Outcomes and outcome measures

INTRODUCTION

Advances in haemophilia treatment have resulted in a near-normal life expectancy, lower burden of bleeding and treatment, and improved quality of life in high-income countries. Bleeding rate is approaching zero and novel parameters should be evaluated to assess the efficacy of treatment not only from the clinical point of view by using new methodologies (e.g. joint health assessment), but also from the patient's perspective (e.g. pain, quality of life, treatment satisfaction).

METHODS AND RESULTS

This approach should be aimed at combining objective clinical methodologies and patient-reported outcomes (PROs). However, some instruments used for assessing PROs are still suboptimal and not properly validated. Recent evidence suggests that these tools can take advantage from a more personalized designed approach and could be effectively improved and serve to facilitate the patient's self-evaluation. For other congenital bleeding disorders (BDs), a set of patient-relevant outcomes has been also defined that overlap substantially those of haemophilia, including bleeding, side effects and complications, and PROs, such as pain, physical functioning, impact on daily life including school and work and mental health. There is a growing focus on addressing women-specific outcomes in BDs, reflecting an increased awareness of the unique challenges faced by women in this context. However, the development of tailored tools is imperative to further advance the progress in managing women with BDs, ensuring more accurate monitoring and personalized care.

CONCLUSIONS

How incorporating these outcome measures in the process of approval of novel treatments for these disorders by regulatory authorities remains to be established.

Determinants of adherence and consequences of the transition from adolescence to adulthood among young people with severe haemophilia (TRANSHEMO): A multicentric French national observational cross-sectional study based on the FranceCoag registry

INTRODUCTION

It is necessary to gain insights into adherence to healthcare in people with severe haemophilia (PwSH), especially during the transition from paediatric to adult care, which is an important phase in lives of young people with childhood chronic disease. This adherence can be considered as a marker of successful transition.

OBJECTIVES

The main objective of the quantitative phase of the TRANSHEMO project was to compare the adherence to healthcare between adolescents and young adults (YAs) with severe haemophilia. The secondary objective was to identify the determinants (facilitators and barriers) of this adherence and associations between these determinants.

METHODS

A multicentre, observational, cross-sectional study was conducted in 2017-2019 on PwSH aged between 14 and 17 years (adolescents) or between 20 and 29 years (YAs), included in the FranceCoag registry and having completed the questionnaires. The adherence to healthcare (treatment regimens and clinical follow-up) was compared between adolescents and YAs using the chi-squared test. The determinants of this adherence were analysed by structural equation modelling.

RESULTS

There were 277 participants, 107 adolescents, and 170 YAs. The rate of adolescents adhering to healthcare was 82.2%, while the rate of YAs was 61.2% (p < .001). The barriers to the adherence to healthcare were being YA, having repeated at least one school grade and presenting mental health concerns.

CONCLUSION

Adolescents had better adherence to healthcare than YAs. According to the determinants enlightened in this project, targeted supportive strategies and adapted therapeutic education programs can be developed for young PwSH to facilitate their adherence to healthcare.

New Inhibitors in the Ageing Population: A Retrospective, Observational, Cohort Study of New Inhibitors in Older People with Hemophilia

INTRODUCTION

 A second peak of inhibitors has been reported in patients with severe hemophilia A (HA) aged >50 years in the United Kingdom. The reason for this suggested breakdown of tolerance in the aging population is unclear, as is the potential impact of regular exposure to the deficient factor by prophylaxis at higher age. No data on hemophilia B (HB) have ever been reported.

AIM

 The ADVANCE Working Group investigated the incidence of late-onset inhibitors and the use of prophylaxis in patients with HA and HB aged ≥40 years.

METHODS

 A retrospective, observational, cohort, survey-based study of all patients aged ≥40 years with HA or HB treated at an ADVANCE hemophilia treatment center.

RESULTS

 Information on 3,095 people aged ≥40 years with HA or HB was collected. Of the 2,562 patients with severe HA, the majority (73% across all age groups) received prophylaxis. In patients with severe HA, the inhibitor incidence per 1,000 treatment years was 2.37 (age 40-49), 1.25 (age 50-59), and 1.45 (age 60 + ). Overall, the inhibitor incidence was greatest in those with moderate HA (5.77 [age 40-49], 6.59 [age 50-59], and 4.69 [age 60 + ]) and the majority of inhibitor cases were preceded by a potential immune system challenge. No inhibitors in patients with HB were reported.

