Introduction/background: Development of neutralizing inhibitors against factor VIII (FVIII) is a major complication of haemophilia A treatment. Aim: The ongoing, international, open-label, uncontrolled, observational immune tolerance induction (ObsITI) study evaluates ITI, the standard of care in patients with inhibitors. Patients/methods: Forty-eight prospective patients in this interim analysis received a single plasmaderived, von Willebrand factor-stabilized, FVIII concentrate (pdFVIII/VWF) for ITI. According to recommended Bonn protocol, 'low responders' at ITI start (<5 BU) received 50-100 IU FVIII kg À1 daily, or every other day; 'high responders' (≥5 BU) received 100 IU FVIII kg À1 every 12 h. Results: Forty of 48 patients (83.3%), had at least one risk factor for poor ITI-prognosis at ITI start (i.e. age ≥7 years, >2 years since inhibitor diagnosis, inhibitor titre ≥10 BU at the start of ITI, or prior ITI failure). Nonetheless, 34 patients (70.8%) achieved complete success, 3 (6.3%) partial success, 1 (2.1%) partial response; ITI failed in 10 patients (20.8%), all with poor prognosis factors. All six low responders achieved complete success. ITI outcome was significantly associated with inhibitor titre level at ITI start (P = 0.0068), number of poor prognosis factors for ITI success (P = 0.0187), monthly bleeding rate during ITI (P = 0.0005) and peak inhibitor titre during ITI (P = 0.0007). Twenty-two of 35 high responder patients (62.9%) with ≥1 poor prognosis factor achieved complete success. Conclusion: Treatment with a single pdFVIII/VWF concentrate, mainly according to the Bonn protocol, resulted in a high ITI success rate in haemophilia A patients with inhibitors and poor prognosis for ITI success.

In vitro and in vivo experiments showed that anticoagulant activity of sulfated polysaccharide from Fucus evanescens (brown algae of the Okhotsk Sea) was similar to that of heparin. Anticoagulant properties of fucoidan are determined by thrombin inhibition mediated via plasma antithrombin III.

BackgroundHeparin therapy and prophylaxis may be accompanied by bleeding and thrombotic complications due to individual responses to treatment. Dosage control based on standard laboratory assays poorly reflects the effect of the therapy. The aim of our work was to compare the heparin sensitivity of new thrombodynamics (TD) assay with sensitivity of other standard and global coagulation tests available to date.Study population and methodsA total of 296 patients with high risk of venous thromboembolism (deep vein thrombosis (DVT), early postoperative period, hemoblastosis) were enrolled in the study. We used a case-crossover design to evaluate the sensitivity of new thrombodynamics assay (TD) to the hemostatic state before and after unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) therapy/prophylaxis and to compare it with the activated partial thromboplastin time (APTT), anti-Xa activity test, thrombin generation test (TGT) and thromboelastography (TEG). A receiver operating characteristic (ROC) curve analysis was used to evaluate changes before and after heparin prophylaxis and therapy. Blood was sampled before heparin injection, at the time of maximal blood heparin concentration and before the next injection.ResultsHypercoagulation before the start of heparin treatment was detected by TD, TGT and TEG but not by APTT. The area under the ROC curve (AUC) was maximal for TD and anti-Xa, intermediate for TGT and TEG and minimal for APTT.ConclusionsThese results indicate that TD has a high sensitivity to the effects of UFH and LMWH after both prophylactic and therapeutic regimes and may be used for heparin monitoring.

Research objective To research the association of prothrombin (factor II) activity given the prothrombin G20210A mutation carriage with its clinical manifestations as thrombotic complications. Materials and methods A prospective clinical cohort study of 290 women of reproductive age was conducted. Two cohort groups were identified: the study group of 140 patients with prothrombin mutation G20210A genotype and the control group of 150 women with G20210G genotype. Results The prothrombin G20210A mutation carriage is associated with the risk of thrombotic complications compared to the wild G20210G type (RR =17.1; p <0.0001) and is characterized by thrombosis localized both in the venous (66.7%) and arterial (33.3%) vascular pools. The threshold value of prothrombin activity (174.8%) for G20210A genotype was calculated, making it possible to conclusively predict the risk of thrombotic events with the accuracy of 90.4%. Conclusion The phenotypic manifestation of the prothrombin G20210A mutation in the form of venous and arterial thromboses in women of reproductive age is associated with a super-threshold increase in prothrombin (factor II) activity, which makes it possible to stratify the patients into the group of high risk of thromboses.