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Introduction Inherited antithrombin (AT) deficiency is a heterogeneous disease. Due to low prevalence, only a few studies are available concerning genotype-phenotype associations. The aim was to describe the clinical, laboratory and genetic characteristics of AT deficiency in a large cohort including children and to add further laboratory data on the different sensitivity of functional AT assays. Patients and methods Non-related AT deficient patients (n = 156) and their family members (total n = 246) were recruited. Clinical and laboratory data were collected, the mutation spectrum of SERPINC1 was described. Three different AT functional assays were explored. Results Thirty-one SERPINC1 mutations including 11 novel ones and high mutation detection rate (98%) were detected. Heparin binding site deficiency (type IIHBS) was the most frequent (75.6%) including AT Budapest3 (ATBp3), AT Padua I and AT Basel (86%, 9% and 4% of type IIHBS, respectively). Clinical and laboratory phenotypes of IIHBS were heterogeneous and dependent on the specific mutation. Arterial thrombosis and pregnancy complications were the most frequent in AT Basel and AT Padua I, respectively. Median age at the time of thrombosis was the lowest in ATBp3 homozygotes. The functional assay with high heparin concentration and pH 7.4 as assay conditions had low (44%) sensitivity for ATBp3 and it was insensitive for AT Basel and Padua I. Conclusion Type IIHBS deficiencies behave differently in clinical and laboratory phenotypes from each other and from other AT deficiencies. Heparin concentration and pH seem to be the key factors influencing the sensitivity of AT functional assays to IIHBS.

In acquired haemophilia A (AHA), risk for recurrent bleeding exists until the inhibitor is detectable. Thus, patients with persisting inhibitor may benefit from prophylaxis with activated prothrombin complex concentrate (aPCC). Potential thromboembolic complications and cost are also factors to consider. Today, no high level evidence or clear recommendations are available on aPCC prophylaxis in AHA. Recently, a small prospective study demonstrated a favourable outcome with short-term, daily administered aPCC infusion. Here we report a retrospective case series of 19 patients with AHA to demonstrate our practice on aPCC prophylaxis. In our practice, clinical bleeding tendency guided our decision on the initiation of aPCC prophylaxis. In patients with serious bleeding tendency, aPCC infusion was prolonged beyond bleeding resolution in a twice-weekly or thrice-weekly regimen. Serious bleeding phenotype included a single episode of life-threatening bleeding or recurrent, severe haemorrhages. Patients who did not present such events were treated on-demand. The preventive dose of aPCC was equal with the lowest effective therapeutic dose. Prophylaxis was continued until the inhibitor disappeared. Eleven patients received aPCC prophylaxis. In nine cases, prophylaxis lasted beyond two months. No severe bleeding developed spontaneously and no thromboembolic complication occurred in the median 16 weeks (interquartile range 9-34) duration of prophylaxis. Eight patients of the nonprophylaxis group did not present any severe haemorrhage. According to our experience, we consider prophylaxis with aPCC effective and well tolerated for patients with AHA and serious bleeding tendency, until the acquired inhibitor persists.

Introduction Hereditary antithrombin (AT) deficiency is a rare thrombophilic disorder with heterogeneous genetic background and various clinical presentations. In this study we identified a novel AT mutation. Genotype-phenotype correlations, molecular characteristics and thrombotic manifestations of the mutation were investigated. Materials and methods Thirty-one members of a single family were included. Clinical data was collected regarding thrombotic history. The mutation was identified by direct sequencing of the SERPINC1 gene. HEK293 cells were transfected with wild type and mutant SERPINC1 plasmids. Western blotting, ELISA and functional amidolytic assay were used to detect wild type and mutant AT. After double immunostaining, confocal laser scanning microscopy was used to localize mutant AT in the cells. Molecular modeling was carried out to study the structural-functional consequences of the mutation. Results Unprovoked venous thrombotic events at early age, fatal first episodes and recurrences were observed in the affected individuals. The median AT activity was 59%. Genetic analysis revealed heterozygous form of the novel mutation p.Leu205Pro (AT Debrecen). The mutant AT was expressed and synthesized in HEK293 cells but only a small amount was secreted. The majority was trapped intracellularly in the trans‑Golgi and 26S proteasome. The mutation is suspected to cause considerable structural distortion of the protein. The low specific activity of the mutant AT suggested functional abnormality. Conclusions AT Debrecen was associated with very severe thrombotic tendency. The mutation led to misfolded AT, impaired secretion and altered function. Detailed clinical and molecular characterization of a pathogenic mutation might provide valuable information for individualized management.

