highly prevalent in older patients. Prediction scores for iTTP diagnoses are not used for children and have a lower sensitivity and specificity in patients over 60 years old. ADAMTS13 remains the unique biological marker that is able to definitely confirm or rule out the diagnosis of iTTP and predict relapses during follow-ups.

Abstract Background Thrombotic thrombocytopenic purpura (TTP) is a life‐threatening thrombotic microangiopathy (TMA) caused by a severe functional deficiency in ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type I repeats‐13), the specific von Willebrand factor (VWF) cleaving protease. ADAMTS13 activity is essential to diagnose TTP but remains challenging to assess, as reference ADAMTS13 activity assays are manual and time consuming. Current techniques also lack robustness in low detectable ADAMTS13 activity range, which could prove problematic for therapy‐driven monitoring. Objectives The HemosIL AcuStar ADAMTS13 activity assay is a fast, automated chemiluminescent assay, the performance of which remains to be evaluated prospectively on very large cohorts of patients with TMA and in real‐life conditions. Patients and Methods Our study was conducted over two successive sequences: a retrospective evaluation followed by a “real‐life” prospective evaluation. Overall, we evaluated the HemosIL AcuStar ADAMTS13 activity assay on 539 citrated plasma samples. We extensively studied linearity, limit of detection, contamination, intra‐assay and interassay precisions with a specific focus on levels

Objective To explore the levels and their possible effects of serum von Willebrand factor (vWF) and vWF lyase (ADAMTS13) in patients with diabetic nephropathy (DN). Methods Fifty cases of healthy physical examination (the normal control group) and 144 patients with type 2 diabetes (the T2DM group) were selected in this study. According to the ratio of urine microalbumin to urine creatinine (ACR), the diabetic T2DM patients were divided into the simple diabetes group (n=42, ACR＜30 mg/g), the microalbuminuria group (n=56, 30 mg/g≤ACR˂300 mg/g), and the macroalbuminuria group (n=46, ACR≥300 mg/g). The immunoturbidimetric method was used to detect vWF levels. The double antibody sandwich method was used to detect ADAMTS13 level, creatinine (sCr), urea nitrogen (BUN) and glycosylated hemoglobin (HbA1c). The glomerular filtration rate (eGFR), D-Dimer and fibrinogen (Fib) were estimated. Results HbA1c, Fib, D-dimer and vWF increased successively in the normal control group, the T2DM group, the microalbuminuria group and the macroalbuminuria group, while ADAMTS13 decreased in turn (P＜0.05). Multiple linear regression analysis showed that albumin and D-dimer were the main factors affecting serum vWF, and D-dimer was the main factor affecting ADAMTS13 levels. ROC curve analysis showed that vWF was more sensitive in diagnosing DN renal damage, while D-dimer had more balanced sensitivity and specificity in the diagnosis of DN renal damage, and specificity was more advantage. Conclusion Serum vWF and ADAMTS13 may play an important role in the occurrence and development of DN, and their levels can be used as clinical indicators for the early diagnosis and prediction of DN. [ABSTRACT FROM AUTHOR]

Abstract Thrombotic microangiopathies are disorders characterized by nonimmune microangiopathic hemolytic anemia, thrombocytopenia, and multi-systemic failure. They are classified as thrombotic thrombocytopenic purpura, atypical hemolytic-uremic syndrome, and typical hemolytic uremic syndrome. The latter is associated with intestinal infections by Shiga toxin-producing bacteria. Typical hemolytic uremic syndrome in adults is an extremely rare condition, characterized by high morbidity and mortality. It has been seldom described in solid organ transplant recipients. Here is presented the case of a kidney transplant recipient who had typical hemolytic uremic syndrome with multisystem commitment, refractory to management and with a fatal outcome.

