First-time development of FVIII inhibitor in haemophilia patients during the postoperative period

Overcoming the challenges of treating hemophilia in resource-limited nations: a focus on medication access and adherence

BACKGROUND

Hemophilia is a high cost low volume disease. Resource limited nations (RLN) usually spend very little on health budget and most of it is spent in dealing with common ailments. Clotting products constitute more than 90% of the total cost of hemophilia care. The manner in which these products can be made accessible for persons with hemophilia (PWH) and how its continuous supply and distribution can be maintained and improved is described in this review.

AREAS COVERED

Number of PWH in the Resource Limited Nations (RLN); minimum amount of concentrate required to keep a PWH relatively free of bleeds; the different products available for management of PWH; means and ways to minimize and optimize the concentrate usage and purchase on a budget; nonfactor therapy; ways and means to improve the management and allow better quality concentrates in higher quantities for PWH in those countries; adherence as a challenge for RLN country and ways to manage them. The time covered is from 1980s till date. Pubmed was searched mainly for review articles with the key words hemophilia, RLN, concentrate access, alternative therapy. Cross references from these reviews as well as some of the abstracts from international conferences were read.

EXPERT OPINION

Developing a patient's society and a bleeding disorder registry are the two most important actions toward ensuring adequate treatment material for PWH in RLN. Government should allocate a budget for hemophilia care depending on the number of PWH diagnosed and future projection of increased numbers of PWH. Population based product requirement may not work initially as only 10-20% of PWH in such a country has been diagnosed hence initial requirement of concentrates should be directed to these patients. Meanwhile efforts should be made to diagnose new cases. Antenatal diagnosis centers should offer antenatal diagnosis and prevent birth of severe hemophilia children. Self sufficiency in plasma based concentrates should be planned and aimed. A national tendering committee can get a good price on the concentrates on global tendering with annual rate contracts (prevents outdating). Avoiding wastage by outdating of the products in large denomination vials will help. Hoarding concentrates in unreasonable amounts should be avoided through good supply chain management. Regular physiotherapy, proper use of optimum amounts of concentrate will reduce per PWH consumption of the factor concentrates. Plasma derived intermediate purity factors, first/second generation recombinant clotting factors are safe and relatively cheaper as well as effective. Also concentrates which are close to their expiry date (>3 < 6 months) are equally effective and cheap. With proper supply chain management such products can be included in the portfolio. Primary prophylaxis with low/ intermediate dose of the concentrates is a cost-effective way to manage the patients and this also reduces inhibitor development. Adherence to therapy is not yet an important issue for RLN countries but will become one in future. With advancement and improvement the country can access alternative non factor concentrates and other newer products.

Inhibitor development in mild haemophilia after a major surgery for periampullary cancer (Whipple's procedure) in an elderly man

Around the world, with the availability of factor concentrates, patients with haemophilia have undergone major and minor surgeries. Inhibitor development in early postoperative period leading to inadequate factor recovery and ongoing bleeding is a nightmare for both operating surgeon as well as haematologists. We describe a case of an elderly man with mild haemophilia A, who was diagnosed with pancreatic carcinoma and underwent Whipple's procedure. After an uneventful procedure, he developed high-titre inhibitors and bleeding a week after surgery posing major challenges in his management. The case highlights the importance of experienced surgeons, trained haematologists, regular monitoring of factor assay/inhibitors, adequate factor and bypassing-agent support while performing such procedures.

F8 gene mutation profile in Indian hemophilia A patients: Identification of 23 novel mutations and factor VIII inhibitor risk association

'FVIII inhibitors', especially in severe hemophilia A (HA) patients, is a serious adverse effect that complicates their clinical management. Many genetic and non-genetic risk factors have been proposed for FVIII inhibitor development, diverse in different population groups. This is the first study in Indian hemophiliacs that analyzes inhibitor risk in relation to the complete F8 mutation profile, in a case-control study that included 145 Indian severe HA patients, i.e. 69 inhibitor positive (with 18 inhibitor concordant/discordant family members), and 58 inhibitor negative patients, after informed consent. While 53.54% (68/127) index cases were positive for intron 22 or intron 1 inversions, 55 causative F8 mutations were detected in the 59 inversion negative patients, of which 23 were novel mutations (in 24 patients) and 32 were reported earlier (in 35 patients). A higher incidence of mutations, in the C1 and C2 domains in inhibitor positive patients, and in the A1 domain in inhibitor negative patients was observed, though not significantly different. The study suggests that large F8 rearrangements (significantly higher in the inhibitor positive patients) pose the highest risk, while missense mutations (significantly higher in the inhibitor negative patients) pose the lowest risk of inhibitor development in Indian hemophilia A patients.

