Cyclophosphamide vs rituximab for eradicating inhibitors in acquired hemophilia A: A randomized trial in 108 patients

BACKGROUND

Acquired hemophilia A (AHA) is a rare autoimmune disorder due to autoantibodies against Factor VIII, with a high mortality risk. Treatments aim to control bleeding and eradicate antibodies by immunosuppression. International recommendations rely on registers and international expert panels.

METHODS

CREHA, an open-label randomized trial, compared the efficacy and safety of cyclophosphamide and rituximab in association with steroids in patients with newly diagnosed AHA. Participants were treated with 1 mg/kg prednisone daily and randomly assigned to receive either 1.5-2 mg/kg/day cyclophosphamide orally for 6 weeks, or 375 mg/m2 rituximab once weekly for 4 weeks. The primary endpoint was complete remission over 18 months. Secondary endpoints included time to achieve complete remission, relapse occurrence, mortality, infections and bleeding, and severe adverse events.

RESULTS

Recruitment was interrupted because of new treatment recommendations after 108 patients included (58 cyclophosphamide, 50 rituximab). After 18 months, 39 cyclophosphamide patients (67.2 %) and 31 rituximab patients (62.0 %) were in complete remission (OR 1.26; 95 % CI, 0.57 to 2.78). In the poor prognosis group (FVIII < 1 IU/dL, inhibitor titer > 20 BU mL-1), significantly more remissions were observed with cyclophosphamide (22 patients, 78.6 %) than with rituximab (12 patients, 48.0 %; p = 0.02). Relapse rates, deaths, severe infections, and bleeding were similar in the 2 groups. In patients with severe infection, cumulative doses of steroids were significantly higher than in patients without infection (p = 0.03).

CONCLUSION

Cyclophosphamide and rituximab showed similar efficacy and safety. As first line, cyclophosphamide seems preferable, especially in poor prognosis patients, as administered orally and less expensive.

FUNDING

French Ministry of Health.

CLINICALTRIALS

gov number: NCT01808911.

The effectiveness and safety of octocog alfa in patients with hemophilia A: up to 7-year follow-up of the real-world AHEAD international study

Background

Real-world data assessing treatment outcomes in patients with hemophilia A in routine clinical practice are limited.

Objective

To evaluate the effectiveness and safety of octocog alfa in patients with moderate/severe hemophilia A receiving treatment in clinical practice.

Design

The international Antihemophilic Factor Hemophilia A Outcome Database study is an observational, noninterventional, prospective, multicenter study.

Methods

This planned interim data read-out was conducted following 7 years of observation of patients receiving octocog alfa (cut-off, 30 June 2020). The primary endpoint was joint health status, assessed by the Gilbert Score. Secondary endpoints included annualized bleeding rates (ABRs), Hemophilia Joint Health Score (HJHS), health-related quality of life, consumption, and safety. This post hoc analysis stratified data by hemophilia severity at baseline [moderate, factor VIII (FVIII) 1-5%; severe, FVIII <1%].

Results

Of the 711 patients in this analysis, 582 (82%) were receiving prophylaxis with octocog alfa at enrollment, and 498 (70%) had severe disease. Median Gilbert Scores were higher with on-demand therapy versus prophylaxis and scores were comparable in moderate and severe disease. In patients receiving prophylaxis, there was an improvement in HJHS Global Gait Score over 7 years of follow-up overall and in patients with severe disease. ABRs and annualized joint bleeding rates were low across all 7 years. An ABR of zero was reported in 34-56% of prophylaxis patients versus 20-40% in the on-demand group. ABRs were similar in severe and moderate disease. In total, 13/702 (1.9%) patients experienced 18 treatment-related adverse events.

Conclusion

These data demonstrate the long-term effectiveness and safety of octocog alfa in patients with moderate and severe hemophilia A, especially in those receiving prophylaxis. The high number of patients receiving on-demand treatment experiencing zero bleeds could be due to selection bias within the study, with patients with less severe disease more likely to be receiving on-demand treatment.

Trial registration

ClinicalTrials.gov: NCT02078427.

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.

Five new F10 variants in hereditary factor x deficiency detected by high-throughput sequencing

INTRODUCTION

Factor X deficiency is a rare inherited bleeding disorder. To date, 181 variants are reported in the recently updated F10-gene variant database.

AIM

This study aimed to describe new F10 variants.

METHOD

The F10 gene was analysed in 16 consecutive families with FX deficiency by a targeted high-throughput sequencing approach, including F10, F9, F8 genes, and 78 genes dedicated to haematological malignancies.