CONCLUSION

 Our data do not identify a second peak of inhibitor development in older patients with hemophilia. Prophylaxis may be beneficial in older patients with severe, and possibly moderate HA, to retain a tolerant state at a higher age.

Managing women-specific bleeding in inherited bleeding disorders: A multidisciplinary approach

INTRODUCTION

Multidisciplinary management of women-specific bleeding is important to preserve quality of life, healthy reproduction and social participation of women and girls with bleeding disorders (WBD).

AIM

To support appropriate multidisciplinary care for WBD in haemophilia treatment centres.

METHODS

Two case examples are presented and management issues discussed from different health care perspectives, including the nurse, patient, psychologist, gynaecologist, geneticist, psychosexual therapist and haematologist.

RESULTS

Woman with bleeding disorders may experience heavy menstruation from menarche onwards. This has a physical and psychosocial impact requiring a multidisciplinary approach. If a woman with an inherited bleeding disorder desires to become pregnant, preconception counselling is essential, to discuss genetic diagnosis, state of the art treatment options for the bleeding disorder in question and possible choices to prevent having an affected child, as well as maternal bleeding risks during conception, delivery and the post-partum period.

CONCLUSION

Adequate management and good education of WBD requires a patient-centred multidisciplinary approach with experienced specialists in a haemophilia treatment centre.

Gastrointestinal bleeding from angiodysplasia in von Willebrand disease: Improved diagnosis and outcome prediction using videocapsule on top of conventional endoscopy

BACKGROUND

Despite a high prevalence of angiodysplasia, no specific guidelines are available for the modalities of endoscopic exploration of gastrointestinal (GI) bleeding in von Willebrand disease (VWD). Whether VWD patients could benefit from video capsule endoscopy (VCE) looking for angiodysplasia eligible to endoscopic treatment or at high risk of bleeding is unknown.

OBJECTIVES

To assess the diagnostic efficacy for angiodysplasia and the prognostic value of VCE on top of conventional endoscopy in VWD patients with GI bleeding.

PATIENTS/METHODS

A survey was sent to the 30 centers of the French-network on inherited bleeding disorders to identify VWD patients referred for endoscopic exploration of GI bleeding from January 2015 to December 2017. Data obtained included patient characteristics, VWD phenotype/genotype, GI bleeding pattern, results of endoscopic investigations, and medical management applied including endoscopic therapy. We assessed by Kaplan-Meier analysis the recurrence-free survival after the first GI bleeding event according to endoscopic categorization and, in patients with angiodysplasia, to the presence of small-bowel localizations on VCE exploration.

RESULTS

GI bleeding source localization was significantly improved when including VCE exploration (P < .01), even in patients without history of angiodysplasia (P < .05). Patients with angiodysplasia had more GI bleeding recurrences (P < .01). A lower recurrence-free survival was observed in patients with angiodysplasia (log-rank test, P = .02), and especially when lesions were located in the small bowel (log-rank test, P < .01), even after endoscopic treatment with argon plasma coagulation (log-rank test, P < .01).

CONCLUSION

VCE should be more systematically used in VWD patients with unexplained or recurrent GI bleeding looking for angiodysplasia eligible to endoscopic treatment or at high risk of relapse.

ITI Treatment is not First-Choice Treatment in Children with Hemophilia A and Low-Responding Inhibitors: Evidence from a PedNet Study

BACKGROUND

 Limited data exist on the clinical impact of low-responding inhibitors and the requirement for immune tolerance induction (ITI) treatment to establish tolerance, reduce bleeding, and improve outcome. The aim of this article is to describe the therapeutic management of children with severe hemophilia A and low-responding inhibitors and its effect on bleeding phenotype.

METHODS

 The REMAIN (Real-life Management of Inhibitors) study is a satellite study of the PedNet registry. It included unselected children with severe hemophilia A (factor VIII [FVIII] < 0.01 IU/mL) born between January 1, 1990 and December 31, 2009 who developed clinically relevant inhibitors and were followed-up for at least 3 years after the first positive inhibitor test.