Antibody profile in Indian severe haemophilia A patients with and without FVIII inhibitors

Diagnosis and management of haemophilia patients with inhibitors is often tricky due to the heterogeneous nature of the antibodies with regard to their kinetics, as well as the co-existence of other interfering antibodies. Plasma samples from severe haemophilia A patients from India with and without FVIII inhibitors were analysed for the presence of possible co-existing antibodies such as lupus anticoagulants (LA), anti-cardiolipin antibodies (ACLA), anti-β2-glycoprotein-I (anti-β2-GP-I) antibodies, viral transfusion transmitted disease (HIV, HBsAg, HCV) related antibodies, anti-cyclic citrullinated peptides (anti-CCP), and anti-nuclear antibodies. A high incidence of LA and anti-HCV antibodies was detected in Indian haemophilia A patients similar to earlier reports. More importantly, a relatively high incidence of autoantibodies to nuclear antigens (18.62%) and anti-CCP antibodies (1.38%) associated with autoimmune disorders was also seen in these congenital haemophilia A patients with and without inhibitors. Knowledge on the antibody profile in these haemophilia patients especially in those with FVIII inhibitors along with correlation with the clinical manifestations and other risk factors for inhibitor development could possibly shed more light on the complex immune response in these patients.

Management of Haemophilia in Developing Countries: Challenges and Options

There are significant challenges in managing haemophilia patients in developing countries. These challenges are (i) Lack of proper health care infrastructure and human resources suitable for haemophilia care (ii) Competing health care priorities of the government. (iii) Lack of penetrance of medical insurance in the population. (iv) Lesser visibility of the haemophilia patients in health care system (v) Low awareness across the medical profession, population and the policy makers about the condition (vi) Non availability of factor concentrates (vii) Inadequate utilization of knowledge for reducing factor concentrate use. (viii) Inadequate pain relief (ix) Challenges due to inhibitor developing (x) Viral hepatitis & (xi) Lack of research publications relevant to the country are some of the challenges faced by PWH for their management in developing country. The solutions are not easy but development of a strong patient organization with linkages with World Federation of Haemophilia is an important initial step. Following that internal and international twinning, use of internal sources, strong advocacy programme targeting government, doctors, opinion makers will solve many of the challenges in the time to come.

The Epidemiology of FVIII Inhibitors in Indian Haemophilia A Patients

A serious complication of replacement therapy in patients with bleeding disorders is the development of 'inhibitors', particularly FVIII inhibitors in haemophilia A patients. This leads to an increase in the management cost, morbidity and mortality, especially post-operatively. The mechanism of FVIII inhibitor development is quite complex and it is difficult to predict inhibitor development, but a prompt and accurate diagnosis is critical as early therapy can save lives. The aim of this study was to screen patients with bleeding disorders in India for inhibitors, and to analyse and compare the prevalence of inhibitors in different regions in India. Patient details were recorded and blood samples were collected in sodium citrate vacutainers from 1,505 patients with bleeding disorders, in different cities in India. Coagulation and inhibitor screening assays were performed, followed by the Bethesda assay in inhibitor positive samples to quantify the FVIII inhibitor titre. Out of the 1,505 samples analysed, 1,285 were Haemophilia A patients, out of which 78 (6.07 %) were positive for 'FVIII Inhibitors'. The highest incidence of FVIII Inhibitors was seen in South India (13.04 %). The highest incidence of 20.99 % was observed in Chennai, followed by Hyderabad (13.33 %), Jammu (9.90 %) and Guwahati (8.51 %), respectively, with respect to the samples analysed. The other regions showed an inhibitor incidence <8 %. The incidence of inhibitors in haemophilia A patients is different in different regions of India; this may be due to the intensity of treatment, type of product or the genetic characteristics of these patients.

Risk of bleeding and inhibitor development after circumcision of previously untreated or minimally treated severe hemophilia A children

BACKGROUND

Surgery and intensive factor VIII (FVIII) replacement may be risk factors for development of inhibitors.

OBJECTIVE

To evaluate time and rate of inhibitor development postcircumcision over 12-month period, and to assess bleeding of children with severe hemophilia A after low-dose FVIII replacement and local hemostasis.