BackgroundKnown risk factors for intracerebral hemorrhage (ICH) include age, hypertension, smoking, alcohol intake, and anticoagulant use. Some previous reports have indicated that hemostatic factors measured many years before the onset of ICH might predict the later occurrence of ICH. The objective of this analysis was to test whether selected hemostatic factors measured years before the onset of ICH could identify patients at higher risk for future ICH.MethodsWe performed a nested case-control study within the Women's Health Initiative (WHI) cohort. Postmenopausal women aged 50-79 years (mean 68) at baseline (1993-1998) were enrolled at 40 Clinical Centers in the United States and followed for adjudicated ICH for a mean of 11.4 years. ICH cases (N = 75) and controls (N = 75) were matched on age, ethnicity, blood pressure, anticoagulant use, and treated hypertension. Stored blood samples from the baseline WHI examination were tested for von Willebrand factor (vWF), a disintegrin-like and metalloprotease domain with thrombospondin type-1 motif, number 13 (ADAMTS13), tissue plasminogen activator (t-PA), and urokinase plasminogen activator (u-PA). Platelet count, white blood cell count, and hemoglobin concentration were also measured.ResultsMean baseline levels of vWF (1.03 and .95 U/mL), ADAMTS13 (1.0 and 1.1 µg/mL), vWF : ADAMTS13 ratio (.99 and .92), t-PA (14.75 and 14.80 IU/mL), and u-PA (.09 and .10 IU/mL) were not significantly different by case-control status. Significant differences were also not identified for platelet count, hemoglobin, white blood count, or reported alcohol use.ConclusionNone of the 4 baseline hemostatic factors nor the platelet count was predictive of future ICH risk in this long-term study of older postmenopausal women.

Abstract Background Thrombotic thrombocytopenic purpura (TTP) is associated with more deleterious outcomes in patients with systemic lupus erythematosus (SLE). However, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) levels and ADAMTS13 inhibitor were not routinely assayed in most previous studies. The objective of this study is to compare the characteristics and outcomes of immune-mediated TTP (iTTP) in patients with and without SLE. Methods The medical data of 28 patients with iTTP from Peking Union Medical College Hospital were analysed. ADAMTS13 activity and ADAMTS13 inhibitor were measured in all patients. Results All 28 patients had ADAMTS13 inhibitor and severe ADAMTS13 deficiency. iTTP was considered SLE-related (SLE-TTP) in 10 patients and primary (primary iTTP) in 18 patients. Renal involvement on presentation was more severe in patients with primary iTTP as determined by higher serum creatinine (162.7 ± 110.6 vs 73.3 ± 13.4 μmol/L, p

Abstract Background In immune‐mediated thrombotic thrombocytopenic purpura (iTTP), patients develop an immune response against the multidomain enzyme ADAMTS13. ADAMTS13 consists of a metalloprotease (M) and disintegrin‐like (D) domain, 8 thrombospondin type 1 repeats (T1‐T8), a cysteine‐rich (C), a spacer (S), and 2 CUB domains (CUB1‐2). Previous epitope mapping studies have used relatively large overlapping ADAMTS13 fragments. Objectives We aimed at developing small nonoverlapping ADAMTS13 fragments to fine map anti‐ADAMTS13 autoantibodies in iTTP patients. Methods A library of 16 ADAMTS13 fragments, comprising several small (M, DT, C, S, T2‐T5, T6‐T8, CUB1, CUB2), and some larger fragments with overlapping domains (MDT, MDTC, DTC, CS, T2‐T8, CUB1‐2, MDTCS, T2‐C2), were generated. All fragments, and ADAMTS13, were expressed as a fusion protein with albumin domain 1, and purified. The folding of the fragments was tested using 17 anti‐ADAMTS13 monoclonal antibodies with known epitopes. An epitope mapping assay using small ADAMTS13 fragments was set up, and validated by analyzing 18 iTTP patient samples. Results Validation with the monoclonal antibodies demonstrated that single S and CUB1 were not correctly folded, and therefore CS and CUB1‐2 fragments were selected instead of single C, S, CUB1, and CUB2 fragments. Epitope mapping of antibodies of patients with iTTP confirmed that 6 nonoverlapping ADAMTS13 fragments M, DT, CS, T2‐T5, T6‐T8, and CUB1‐2 were sufficient to accurately determine the antibody‐binding sites. Conclusion We have developed a tool to profile patients with iTTP according to their anti‐ADAMTS13 antibodies for a better insight in their immune response.