RESULTS

We identified 19 variants (17 missense, one nonsense and one frameshift) and two copy number variations. Two patients presenting a combined FVII-FX deficiency showed a loss of one F10 gene copy (del13q34) associated with a missense variant on the remaining allele, leading to a FX:C significantly lower than the FVII:C level and explaining their unusual bleeding history. We reported five novel variants. Three missense variants (p.Glu22Val affecting the signal peptide cleavage site, p.Cys342Tyr removing the disulphide bond between the FX heavy and light chains, and p.Val385Met located in FX peptidase S1 domain) were detected at compound heterozygosis status in three patients with severe bleeding symptoms and FX:C level below 10 IU/dL. Two truncating variants p.Tyr279* and p.Thr434Aspfs*13 leading to an altered FX protein were found at heterozygous state in two patients with mild bleeding history.

CONCLUSION

This study showed the feasibility and the interest of high-throughput sequencing approach for rare bleeding disorders, enabling the report of F10 gene screening in a 3-weeks delay, suitable for clinical use. The description of five new variants may contribute to a better understanding of the phenotype-genotype correlation in FX deficiency.

A focus on dominant negative variants in a series of 170 heterozygous FXI-deficient patients

INTRODUCTION

Dominant-negative effects have been described for 10 F11 variants in the literature.

AIM

The current study aimed at identifying putative dominant-negative F11 variants.

MATERIAL AND METHODS

This research consisted in a retrospective analysis of routine laboratory data.

RESULTS

In a series of 170 patients with moderate/mild factor XI (FXI) deficiencies, we identified heterozygous carriers of previously reported dominant-negative variants (p.Ser243Phe, p.Cys416Tyr, and p.Gly418Val) with FXI activities inconsistent with a dominant-negative effect. Our findings also do not support a dominant-negative effect of p.Gly418Ala. We also identified a set of patients carrying heterozygous variants, among which five out of 11 are novel, with FXI activities suggesting a dominant-negative effect (p.His53Tyr, p.Cys110Gly, p.Cys140Tyr, p.Glu245Lys, p.Trp246Cys, p.Glu315Lys, p.Ile421Thr, p.Trp425Cys, p.Glu565Lys, p.Thr593Met, and p.Trp617Ter). However, for all but two of these variants, individuals with close to half normal FXI coagulant activity (FXI:C) were identified, indicating an inconstant dominant effect.

CONCLUSION

Our data show that for some F11 variants recognized has having dominant-negative effects, such effects actually do not occur in many individuals. The present data suggest that for these patients, the intracellular quality control mechanisms eliminate the variant monomeric polypeptide before homodimer assembly, thereby allowing only the wild-type homodimer to assemble and resulting in half normal activities. In contrast, in patients with markedly decreased activities, some mutant polypeptides might escape this first quality control. In turn, assembly of heterodimeric molecules as well as mutant homodimers would result in activities closer to 1:4 of FXI:C normal range.

rFVIII-Fc in severe haemophilia A: The incentive switch in case of high risk of joint bleedings

BACKGROUND

Efmoroctocog alfa, the first recombinant factor VIII fusion protein with extended half-life (rFVIII-Fc), has been hypothesized to lower FVIII consumption in patients with severe Haemophilia A (pwSHA), without reducing clinical efficacy. What about real life?

METHOD

MOTHIF-II was a noninterventional, multicentre, before/after study, via the collection of retrospective data from July 2015 to June 2016 (called T1), and from July 2017 to June 2018 (called T2), in 7 French haemophilia treatment centres. We examined the prescriptions and dispensations of factor VIII and the Annual Bleeding Rate (ABR), in pwSHA without current inhibitors on prophylaxis, before and after the introduction of rFVIII-Fc. The data gathered from the BERHLINGO research database and from the French Healthcare claims database with a determinist pairing process based on the national unique identification number.

RESULTS

A total of 156 pwSHA were included in the prescription cohort and 83 in the ABR cohort. For switched patients, the mean amounts of prescribed FVIII were significantly higher during T1 compared to T2 (4333 (2052) vs. 3921 (2029) IU/kg/year/patient, p: 0.028); a significant decrease in their ABR was also observed between T1 and T2 (6.3 (6.0) vs. 4.4 (5.4), p: 0.047). These patients had a more severe bleeding profile centred on haemarthrosis.

CONCLUSION

The results are related to those of the pivotal clinical trials for the reduction in FVIII consumption following the switch to rFVIII-Fc, with a significant improvement in the haemorrhagic phenotype for pwSHA.