PATIENTS AND METHODS

Sixty-one previously untreated patients (PUPs) or minimally treated patients (MTPs) with severe hemophilia A less than 36 months were enrolled; 25 underwent circumcision during the 18-month enrollment period, and 36 matched patients were not circumcised. All patients were treated on demand with plasma-derived FVIII, and all were inhibitor negative at the time of enrollment. Intron 22 inversion was analyzed. A potent hemostatic agent (gelatin sponge) was applied on the site of surgery, and then dressed with gauze. Two doses of FVIII concentrate (25 U/kg) were given, 1 hour before circumcision and 1 hour before removal of dressing. The inhibitor was determined every 8 exposure days (EDs).

RESULTS

None of the patients had bleeding or infection, except one who had minimal transient bleeding 8 days after surgery, and was treated easily by a single dose of FVIII (50 U/kg). After a median of 16 EDs, high-titer inhibitors developed in seven patients: three patients in the circumcised group (12%) in contrast to four patients (11.1%) in the noncircumcised group.

CONCLUSION

Two doses factor concentrate and gelatin sponge application were generally enough to prevent bleeding after circumcision of severe hemophilia A. Circumcision and low-dose FVIII protocol were not an additional risk for development of high-titer inhibitor.

Immune regulatory gene polymorphisms as predisposing risk factors for the development of factor VIII inhibitors in Indian severe haemophilia A patients

Development of inhibitors to factor VIII, a serious complication of replacement therapy in haemophilia A patients, leads to increased bleeding, morbidity and mortality. There is no data on the risk factors for inhibitor development in Indian patients with severe haemophilia A. Our aim was to study the role of immune regulatory gene polymorphisms in the development of inhibitors. Fourteen immune regulatory gene polymorphisms (IL1β, IL4, IL10, TNFA and CTLA4) were analysed in 120 patients with severe haemophilia A, i.e. 50 inhibitor positive patients, and 70 inhibitor negative control patients, by PCR-RFLP, DNA sequencing and allele-specific PCRs. The IL10 promoter 'GCC' haplotypes overall (P: 0.002, OR: 3.452, 95% CI: 1.607-7.416), and 'GCC/ATA' (P: 0.011, OR: 3.492, 95% CI: 1.402-8.696) haplotype, associated with high and intermediate IL10 production, respectively, were significantly higher in inhibitor positive patients, whereas the 'non-GCC' haplotypes overall (P: 0.002,OR: 0.290, 95% CI 0.135-0.622) and 'ATA/ATA' haplotype (P: 0.025, OR: 0.278, 95% CI: 0.096-0.802), associated with low IL10 synthesis, were significantly higher among inhibitor negative patients. The TNFA rs1799724 C/T heterozygote prevalence was significantly higher in the inhibitor positive group (P: 0.021, OR: 3.190, 95% CI: 1.273-7.990), whereas the other polymorphisms showed no statistically significant association with the presence of inhibitors. Different immune regulatory gene polymorphisms play a significant role as possible risk factors for the development of inhibitors in severe haemophilia A patients.

Hemostasis research in India: past, present, and future

Hemostasis research in India has a long history considering the fact that it is one of the youngest specialities in the world. If we take creation of prothrombin time (PT) test as one of the beginning of modern hemostsis research, then the specialty is no older than 60 years. School of Tropical Medicine Kolkata, Banaras Hindu University, All India Institute of Medical Sciences at Delhi, Christian Medical College at Vellore, Post Graduate Institute of Medical Education and Research at Chandigarh, and KEM Hospital at Mumbai contributed substantially in defining various bleeding disorders in our country. Unfortunately, some of these institutes are no longer as active in the field as they used to be. Currently, the Institute of Immunohaematology at Mumbai, Chrstian medical College at Vellore, and All India Institute of Medical Sciences at Delhi are actively engaged in hemostsis research in India. Developing prenatal diagnostic technologies, mutation detection of various hemostatic disorders, developing low-cost management technologies for hemophilia, and other bleeding disorders are becoming important present day research activity in the area of hemostasis in addition to age old areas of prevalence and unusual case description studies. Entry of many new corporate hospitals, development of structured postgraduate training program in hematology, and easy availability of instruments and reagents are likely to foster further growth in this area of medical research in India in future.