Our design aimed to explore the potential involvement of matrix metalloproteinase-9 (MMP-9) in the inflammatory response associated with acute ischemic stroke (AIS). We also aimed to preliminarily examine the potential impact of a disintegrin-like and metalloprotease with thrombospondin type I repeats-13 (ADAMTS13) on MMP-9 in AIS. We conducted oxygen-glucose deprivation models of microglia cells and mice models of AIS with middle cerebral artery occlusion (MCAO). We assessed the expression pattern of MMP-9 with western blotting (WB) and real-time quantitative PCR both in vivo and in vitro. MMP-9 downregulation was achieved by using ACE inhibitors such as trandolapril. For the MCAO model, we used ADAMTS13-deficient mice. We then evaluated the related neurological function scores, cerebral edema and infarct volume. The levels of inflammation-related proteins, such as COX2 and iNOS, were assessed using WB, and the expression of inflammatory cytokines was measured via enzyme-linked immuno sorbent assay in vivo. Our findings indicated that MMP-9 was up-regulated while ADAMTS13 was down-regulated in the MCAO model. Knockdown of MMP-9 reduced both inflammation and ischemic brain injury. ADAMTS13 prevented brain damage, improved neurological function and decreased the inflammation response in mice AIS models. Additionally, ADAMTS13 alleviated MMP-9-induced neuroinflammation in vivo. It showed that ADAMTS13 deficiency exacerbated ischemic brain injury through an MMP-9-dependent inflammatory mechanism. Therefore, the ADAMTS13-MMP-9 axis could have therapeutic potential for the treatment of AIS., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

ADAMTS13, a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13, regulates the length of Von Willebrand factor (VWF) multimers and their platelet-binding activity. ADAMTS13 is constitutively secreted as an active protease and is not inhibited by circulating protease inhibitors. Therefore, the mechanisms that regulate ADAMTS13 protease activity are unknown. We performed an unbiased proteomics screen to identify ligands of ADAMTS13 by optimizing the application of BioID to plasma. Plasma BioID identified 5 plasma proteins significantly labeled by the ADAMTS13-birA* fusion, including VWF and plasminogen. Glu-plasminogen, Lys-plasminogen, mini-plasminogen, and apo(a) bound ADAMTS13 with high affinity, whereas micro-plasminogen did not. None of the plasminogen variants or apo(a) bound to a C-terminal truncation variant of ADAMTS13 (MDTCS). The binding of plasminogen to ADAMTS13 was attenuated by tranexamic acid or ε-aminocaproic acid, and tranexamic acid protected ADAMTS13 from plasmin degradation. These data demonstrate that plasminogen is an important ligand of ADAMTS13 in plasma by binding to the C-terminus of ADAMTS13. Plasmin proteolytically degrades ADAMTS13 in a lysine-dependent manner, which may contribute to its regulation. Adapting BioID to identify protein-interaction networks in plasma provides a powerful new tool to study protease regulation in the cardiovascular system., (© 2024. The Author(s).)

Obesity and low enzyme A disintegrin and metalloproteinase with thrombospondin type-1 motif-13 (ADAMTS13) activity have been linked to poor coronavirus disease 2019 (COVID-19). Given that obesity may influence ADAMTS13 activity, it is feasible; however, it remains unclear whether ADAMTS13 activity acts as a mediator between obesity and COVID-19 outcomes. We investigated the link between body mass index (BMI) and COVID-19 outcomes, using ADAMTS13 activity as a mediator. ADAMTS13 activity was measured in 86 hospitalized COVID-19 patients. BMI, ADAMTS13 activity, and COVID-19 outcomes were assessed. Obese patients had a high odds ratio for low ADAMTS13 levels. When different levels of ADAMTS13 activity were considered, the severity of COVID-19 in obese patients was 4.5 times that in the normal BMI group. Furthermore, increased coagulopathy indicators correlated with low ADAMTS13 activity. Patients with elevated ALT and AST levels showed a 3 to 4-fold increase in the chances of low ADAMTS13 activity (OR:3.19, 95% CI:1.22-8.90, P = .021; OR:2.17, 95% CI:0.91-5.27, P = .082, respectively). When ADAMTS13 activity was considered, obese patients had greater COVID-19 severity and slower viral clearance than those with normal BMI. Low ADAMTS13 activity and impaired liver function are associated with poor COVID-19 outcomes. These findings encourage researchers to use molecular component identification to study the effects of obesity on the von Willebrand factor (VWF)/ADAMTS13 axis, COVID-19 pathogenesis, and outcomes., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic disorder associated with a severe deficiency of ADAMTS-13-the protease that cleaves von Willebrand factor. Plasma therapy is the current standard of care for managing acute episodes of TTP, which involves removing patient plasma and replacing it with donor plasma to raise the level of ADAMTS-13 activity. Recently, therapies aimed at replacing ADAMTS-13 have been investigated as possible substitutes or add-ons to plasma therapy for congenital and immune-mediated TTP. Enzyme replacement therapy provides recombinant ADAMTS-13 via intravenous (i.v.) infusion to restore enzyme activity. Recombinant ADAMTS-13-loaded platelets localize to the site of thrombus formation in a more concentrated manner than enzyme replacement or plasma therapy. ADAMTS-13-encoding messenger RNA aims to induce a steady supply of secreted protein and gene therapy is a potentially curative strategy. Overall, targeted ADAMTS-13 replacement therapies may provide better outcomes than plasma therapy by achieving higher levels of ADAMTS-13 activity and a more sustained response with fewer adverse events. Herein, we describe targeted ADAMTS-13 replacement therapies for the treatment of TTP and discuss the advantages and limitations of each approach., Competing Interests: Declaration of competing interests None of the authors have any competing interests to disclose., (Copyright © 2023 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