RESULTS

 A total of 260 patients with inhibitors were identified and 68 of them (26%) had low-responding inhibitors (peak < 5 BU/mL). Five patients were lost to follow-up and 63 were included in this study. The median follow-up was 3.7 years (interquartile range: 3.0-7.5). ITI was started in 51/63 (81%) patients. The median time from ITI start to first negative inhibitor titer was similar with low-dose and high-dose ITI regimens (2.5 and 3.1 months, respectively). Ten of the 12 patients who did not receive ITI were treated with regular prophylaxis and reached a negative titer after a median of 6.5 months. Bleeding rate was low in all patients with no difference between treatment regimens.

CONCLUSION

 In children with low-responding inhibitors negative titers were reached with regular FVIII treatment irrespective of the regimen (i.e., prophylaxis or ITI).

Clinical management of woman with bleeding disorders: A survey among European haemophilia treatment centres

INTRODUCTION

The impact of bleeding for women with bleeding disorders (WBD) is of increasing focus and importance. Despite this, optimal management strategies are unclear and knowledge gaps persist.

AIM

To examine practices and define research priorities on diagnosis and management of WBD in Europe.

METHODS

An electronic survey on clinical management of WBD was sent to 136 European haemophilia treatment centres (HTCs), including open questions on knowledge gaps and research priorities.

RESULTS

Fifty-nine HTCs from 12 Western (WE) and 13 Central/Eastern European (CEE) countries completed the survey. Less than half runs a joint clinic (24 HTCs, 42%). Most centres without a joint clinic have a named obstetrician (81%) and/or gynaecologist (75%) available for collaboration. Overall 18/54 (33%) European HTCs do not offer preimplantation genetic diagnosis. Third trimester amniocentesis to guide obstetric management is available 28/54 HTCs (52%), less frequent in CEE compared to WE countries (5/17 vs 23/37, P = .03). 53% of HTCs (28/53) reported that only 0%-25% of WBD seek medical advice for heavy menstrual bleeding (HMB). An algorithm managing acute HMB in WBD is lacking in 22/53 (42%) HTCs. The main reported knowledge and research gaps are lack of awareness & education on WBD among patients and caregivers, optimal diagnostic strategies and effective multidisciplinary management of pregnancy & HMB.

CONCLUSION

Joint clinics, prenatal diagnostics and algorithms for managing acute HMB are lacking in many European HTCs. HMB may be an underestimated issue. This survey highlights the need to prioritize improvement of knowledge and patient care for WBD across Europe.

The International Prospective Glanzmann Thrombasthenia Registry: Pediatric Treatment and Outcomes

Background  Standard treatment for Glanzmann thrombasthenia (GT), a severe inherited bleeding disorder, is platelet transfusion. Recombinant activated factor VII (rFVIIa) is reported to be effective in GT with platelet antibodies and/or refractoriness to platelet transfusions.

Methods  We evaluated rFVIIa effectiveness and safety for the treatment and prevention of surgical and nonsurgical bleeding in children <18 years old, with or without platelet antibodies and/or refractoriness, as reported in the GT Registry (GTR). Data were used from the GTR, an international, multicenter, observational, postmarketing study of rFVIIa that prospectively collected data on the treatment and outcomes of bleeds in patients with GT. Only patients with a diagnosis of congenital GT were included in the registry.

Results  Between 2007 and 2011, 27 children were treated for 44 surgical procedures (minor: 36; major: 8); nonsurgical bleeds occurred in 104 patients (599 episodes: severe, 145; moderate, 454; spontaneous, 423; posttraumatic, 176). The effectiveness of treatment for minor procedures, major procedures, nonsurgical bleeds was 6/6, 1/1, and 75/84 for rFVIIa, 6/6, 2/2, and 64/76 for rFVIIa + antifibrinolytics (AF), 11/12, 1/1, and 162/214 for platelets ± AF, and 5/6, 0/3, and 33/45 for rFVIIa + platelets ± AF. In all, 25 adverse events were reported in children; no thromboembolic events were reported.

Conclusion  For all patients, regardless of platelet antibody or refractoriness status, rFVIIa, administered with or without platelets (± AF), provided effective hemostasis with a low frequency of adverse events in surgical, as well as nonsurgical, bleeding in patients with GT.

clinicaltrials.gov identifier: NCT01476423.

Common themes and challenges in hemophilia care: a multinational perspective

OBJECTIVE

To identify ways that provision of hemophilia care can be maximized at the local level, irrespective of available resources or cultural or geographic challenges.