A case report on the surgical treatment of the huge inflammatory pseudotumor in the AIDS patient with hemophilic

An HIV infected hemophilia patient with huge inflammatory pseudotumor was in severe ill condition. The operation of right hip joint amputation was performed on the patient with perioperative infusion of coagulation factor VIII and highly active antiretroviral therapy (HAART). The pathological found that Inflammatory cell infiltration, formation of folliculus lymphaticus, muscular fiber breakage, and fibrous tissue hyperplasy, necrosis in both soft tissue and bone were seen in inflammatory pseudotumour. The vital signs remained stable during the operation and patient's overall health condition improved significantly ten months after operation. With the infusion of coagulation factor VIII and HAART, HIV infected hemophilia patient can be safety operation and may get effective result.

Hemophilia care in India: a review and experience from a tertiary care centre in uttar pradesh

Approximately 14,000 people with hemophilia are registered at the Hemophilia Federation of India; however, hemophilia remains under-diagnosed and many cases are not registered. In June 2009, the Government of Uttar Pradesh made anti-hemophilic factors available at a few centers, including the Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow. Consequently, the level of hemophilia care has improved considerably in recent times. Amongst the many challenges facing people with hemophilia, the development of inhibitors, which neutralize clotting factors provided by replacement therapy, is the most feared one. Healthcare professionals who treat people with hemophilia should not only be knowledgeable about the condition and committed to bettering the management of hemophilia, but also take responsibility for the judicious allocation of resources for various aspects of managing hemophilia. This manuscript aims to raise awareness regarding the detection and management of inhibitors in hemophilia based on the experience of a tertiary care hemophilia treatment centre in Uttar Pradesh, India.

Haematology research in India: past, present and future

Haematology research in India is relatively recent in origin. However the pioneers in the field not only did exemplary work when compared to advanced western countries, they also made it a point to develop centres of excellence and human resources for future of haematology work in this country. In this brief overview an effort has been made to give a taste of quality and expanse of haematology research in this country. This review does not claim to have described every bit of haematology research in this country. Our pioneers worked under extremely difficult and trying circumstances on a subject which was limited to funding available from Indian Council of Medical Research. Now the times have changed, several funding agencies in the country are able to provide substantial fund for research. Modern state of the art basic research institutions are tying up with medical colleges for good quality research and the seeds which our pioneers had planted have grown into a mighty tree. It would not be an exaggeration to say we are on the threshold of the golden era of haematology research in this country.

Non-genetic risk factors and the development of inhibitors in haemophilia: a comprehensive review and consensus report

SUMMARY

The development of inhibitors to the infused factor in patients with haemophilia is a serious clinical problem. Recent evidence suggests that alongside the strong genetic contribution to inhibitor formation, there are a number of non-genetic factors--perceived by the immune system as danger signals--which promote formation of inhibitors. This study provides a comprehensive review of clinical studies relating to these factors and also presents a survey of opinion concerning their importance and clinical influence, conducted among the members of the European Haemophilia Treatment Standardisation Board (EHTSB). Taken together, this information highlights the lack of robust data concerning the influence of several non-genetic risk factors on inhibitor development, and an urgent need for prospective, well-conducted studies that adhere to recommendations made by the European Medicines Agency (EMEA) for studying inhibitors. Based on current literature, the EHTSB formulated consensus recommendations. It is desirable to minimize intensive treatment wherever possible, given the clinical situation. Prophylaxis should be offered to all children, although we still need to determine optimal dosing with respect to inhibitor development, and age for starting treatment. Vaccinations should be given subcutaneously and concomitant factor concentrate infusions avoided. According to the board, there is no evidence in the literature supporting suggestions that the type of concentrate influences inhibitor risk; but all patients should be monitored during their first exposures. Furthermore, there is no evidence to support an association between pregnancy-related issues, breast feeding and treatment-related factors (e.g. route of administration, or use of blood components) and inhibitor development.

