Recurrent stroke in an African female with idiopathic thrombotic thrombocytopenic purpura: A case report

We report on a young Ghanaian female who was diagnosed with thrombotic thrombocytopenic purpura (TTP) but had an ischemic stroke as the initial presentation. She was successfully treated with therapeutic plasma exchange. This case illustrates how TTP can masquerade as ischemic stroke and the application of PLASMIC score without ADAMTS-13 assay in risk prediction.

Diagnostic-therapeutic algorithm for thrombotic microangiopathy. A report of two cases

Thrombotic microangiopathies (TMA) are a group of clinical syndromes associated with haemolytic anaemia, thrombocytopenia and organ dysfunction, mainly renal or neurological. They are associated with significant morbidity and mortality, so early diagnosis and treatment are essential. In this article we report two cases of TMA; a patient with thrombotic thrombocytopenic purpura (TTP) and a patient with atypical haemolytic uraemic syndrome (aHUS).

Atypical Presentation of Thrombotic Thrombocytopenic Purpura without Hematological Features

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease, usually diagnosed with high index of suspicion. The pathophysiology of TTP is due to severe deficiency of von Willebrand factor cleaving protease, known as ADAMTS 13. Early diagnosis is crucial as without treatment TTP is associated with high mortality rate. Plasma exchange is currently the mainstay of treatment. Nonetheless, the classical pentad of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, neurological dysfunction, kidney dysfunction and fever are seen only in 40 percent of the patients. MAHA and thrombocytopenia are the common presenting features. Presentation with thrombotic complication without hematological features (MAHA and thrombocytopenia) is rare and makes the diagnosis difficult. Herein, we report an unusual presentation of a 53-year-old male, who was initially presented in 2014 with classical features of TTP, however had an atypical presentation of TTP in 2016 with only neurological features without hematological features.

Clinical Features and Gene Mutation Analysis of Congenital Thrombotic Thrombocytopenic Purpura in Neonates

Congenital thrombotic thrombocytopenic purpura (TTP) is a rare hereditary disease with a high mortality rate; however, improved patient survival is possible with prompt diagnosis and treatment. The clinical features and mutation sites of a disintegrin and metalloproteinase with thrombospondin motifs 13 (ADAMTS13) in congenital TTP were analyzed in a neonate with suspected congenital TTP. High-throughput sequencing, polymerase chain reaction, and Sanger sequencing were utilized for screening of genes related to thrombocytopenic diseases and ADAMTS13 gene mutation testing on blood samples from the neonate and the parents. Domestic and foreign literature reporting the clinical features and variants of ADAMTS13 in neonates with congenital TTP were retrieved, compared, and analyzed. The patient in this case was a girl who had been born for 1 h and admitted to the hospital due to "dyspnea for 1 h." Routine blood tests on admission revealed profound thrombocytopenia. She quickly developed symptoms of systemic hemorrhage and eventually died. The neonate had two older sisters who had died of idiopathic thrombocytopenia and hemorrhage within 24 h of birth. Genetic testing showed that the neonate harbored a compound heterozygous mutation in ADAMTS13, c.1187G>A/c.1595G>T, which is a novel variant. Of the 12 cases (1 case in China and 11 cases in other countries) of congenital TTP in neonates that have been reported globally, ADAMTS13 mutation analysis was only performed in eight neonates. Common clinical manifestations included dyspnea of unknown etiology, bruising, jaundice, hemorrhage, and thrombocytopenia. Hence, the current case contributes to our understanding of the clinical manifestations and types of variants in neonates with congenital TTP. Our results demonstrate the efficacy of high-throughput sequencing technology in genetic testing of neonates suspected with congenital TTP and have revealed a novel compound missense mutation in ADAMTS13 that has not been reported in China or elsewhere.

Recombinant ADAMTS 13 Attenuates Brain Injury After Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Inflammatory responses and blood-brain barrier (BBB) dysfunction play important roles in brain injury after intracerebral hemorrhage (ICH). The metalloprotease ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin type I motif, member 13) was shown to limit inflammatory responses through its proteolytic effects on von Willebrand factor. In the present study, we addressed the role of ADAMTS 13 after experimental ICH.