[Acquired hemophilia and pregnancy: A necessarily multidisciplinary approach]

The occurrence of acquired hemophilia during pregnancy or postpartum is rare (2 to 10 % in series). It is generally suspected in the presence of haemorrhagic manifestations (especially subcutataneous or mucosal bleeding) associated with an isolated prolongation of the activated partial thromboplastin time (APTT). The diagnosis is confirmed by the association of a low level of factor VIII (FVIII) and the presence of an anti-FVIII inhibitor. Postpartum management is similar to that of other acquired haemophilias: correction of a severe haemorrhagic syndrome by "bypassing" agents, eradication of the inhibitor by corticosteroids alone or in combination with another immunosuppressive agent depending on the residual level of FVIII and the titer of the inhibitor. Management of the forms occurring during pregnancy is based on rare experiences or expert opinions. The management of childbirth is particularly delicate in terms of haemorrhage, especially if the anti-FVIII inhibitor is still present, and must be prepared in a multidisciplinary manner. Finally, as with any acquired hemophilia, a relapse is possible, especially in the year following remission. During a subsequent pregnancy, the risk of recurrence is possible but should not be a contraindication to a new pregnancy.

Long-Term Antithrombotic Treatments Prescribed for Cardiovascular Diseases in Patients with Hemophilia: Results from the French Registry

Cardiovascular diseases (CVDs) are a major issue in aging patients with hemophilia (PWHs). Antithrombotic agents are widely used in the general population for CVD treatment, but this recommendation is not fully applicable to PWHs. To improve treatment strategies, a prospective case-control study (COCHE) that analyzed CVD management and follow-up (2 years/patient) in PWHs was performed in France from 2011 to 2018. In total, 68 PWHs (median age: 65 years [39-89]; 48 mild, 10 moderate, and 10 severe hemophilia) were included (n = 50 with acute coronary syndrome, n = 17 with atrial fibrillation, n = 1 with both). They were matched with 68 control PWHs without antithrombotic treatment. In our series, bleeding was significantly influenced by (1) hemophilia severity, with a mean annualized bleeding ratio significantly higher in COCHE patients than in controls with basal clotting factor level up to 20%, (2) antihemorrhagic regimen (on-demand vs. prophylaxis) in severe (hazard ratio [HR] = 16.69 [95% confidence interval, CI: 8.2-47.26]; p < 0.0001) and moderate hemophilia (HR = 42.43 [95% CI: 1.86-966.1]; p = 0.0028), (3) type of antithrombotic treatment in mild hemophilia, with a significantly higher risk of bleeding in COCHE patients than in controls for dual-pathway therapy (HR = 15.64 [95% CI: 1.57-115.8]; p = 0.019), anticoagulant drugs alone (HR = 9.91 [95% CI: 1.34-73.47]; p = 0.0248), dual antiplatelet therapy (HR = 5.31 [95% CI: 1.23-22.92]; p = 0.0252), and single antiplatelet therapy (HR = 3.76 [95% CI: 1.13-12.55]; p = 0.0313); and (4) HAS-BLED score ≥3 (odds ratio [OR] = 33 [95% CI: 1.43-761.2]; p = 0.0065). Gastrointestinal bleeding was also significantly higher in COCHE patients than in controls (OR = 15 [95% CI: 1.84-268]; p = 0.0141). The COCHE study confirmed that antithrombotic treatments in PWHs are associated with increased bleeding rates in function of hemophilia-specific factors and also of known factors in the general population.

Bleeding complications during pregnancy and delivery in haemophilia carriers and their neonates in Western France: An observational study

BACKGROUND

Pregnancy, delivery and the postpartum period expose haemophilia carriers, as well as their potentially affected neonates to a high risk of haemorrhagic complications.

OBJECTIVES

To describe bleeding complications in haemophilia carriers and their newborns throughout pregnancy and postpartum and to identify potential factors increasing the risk of bleeding in this population.

PATIENTS/METHODS

The ECHANGE multicentre observational cohort study was conducted between January 2014 and February 2019 using the BERHLINGO database comprised of patients from seven French haemophilia centres.

RESULTS

During the 5 years study period, a total of 104 haemophilia carriers and 119 neonates were included, representing 124 pregnancies and 117 deliveries. Thirty-five (30%) bleeding events were observed, most of them (83%) occurred during the postpartum period, and 37% were reported during the secondary postpartum. Neuraxial anaesthesia was not complicated by spinal haematoma. Three (2.5%) neonates experienced cerebral bleeding. Caesarean section was associated with an increased risk of maternal bleeding in primary and secondary postpartum periods. Basal factor level <0.4 IU/mL was also found to be associated with an increased risk of bleeding during secondary postpartum.

CONCLUSION

In our cohort, bleeding events occurred in more than a third of haemophilia carriers mainly in the postpartum period, and a significant portion of this bleeding occurred during the secondary postpartum. Haemophilia carriers warrant specific attention during primary and secondary postpartum, in particular in case of caesarean section and low basal factor level. The ECHANGE study is registered at clinicaltrials.gov identifier: NCT03360149.

