Effect of the Factor V Leiden Mutation on the Clinical Expression of Severe Hemophilia A

To determine whether the factor V Leiden mutation is associated with decreased bleeding in individuals with severe hemophilia A, factor concentrate utilization, maximum annual number of bleeding episodes, and the prevalence of hemophilic arthropathy between carriers and non-carriers of the factor V Leiden mutation were compared. Heterozygosity for the factor V Leiden mutation was found in 6 of 137 subjects (4.4%). Carriers of the factor V Leiden mutation utilized less factor concentrate (geometric mean: 310 vs. 1185 units/kg/year) and had fewer bleeding episodes than non-carriers (proportion with 10 or fewer bleeding episodes in their worst year: 50 vs. 11%). However, the factor V Leiden mutation was not associated with the absence of arthropathy. The intron 22 inversion mutation of the factor VIII gene was tested for in a subgroup of 80 subjects, but it was not found to be a significant variable for any of the bleeding endpoints. The results of this small study are consistent with the hypothesis that the factor V Leiden mutation imparts a protective effect; however, a larger confirmatory study in which the factor VIII molecular defects can be controlled for is needed. Furthermore, most severe hemophiliacs who used fewer than 200 units/kg/year of factor concentrate or who had experienced 10 or fewer bleeding episodes per year did not carry the factor V Leiden mutation, suggesting that the proportion of severe hemophiliacs whose mild clinical course can be attributed to the factor V Leiden mutation is small.

Efficacy and Safety of the Factor VIII/von Willebrand Factor Concentrate, Haemate-P/Humate-P: Ristocetin Cofactor Unit Dosing in Patients with von Willebrand Disease

The present study was initiated to evaluate the safety and efficacy of Haemate-P® (Humate-P® in North America) (anti-hemophilic FVIII/VWF complex [human] dried, pasteurized) dosed in ristocetin cofactor units (VWF:RCo) in the treatment of von Willebrand disease (VWD) patients in Canada. This retrospective data collection reviewed the medical records of VWD patients treated under the Canadian Emergency Drug Release Program from November 22, 1991, to April 30, 1996. Data collection was accomplished by on-site retrieval from source data for 97 patients. Dosing was based on the German package insert, which lists only Factor VIII:C (FVIII:C) units, which were converted in the study analysis to VWF:RCo units based on the analysis of the individual manufactured lots of product used in these patients (average ratio of 2.6 IU VWF:RCo per IU FVIII:C). Twenty five different lots of Haemate-P/Humate-P were used to treat 437 different events in the 97 study patients (344 hemorrhagic events, 73 surgical interventions and 20 prophylactic infusion cycles). Overall, the median dose of concentrate per infusion used to treat surgical events was 69.1 IU VWF:RCo/kg (range 11.9-222.8); bleeding events 55.3 IU VWF:RCo/kg (range 17.1-227.5) and prophylaxis 41.6 IU VWF:RCo/kg (range 34.6-81.0). Treatment periods varied, with the majority of events treated for ≤ 10 days (91%). Fifty percent of events that were treated longer than 10 days were given for prophylactic reasons. Efficacy was determined in a standardized manner by the physician, based on dosing in VWF:RCo activity. An overall clinical result of “excellent” or “good” was reported in 97% (424/437) of treatment events. A pediatric sub-population analysis of the patient population reported “excellent/good” efficacy in 100% (17/17) of treatment events in infants, 95% (155/164) in children, and 94% (76/81) in adolescent patients. Related adverse events (AEs) were observed in only 4 (4%) patients and were not deemed to be serious. The findings in this study confirm the safety and efficacy of Haemate-P/Humate-P using VWF:RCo dosing in pediatric and adult patients with various types of VWD.

Describing the quality of life of boys with haemophilia in China: Results of a multicentre study using the CHO-KLAT

INTRODUCTION

The treatment of haemophilia varies across countries and across regions within some countries. Similar variation has been observed in health-related quality of life (HR-QoL). Relatively little is known about the HR-QoL of boys with haemophilia in China.

AIM

The aim of this study was to describe the HR-QoL of boys with haemophilia in China using the Canadian Haemophilia Outcomes-Kids Life Assessment Tool (CHO-KLAT).

METHODS

Boys (4-18 years of age) with haemophilia and their parents were enroled in a cross-sectional study. All parents/guardians of study subjects were requested to complete a CHO-KLAT questionnaire during a clinic visit, and report on several other clinical and socioeconomic factors in the past year. Boys who were > 7 years also completed the CHO-KLAT.

