The use of 1E12, a monoclonal anti-platelet factor 4 antibody, to improve the diagnosis of vaccine-induced immune thrombotic thrombocytopenia.

BACKGROUND: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a complication of adenoviral-based vaccine against SARS-CoV-2 due to prothrombotic immunoglobulin (Ig) G antibodies to platelet factor 4 (PF4) and may be difficult to distinguish from heparin-induced thrombocytopenia (HIT) in patients treated with heparin. OBJECTIVES: We assessed the usefulness of competitive anti-PF4 enzyme immunoassays (EIAs) in this context. METHODS: The ability of F(ab')2 fragments of 1E12, 1C12, and 2E1, 3 monoclonal anti-PF4 antibodies, to inhibit the binding of human VITT or HIT antibodies to PF4 was evaluated using EIAs. Alanine-scanning mutagenesis was performed to define the amino acids involved in the interactions between the monoclonal antibodies and PF4. RESULTS: A strong inhibition of VITT IgG binding to PF4 was measured with 1E12 (median inhibition, 93%; n = 8), whereas it had no effect on the binding of HIT antibodies (median, 6%; n = 8). In contrast, 1C12 and 2E1 inhibited VITT (median, 74% and 76%, respectively) and HIT antibodies (median, 68% and 53%, respectively) binding to PF4. When a competitive anti-PF4 EIA was performed with 1E12 for 19 additional VITT samples, it strongly inhibited IgG binding to PF4, except for 1 patient, who had actually developed HIT according to the clinical history. Epitope mapping showed that 1E12 interacts with 5 key amino acids on PF4, of which 4 are also required for the binding of human VITT antibodies, thus explaining the competitive inhibition. CONCLUSION: A simple competitive anti-PF4 EIA with 1E12 could help confirm VITT diagnosis and distinguish it from HIT in patients when both diagnoses are possible.

Key Drivers of Coagulation Factor Use in Von Willebrand Disease During Hospitalization: An Overview of the French BERHLINGO Cohort.

BACKGROUND: Von Willebrand disease (VWD) is the most common inherited bleeding disorder. However, studies of hospitalisation patterns with replacement treatment are scarce. OBJECTIVES: The aim of this study was to investigate the current therapeutic management of VWD and determine the key drivers of coagulation factor uses in patients during hospitalisation. METHODS: Hopscotch-WILL was a multi-centric retrospective study conducted over a 48-month period in any patients with VWD. The data were collected from the BERHLINGO Research Database and the French Hospital database. RESULTS: A total of 988 patients were included; 153 patients (15%) were hospitalised during 293 stays requiring treatment with von Willebrand factor (VWF) concentrates-pure or in association with Factor VIII (FVIII). Their median basal concentrations of VWF and FVIII were significantly lower than in untreated patients: VWF antigen < 30 IU/dL, VWF activity < 20 IU/dL and FVIII:C < 40 IU/dL. The median (interquartile range) concentrate consumption was similar between highly purified VWF or VWF combined with FVIII (72 [110] vs 57 [89] IU/kg/stay, p = 0.154). The use of VWF was highly heterogeneous by VWD type; type 3 had a particularly high impact on VWF consumption in non-surgical situations. The main admissions were for ear/nose/throat, hepato-gastroenterology, and trauma/orthopaedic conditions, besides gynaecological-obstetric causes in women. CONCLUSIONS: The use of VWF concentrates is mostly influenced by low basal levels of VWF and FVIII, but also by VWD type or the cause for hospitalisation. These results could inform future studies of newly released recombinant VWF.

Efficacy and safety of turoctocog alfa in patients with hemophilia A requiring surgical procedures: A multicentre retrospective study.