In Vivo Feasibility of Arterial Embolization with Permanent and Absorbable Suture: The FAIR-Embo Concept

PURPOSE

Arterial embolization has been shown to be effective and safe for the management of bleeding, especially for postpartum and pelvic traumatic bleeding. We propose to evaluate the proof of concept of feasibility and effectiveness of arterial embolization with absorbable and non-absorbable sutures in a porcine model.

MATERIALS AND METHODS

In the acute setting (n = 1), several different arteries (mesenteric, splenic, pharyngeal, kidney) were embolized using non-absorbable sutures (NAS): Mersutures™ braided sutures (polyethylene terephthalate). In the chronic setting (n = 3), only lower pole renal arteries were embolized. On the right side, NAS was used, whereas on the left side embolization was realized with absorbable suture (AS): Vicryl^® braided suture (polyglactin 910). The chronic group was followed for 3 months. The pigs received contrast-enhanced CT the day before embolization (D-1), after the embolization (D0), at 1 month and 3 months after embolization (M1 and M3); digital subtraction angiography (DSA) was done at D0 and M3 and histological analysis at M3.

RESULTS

All vascular targets were effectively embolized without any pre- or postoperative complications. Both DSAs and CTs at M3 showed a 100% recanalization rate for the AS embolization and a partial reversal rate for the NAS embolization. A renal hypotrophy in the embolized region was observed during both the M1 and M3 scans for both sutures (AS and NAS) with a clear hypotrophy for the NAS embolized kidney.

CONCLUSION

Embolization by AS and NAS (FAIR-Embo) is a feasible and effective treatment which opens up the possibility of global use of this inexpensive and widely available embolization agent.

Determinants of adherence and consequences of the transition from adolescence to adulthood among young people with severe haemophilia (TRANSHEMO): study protocol for a multicentric French national observational cross-sectional study

INTRODUCTION

Severe haemophilia is a rare disease characterised by spontaneous bleeding from early childhood, which may lead to various complications, especially in joints. It is nowadays possible to avoid these complications thanks to substitutive therapies for which the issue of adherence is major. The transition from adolescence to adulthood in young people with severe haemophilia is a critical period as it is associated with a high risk of lack of adherence to healthcare, which might have serious consequences on daily activities and on quality of life.

METHODS AND ANALYSIS

We present the protocol for a cross-sectional, observational, multicentric study to assess the differences between adolescents and young adults with severe haemophilia in France through the transition process, especially on adherence to healthcare. This study is based on a mixed methods design, with two complementary and consecutive phases, comparing data from a group of adolescents (aged 14-17 years) with those from a group of young adults (aged 20-29 years). The quantitative phase focuses on the determinants (medical, organisational, sociodemographic and social and psychosocial and behavioural factors) of adherence to healthcare (considered as a marker of the success of transition). The qualitative phase explores participants' views in more depth to explain and refine the results from the quantitative phase. Eligible patients are contacted by the various Haemophilia Treatment Centres participating in the French national registry FranceCoag.

ETHICS AND DISSEMINATION

The study was approved by the French Ethics Committee and by the French National Agency for Medicines and Health Products Safety (number: 2016-A01034-47). Study findings will be disseminated to the scientific and medical community in peer-reviewed journals and presented at scientific meetings. Results will be popularised to be communicated via the French association for people with haemophilia to participants and to the general public.

TRIAL REGISTRATION NUMBER

NCT02866526; Pre-results.

Outcome of acquired haemophilia in France: the prospective SACHA (Surveillance des Auto antiCorps au cours de l'Hémophilie Acquise) registry

Although extremely rare, acquired haemophilia A (AHA) can cause severe bleeding, which may be fatal. The underlying causes of autoantibody development are not fully understood. Treatment goals are bleeding control and autoantibody eradication. At the time of our study, there was no consensus on a standard treatment strategy for AHA. Previous data were mainly retrospective or from single-centre cohorts. We conducted a prospective, controlled, registry-based study of patients with AHA in France. The prospective French registry (Surveillance des Auto antiCorps au cours de l'Hémophilie Acquise [SACHA]) collected data on prevalence, clinical course, disease associations and outcomes for haemostatic treatment and autoantibody eradication in 82 patients with a 1-year follow-up. Similar to earlier studies, the prevalence of AHA was higher in the elderly, with two thirds of patients aged >70 years. Around half of AHA cases were associated with underlying disease, most commonly autoimmune disease and cancer in younger and older patients respectively. Haemostatic treatment was initially administered to 46% of patients. Complete resolution or improvement of initial bleeding occurred in 22/27 (81%) rFVIIa-treated patients and in all six cases receiving pd-aPCC. The majority of patients (94%) received immunosuppressive therapy, with complete remission at 3 months in 61% (36/59) and in 98% (50/51) at 1 year. Overall mortality was 33%: secondary to bleeding in only three patients but to sepsis in 10. Bypassing agents were effective at controlling bleeding in patients with AHA. Immunosuppressive therapy should be used early but with caution, particularly in elderly patients.