METHODS

The SHIELD group used its multinational experience to share examples of local initiatives that have been employed to deliver optimal hemophilia care.

RESULTS

The examples were reviewed and categorized into four key themes: guidelines and algorithms for delivery of care; collaboration with patients and allied groups for care and education; registries for the monitoring of treatment and outcomes and health care planning and delivery; and opportunities for personalization of care. These themes were then incorporated into a road map for collaborative care in hemophilia that reflected the contribution of best practice.

DISCUSSION

Differing healthcare reimbursement systems, budgetary constraints, and geographical and cultural factors make it difficult for any country to fully deliver ideal care for people with hemophilia. The SHIELD approach for collaborative care provides illustrative examples of how four key themes can be used to optimize hemophilia care in any setting.

ABBREVIATIONS

AHCDC: Association of Hemophilia Clinic Directors of Canada; AICE: Italian Association of Hemophilia Centres; ATHN: American Thrombosis and Hemostasis Network; EAHAD: European Association for Haemophilia and Allied Disorders; EHC: European Hemophilia Consortium; FIX: Coagulation Factor IX; FVIII: Coagulation Factor VIII; HAL: Haemophilia Activity List; HJHS: Haemophilia Joint Health Score; HTC: Hemophilia Treatment Centre; HTCCNC: Hemophilia Treatment Centre Collaborative Network of China; MASAC: Medical and Scientific Advisory Council; MDT: Multidisciplinary team; NHD: National Haemophilia Database; NHF: National Hemophilia Foundation; PK: Pharmacokinetics; POCUS: Point of care ultrasound; PWH: People with haemophilia; SHIELD: Supporting Hemophilia through International Education, Learning and Development; WFH: World Federation of Hemophilia.

Restricted BV gene usage by factor VIII-reactive CD4+ T cells in inhibitor-positive patients with severe hemophilia A

In the present study, we have analyzed the T cell receptor (TCR) repertoires of CD4+ T cells isolated from peripheral blood of 10 inhibitor-positive patients with severe hemophilia A. The distribution of complementarity determining region (CDR3) lengths of the beta chain of the TCRs was analyzed by spectratyping prior to and following in vitrostimulation of the cells with human factor VIII (FVIII). The repertoires of CD4+ T cells of patients were perturbed when compared to those of healthy blood donors. The perturbations of T cell repertoires were heterogeneous among patients with respect to the number and the nature of V-beta (BV) families that exhibited expansion following incubation with FVIII. Some patients showed alterations in one or two BV families, others exhibited more perturbed repertoires affecting 5 to 8 of the 14 BV families tested. Alterations of BV2, BV5 and/or BV9 were consistently found after incubation of CD4+ T cells in the presence of FVIII in 80% of the patients. These findings indicate that the presence of FVIII inhibitors in patients with severe hemophilia A is associated with measurable perturbations of the CD4+ T cell repertoire that results from oligoclonal expansion of FVIII-specific cells and may be relevant for the design of strategies aimed at modulating the anti-FVIII immune responses by T cell-targeted therapy

Development of inhibitory antibodies to therapeutic factor VIII in severe hemophilia A is associated with microsatellite polymorphisms in the HMOX1 promoter

Induction of heme oxygenase-1, a stress-inducible enzyme with anti-inflammatory activity, reduces the immunogenicity of therapeutic factor VIII in experimental hemophilia A. In humans, heme oxygenase-1 expression is modulated by polymorphisms in the promoter of the heme oxygenase-1-encoding gene (HMOX1). We investigated the relationship between polymorphisms in the HMOX1 promoter and factor VIII inhibitor development in severe hemophilia A. We performed a case-control study on 99 inhibitor-positive patients and 263 patients who did not develop inhibitors within the first 150 cumulative days of exposure to therapeutic factor VIII. Direct sequencing and DNA fragment analysis were used to study (GT)n polymorphism and single nucleotide polymorphisms located at -1135 and -413 in the promoter of HMOX1. We assessed associations between the individual allele frequencies or genotypes, and inhibitor development. Our results demonstrate that inhibitor-positive patients had a higher frequency of alleles with large (GT)n repeats (L: n≥30), which are associated with lesser heme oxygenase-1 expression (odds ratio 2.31; 95% confidence interval 1.46-3.66; P<0.001]. Six genotypes (L/L, L/M, L/S, M/M, M/S and S/S) of (GT)n repeats were identified (S: n<21; M: 21≤n<30). The genotype group including L alleles (L/L, L/M and L/S) was statistically more frequent among inhibitor-positive than inhibitor-negative patients, as compared to the other genotypes (33.3% versus 17.1%) (odds ratio 2.21, 95% confidence interval 1.30-3.76; P<0.01). To our knowledge, this is the first association identified between HMOX1 promoter polymorphism and development of anti-drug antibodies. Our study paves the way towards modulation of the endogenous anti-inflammatory machinery of hemophilia patients to reduce the risk of inhibitor development.