METHODS

ICH was induced in mice by intracerebral infusion of autologous blood. The peri-hematomal inflammatory responses, levels of matrix metalloproteinase-9 and intercellular adhesion molecule-1, pericyte coverage on brain capillaries, and BBB permeability were quantified at 24 hours. Functional outcomes, cerebral edema, and hemorrhagic lesion volume were quantified at day 3.

RESULTS

Treatment with recombinant ADAMTS 13 (rADAMTS 13) reduced the levels of chemokines and cytokines, myeloperoxidase activity, and microglia activation and neutrophil recruitment after ICH. rADAMTS 13 also decreased interleukin-6 expression in brain endothelial cells stimulated by lipopolysaccharide, whereas recombinant von Willebrand factor reversed this effect. The anti-inflammatory effect of rADAMTS 13 was accompanied by reduced expression of intercellular adhesion molecule-1 and less activation of matrix metalloproteinase, enhanced pericyte coverage of brain microvessels, and attenuated BBB disruption. Furthermore, neutrophil depletion protected against BBB damage, and rADAMTS 13 treatment had no further beneficial effect. Finally, treatment of mice with rADAMTS 13 reduced cerebral edema and hemorrhagic lesion volume and improved neurological functions.

CONCLUSIONS

Our findings reveal the importance of rADAMTS 13 in regulating pathological inflammation and BBB function and suggest that rADAMTS 13 may provide a new therapeutic strategy for ICH.

Idiopathic Non-Cirrhotic Intrahepatic Portal Hypertension (NCIPH)-Newer Insights into Pathogenesis and Emerging Newer Treatment Options

Chronic microangiopathy of portal venules results in idiopathic non-cirrhotic intrahepatic portal hypertension (NCIPH). Recent data suggest a role for vasoactive factors of portal venous origin in the pathogenesis of this 'pure' vasculopathy of the liver. Enteropathies (often silent), are an important 'driver' of this disease. NCIPH is under-recognized and often mis-labeled as cryptogenic cirrhosis. Liver biopsy is needed to prove the diagnosis of NCIPH. In these patients, with advancing disease and increased porto-systemic shunting, the portal venous vasoactive factors bypass the liver filter and contribute to the development of pulmonary vascular endothelial disorders-porto-pulmonary hypertension and hepato-pulmonary syndrome as well as mesangiocapillary glomerulonephritis. Prognosis in NCIPH patients is determined by presence, recognition and management of associated disorders. With better understanding of the pathogenesis of NCIPH, newer treatment options are being explored. Imbalance in ADAMTS 13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13): vWF (von-Willebrand factor) ratio is documented in NCIPH patients and may have a pathogenic role. Therapeutic interventions to correct this imbalance may prove to be important in the management of NCIPH.

High shear dependent von Willebrand factor self-assembly fostered by platelet interaction and controlled by ADAMTS13

INTRODUCTION

The paradigm of activation induced platelet aggregation has recently been refuted under blood flow conditions with shear rates exceeding 20,000s(-1). These lead to reversible rolling platelet aggregates, which were dependent on the presence of immobilized and soluble von Willebrand factor.

MATERIAL AND METHODS

In vitro experiments using direct fluorescence video-microscopy were performed in wall parallel and stagnation point flow chambers with shear rates raised from 20,000 to 50,000s(-1). Washed blood cell suspension containing recombinant von Willebrand factor (rVWF) was perfused over rVWF or collagen coated surfaces.

RESULTS

Here we show for the first time with the visualization of rVWF that not only colloid and polymer, i.e. platelets and VWF, form a composite, but that VWF itself is capable of entirely reversible self-assembly. On a collagen surface the platelet-VWF-conglomerates did not roll but VWF nets bound permanently to the collagen fibers and captured and immobilized platelets from the flow. Lowering the shear rate below the threshold of 20,000s(-1) no longer dissolved these deposits. Ultralarge multimer containing rVWF was most effective compared to normal sized rVWF. The presence of ADAMTS13 limited rolling aggregate and platelet-VWF-conglomerate formation to a time window of 7-8minutes. Changing wall parallel flow to stagnation point flow halved the required shear rate threshold.

CONCLUSION

We conclude that flow dynamics can trigger reversible von Willebrand factor self-assembly and platelet-VWF-conglomerate accrual, which are regulated by ADAMTS13 to a time span needed by coagulation to stabilize it, e.g. in case of vessel injury.