[Cell therapy for stroke: from myth to reality]

INTRODUCTION

Stroke is one of the leading causes of death and disability worldwide. Intravenous recombinant tissue plasminogen activator is the only available therapy for acute ischemic stroke, but its use is limited by a narrow therapeutic window and cannot stimulate endogenous repair and regeneration of damaged brain tissue. Stem cell-based approaches hold much promise as potential novel treatments to restore neurological function after stroke.

STATE OF THE ART

In this review, we summarize data from preclinical and clinical studies to investigate the potential application of stem cell therapies for treatment of stroke. Stem cells have been proposed as a potential source of new cells to replace those lost due to central nervous system injury, as well as a source of trophic molecules to minimize damage and promote recovery. Various stem cells from multiple sources can generate neural cells that survive and form synaptic connections after transplantation in the stroke-injured brain. Stem cells also exhibit neurorevitalizing properties that may ameliorate neurological deficits through stimulation of neurogenesis, angiogenesis and inhibition of inflammation.

PERSPECTIVES/CONCLUSION

Performed in stroke, cell therapy would decrease brain damage and reduce functional deficits. After the damage has been done, it would still improve neurological functions by activating endogenous repair. Nevertheless, many questions raised by experimental studies particularly related to long-term safety and technical details of cell preparation and administration must be resolved before wider clinical use.

Priming of late endothelial progenitor cells with erythropoietin before transplantation requires the CD131 receptor subunit and enhances their angiogenic potential

BACKGROUND

 Endothelial colony-forming cells (ECFCs) are promising candidates for cell therapy of ischemic diseases. Erythropoietin (EPO) is a cytokine that promotes angiogenesis after ischemic injury. EPO receptors (EPORs) classically include two EPOR subunits, but may also associate with the β-common chain (CD131) in a newly identified receptor involved in EPO cytoprotective effects.

OBJECTIVE

The aim was to take advantage of the proangiogenic properties of EPO to enhance ECFC graft efficiency. We postulated that priming ECFCs by adding epoietin α in culture medium prior to experiments might increase their angiogenic properties. We also explored the role of the CD131 subunit in EPO priming of ECFCs.

METHODS AND RESULTS

By western blotting on cord blood ECFC lysates, we showed that EPOR and CD131 expression increased significantly after EPO priming. These proteins coimmunoprecipitated and colocalized, suggesting that they are covalently bound in ECFCs. EPO at 5 IU mL(-1) significantly stimulated proliferation, wound healing, migration and tube formation of ECFCs. EPO priming also increased ECFC resistance to H2 O2-induced apoptosis and survival in vivo. Similarly, in vivo studies showed that, as compared with non-primed ECFC injection, 5 IU mL(-1) EPO-primed ECFCs, injected intravenously 24 h after hindlimb ischemia in athymic nude mice, increased the ischemic/non-ischemic ratios of hindlimb blood flow and capillary density. These effects were all prevented by CD131 small interfering RNA transfection, and involved the phosphoinositide 3-kinase-Akt pathway.

CONCLUSION

These results highlight the potential role of EPO-primed ECFCs for cell-based therapy in hindlimb ischemia, and underline the critical role of CD131 as an EPO coreceptor.

Erythropoietin 2nd cerebral protection after acute injuries: a double-edged sword?

Over the past 15 years, a large body of evidence has revealed that the cytokine erythropoietin exhibits non-erythropoietic functions, especially tissue-protective effects. The discovery of EPO and its receptors in the central nervous system and the evidence that EPO is made locally in response to injury as a protective factor in the brain have raised the possibility that recombinant human EPO (rhEPO) could be administered as a cytoprotective agent after acute brain injuries. This review highlights the potential applications of rhEPO as a neuroprotectant in experimental and clinical settings such as ischemia, traumatic brain injury, and subarachnoid and intracerebral hemorrhage. In preclinical studies, EPO prevented apoptosis, inflammation, and oxidative stress induced by injury and exhibited strong neuroprotective and neurorestorative properties. EPO stimulates vascular repair by facilitating endothelial progenitor cell migration into the brain and neovascularisation, and it promotes neurogenesis. In humans, small clinical trials have shown promising results but large prospective randomized studies failed to demonstrate a benefit of EPO for brain protection and showed unwanted side effects, especially thrombotic complications. Recently, regions have been identified within the EPO molecule that mediate tissue protection, allowing the development of non-erythropoietic EPO variants for neuroprotection conceptually devoid of side effects. The efficacy and the safety profile of these new compounds are still to be demonstrated to obtain, in patients, the benefits observed in experimental studies.

