No abstract

Factor VIII inhibitor bypass activity (FEIBA) is a recommended first-line bypassing agent for bleeding episodes in patients with acquired haemophilia A (AHA). Due to the low incidence of AHA, available clinical data on FEIBA treatment are limited. The study aim was to delineate practice patterns in FEIBA treatment of AHA patients, the haemostatic efficacy of FEIBA, including criteria for its assessment, and safety. A prospective registry was established of AHA patients receiving FEIBA for bleeding episodes or prophylaxis at the time of invasive procedures. Data were collected at 16 participating centres in France. Patients were followed up for 3 months. Haemostatic efficacy, FEIBA regimen and FEIBA-related adverse events were documented. Thirty-four patients averaging 81.8 years old with standard deviation (SD) 8.1 years were included in the study: 33 for acute bleeding and one for haematoma evacuation. The mean initial dose of FEIBA for acute bleeding was 75.4 U kg(-1) (SD, 7.7 U kg(-1) ), most often administered twice daily, and the median duration of FEIBA treatment was 4.0 days (interquartile range, 2.2-8.0 days). FEIBA was effective in managing 88.0% of bleeding episodes (95% confidence interval, 75.8-94.5%). No baseline variables influencing treatment response could be identified. The sensitivity and specificity of an objective haemostatic efficacy scale in predicting sequential investigator assessments of haemostatic efficacy were 45.3% and 84.1% respectively. Four patients experienced a total of six serious adverse events possibly related to FEIBA. In the first prospective study specifically focused on FEIBA treatment of patients with AHA, 88.0% of bleeding episodes were effectively managed.

SummaryQuantification of lupus anticoagulant (LA) in clinical samples is hampered by the lack of a suitable standard of activity. We evaluated the use of mAbs displaying LA activity for this purpose. As most patient samples contain both β2Glycoprotein I (β2GP1) and prothrombin dependent LA, a combination of two mAbs, one of each specificity, was added to normal plasma in a concentration from 0 to 60 g/ml. Eight assay systems using different reagents and instruments were used. The calibration curves were linear for all but one, with marked differences between the responsiveness to each mAb. A panel of plasmas from 69 patients with persistent LA diagnosed using the SSCISTH criteria was tested. An antiphospholipid syndrome (APS) was present in 40, whereas 29 were asymptomatic. LA activities of individual plasmas varied between assays (p <10–4), but homogeneous subgroups were identified. In a majority of samples, LA activity displayed a prothrombin-dependent profile, with a variable contribution of β2GP1-dependent activity. The latter was associated to β2GP1 antibodies detected by solid-phase immunoassay. By using 3 dilute Russell viper venom time assays, higher LA titers were found in APS, compared to asymptomatic patients (p <0.05).

A total of 139 young stroke patients were consecutively examined and tested for antiphospholipid antibodies (APLA) to evaluate the role of these antibodies in cerebral ischaemia before the age of 45. APLA were found in 28.8% of patients. Two factors, hypertriglyceridaemia and alcohol abuse, were significantly more frequent in patients with a positive APLA test. The demographic characteristics, other risk factors, history of prior thrombotic events and distribution of aetiopathogenic types of cerebral ischaemia were not different in patients with or without APLA. Laboratory assays for APLA were highly positive for only two patients, who both had autoimmune diseases. These results suggest that with the exception of a clinical context of antiphospholipid syndrome or other autoimmune diseases, the usefulness of this diagnostic tool in the management of cerebral ischaemia remains limited.