Immune response to FVIII in hemophilia A: an overview of risk factors

Development of inhibitors is perhaps the most serious complication of factor VIII (FVIII) replacement therapy, which can practically preclude efficient clinical management of patients with hemophilia A. Much effort therefore has been focused both in improving our understanding of the reasons for the formation of FVIII antibodies and to find alternative methods of treatment. Several patient-related factors have been related to the risk of inhibitor development such as ethnicity, FVIII gene mutation type, family history of inhibitors, HLA haplotype, polymorphisms in the promoter regions of IL 10 gene, single nucleotide polymorphisms of tumor necrosis factor alpha gene, and so on. In addition to the genetic determinants, there are several nongenetic factors which mainly include treatment characteristics like the type and purity of coagulation factor concentrates used for treatment, age at the time of initial treatment, initial doses of concentrate, mode of infusion, surgery, frequency of dosing prior to inhibitor development, and intensity of treatment or regular prophylaxis. Inflammatory processes in early childhood are under discussion as being an environmental factor that may modify the immune response to a foreign antigen. The genetic risks cannot be changed, while environmental factors may increase or decrease the inhibitor risk in an individual patient. In addition, there are other causes of inhibitor development against FVIII like stress, age, malignancy, infection, pregnancy, antibiotics, etc. Development of inhibitors in such cases happens in individuals who are not hemophilic and have normal plasma FVIII levels. Acquired inhibitors to FVIII in nonhemophiliacs (autoantibodies) pose a further challenge to treatment, as this is often associated with significant morbidity and mortality. Prognosis in case of autoantibodies is related to the underlying disease process and is associated with high mortality. Improved understanding of these complex interactions may lead to the development of preventive measures to minimize FVIII inhibitor formation. The modifiable risk factors for inhibitor formation may provide the key to predict and perhaps prevent the formation of inhibitors in hemophilia patients.

The need for previously untreated patient population studies in understanding the development of factor VIII inhibitors

The presence of inhibitory antibodies to factor VIII (FVIII) remains one of the most serious complications of haemophilia therapy. Accordingly, understanding risk factors that may contribute to inhibitor developments in young patients with haemophilia A continues to be an area of great interest. Previously untreated patient (PUP) population studies have been instrumental in understanding the aetiology of inhibitor development. These studies have revealed the importance of risk factors such as clotting factor exposure history, ethnicity, and FVIII genotype in the development of inhibitors, while also providing insights into potential risk factors that may be related to therapeutic practice. However, due to differences in study designs and patient populations among previous PUP studies, there are limitations to the value of these studies in deciphering the role of potential risk factors. Therefore, future PUP studies should be prospective, consistent in their study designs and consider all established parameters and also those that possibly may influence inhibitor formation, thereby facilitating a better understanding of the aetiology of inhibitor formation in haemophilia A patients.

Continuous infusion of coagulation factors: current opinion

PURPOSE OF REVIEW

To review the most recent reports on continuous infusion of coagulation factors, focusing on the current issues relating to this mode of therapy.

RECENT FINDINGS

Continuous infusion has been extensively used as an alternative to intermittent bolus factor replacement since the 1990s. To date, more than 100 reports comprising more than 800 continuous infusion treatments in various clinical situations have been published, with an increase in the current utilization of recombinant coagulation factors. An excellent hemostatic efficacy of continuous infusion has been reported. Continuous infusion protocols, however, still vary widely in terms of the different hemostatic levels targeted, dosage regimens, modes of continuous infusion and duration of therapy, which obviously result in variations in the cost-effectiveness reported by different centers.

SUMMARY

Continuous infusion has been shown to be a safe and cost-effective mode of replacement for treatment of hemophilia. The lack of evidence-based information on the hemostatic levels to be maintained in specific clinical situations, and recent concerns regarding the development of inhibitors, particularly in patients with mild hemophilia treated with continuous infusion, need to be addressed by prospective, randomized studies that compare traditional intermittent injections and the continuous infusion mode of factor replacement.

Prophylactic treatment effects on inhibitor risk: experience in one centre

Nowadays, the elective treatment for children with haemophilia is prophylaxis. There is a common consensus that this modality of therapeutic approach is not associated with a higher risk of inhibitor development. We analysed the inhibitor incidence in 50 haemophiliac children and its relationship with mutations, type of clotting factor used and treatment modality. There was a significant correlation between receiving on-demand treatment and an increased incidence of inhibitors, independently of mutations or factor used. We advise putting haemophiliac children under prophylactic treatment as soon as possible, especially if they have mutations associated with high risk of inhibitor development, as prophylaxis is negatively associated with the development of inhibitors.