Efficacité du rituximab dans les hémophilies acquises: à propos de deux cas et revue de la littérature

INTRODUCTION

Acquired hemophilia due to an inhibitor of factor VIII is a rare clinical situation.

EXEGESIS

Rituximab is now used in the treatment of acquired hemophilia. We report two cases of acquired hemophilia treated by rituximab with efficiency.

CONCLUSION

Rituximab appears to be a first line immunosuppressive therapy in acquired hemophilia, especially in post-partum hemophilia.

Detection of 28 novel mutations in the Wiskott–Aldrich syndrome and X-linked thrombocytopenia based on multiplex PCR

The Wiskott-Aldrich syndrome (WAS) is an X-linked disorder including microthrombocytopenia, eczema and immunodeficiency. A mild form is known as the X-linked thrombocytopenia (XLT). We screened 150 individuals or families based on a multiplex PCR method. We found 28 novel mutations (7 missense, 1 nonsense, 1 nonstop change, 5 splice site mutations and 14 deletions or insertions). The method relied on the co-synthesis of 5 amplicons and direct sequencing, optimizing the novel protocol proposed by Jones et al. [L.N. Jones, M.I. Lutskiy, J. Cooley, et al. A novel protocol to identify mutations in patients with Wiskott-Aldrich syndrome, Blood Cells Mol. Dis. 28 (2002) 392-398]. It was thus possible to identify faster and at a lower cost the mutations in newly diagnosed patients. The mutation distribution, according to the type, was in keeping with the distribution reported previously. No clear-cut genotype-phenotype correlation was observed.

Detection of 95 novel mutations in coagulation factor VIII gene F8 responsible for hemophilia A: results from a single institution

Hemophilia A (HA) is an X-linked hereditary bleeding disorder defined by a qualitative and/or quantitative factor VIII (FVIII) deficiency. The molecular diagnosis of HA is challenging because of the high number of different causative mutations that are distributed throughout the large F8 gene. The putative role of the novel mutations, especially missense mutations, may be difficult to interpret as causing HA. We identified 95 novel mutations out of 180 different mutations responsible for HA in 515 patients from 406 unrelated families followed up at a single hemophilia treatment center of the Bicêtre university hospital (Assistance Publique-Hôpitaux de Paris [AP-HP], Le Kremlin-Bicêtre). These 95 novel mutations comprised 55 missense mutations, 12 nonsense mutations, 11 splice site mutations, and 17 small insertions/deletions. We therefore developed a mutation analysis based on a body of proof that combines the familial segregation of the mutation, the resulting biological and clinical HA phenotype, and the molecular consequences of the amino acid (AA) substitution. For the latter, we studied the putative biochemical modifications: its conservation status with cross-species FVIII and homologous proteins, its putative location in known FVIII functional regions, and its spatial position in the available FVIII 3D structures. The usefulness of such a strategy in interpreting the causality of novel F8 mutations is emphasized.

Neuroprotective effects of tacrolimus (FK506) in a model of ischemic cortical cell cultures: role of glutamate uptake and FK506 binding protein 12 kDa

BACKGROUND

The mechanisms underlying the neuroprotective effects of the immunosuppressant tacrolimus, observed in vivo, remain unclear. Here we quantify these effects in vitro, and evaluate the potential involvement of the glutamate and/or immunophilin FK506 binding protein 12 kDa in tacrolimus-induced neuroprotection.

METHODS

Primary cultures of neurons and astrocytes from rat cerebral cortex were subjected to transient oxygen-glucose deprivation. Neuronal injury was evaluated by cell counting after immunostaining experiments, lactate dehydrogenase release and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction. The involvement of the immunophilin FK506 binding protein 12 kDa was explored using an anti-FK506 binding protein 12 kDa antibody, (3-3-pyridyl)-1-propyl(2 s)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidine carboxylate and rapamycin. Extracellular glutamate and glutamate uptake were respectively measured by high performance liquid chromatography and l-[3H]glutamate incorporation.

RESULTS

When added during either oxygen-glucose deprivation or reoxygenation, FK506 (50-500 pM) offered significant neuroprotection. During oxygen-glucose deprivation, it was able to reverse the oxygen-glucose deprivation-induced increase in extracellular glutamate and decrease in glutamate uptake and this effect was reversed in the presence of threo-3-methyl glutamate, a specific inhibitor of glutamate transporter-1. Blocking FK506 binding protein 12 kDa inhibited the neuroprotection induced by tacrolimus added during either oxygen-glucose deprivation or reoxygenation. Tacrolimus-induced neuroprotection was also reversed in the presence of rapamycin, an immunosuppressant FK506 binding protein 12 kDa ligand devoid of neuroprotective properties and (3-3-pyridyl)-1-propyl(2 s)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidine carboxylate, a non-immunosuppressant ligand of FK506 binding protein 12 kDa, exerteing neuroprotective effects.