RESULTS

A total of 269 parents of boys with haemophilia, from 13 hospitals in 12 provinces, were enroled during 2014. The boys ranged from 4.0 to 17.9 years of age; 91% had haemophilia A, most had moderate (52%) or severe (36%) disease, and most were receiving sub-optimal on-demand therapy or low-dose prophylactic therapy. Child self-report CHO-KLAT scores were available for 171 boys ≥7 years of age and ranged from 24.2 to 85.3 with a mean of 57.6 (n = 171). Parent proxy-reported CHO-KLAT scores ranged from 25.0 to 88.7 with a mean of 55.1 (n = 269).

CONCLUSION

HR-QoL scores in boys with haemophilia in China were substantially lower than reported from Canadian and European boys with haemophilia. Longer term prospective studies are required to examine the factors impacting the HR-QoL for boys with haemophilia in China.

Patterns of tertiary prophylaxis in Canadian adults with severe and moderately severe haemophilia B

From a young age patients with severe and moderately severe FIX deficiency (haemophilia B) can experience spontaneous or traumatic bleeding and joint destruction may result. The use of coagulation factor IX concentrate to prevent anticipated bleeding, as primary or secondary prophylaxis, has become a common and recommended practice in children. The current practice of using tertiary prophylaxis, in the presence of established joint arthropathy, in adults with haemophilia B is not well characterized. This observational study was conducted to gain a better understanding of the recent Canadian experience with tertiary prophylaxis in adults with severe and moderately severe haemophilia B. Data were collected from all eligible adult (≥ 18 years of age) males with baseline FIX:C ≤ 2% from seven Canadian Hemophilia Treatment centres over a 2-year observation period from 2009 to 2011. Thirty-four per cent of the 67 subjects with moderately severe haemophilia B were exposed to prophylaxis with the majority as continuous prophylaxis (≥45 weeks year(-1) ). The severe subgroup (FIX:C < 1%) demonstrated a 52% exposure rate. None had primary prophylaxis exposure in childhood. Eighty-one per cent used once or twice weekly infusion regimens and reported a median annual bleeding rate of five bleeds per year versus four bleeds per year for those using on-demand treatment. Annual median factor utilization for all subjects using prophylaxis was 196,283 U year(-1) compared to 46,361 U year(-1) for on demand. Approximately 50% of adults with severe haemophilia B are using continuous tertiary prophylaxis in Canada, a practice likely to increase which warrants further study.

Can activated recombinant factor VII be used to postpone the exposure of infants to factor VIII until after 2 years of age?

Two retrospective studies have suggested that exposure to factor VIII (FVIII) in early infancy is associated with an increased risk of FVIII inhibitor development. We prospectively studied 11 infants who needed replacement therapy for bleeding episodes before the age of 2 years. They received activated recombinant factor VII (rFVIIa) concentrate on demand, with the intention of postponing their first exposure to FVIII after 2 years of age. Thirty-three bleeding episodes were treated with 154 doses of rFVIIa with no evidence of adverse effect. Bleeding was controlled in 27 of 33 episodes. Mouth bleeds were most difficult to treat. The use of rFVIIa allowed postponement of the use of FVIII for a mean of 5.5 months (median 4, range 0-12) but in only three of 11 children could be the first exposure to factor postponed after the age of 2 years. With this modest effect of rFVIIa in postponing the first exposure to FVIII, more convincing evidence for the benefit of such a postponement will have to be demonstrated before rFVIIa could be recommended for this indication.

Efficacy and safety of the factor VIII/von Willebrand factor concentrate, haemate-P/humate-P: ristocetin cofactor unit dosing in patients with von Willebrand disease