How I treat inhibitors in haemophilia

The management of patients with inhibitors is the greatest challenge facing haemophilia health professionals. Immune tolerance induction (ITI) can be successful in eliminating the inhibitor in the majority of patients, provided it is started soon after the inhibitor develops and the titre of the inhibitor is <10 BU at commencement of ITI. Acute bleeding is treated using one of two bypassing agents, which exhibit similar efficacy and safety. Surgery in inhibitor patients is challenging and should only be carried out in experienced centres.

Successful immune tolerance induction by FVIII in hemophilia A patients with inhibitor may occur without deletion of FVIII-specific T cells

BACKGROUND

 The development of an inhibitor is the major complication facing patients with hemophilia A treated by administration of factor (F) VIII concentrates. Restoration of tolerance to FVIII can be achieved by prolonged administration of FVIII (immune tolerance induction, ITI). Although ITI has been used for more than 30years in patients with hemophilia A and inhibitor, its mechanism of action is still poorly understood.

OBJECTIVES

 As administration of high doses of antigen can induce the apoptosis of the T cells recognizing the antigen, a potential mechanism of action of ITI may be the deletion of FVIII-specific T cells.

PATIENTS/METHODS

 We studied the CD4+ T-cell response to FVIII in five (one mild, one moderate and three severe) patients successfully desensitized by administration of FVIII and in control subjects.

RESULTS

 Following repeated stimulation with autologous dendritic cells loaded with FVIII, FVIII-specific T oligoclonal cell lines were expanded from the blood of one of the successfully desensitized patients. The FVIII-specific T cells produced IL-5, IL-13 and IL-2. By contrast, FVIII-specific T-cell lines could not be derived from three patients with mild hemophilia A without inhibitor or from four normal control subjects.

CONCLUSIONS

 These data represent the first analysis of the cellular mechanisms regulating the induction of tolerance to FVIII. They demonstrate that successful tolerance induction may occur without deletion of FVIII-specific T cells.

Factor VIII genotype and inhibitor development in patients with haemophilia A: highest risk in patients with splice site mutations

The appearance of inhibitory antibodies against factor VIII (FVIII) is the most severe and costly complication of replacement therapy in patients with haemophilia A (HA). To determine the relationship between FVIII genotype and inhibitor development, baseline FVIII activity, genotype and inhibitor development were reviewed in 1104 patients with HA. In patients with severe HA, splicing errors present the highest frequency of inhibitors, ahead of inversion of intron 1 and of intron 22, nonsense mutations and large deletions. The lowest inhibitor frequency in severe HA is found in patients with missense mutations and small deletions/insertions. Subanalyses indicate that nonsense mutations and small deletions/insertions leading to a frameshift in the light chain are associated with a significant higher risk of inhibitor formation than similar mutations occurring in the heavy chain (27% vs. 14%). These mutation types also have a higher frequency of inhibitors when occurring in exons 23-26, where a second FVIII transcript originates, compared with similar mutations in exons 1-22 (28% vs. 17%). These results suggest that complete absence of FVIII because of null mutations, including splice site mutations, or the absence of a second transcript result in an increased risk of inhibitor development.

A systematic approach to controlling problem bleeds in patients with severe congenital haemophilia A and high-titre inhibitors

The presence of inhibitory antibodies to clotting factors complicates the treatment of bleeding in haemophilia patients. For patients with high-titre inhibitors, bypassing agents are essential to haemostatic management. To determine optimal treatment practices, an international panel of physicians convened to develop a systematic treatment approach for problem bleeds (i.e. bleeds that are unresponsive to initial therapy with a single agent within a reasonable amount of time) in haemophilia patients with inhibitors.