CONCLUSION

The beneficial effects of tacrolimus during in vitro ischemia/reperfusion seem to indicate the restoration of a glutamate transporter-1-mediated activity and could be mediated by a FK506 binding protein 12 kDa pathway.

Factor XI deficiency: identification of six novel missense mutations (P23L, P69T, C92G, E243D, W497C and E547K)

Factor XI (FXI) deficiency is a rare coagulation disorder associated with bleeding of variable severity but without a clear relationship between bleeding and FXI levels. This study reports the molecular genetic analysis of FXI deficiencies in thirteen patients. Six novel missense mutations were identified: P23L, P69T, C92G, E243D, W497C and E547K.

Recurrent V75M mutation within the Wiskott-Aldrich syndrome protein: description of a homozygous female patient

The Wiskott-Aldrich syndrome is a rare genetic disorder due to mutations in the WAS gene situated on chromosome X. It is comprised of microthrombocytopenia, eczema and immunodeficiency. However, the phenotypical presentation may vary as to the number and intensity of its manifestations. A milder form of Wiskott-Aldrich syndrome is known as the X-linked thrombocytopenia. We independently found eight individual or familial cases with the V75M substitution (9.76%). This high incidence was partly accounted for by the fact that three cases turned out to be related. The V75M mutation is recurrent, however, due to a CpG island. A genuine homozygous female patient was found. She showed microthrombocytopenia and infections to the same degree as her hemizygous father and brother. The WAS protein was decreased in a comparable fashion in the hemizygotes and the homozygote as well. Its amount was about 10% and 15% of normal in platelets and mononucleated white cells, respectively. In all patients was the picture consistent with XLT.

Chronic L-DOPA treatment increases extracellular glutamate levels and GLT1 expression in the basal ganglia in a rat model of Parkinson's disease

There is growing experimental evidence for the implication of glutamate-mediated mechanisms both in the pathophysiology of Parkinson's disease and in the development of dyskinesias with long-term administration of L-3,4-dihydroxyphenylalanine (L-DOPA). However, the impact of this treatment on glutamate transmission in the basal ganglia has been poorly investigated. In this study, we examined the effects of 6-hydroxydopamine-induced lesion of nigral dopamine neurons with or without subsequent chronic L-DOPA treatment on several parameters of glutamate system function in the rat striatum and substantia nigra pars reticulata. All the lesioned animals treated with L-DOPA developed severe dyskinesias. Extracellular glutamate levels, measured by microdialysis in freely moving conditions, and gene expression of the glial glutamate transporter GLT1, assessed by in situ hybridization, were unaffected by dopamine lesion or L-DOPA treatment alone, but were both markedly increased on the lesion side of rats with subsequent L-DOPA treatment. No change in the expression of the vesicular glutamate transporters vGluT1 and vGluT2 was measured in striatum. These data show that chronic L-DOPA treatment leading to dyskinesias increases basal levels of glutamate function in basal ganglia. The L-DOPA-induced overexpression of GLT1 may represent a compensatory mechanism involving astrocytes to limit glutamate overactivity and subsequent toxic processes.

Protein A Sepharose immunoadsorption can restore the efficacy of platelet concentrates in patients with Glanzmann's thrombasthenia and anti-glycoprotein IIb-IIIa antibodies

Type I Glanzmann's thrombasthenia is a rare congenital platelet function disorder, characterized by undetectable platelet membrane glycoprotein IIb-IIIa (GPIIb-IIIa). Severe bleeding is controlled by transfusion of normal platelets, leading in some cases to the occurrence of anti-GPIIb-IIIa isoantibodies, which induces a loss of transfused platelet efficacy. We used immunoadsorption on protein A Sepharose (IA-PA), which has been shown to be efficient in decreasing the titre of antibodies in several immune diseases, in three patients with Glanzmann's thrombasthenia and anti-GPIIb-IIIa isoantibodies on five different occasions. IA-PA was well tolerated with no deleterious side-effects reported. It induced a dramatic decrease of total immunoglobulin (Ig)G, including anti-GPIIb-IIIa isoantibody levels, as assessed by the monoclonal antibody-specific immobilization of platelet antigens test and the ex vivo inhibition of normal platelet aggregation induced by the patient's platelet-rich or platelet-poor plasma. Elimination of the antibody was associated with a correction of the bleeding time following platelet transfusion. IA-PA combined with platelet transfusion made it possible to control two life-threatening haemorrhages, and allowed two surgical procedures and one bone marrow transplantation to be performed safely. Our experience suggests that IA-PA, which restores the haemostatic efficacy of platelet transfusion, is a valuable therapeutic strategy in patients with Glanzmann's thrombasthenia and anti-GPIIb-IIIa isoantibodies.