BACKGROUND: Turoctocog alfa is a recombinant Factor VIII used in patients with hemophilia A. The aim is to assess the real-life evidence of turoctocog alfa in surgery. STUDY DESIGN AND METHODS: Data were extracted from a national database. RESULTS: Turoctocog alfa was used for 86 surgeries (49 major and 37 minor) in 56 patients. The results are expressed as medians (interquartile range). Six (10.7%) patients had severe hemophilia A, four (7.1%) moderate, and 46 (82.2%) mild. For patients who underwent major surgeries, basal plasma FVIII coagulant activity (FVIII:C) levels were 15 IU.dL-1 (8-22). Eight (5-14) infusions were given, at a preoperative loading dose of 40.0 (35.0-45.5) IU.kg-1 and a total dose of 253.3 (125.0-507.0) IU.kg-1 . In patients who underwent minor surgeries, basal FVIII:C levels were 18 IU.dL-1 (9-31). Two (1-3) infusions were required, at a preoperative loading dose of 34.0 (28.8-38.5) IU.kg-1 and a total dose of 73.7 (37.6-122.1) IU.kg-1 . The overall clinical efficacy was judged excellent/good in 77 procedures (89.5%) and fair/poor in nine (10.5%). The fair/poor efficacy concerned seven patients (six mild hemophilia and one severe), for four urological surgeries, two dermatological procedures, one heart surgery, one ear-nose-throat procedure, and one dental avulsion in the patient with severe hemophilia. Three out of those seven patients received antiplatelet therapy. No thromboembolic events, anti-FVIII antibodies, or adverse events were reported. DISCUSSION: The efficacy and safety of turoctocog alfa were confirmed for the management of surgery in patients with hemophilia A. No adverse events were observed and overall efficacy was good.

Prothrombin consumption as an indicator of hemorrhagic phenotype in mild platelet function disorders.

BACKGROUND: The bleeding risk of patients with mild platelet function disorders is difficult to assess and their phenotype remains ill-explored. AIM: This study was designed to establish a comprehensive biological phenotype of patients with mild platelet function disorders. METHODS: Twenty patients were included with persistent abnormal light transmission aggregometry (LTA). The ISTH bleeding assessment tool (ISTH-BAT) was assessed to identify laboratory analyses associated with an abnormal hemorrhagic score. RESULTS: The majority of patients had defects that might affect Gαi protein signaling pathways or minor abnormalities. No LTA nor flow cytometry parameters were associated with an above-normal hemorrhagic score. However, prothrombin consumption, which corresponds to the ratio of serum residual factor II to plasma residual factor II, was significantly higher (p = .006) in the abnormal ISTH-BAT group (mean = 14%, SD = 6) compared with the normal ISTH-BAT group (mean = 8%, SD 4). Prothrombin consumption was significantly associated with ISTH-BAT score (r = .5287, IC 95% 0.0986-0.7924, p = .0165). CONCLUSION: In this group of patients, there was an association between a pathological bleeding score and increased prothrombin consumption. This test could be used as an additional indicator of platelet function abnormality liable to be related to bleeding risk.

Obstetrical complications in hereditary fibrinogen disorders: the Fibrinogest study.