Management of haemophilia and its complications in developing countries

Eighty per cent of people with haemophilia live in developing countries, where technical expertise and health care facilities may be less than optimal. Haemophilia is a relatively rare disease and high-cost, technology-intensive therapy is not a high priority for the governments of developing countries. The rapid spread of transfusion-related viral infections in many developing countries presents further problems for haemophiliacs. However, it is possible to manage haemophiliacs patients with limited resources. Strategies for conserving factor concentrates, include education of doctors and patients, prenatal diagnosis, increasing the use of anti-fibrinolytic agents, physiotherapy, the use of fibrin glue, and simple orthotics and prosthetic measures. These approaches are helpful in the majority of these patients. Meanwhile, with the help of the World Federation of Haemophilia (WFH), all developing countries are gradually improving management skills for this relatively rare but disabling disease. The present review broadly describes the management of various aspects of severe haemophilia in developing countries.

Role of epsilon amino caproic acid in the management of haemophilic patients with inhibitors

We managed bleeding crisis in 10 consecutive severe haemophilic patients with inhibitors (eight had an inhibitor level of >5 BU mL(-1)) mainly with the antifibrinolytic agent, i.e. epsilon amino caproic acid (EACA). EACA was used by local, oral or intravenous routes either in combination or separately. Five patients developed inhibitors postoperatively and among the remaining five, four had recurrent haemarthrosis or soft tissue bleeds and one patient presented with severe gastrointestinal bleeding without demonstrable lesion. In all the patients, addition of EACA to their management protocol resulted in stoppage and/or reduced frequency of bleeding. In six of 10 patients, the results were excellent; of these six patients, five developed inhibitors postoperatively. Although a reduction in the frequency of bleeding was observed in patients with haemarthrosis and soft tissue bleed, it was not spectacular and the patients required additional therapy. Hence the results could be described as poor. No patient needed to stop the medicine because of the side-effect of EACA. Symptoms like mild nausea and vertigo were seen as the side-effects of this medicine when high intravenous dosage was administered. EACA thus appears to be an excellent adjuvant therapy for haemophilic patients with inhibitors. Besides its well-recognized antifibrinolytic activity, EACA may have additional mechanisms of action in haemophilic patients with inhibitors. More extensive use of this cheap and safe product is warranted in haemophilic patients with inhibitors. If larger studies confirm this observation, then using antifibrinolytics will allow substantial reduction of FEIBA or activated prothrombin complex (APCC) usage in such patients without necessarily increasing the thrombotic complications or reduction of the clinical efficacy, when compared with higher dosage of FEIBA or APCC alone. This will lead to substantial financial savings in countries where up to 35% of severe haemophilia A patients develop inhibitors.

Congenital bleeding disorders

Both clinical and basic problems related to the congenital bleeding disorders continue to confront hematologists. On the forefront are efforts to bring genetic correction of the more common bleeding disorders such as hemophilia A to the clinic in a safe and accessible manner. A second issue, particularly for patients with hemophilia, is the development of inhibitors-questions of how they arise and how to prevent and treat these problems that confound otherwise very successful replacement therapy and allow patients to maintain normal lifestyles. A third issue is the continuing question of diagnosis and management of von Willebrand disease, the most common congenital bleeding disorder, especially in individuals who have borderline laboratory values, but have a history of clinical bleeding. In Section I, Dr. Christopher Walsh discusses general principles of effective gene transfer for the hemophilias, specific information about viral vectors and non-viral gene transfer, and alternative target tissues for factor VIII and factor IX production. He highlights information about the immune response to gene transfer and reviews data from the hemophilia gene transfer trials to date. The future prospects for newer methods of therapy such as RNA repair and the use of gene-modified circulating endothelial progenitors are presented as possible alternatives to the more traditional gene therapy approaches. In Section II, Dr. Nigel Key focuses on inhibitor development in patients with hemophilia A. He reviews the progress in our understanding of the risk factors and presents newer information about the immunobiology of inhibitor development. He discusses the natural history of these inhibitors and the screening, laboratory diagnosis, and treatment, including the use of different modalities for the treatment of acute bleeding episodes. Dr. Key also presents information about the eradication of inhibitors by immune tolerance induction and reviews recent information from the international registries regarding the status and success of immune tolerance induction. In Section III, Dr. Margaret Rick discusses the diagnosis, classification, and management of von Willebrand disease. Attention is given to the difficulty of diagnosis in patients with mild bleeding histories and borderline laboratory test results for von Willebrand factor. She presents the value of different laboratory assays for both diagnosis and classification, and she relates the classification of von Willebrand disease to the choice of treatment and to the known genetic mutations. Practical issues of diagnosis and treatment, including clinical cases, will be presented.