Evaluation of complement regulatory components in patients with atypical hemolytic uremic syndrome

BACKGROUND

Atypical hemolytic uremic syndrome (aHUS), a rare disorder characterized by thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure, is associated with mutations and polymorphisms in various components and regulators of the complement alternative pathway (AP), including factor H, factor I, membrane cofactor protein (MCP or CD46) and factor B. This impaired regulation of the alternative pathway leads to a procoagulant state with microthrombi formation in the renal vasculature, which influences disease onset and progression.

AIM OF THE STUDY

To evaluate the role of complement regulatory factors in occurrence of aHUS; we also included evaluation of ADAMTS13 activity and autoantibody against ADAMTS13 in order to exclude thrombotic thrombocytopenic purpura (TTP) cases, which might have overlapping clinical and laboratory findings.

MATERIAL AND METHODS

This study was conducted on 273 individuals with aHUS. Diagnosis was based on clinical manifestations, kidney function tests, red blood cell count, morphology and reticulocyte count. Then, the ADAMTS 13 autoantibody and activity and also complement factor B, complement factor H (CFH) and complement factor-I (CIF) were analyzed. Finally, the statistical analysis was performed by SPSS software.

RESULTS

The mean age of our patients was 27.3 years, 55% were female and 45% were male. The mean levels of urea and creatinine concentration were 92.9 mg/dl and 5.1 mg/dl, respectively. The mean levels of RBC count, Hb and HCT in these patients were lower than normal but the mean percentage of reticulocyte count was higher than normal (2.5%). The assessment of complement regulatory factors revealed that the B and H factors levels were normal except in two cases but the level of factor I was higher than normal.

CONCLUSIONS

According to the results of this study, it seems that up regulation of factor I had a significant role in occurrence of aHUS in our study group.

Analysis of clinical and laboratory characteristics in 42 patients with thrombotic thrombocytopenic purpura from a single center in China

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease characterized by microvascular platelet deposition and thrombus formation with resulting microangiopathic hemolytic anemia. Deficiency of the von Willebrand factor cleavage protease, also known as ADAMTS 13, has been implicated as an important etiological factor in TTP. Little studies were obtained on Chinese patients with TTP until now. Our aim was to analyze the clinical features, outcome and laboratory characteristics of Chinese TTP patients, and determine whether plasma ADAMTS 13 activity is decreased in TTP and its diagnostic value for TTP. Forty-two TTP patients (29 females; 13 males) admitted to our hospital from 1998 to 2010 were analyzed. There were 34 patients (81%) with the triad of TTP, including hemolytic anemia, thrombocytopenia and neurologic abnormalities; 7 (16.7%) had the classical pentad of TTP. Major etiologic factors were acquired autoimmunological abnormalities (31%); no familial TTP was identified in this series. The schistocytes of peripheral blood smears were present in all cases with a mean frequency of 4.6% (range from 0.3% to 13.4%). Plasma ADAMTS 13 activity was determined in 22 patients with the FRET-vWF86 assay. Only 4 idiopathic TTP patients (18.2%) had severe ADAMTS 13 deficiency (activity<10%); 9 (40.9%) had moderate decrease of ADAMTS 13 activity (activity: 10-40%); another 9 (40.91%) had normal ADAMTS 13 activity (>40%). T lymphocyte subpopulation was measured in 23 TTP patients with FACS Calibur; 14 of the 23 (60.9%) had significantly decreased CD4 cells count and CD4/CD8 ratio, suggesting cellular immune dysfunction may be involved in the pathogenesis of TTP. In the studies, plasmapheresis is the main therapeutic method. 26 of 31 patients (83.9%) accepting plasmapheresis achieved complete remission; those patients who only underwent plasma infusion had low remission rate (18.2%) and high mortality (9/11; 81.8%). Four patients with packed RBC infusion manifested transient exacerbation of neurologic or psychiatric symptoms. In conclusion, the diagnosis of TTP in China is still based on clinical features including evidence of microangiopathic hemolysis. Severe ADAMTS 13 activity deficiency might be a valuable indicator for idiopathic TTP diagnosis. Further studies are needed to determine the real value of ADAMTS 13 activity for TTP diagnosis and whether T lymphocytes subset dysregulation plays important role in TTP pathogenesis.