BACKGROUND: Women with hereditary fibrinogen disorders (HFDs) seem to be at an increased risk of adverse obstetrical outcomes, but epidemiologic data are limited. OBJECTIVES: We aimed to determine the prevalence of pregnancy complications; the modalities and management of delivery; and the postpartum events in women with hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia. METHODS: We conducted a retrospective and prospective multicentric international study. RESULTS: A total of 425 pregnancies were investigated from 159 women (49, 95, and 15 cases of hypofibrinogenemia, dysfibrinogenemia, and hypodysfibrinogenemia, respectively). Overall, only 55 (12.9%) pregnancies resulted in an early miscarriage, 3 (0.7%) resulted in a late miscarriage, and 4 (0.9%) resulted in an intrauterine fetal death. The prevalence of live birth was similar among the types of HFDs (P = .31). Obstetrical complications were observed in 54 (17.3%) live birth pregnancies, including vaginal bleeding (14, 4.4%), retroplacental hematoma (13, 4.1%), and thrombosis (4, 1.3%). Most deliveries were spontaneous (218, 74.1%) with a vaginal noninstrumental delivery (195, 63.3%). A neuraxial anesthesia was performed in 116 (40.4%) pregnancies, whereas general or no anesthesia was performed in 71 (16.6%) and 129 (44.9%) pregnancies, respectively. A fibrinogen infusion was administered in 28 (8.9%) deliveries. Postpartum hemorrhages were observed in 62 (19.9%) pregnancies. Postpartum venous thrombotic events occurred in 5 (1.6%) pregnancies. Women with hypofibrinogenemia were at an increased risk of bleeding during the pregnancy (P = .04). CONCLUSION: Compared with European epidemiologic data, we did not observe a greater frequency of miscarriage, while retroplacental hematoma, postpartum hemorrhage, and thrombosis were more frequent. Delivery was often performed without locoregional anesthesia. Our findings highlight the urgent need for guidance on the management of pregnancy in HFDs.

Management of rare inherited bleeding disorders: Proposals of the French Reference Centre on Haemophilia and Rare Coagulation Disorders.

INTRODUCTION: The rare coagulation disorders may present significant difficulties in diagnosis and management. In addition, considerable inter-individual variation in bleeding phenotype is observed amongst affected individuals, making the bleeding risk difficult to assess in affected individuals. The last international recommendations on rare inherited bleeding disorders (RIBDs) were published by the United Kingdom Haemophilia Centre Doctors' Organisation in 2014. Since then, new drugs have been marketed, news studies on surgery management in patients with RIBD have been published, and new orphan diseases have been described. AIM: Therefore, the two main objectives of this review, based on the recent recommendations published by the French Reference Centre on Haemophilia and Rare Bleeding Disorders, are: (i) to briefly describe RIBD (clinical presentation and diagnostic work-up) to help physicians in patient screening for the early detection of such disorders; and (ii) to focus on the current management of acute haemorrhages and long term prophylaxis, surgical interventions, and pregnancy/delivery in patients with RIBD.

Biological, clinical features and modelling of heterozygous variants of glycoprotein Ib platelet subunit alpha (GP1BA) and glycoprotein Ib platelet subunit beta (GP1BB) genes responsible for constitutional thrombocytopenia.

Constitutional thrombocytopenias are rare disorders, often difficult to discriminate from acquired thrombocytopenias. More than 80 genes have been described as being at the origin of these diseases. Among them, several variants of the glycoprotein Ib platelet subunit alpha (GP1BA) and glycoprotein Ib platelet subunit beta (GP1BB) genes, coding for the GpIb-IX-V glycoprotein complex, have been reported in the literature. The study reported here aimed at describing newly identified monoallelic anomalies affecting the GP1BA and GP1BB genes on a clinical, biological and molecular level. In a cohort of nine patients with macrothrombocytopenia, eight heterozygous variants of the GP1BA or GP1BB genes were identified. Five of them had never been described in the heterozygous state. Computer modelling disclosed structure/function relationships of these five variants.

Platelet features allow to differentiate immune thrombocytopenia from inherited thrombocytopenia.

Immune thrombocytopenia (ITP) is an acquired bleeding disorder, for which no specific diagnostic test exists. Inherited thrombocytopenia (IT) can mimic ITP and lead to unappropriated management with significant morbidity. Here, in small cohorts of these two disorders, we explored whether platelet sialylation and platelet activation could allow to discriminate the two conditions. We also aimed to confirm the value of immature platelet counts in this discrimination. Platelet sialylation and the expression level of P-selectin were assessed by multiparameter flow cytometry. Immature platelets were estimated on a Sysmex XN 9000 analyzer. No significant difference in platelet sialylation was observed between ITP and IT. Contrarily, platelet activation was significantly higher in ITP patients (p = 0.008). The immature platelet fraction, as previously demonstrated, was significantly lower in the ITP group compared to the IT group (p = 0.014). That statistical significance was achieved in this small pilot study suggests that the two easily available assays of immature platelet count and P-selectin expression could help physicians to reach the proper diagnosis in complex cases of thrombocytopenia.