Acquired thrombotic thrombocytopenic (aTTP) purpura is a life-threatening condition that can lead to devastating thromboembolic events. Recently, caplacizumab has been shown to rapidly restore platelet numbers and reduce the risk of severe end-organ damage when added to plasma exchanges (PEXs) and immunosuppression (IST). Here, we report the outcomes in 3 children with aTTP who were treated with caplacizumab in combination with PEXs and IST. In all 3 patients, platelet count increased to >15,000/mm 3 in 24 h and normalized on day 4, whereas normalization of ADAMTS13 activity >50% and elimination of the inhibitor was achieved after 18 to 89 days. Epistaxis was observed in 2 patients and was the only side effect related to caplacizumab. Caplacizumab is a promising agent for first-line treatment of children with aTTP., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening disease that may result from drug exposure. We report a case of iTTP occurring in a 39-year-old patient, 45 months following introduction of the anti-CD52 lymphoid cell depleting monoclonal antibody alemtuzumab, to treat a relapsing-remitting multiple sclerosis. Treatment consisted in plasma exchange, corticosteroids and caplacizumab, allowing clinical remission 3 months after the diagnosis, attested by the absence of thrombocytopenia and recovery of ADAMTS-13 activity. As other autoimmune disorders, iTTP may occur following alemtuzumab. This diagnosis should be suspected in patients with features of thrombotic microangiopathy following this treatment., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Aim: We investigated the von Willebrand factor to ADAMTS13 ratio (von Willebrand factor [VWF]:Ag/ADAMTS13:AC) as a potential biomarker for the outcomes of acute kidney injury (AKI) in liver cirrhosis (LC)., Methods: This retrospective cross-sectional study included patients with LC who developed AKI (AKI group: n = 91) and patients with LC who did not develop AKI [non-AKI (NAKI) group, n = 91] as a control group. Plasma levels of the von Willebrand factor antigen (Ag) and ADAMTS13 activity (AC) were measured in patients with AKI or NAKI. Moreover, risk factors for onset of AKI, AKI-associated 90-day mortality, and poor AKI treatment response were identified., Results: The AKI group had a significantly higher VWF:Ag/ADAMTS13:AC than the NAKI group. Values of VWF:Ag/ADAMTS13:AC ≥ 5.7 were identified as risk factors for AKI onset in patients with LC (odds ratio [OR] 2.56; 95% CI 1.26-4.99; p < 0.001). Among patients with AKI, values of VWF:Ag/ADAMTS13:AC ≥ 9.0 were identified as risk factors for 90-day mortality (OR 6.83; 95% CI 2.32-20.10; p < 0.001). Cumulative survival was significantly lower in those with high (≥ 9.0) than in those with low (< 9.0) VWF:Ag/ADAMTS13:AC. Furthermore, values of VWF:Ag/ADAMTS13:AC ≥ 7.4 were identified as risk factors for poor treatment response (OR 4.2; 95% CI 1.39-12.70; p < 0.001). The treatment response rates were significantly higher in those with low (< 7.4) VWF:Ag/ADAMTS13:AC than in those with high (≥ 7.4) VWF:Ag/ADAMTS13:AC., Conclusion: VWF:Ag/ADAMTS13:AC potentially predicts the onset, prognosis, and treatment response of AKI in patients with LC., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