The present study was initiated to evaluate the safety and efficacy of Haemate-P (Humate-P in North America) (anti-hemophilic FVIII/VWF complex [human] dried, pasteurized) dosed in ristocetin cofactor units (VWF:RCo) in the treatment of von Willebrand disease (VWD) patients in Canada. This retrospective data collection reviewed the medical records of VWD patients treated under the Canadian Emergency Drug Release Program from November 22, 1991, to April 30, 1996. Data collection was accomplished by on-site retrieval from source data for 97 patients. Dosing was based on the German package insert, which lists only Factor VIII:C (FVIII:C) units, which were converted in the study analysis to VWF:RCo units based on the analysis of the individual manufactured lots of product used in these patients (average ratio of 2.6 IU VWF:RCo per IU FVIII:C). Twenty five different lots of Haemate-P/Humate-P were used to treat 437 different events in the 97 study patients (344 hemorrhagic events, 73 surgical interventions and 20 prophylactic infusion cycles). Overall, the median dose of concentrate per infusion used to treat surgical events was 69.1 IU VWF:RCo/kg (range 11.9-222.8); bleeding events 55.3 IU VWF:RCo/kg (range 17.1-227.5) and prophylaxis 41.6 IU VWF:RCo/kg (range 34.6-81.0). Treatment periods varied, with the majority of events treated for < or = 10 days (91%). Fifty percent of events that were treated longer than 10 days were given for prophylactic reasons. Efficacy was determined in a standardized manner by the physician, based on dosing in VWF:RCo activity. An overall clinical result of "excellent" or "good" was reported in 97% (424/437) of treatment events. A pediatric sub-population analysis of the patient population reported "excellent/good" efficacy in 100% (17/17) of treatment events in infants, 95% (155/164) in children, and 94% (76/81) in adolescent patients. Related adverse events (AEs) were observed in only 4 (4%) patients and were not deemed to be serious. The findings in this study confirm the safety and efficacy of Haemate-P/Humate-P using VWF:RCo dosing in pediatric and adult patients with various types of VWD.

Use of recombinant factor VIIa (NovoSeven) in patients with Glanzmann thrombasthenia

Recombinant factor VIIa (rFVIIa; NovoSeven, Novo Nordisk, Bagsvaerd, Denmark) appears effective and relatively safe for the treatment of bleeding and for surgical prophylaxis in patients with Glanzmann thrombasthenia as reported to the International Registry on rFVIIa and Congenital Platelet Disorders. One of the shortcomings of the Registry data is the heterogeneity of treatment protocol, including dosage, number of doses used, duration of treatment before declaration of failure, and mode of rFVIIa administration (bolus v continuous infusion). The data are not yet sufficient to define optimal regimens for various indications such as the type of bleeding or the type of procedures. The place of this drug compared to platelet transfusion in the overall management of patients with Glanzmann thrombasthenia will need to be determined in relationship to a number of challenges and unresolved issues in the clinical care of these patients. These issues include: how to improve local measures for patients with mucosal bleeds, optimal management of young women during menarche, optimal platelet transfusion regimens for various indications, the relationship between antiplatelet antibodies detected by monoclonal antibody-specific immobilization of platelet antigens (MAIPA) and effectiveness of platelet transfusion, whether there are other biological tests that may correlate with effectiveness of platelet transfusion, and management of pregnancy and delivery regarding antiplatelet immunization.

Use of recombinant factor VIIa in hereditary bleeding disorders

Recombinant factor VIIa is effective as a factor VIII or IX bypassing agent and is relatively safe for the management of bleeding and surgical procedures in patients with factor VIII or IX inhibitors (congenital or acquired hemophilia). It is one of several options in the overall treatment strategy for patients with these difficult conditions. This drug has also been used off label in a limited number of patients with other hereditary bleeding disorders (e.g., factor VII deficiency or antibodies to other clotting factors, and platelet disorders such as Glanzmann thrombasthenia). This paper reviews the proposed mechanisms of action, clinical effectiveness, and safety of rFVIIa for treatment of these disorders and points out areas that require further studies. With expanding indications and more widespread use, thromboembolic complications must be carefully monitored, especially in patients at risk for thromboembolism. The high cost of this drug may be a limiting factor.

Therapeutic choices for patients with hemophilia and high-titer inhibitors

Effective treatment of bleeding episodes in hemophilia with high titer inhibitors (HTI) remains a challenge, despite the fact that the therapeutic armamentarium has expanded considerably over the past few years. Treatment safety has improved with the availability of porcine factor VIII (FVIII) and bypassing products such as recombinant factor VIIa (rFVIIa), and plasma-derived activated Prothrombin Complex Concentrates (aPCCs) that are virally inactivated. The major drawbacks of rFVIIa and aPCCs are their unpredictable hemostatic effect, lack of laboratory assays to monitor efficacy and dosing frequency, and the risk of thrombosis. The proceedings of a one-day workshop of physicians who specialized in treating patients with hemophilia held in Vienna on May 13, 2000 have been summarized. In making a decision regarding the choice of product, physicians often consider the type of bleeding episode (life or limb threatening), age of the patient, volume of the reconstituted product, previous exposure to plasma derived products, cost, efficacy, and safety. For plasma naïve patients, to achieve rapid hemostasis a majority of the panelists used porcine FVIII (for patients who lack porcine inhibitory antibodies) or rFVIIa. For patients previously treated with plasma derived factors, in addition to the above concentrates, aPCCs were recommended. Although no data exists regarding safety and efficacy, switching products was routinely practiced either because of availability or cost. Furthermore, the panelists were uncertain about the efficacy of bypassing agents in the prevention of joint disease in inhibitor patients. The workshop participants felt that future research offers the best solution to resolve some of the dilemmas faced by clinicians and may help individualise treatment in a hemophilia patient with a high titer inhibitor.