Prostate interventions in patients with mild haemophilia: Safe and feasible.

INTRODUCTION: To date, there is no specific recommendation or evaluation of the morbidity of prostate surgery in patients with haemophilia (PWH) although this surgery is common and at high risk of bleeding. AIM: To assess the post-operative morbidity of benign prostate hyperplasia (BPH) surgeries and of oncological prostate interventions in patients with mild haemophilia A or B. METHODS: We performed a monocentre, epidemiological, in real life study. Data were collected between 1 January, 1997 and 1 September, 2020 and focused on prostate biopsy, radical prostatectomy, prostate radiotherapy, simple prostatectomy, transurethral resection of prostate (TURP) and laser-vaporisation in patients with mild haemophilia A or B. RESULTS: Between 1 January, 1997 and 1 September, 2020, 51 interventions were performed on 30 patients with mild haemophilia. Haemophilia A represented 93.33% of the population and haemophilia B 6.67%. For prostate biopsies (n = 24), median length of hospitalisation was 4 days and only one patient needed a blood transfusion. No patient needed re-admission. For prostatectomy (n = 10), one patient presented with intra-operative and post-operative bleeding. Two patients required re-admission. The other patients did not present any significant haemorrhagic symptoms. For radiotherapy (n = 4), two patients presented a grade II complication (radiocystitis and radiorectitis). For BPH surgeries, during hospitalisation, laser-vaporisation (n = 5) was less haemorrhagic than TURP (n = 5) but after hospital discharge, 60% of patients presented a haemorrhagic complication with two readmissions and one surgical re-explorations. CONCLUSION: Performed in a specialised centre, prostate surgeries and interventions in patients with mild haemophilia is feasible with acceptable morbidity.

Efficacy and safety of a recombinant Von Willebrand Factor treatment in patients with inherited Von Willebrand Disease requiring surgical procedures.

INTRODUCTION: Von Willebrand Disease is a common inherited haemorrhagic disorder due to a deficiency of Von Willebrand Factor (VWF). In case of surgical procedures in patients who are not responsive or have contraindications to desmopressin, replacement therapy with VWF concentrates is indicated. Until recently, only plasma-derived VWF concentrates were available. A new recombinant VWF (rVWF) concentrate that contains no Factor VIII (FVIII) but a high amount of high molecular weight VWF multimers has been available in France since 2018. AIM: Describe real-world experience of using rVWF in surgical procedures. METHODS: Sixty-three surgeries for 55 patients were retrospectively analysed in 7 French haemostasis centres. RESULTS: During minor surgeries, the median (range) number of infusions was 1 (1-8) with a preoperative loading dose of 35 (19-56) rVWF IU/kg and a total median dose of 37.5 IU (12-288). During major surgeries, the median (range) number of infusions was only 3 (1-14) with a median preoperative loading dose of 36 IU (12-51) rVWF IU/kg, and a total median dose of 108 IU (22-340) rVWF IU/kg. The overall clinical efficacy was qualified as excellent/good in 61 of the procedures (97%), moderate in 1 (1.5%) and poor in 1 (1.5%). There was no accumulation of VWF or FVIII during postoperative monitoring. No thromboembolic events, anti-VWF antibodies or adverse events were reported. CONCLUSION: This French 'real-world' experience shows that a few infusions and low doses of rVWF provided effective prevention of bleeding in major and minor surgeries in inherited VWD, with no clinically significant safety concerns.

An UPLC-MSMS method to measure plasma homocysteine concentration.