It has been proposed that the onset of Acquired Thrombotic Thrombocytopenic Purpura (iTTP) is more severe than subsequent relapses; however, existing studies have limitations. We conducted a retrospective observational study to compare analytical and clinical severity of onset and relapse aTTP cases between 2012 and 2023. A total of 370 episodes of aTTP were analyzed, comprising 272 at initial diagnosis and 98 relapses. At onset, analytical parameters indicative of severity (low hemoglobin, low platelet count, and increased LDH) were significantly worse; patients had severe neurological symptoms (p<0.001) and ≥ 3 points in the TMA mortality score (p<0.001). In conclusion, the onset of aTTP is associated with worse analytical parameters and severe neurological involvement., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Thrombotic thrombocytopenic purpura (TTP) is a low prevalence disease characterized by severe deficiency of the enzyme ADAMTS13, leading to the development of thrombotic microangiopathy (TMA) and often resulting in severe organ disfunction. TTP is an extremely serious condition and, therefore, timely and appropriate treatment is critical to prevent life-threatening complications.Over the past 25 years, significant advances in the understanding of the pathophysiology of immune TTP have led to the development of readily available techniques for measuring ADAMTS13 levels, as well as new drugs that are particularly effective in the acute phase and in preventing relapses. These developments have improved the course of the disease.Given the complexity of the disease and its various clinical and laboratory manifestations, early diagnosis and treatment can be challenging.To address this challenge, a group of experienced professionals from the Catalan TTP group have developed this consensus statement to standardize terminology, diagnosis, treatment and follow up for immune TTP, based on currently available scientific evidence in the field. This guidance document aims to provide healthcare professionals with a comprehensive tool to make more accurate and timely diagnosis of TTP and improve patient outcomes.

Background and Objectives: Malignant hypertension (MHT) characterized by acute hypertension with retinopathy or multiorgan damage, is a severe form of hypertensive emergency and associated with target organ involvement and poor kidney outcome. However, the underlying mechanisms are unclear., Methods: Eighty-four patients with acute severe hypertension from the Nephrology Department and Emergency Department in a single center during January 2016 and December 2017 were prospectively enrolled and divided into MHT ( n  = 48) and non-MHT ( n  = 36) subgroups according to target organ evaluation. Forty healthy controls were recruited. Serum soluble Fms-like tyrosine kinase-1 (sFlt-1) levels and plasma ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13) activity were examined at baseline and 12-month follow-up. Renal endpoints were defined as a significant decrease in the estimated glomerular filtration rate (eGFR) of more than 40% or the occurrence of end-stage renal disease., Results: Serum sFlt-1 levels were persistently elevated in MHT. Baseline serum sFLT-1 levels were correlated with plasma ADAMTS13 activity and markers of target organ damage. Plasma ADAMTS13 activity was reduced in both MHT and non-MHT patients and recovered to the normal range at 12-month follow-up. During an average follow-up time of 53 ± 13 months, the restoration of reduced ADAMTS13 activity was correlated with the improvement of kidney function and independently reduced the risk of renal endpoints., Conclusions: Abnormal angiogenesis and endothelial damage are involved in the pathophysiology of hypertensive emergency. Evaluation of ADAMTS13 and sFlt-1 may help in the diagnosis and assessment of MHT. Recovery of ADAMTS13 predicts better renal outcome in patients with hypertensive emergencies., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare condition caused by severe ADAMTS13 deficiency, leading to platelet aggregation and thrombosis. Despite treatment, patients are prone to cognitive impairment and depression. We investigated brain changes in iTTP patients during remission using advanced magnetic resonance imaging (MRI) techniques, correlating these changes with mood and neurocognitive tests. Twenty iTTP patients in remission (30 days post-haematological remission) were compared with six healthy controls. MRI scans, including standard and specialized sequences, were conducted to assess white matter health. Increased T1 relaxation times were found in the cingulate cortex (p < 0.05), and elevated T2 relaxation times were observed in the cingulate cortex, frontal, parietal and temporal lobes (p < 0.05). Pathological changes in these areas are correlated with impaired cognitive and depressive scores in concentration, short-term memory and verbal memory. This study highlights persistent white matter damage in iTTP patients, potentially contributing to depression and cognitive impairment. Key regions affected include the frontal lobe and cingulate cortex. These findings have significant implications for the acute and long-term management of iTTP, suggesting a need for re-evaluation of treatment approaches during both active phases and remission. Further research is warranted to enhance our understanding of these complexities., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Portal vein thrombosis (PVT), one of the most prevalent hepatic vascular conditions in patients with liver cirrhosis (LC), is associated with high mortality rates. An imbalance between a disintegrin-like metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS-13) enzyme and von Willebrand factor (VWF) is responsible for hypercoagulability, including spontaneous thrombus formation in blood vessels. Herein, we aimed to identify potential prognostic and diagnostic biomarkers in Japanese patients with LC and PVT. In total, 345 patients were divided into two groups: 40 patients who developed PVT (PVT group) and 305 who did not develop PVT (NPVT group). Among the 345 patients with LC, 81% (279/345) were deemed ineligible due to the presence of preventive comorbidities, active or recent malignancies, and organ dysfunction. The remaining 66 patients were divided into two groups: the PVT group (n = 33) and the NPVT group (n = 33). Plasma ADAMTS-13 activity (ADAMTS-13:AC) and the vWF antigen (VWF:Ag) were measured using enzyme-linked immunosorbent assays. Contrast-enhanced, three-dimensional helical computed tomography (CT) was used to detect and characterize PVT. ADAMTS-13:AC was significantly lower in the PVT group than in the NPVT group. No significant differences in plasma vWF:Ag or liver stiffness were observed between the two groups. ADAMTS-13:AC of <18.8 was an independent risk factor for PVT on multivariate analyses (odds ratio: 1.67, 95% confidence interval: 1.21-3.00, p < 0.002). The receiver operating characteristic analysis of ADAMTS-13:AC revealed an area under the curve of 0.913 in PVT detection. Patients with PVT having ADAMTS-13:AC ≥18.8 (n = 17) had higher albumin levels and better prognoses than those with ADAMTS-13:AC <18.8 (n = 16). No significant correlations of ADAMTS-13:AC levels with either fibrin degradation product or D-dimer levels were observed. ADAMTS-13:AC levels could be potential diagnostic and prognostic biomarkers for PVT in Japanese patients with LC.