Developmental expression and activity of high affinity glutamate transporters in rat cortical primary cultures

The expression and activity of glutamate transporters (EAAC1, GLAST and GLT1) were examined during the development of cortical neuron-enriched cultures. Protein content and mitochondrial respiration both increased during the first 7 days, later stabilized and decreased from DIV14. Glutamate transport and extracellular concentration were relatively constant from DIV3 to 18. The kinetic parameters of glutamate transport were at DIV7: K(m)=19+/-3 microM and V(max)=1068+/-83 pmol/mg protein/min and at DIV14: K(m)=40.8+/-9.3 microM and V(max)=1060+/-235 pmol/mg protein/min. The shift in K(m) towards higher values suggest a more important participation of GLAST after DIV14. At DIV7 and 14, glutamate transport was poorly sensitive to dihydrokaïnate (DHK) suggesting a weak participation of GLT1 in glutamate transport. Western blot experiments and immunocytochemistry showed that EAAC1 was expressed by neurons whatever the stage of the culture. GLAST was found in astrocytes as soon as DIV3 and labeling increased during the development of the culture. There was little neuronal GLT1 immunoreactivity at DIV7, only detected by immunocytochemistry. From DIV10 to 18, an increasing astrocytic expression of GLT1 was observed, also detected by Western blotting. These results show that: (1) glutamate uptake remains stable all along the development of the cultures although the pattern of expression of the different transporters is changing, suggesting that glutamate transport is highly regulated; (2) neuronal EAAC1 may play a critical role during the early stages of the culture when it is expressed alone; and (3) the developmental expression pattern of glutamate transporters in cortical neuron-enriched cultures is quite similar to that observed in vivo during early postnatal development.

Protein A sepharose immunoadsorption: immunological and haemostatic effects in two cases of acquired haemophilia

Acquired haemophilia is a life-threatening disorder caused by circulating auto-antibodies that inhibit factor VIII coagulant activity (FBIII:C). Immunoadsorption on protein A sepharose (IA-PA) was performed in two bleeding patients with acquired haemophilia: we observed a dramatic and quick decrease in the anti-FVIII:C inhibitor titre leading to a normal, albeit transient, haemostatic status. In one case, IA-PA was the only procedure which succeeded in stopping massive haemorrhage. In the second case, IA-PA reinforced the haemostatic effect of recombinant activated factor VII by increasing the endogenous plasma factor VIII level. The efficacy of IA-PA was sustained with immunosuppressive treatment introduced, respectively, 10 and 15 d before the IA-PA procedures. Our experience with IA-PA suggests that this extracorporeal anti-FVIII:C removal procedure is a valuable therapeutic tool for acquired haemophilia and can alleviate life-threatening haemorrhages.

[Acquired hemophilia: current diagnostic and therapeutic approaches]

PURPOSE

Acquired haemophilia is a rare disease, occurring most frequently in elderly patients, caused by the development of autoantibodies against factor VIII.

CURRENT KNOWLEDGE AND KEY POINTS

The disease is characterised by spontaneous haemorrhagic complications which can be fatal in 15-20% of the patients. However spontaneous remission is possible and in fact natural evolution and aetiology are still partly unknown. Acquired haemophilia may arise in association with auto-immune diseases, lymphoproliferative malignancy, pregnancy and also as a drug reaction. The aims of the treatment are first to treat the bleeding which is the most common cause of morbidity and mortality, and second to eliminate the inhibitor by immunosuppression. However no consensus exists for these two parts of the treatment. Bleeding may be controlled by prothrombin complex concentrates, recombinant factor VIIa or porcine factor VIII. The inhibitor is abolished in up 70% of patients using prednisone and cyclophosphamide. Other combinations of prednisone with azathioprine or with cyclophosphamide and vincristine or the use of high-dose immunoglobulin or double-filtration plasmapheresis have also proven effective in some patients.

FUTURE AND PROJECTS

The rare occurrence of the disease, the associated with various diseases, and lack of consensus about treatment, require multicentric prospective studies.

Pollen-rain-vegetation relationships along a forest-savanna transect in southeastern Cameroon

Modern soil and litter samples from southeastern Cameroon, collected along a continuous forest-savanna transect were analysed for pollen content to define modern pollen-vegetation relationships. The pollen results, completed and compared with botanical inventories, leaf area index and basal area measurements performed in the same area, clearly registered the physiognomy, the main floristic composition and floral richness of the two sampled ecosystems. Distortions were observed between sampled vegetations and their pollen rain, related to important differences in pollen production and dispersal of plant species: this is a general feature in many tropical regions. The pollen data in the area studied reflected well the recent transgression of forest versus savanna. This permitted us to define inside the forest ecosystem more successional vegetation communities than the botanical surveys allowed.