AIM

The goal of this panel was to develop a consensus algorithm that would aid physicians in considering a variety of treatment approaches to optimize patient care by preventing extensive therapy with inadequate treatments that may lead to suboptimal patient outcomes and unnecessary costs.

METHODS

Consensus opinions were analyzed for clinical preferences at different time periods, depending on patient response to treatment. Decision-making points were defined based on the type of bleed: every 8-12 h for the first 24 h, then every 24 h thereafter for limb-threatening bleeds; every 2-4 h for 2-7 days for life-threatening bleeds.

RESULTS

The resultant consensus guidelines provide a generalized methodology to guide the treatment of problem bleeds in patients with severe haemophilia A and inhibitors, and emphasize changing treatment at the first sign of an inadequate haemostatic response. The treatment algorithms apply to both paediatric and adult patients, although the differences between the two groups were reviewed.

CONCLUSION

These guidelines are focused on optimising the timing of treatment decisions, which may lead to faster responses and improved outcomes.

Reappraisal of in utero stem cell transplantation based on long-term results

The therapeutic field of in utero transplantation of stem cells, into human fetuses, has developed since 1988 with the hope of improved probability of engraftment and tolerance, due to immune immaturity of the host. Fifteen years later, it is possible to evaluate the results that we and others have obtained in the treatment of several fetal diseases. Seven fetal patients have been treated in Lyon: In 2 cases, pregnancy termination was induced by the in utero injection; in the 5 other cases, engraftment was obtained and repeatedly documented with presence of donor HLA antigens and/or Y chromosome in recipients. In the 2 patients with combined immunodeficiency disease, a sustained reconstitution of immunity was obtained as a result of the transplant but other complications occurred thereafter. In patients with thalassemia major, Niemann-Pick disease or hemophilia, a very partial and very transitory benefit was only obtained. Approximately 33 other patients with immunodeficiencies, hemoglobinopathies or inborn errors of metabolism have been treated worldwide, over the last 13 years, with a comparable method, using parental or fetal stem cells transplanted in utero. Successful treatment has usually been recorded in immunodeficiencies, and insufficient results have been obtained in the other cases. This form of treatment can therefore be recommended after prenatal diagnosis of combined immunodeficiency but additional research is required to improve the degree of engraftment, the lack of resistance of the host and the 'space' available for hematopoiesis in the other conditions.

Prophylactic and therapeutic recombinant factor VIIa administration to patients with Glanzmann's thrombasthenia: results of an international survey

BACKGROUND

Antibodies to glycoprotein (GP) IIb-IIIa and/or HLA may render platelet transfusions ineffective to stop bleeding or to cover surgery in patients with Glanzmann's thrombasthenia (GT). Anecdotal reports suggest recombinant factor (rF)VIIa might be a therapeutic alternative in these situations.

OBJECTIVES

An international survey was conducted to evaluate further the efficacy and safety of rFVIIa in GT patients.

PATIENTS

We analyzed the use of rFVIIa during 34 surgical/invasive procedures and 108 bleeding episodes in 59 GT patients including 29 with current or previous antiplatelet antibodies, and 23 with a history of refractoriness to platelet transfusion.

RESULTS

rFVIIa was effective in 29 of the 31 evaluable procedures, and in 77 of the 103 evaluable bleeding episodes of which eight had a recurrence. A significantly higher success rate was observed in severe bleeding episodes when an arbitrarily defined 'optimal regimen' derived from the Canadian pilot study results (> or = 80 micro g kg(-1) rFVIIa/injection, dosing interval < or = 2.5 h, three or more doses before failure declaration) was used compared with other regimens (77%; 24/31 vs. 48%, 19/40; chi(2), P = 0.010). Patients given maintenance doses had significantly fewer recurrences within 48 h of bleed cessation compared with those not given any (Fisher's exact test, P = 0.022). One thromboembolic event and one blood clot in the ureter occurring in surgical patients following prolonged continuous infusion of high-dose rFVIIa and antifibrinolytic drug use have been previously reported.

CONCLUSION

rFVIIa seems a potential alternative to platelet transfusion in GT patients, particularly in those with antiplatelet antibodies and/or platelet refractoriness.