Background and Objectives : congenital heart disease (CHD), cyanotic and, to a lesser degree, acyanotic, often are accompanied by coagulation abnormalities, impacting substantially morbidity and mortality. Until now, no consistent hemostatic patterns have been demonstrated in neonates and children with CHD because they represent a variable and heterogenous population. The aim of the present study is to investigate the hemostatic profile, as well as the role of ADAMTS-13 (a disintegrin and metalloprotease with thrombospondin type-1 motives), the cleaving protein of von Willebrand factor (VWF) in neonates with CHD and compare them to healthy age-matched controls. Materials and Methods : twenty neonates with a mean gestational age of 37.1 ± 2.5 weeks were included in the CHD group, and 18 healthy neonates with a mean gestational age of 38.2 ± 1.5 weeks were in the control group. Results: prothrombin time was significantly prolonged, and accordingly, factor VII (FVII) levels were significantly decreased in the CHD group in comparison to controls. Factor VIII (FVIII), VWF, and ristocetin cofactor activity (Rcof) levels were significantly higher in the study vs. control group. Concentrations of ADAMTS-13 were decreased in the CHD vs. control group, but the difference was not statistically significant. Our results, in combination, indicate a balanced hemostatic mechanism, although with greater variability in neonates with CHD, while developmental aspects of coagulation are evident in the specific patient population. Conclusions: the coagulation profile is moderately impaired early in the course of CHD, though increased thrombogenicity is already present and should not be ignored.

Abstract: Sepsis is defined as a life-threatening organ dysfunction caused by excessive host response to infection, and represents the most common cause of in-hospital deaths. Sepsis accounts for 30% of all critically ill patients in the intensive care unit (ICU), and has a global mortality rate of 20%. Activation of blood coagulation during sepsis and septic shock can lead to disseminated intravascular coagulation, which is characterized by microvascular thrombosis. Von Willebrand factor (VWF) and ADAMTS13 are two important regulators of blood coagulation that may be important links between sepsis and mortality in the ICU. Herein we review our current understanding of VWF and ADAMTS13 in sepsis and other critical illnesses and discuss their contribution to disease pathophysiology, their use as markers of severe illness, and potential targets for new therapeutic development., (Copyright © 2023 by the Shock Society.)