Homocysteine (Hcy) is monitored in a growing number of diseases and requires a rapid and reliable method to measure its concentration in routine practice. We validated a new mass spectrometry method to measure plasma Hcy concentration and to determinate our own targeted concentrations according to COFRAC (French accreditation committee) recommendations. We collected the Hcy concentrations measured in the laboratory from 2014 to 2015 and we compared the values between different clinical groups. We obtained excellent performances of reproducibility, sensitivity (coefficient of variation <10%). We determined new ranges of normal values 12.4 [11.8-13.0] µmol/L. This new method is thus rapid, robust and suitable for its use in routine practice to respond to the increase of prescriptions.

Use of calcofluor-blue brightener for the diagnosis of Pneumocystis jirovecii pneumonia in bronchial-alveolar lavage fluids: A single-center prospective study.

The biological diagnosis of Pneumocystis jirovecii pneumonia (PjP) is based on the investigation of respiratory fluids by conventional staining methods and/or molecular biology. Diagnostic performance of an in-house technique based on calcofluor-blue brightener for the direct detection of P. jirovecii cysts was prospectively assessed in bronchial-alveolar lavage fluids (BALF) from patients with a suspected PjP infection over a three-year period in a single center: the diagnostic yield was compared to that of a commercial kit based on monoclonal immunofluorescence assay (IFA) on replicate smears. May-Grünwald Giemsa (MGG) staining and quantitative Polymerase Chain Reaction (qPCR) were also performed. The gold standard for each patient was the definitive diagnosis of PjP infection by an independent committee based on clinical, radiological, and biological data. Overall, 481 BALF were assessed: 42 were found to be positive for the detection of P. jirovecii by at least one laboratory technique, but only 35 were actually judged to be in agreement with the definitive diagnosis of PjP infection. The sensitivity of the calcofluor-blue brightener technique was 74.3% vs. 60.0%, 34.6%, and 82.9% for IFA, MGG, and qPCR, respectively; and its specificity was 99.6% vs. 99.3%, 100.0%, and 99.4% for IFA, MGG, and qPCR. No technique was shown to be statistically superior to calcofluor-blue brightener. Further validation of the test through multicenter studies is now required, but in light of its low cost and easy preparation, the use of calcofluor-blue brightener in BALF appears to be a valuable alternative method for the routine first-line diagnosis of PjP infection.

Micellar catalysis using a photochromic surfactant: application to the Pd-catalyzed Tsuji-Trost reaction in water.

The first example of a Pd-catalyzed Tsuji-Trost reaction, applied in a photochromic micellar media under conventional heating and microwave irradiation, is reported. The surfactant activity and recycling ability were investigated and compared with those of a few commercially available surfactants. The synthetic photochromic surfactant proved to be efficient, recyclable, and versatile for Pd-catalyzed coupling reactions.

Synthesis and evaluation of a photochromic surfactant for organic reactions in aqueous media.

A novel photochromic azobenzene-based surfactant was described for organic chemistry in water. The molecule 4-butylazobenzyl-4'-triazologlucuronic acid sodium salt thus synthesized can be isomerized from its trans to its cis form reversibly in solution by simple light irradiation. That property allowed the recyclability of a model acetylation reaction performed in the surfactant media, compared to the well-known, commercially available sodium dodecyl sulfate surfactant media.

Synthesis of S-glycosyl primary sulfonamides.

The synthesis of S-glycosyl sulfonamides wherein the primary sulfonamide functional group (-SO(2)NH(2)) is directly attached to the anomeric position of a carbohydrate moiety is reported. Our general approach consists of first introducing a thioacetate group at the anomeric center of a per-O-acetylated sugar derivative. From this follows formation of a glycosyl sulfenamide (sugar-SNR(2)), oxidation of the sulfenamide to give a glycosyl N-protected sulfonamide (sugar-SO(2)NR(2)), and removal of the sulfonamide protecting (R) group to yield a primary sulfonamide at the anomeric center (sugar-SO(2)NH(2)). A variety of mono- and disaccharide derivatives were synthesized using this new methodology.