Summary. Background: Ultra-large von Willebrand factor and deficiency of its cleaving protease are important factors in the events leading to thrombotic microangiopathy; however, the mechanisms involved are only partly understood. Whereas pathological activation of the alternative complement pathway is linked to atypical hemolytic uremic syndrome, the role of complement activation in thrombotic thrombocytopenic purpura (TTP) is unknown. The aim of this study was to investigate whether signs of complement activation are characteristic of TTP. Patients and methods: Twenty-three patients with TTP (18 women, median age 38 years) and 17 healthy controls (13 women, median age 38 years) were included. Complement parameters (C3, Factors H, I, B and total alternative pathway activity) together with complement activation fragments (C3a) or complexes (C1rs-INH, C3bBbP, sC5b9) were measured by ELISA or RID. ADAMTS13 activity and anti-ADAMTS13 inhibitory antibodies were measured by the VWF-FRET73 assay. Results: Increased levels of C3a, and SC5b9 were observed in TTP during acute episodes, as compared with healthy controls. Decreased complement C3 levels indicative of complement consumption occurred in 15% of acute TTP patients. Significant decrease of complement activation products C3a and SC5b9 was observed during plasma exchange (PEX). The sustained presence of anti-ADAMTS13 inhibitory antibodies in complete remission was associated with increased complement activation. Conclusion: These data document in an observational study the presence of complement activation in TTP. Further investigation is needed to determine its potential pathogenetic significance.

No effective blood-flow enhancement therapies are available for patients with severe peripheral arterial disease (SPAD), thus amputation remains the only option for relief of rest pain or gangrene. Autologous bone marrow—derived stem cell therapy (ABMSCT) is an emerging modality to induce angiogenesis from endothelial progenitors. A total of 5 patients with SPAD were treated by ABMSCT using isolated CD34+ cells with characterized phenotype administered by intramuscular injections. The follow-up before and 1, 3, 6, 9, and 12 months after ABMSCT was based on clinical (rest pain, walking distance without pain, nonhealing ulcers, ankle-brachial index [ABI]) and laboratory (angiography, duplex and laser ultrasonography, TcPO2) parameters. Significant improvement of pain and walking distance was observed in all patients. Nonhealing ulcers disappeared in 3 patients and became smaller and thinner in 1 patient. The average of ABI improved significantly on the treated limb but did not change on the contralateral limb. New collaterals were detected by angiography in 3 patients, but duplex ultrasonography detected improvement in one patient only. Laser ultrasonography showed a mild significant change, TcPO2 values improved mainly on the foot. Severe adverse events were not observed. We conclude that ABMSCT with isolated CD34+ cells is safe, effective, and results in sustained clinical benefit for patients with SPAD.

Acquired hemophilia is a rare and life-threatening disease that in some cases develops as a paraneoplastic syndrome of different malignancies. Acquired hemophilia caused by ureteral tumor has not been reported previously. The treatment of acquired hemophilia has 2 main goals: to achieve hemostasis during the bleeding period and to decrease the risk of bleeding by eradication of the inhibitor. We report a case of hematuria caused by ureteral tumor. Nephroureterectomy was performed, but continuous bleeding was observed after the operation. We thus administered blood transfusions and performed reoperations, but we could not stop the bleeding. Later, we realized that the prolonged activated partial thromboplastin time was caused by the low activity of factor VIII (2%), which indicated the presence of acquired hemophilia. We thus administered activated prothrombin complex concentrate and recombinant activated factor VII. Three months after the initial operation, an immune tolerance induction treatment was administered, after which the activity of factor VIII reverted to normal.

Heparin-induced thrombocytopenia (HIT) is one of the most common immune-mediated drug reactions. Immunoglobulin G-type antibodies against platelet factor 4(PF4)/heparin complexes are known to play a key role in the pathogenesis of HIT. Rapid-onset HIT is caused by the presence of circulating HIT antibodies at the time of heparin readministration. These antibodies are generally resulted from a recent immunizing exposure to heparin. Here we report a case of rapid-onset HIT developed after a septicemia without previous heparin exposure. The diagnosis of HIT as well as the presence of platelet activating and heparin-dependent antibodies was confirmed by ELISA and flow cytometric functional assays. Our case report reinforces that rapid-onset HIT cannot be excluded only based on the absence of previous heparin exposure. In addition, it may support the new theory of pre-immunization by PF4-coated bacteria in the pathomechanism of HIT. We also call the attention that venous limb gangrene can be rarely associated with HIT and thrombosis even in the absence of coumarin therapy. Furthermore, transient presence of anti-phospholipid antibodies can cause a differential diagnostic problem in the cases of HIT.

Temporarily successful eradication therapy in acquired haemophilia with high inhibitor titer: A case report with a new protocol