The coexistence of anti-glomerular basement membrane (anti-GBM) disease with thrombotic microangiopathy (TMA) is rarely encountered, and the clinical characteristics of this phenomenon are not well known.A 76-year-old Japanese woman with a history of idiopathic pulmonary disease was diagnosed with anti-GBM disease due to rapidly progressive glomerulonephritis and a positive anti-GBM antibody test result. We treated the patient with hemodialysis, glucocorticoids, and plasmapheresis. During treatment, the patient suddenly became comatose. TMA was then diagnosed because of thrombocytopenia and microangiopathic hemolytic anemia. The activity of a disintegrin-like and metalloproteinase with thrombospondin type 1 motif 13 (ADAMTS-13) was retained at 48%. Although we continued the treatment, the patient died of respiratory failure. An autopsy revealed the cause of respiratory failure to be an acute exacerbation of interstitial pneumonia. The clinical findings of the renal specimen indicated anti-GBM disease; however, there were no lesions suggestive of TMA. A genetic test did not reveal an apparent genetic mutation of the atypical hemolytic uremic syndrome.We conducted a literature review of past case reports of anti-GBM disease with TMA. The following clinical characteristics were obtained. First, 75% of the cases were reported in Asia. Second, TMA tended to appear during the treatment course for anti-GBM disease and usually resolved within 12 weeks. Third, ADAMTS-13 activity was retained above 10% in 90% of the cases. Fourth, central nervous system manifestations occurred in more than half of the patients. Fifth, the renal outcome was very poor. Further studies are required to understand the pathophysiology of this phenomenon., (© 2023. The Author(s) under exclusive licence to The Japan Society of Nephrology.)

Background: Preeclampsia is a gestational hypertensive disorder characterized by maternal endothelial activation and increased ratio of soluble fms-like tyrosine kinase-1 (sFlt-1) inhibitor to placental growth factor (PlGF). The von Willebrand factor (VWF)/ADAMTS-13 axis is of interest because of the underlying endothelial activation and clinical overlap with pregnancy-associated thrombotic thrombocytopenic purpura., Objectives: To assess VWF, ADAMTS-13, and VWF/ADAMTS-13 ratio in preeclampsia and look for associations with sFlt-1/PlGF ratio and clinical features., Methods: Thirty-four preeclampsia cases and 48 normal pregnancies were assessed in a case-control study. Twelve normal pregnancies in women with a history of preeclampsia formed an additional comparator group. VWF antigen (VWF:Ag) and VWF activity (VWF:Ac [VWF:glycoprotein IbM]) were measured via automated immunoturbidimetric assay, ADAMTS-13 activity was measured via fluorescence resonance energy transfer-VWF73 assay, and sFlt-1 and PlGF were measured via enzyme-linked immunosorbent assay., Results: VWF:Ag was higher in preeclampsia than in normal pregnancy (median, 3.07 vs 1.87 IU/mL; P < .0001). ADAMTS-13 activity was slightly lower (median, 89.6 vs 94.4 IU/dL; P = .02), with no severe deficiencies. Significant elevations in VWF:Ac were not observed in preeclampsia, resulting in reduced VWF:Ac/VWF:Ag ratios (median, 0.77 vs 0.97; P < .0001). VWF:Ag/ADAMTS-13 ratios were significantly higher in preeclampsia (median, 3.42 vs 2.06; P < .0001), with an adjusted odds ratio of 19.2 for a ratio of >2.7 (>75th centile of normal pregnancy). Those with a history of preeclampsia had similar ratios to normal pregnant controls. VWF:Ag/ADAMTS-13 and sFlt-1/PlGF were not correlated. However, percentage reduction in platelets correlated positively with VWF:Ac (P = .01), VWF:Ac/VWF:Ag ratio (P = .004), and sFlt-1/PlGF ratio (P = .01)., Conclusion: The VWF/ADAMTS-13 axis is significantly altered in preeclampsia. Further investigation of potential clinical utility is warranted., Competing Interests: Declaration of competing interests L.N. has served on an advisory board for Alexion. M.T. has served on advisory boards for Ablynx, Sanofi, and Bayer; received speaker fees for Bayer, Sanofi, and Anthos; and received consultancy fees from Bayer. M.S. has received speaker fees from and has served on advisory boards for Alexion, Novartis, Takeda, Sanofi, and Octapharma and has received research grants from Shire and Alexion. The remaining authors have no conflicts of interest to declare., (Copyright © 2023 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