Molecular mechanisms of mild and moderate hemophilia A

Mutations responsible for mild/moderate hemophilia A were extensively characterized over the last 15 years and more than 200 mutations have been identified. However, most of the molecular mechanisms responsible for the reduced factor (F)VIII levels in patients' plasma were determined only recently. Recent progresses in the study of the FVIII molecule three-dimensional structure provided a major insight for understanding molecular events leading to mild/moderate hemophilia A. This allowed prediction of mutations impairing FVIII folding and intracellular processing, which result in reduced FVIII secretion. Mutations potentially slowing down FVIII activation by thrombin were also identified. A number of mutations were also predicted to result in altered stability of activated FVIII. Biochemical analyses allowed identification of mutations reducing FVIII production. Mutations impairing FVIII stability in plasma, by reducing FVIII binding to von Willebrand factor (VWF) were also characterized. Defects in FVIII activity, notably slow activation by thrombin, or abnormal interaction with FIXa, were also recently demonstrated. Biochemical analysis of FVIII variants provided information regarding the structure/function relationship of the FVIII molecule and validated predictions of the three-dimensional structure of the molecule. These observations also contributed to explain the discrepant activities recorded for some FVIII variants using different types of FVIII assays. Altogether, the study of the biochemical properties of FVIII variants and the evaluation of the effects of mutations in three-dimensional models of FVIII identified molecular mechanisms potentially explaining reduced FVIII levels for a majority of patients with mild/moderate hemophilia A. It is expected that these studies will improve diagnosis and treatment of this disease.

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.

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.

[Which urologic treatment alternatives are there for the hemophiliac patient?]

OBJECTIVE

Urological procedures are hazardous for hemophilic patients. The aim of this work is to report the treatment of 22 hemophilic patients in order to define prognosis factors and treatment options.

MATERIAL AND METHODS

22 patients have been treated: 8 had severe hemophilia, 5 A (FVIII < 1%), 3 B (F IX < 1%), 2 had moderate hemophilia A (FVIII 2 to 6%) and 10 minor hemophilia A (F VIII 7 to 30%). Two had acquired hemophilia with auto-anti-FVIII antibodies (ab). Four patients were HIV+. Eighteen patients were first referred to our hospital, and 3 were transferred from an other institution for persistent hematuria: one with anuria, one after bladder neck incision, and the other following suprapubic prostatectomy.

RESULTS

For patients without FVIII ab, a sufficient level of FVIII or IX (> 60%), could be achieved pre-operatively and maintained post operatively (4 to 20 days, according to the surgical procedure) by injections of FVIII, FIX or by injections of desmopressin. For one haemophilia A patient with anti-F VIII ab, transferred for uncontrollable bleeding after bladder neck incision, selective arterial embolization was successful. But for 2 patients with acquired haemophilia, improvement of the coagulation was insufficient, with human or porcine FVIII, activated prothombic complex concentrates or recombinant activated FVII. In spite of surgical procedures and arterial embolizations the 2 patients died.

CONCLUSION

The urological treatment of haemophilic patients needs to be performed in specialised centers. For patients without FVIII ab, classical urological procedures can be performed. But for patients with FVIII ab when alternative treatments (radiotherapy, LHRH agonists) can be used, the surgical procedures must be delayed; in emergency if hemostasis cannot be achieved arterial embolization could be useful.

Antibodies to the FVIII light chain that neutralize FVIII procoagulant activity are present in plasma of nonresponder patients with severe hemophilia A and in normal polyclonal human IgG

We have analyzed the properties of anti-factor VIII (FVIII) immunoglobulin (Ig) G recovered by affinity chromatography on FVIII-Sepharose from the IgG fraction of the plasma of healthy individuals and nonresponder patients with hemophilia A. Affinity-purified anti-FVIII antibodies were found to neutralize FVIII activity and to bind to FVIII with an affinity similar to that of anti-FVIII IgG that had been affinity-purified from the plasma of inhibitor-positive hemophilia patients and of patients with anti-FVIII autoimmune disease. The antibodies also exhibited patterns of reactivity with thrombin-digested FVIII similar to those of FVIII inhibitors and preferentially recognized epitopes located in the light chain of FVIII. These observations suggest that FVIII inhibitors occurring in hemophilia A and in patients with anti-FVIII autoimmune disease originate from the expansion of preexisting natural anti-FVIII clones that exhibit FVIII-neutralizing properties.