One hundred years ago, in 1924, the first description of a patient with a disease, now known as thrombotic thrombocytopenic purpura (TTP) was published by Dr. Eli Moschcowitz. In honor of this report, this article, written by distinguished specialists in TTP, reviews the increase in scientific knowledge on this disease during the last 100 years. It covers the scientific progress from plasma therapy, the first beneficial treatment for TTP, to the elucidation of the pathophysiology, the discovery of ADAMTS13, the development of assays and targeted therapies up to the modern treatment concepts, that improved the outcome of TTP from an incurable disease to a well understood and treatable disorder., Competing Interests: PK: Grants or contracts from any entity: Sanofi/Ablynx, Novo Nordisk, Takeda, Roche. Consulting fees: Sanofi/Ablynx, Novo Nordisk, Takeda, Roche. Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: Sanofi/Ablynx, Novo Nordisk, Takeda, Roche, Technoclone. Support for attending meetings and/or travel: Sanofi/Ablynx, Novo Nordisk, Takeda, Roche. Participation on a Data Safety Monitoring Board or Advisory Board: Sanofi/Ablynx, Novo Nordisk, Takeda.BL: Consulting fees: Hämatologie Praxis Bern, Monthly consultation and case discussions. Payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events: Lecture fee, Long-term burden of TTP, Virtual meeting Takeda 18.05.2021; Lecture fee, History of ADAMTS13 and TTP, Educational meeting Alexion, Liverpool, 20.09.2023. Participation on a Data Safety Monitoring Board or Advisory Board: Chairman of DMCs for studies of recombinant ADAMTS13 in hereditary and acquired TTP, run by Takeda; Chairman of DMC of Mayari study, treatment of acquired TTP using caplacizumab and immunosuppression without plasma exchange, run by Sanofi., (Thieme. All rights reserved.)

Background: ADAMTS-13 adopts an open conformation in patients with immune-mediated thrombotic thrombocytopenic purpura (iTTP) in acute phase while being closed in healthy donors. We reported that a substantial number of patients with iTTP in remission with restored ADAMTS-13 activity (>50%) still had an open ADAMTS-13 conformation, although a closed conformation is expected given the extent of remission., Objectives: To investigate whether open ADAMTS-13, represented by a conformation index >0.5, is associated with a risk of earlier ADAMTS-13 and/or clinical relapse., Methods: We collected follow-up data (ADAMTS-13 parameters, ADAMTS-13 and clinical relapse, and treatment) from 81 patients with iTTP in remission with ADAMTS-13 activity >50%., Results: During follow-up, 19 ADAMTS-13 and 10 clinical relapses were reported (median follow-up period, 20 months). First, open or closed ADAMTS-13 conformation was dichotomized based on the 0.5 conformation index cutoff. Open ADAMTS-13 (conformation index, >0.5) was not identified as a risk factor for ADAMTS-13 and clinical relapse (log-rank test and Cox regression model). In contrast, by identifying the optimal conformation index cutoff for relapse prediction, using classification and regression tree analysis, a conformation index >0.645 and >0.835 was shown to be a risk factor for ADAMTS-13 relapse (hazard ratio, 3.3; 95% CI, 1.3-8.3; P = .01) and clinical relapse (hazard ratio, 4.4; 95% CI, 1.3-15.3; P = .02), respectively., Conclusion: Patients with open ADAMTS-13 with a conformation index >0.645 and >0.835 have a >3- and >4-fold higher risk of earlier ADAMTS-13 and clinical relapse, respectively. Hence, ADAMTS-13 conformation index could be used to complement ADAMTS-13 activity monitoring to timely notice ADAMTS-13 relapse and prevent clinical relapse., Competing Interests: Declaration of competing interests K.V. is a member of the advisory board of Takeda. I.M. received honoraria for participating as a speaker at educational meetings organized by Instrumentation Laboratory and Sanofi. F.P. has received honoraria for participating as a speaker in education meetings organized by Grifols and Roche, and she is a member of the scientific advisory boards of BioMarin, Roche, Sanofi, Sobi, and Takeda. B.L. is chairman of the Data Monitoring Committees of studies of recombinant ADAMTS-13 in patients with congenital thrombotic thrombocytopenic purpura (TTP) and immune-mediated TTP by Takeda (Takeda 2811 02, TAK-755-3002, Takeda SHP 605-201). He is chairman of the Data Monitoring Committees of a study investigating therapy of immune-mediated TTP with caplacizumab and immunosuppression without plasma exchange by Sanofi. He received lecture fees and/or congress travel support from Ablynx, Alexion, Siemens, Bayer, Roche, Sanofi, and Takeda. P.C. is a member of the Clinical Advisory Board of and received speaker fees from Alexion, Sanofi, and Takeda. A.V. is a member of the Advisory board for caplacizumab Sanofi and rhADAMTS-13 Takeda. Other coauthors do not have any conflicts of interest to disclose., (Copyright © 2023 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)