Early outcomes after allogeneic stem cell transplantation for leukemia and myelodysplasia without protective isolation: a 10-year experience

Although it is common practice to use some form of isolation to protect allogeneic stem cell transplant patients from infection, the necessity for these practices in all environments has not been demonstrated. The current study evaluated patterns of infection and 100-day transplant-related mortality in 288 patients with myelodysplasia and leukemia transplanted without isolation. Patients were allowed out of hospital at any time within constraints of the medication schedule. Fever, foci of infection, and positive cultures within 28 days and death within 100 days because of the transplant procedure were recorded. Fever occurred in 57% of patients, and 10% had a clinical or radiographic focus of infection. Most infections were apparently endogenous; blood cultures from 24% of recipients grew organisms, 87% of which were gram-positive bacteria. Four patients (1%) died with aspergillus infection in circumstances indicating that isolation would not have been helpful. Twenty percent of patients remained without evidence of infection throughout. Transplant-related mortality at 100 days was 1% for 108 patients with early leukemia receiving transplants from matched siblings. For patients at higher risk, by virtue of donor and/or disease status, mortality was 21%. These figures compare favorably with those reported to the International Bone Marrow Transplant Registry, the majority of patients having been subjected to some form of isolation. We conclude that allogeneic stem cell transplantation can be safely performed in some environments without confining patients continuously to the hospital.

Recombinant activated factor VII (NovoSeven) treatment of platelet-related bleeding disorders. International Registry on Recombinant Factor VIIa and Congenital Platelet Disorders Group

Recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk A/S, Bagsvaerd, Denmark), used extensively for the management of hemophilia patients with inhibitors, has also been shown to be effective in the treatment of severe bleeding episodes and for coverage of surgical procedures in patients with platelet disorders. Cases include seven patients with congenital platelet disorders [Glanzmann thrombasthenia (n = 5), Bernard-Soulier syndrome (n = 1), platelet type (pseudo-) von Willebrand disease (n = 1)] and two patients with acquired thrombocytopathy associated with myelodysplastic syndrome and uremia. The clinical efficacy of rFVIIa in functional platelet disorders has been reported as good or excellent, although some cases of ineffectiveness exist. The agent is well tolerated with a single published case of thromboembolism as a postoperative complication. In addition to these reported cases, there are others that remain unreported and unpublished. An International Registry on Recombinant Factor VIIa and Congenital Platelet Disorders (forms in Appendix 1) has been established to obtain more safety and efficacy data on patients with congenital platelet disorders treated with NovoSeven. Analysis of data from this larger population will allow better comprehension of the role of NovoSeven in these disorders, and assist in the design of formal studies to address issues associated with the treatment of these disorders.

Effect of the factor V Leiden mutation on the clinical expression of severe hemophilia A

To determine whether the factor V Leiden mutation is associated with decreased bleeding in individuals with severe hemophilia A, factor concentrate utilization, maximum annual number of bleeding episodes, and the prevalence of hemophilic arthropathy between carriers and non-carriers of the factor V Leiden mutation were compared. Heterozygosity for the factor V Leiden mutation was found in 6 of 137 subjects (4.4%). Carriers of the factor V Leiden mutation utilized less factor concentrate (geometric mean: 310 vs. 1185 units/kg/year) and had fewer bleeding episodes than non-carriers (proportion with 10 or fewer bleeding episodes in their worst year: 50 vs. 11%). However, the factor V Leiden mutation was not associated with the absence of arthropathy. The intron 22 inversion mutation of the factor VIII gene was tested for in a subgroup of 80 subjects, but it was not found to be a significant variable for any of the bleeding endpoints. The results of this small study are consistent with the hypothesis that the factor V Leiden mutation imparts a protective effect; however, a larger confirmatory study in which the factor VIII molecular defects can be controlled for is needed. Furthermore, most severe hemophiliacs who used fewer than 200 units/kg/year of factor concentrate or who had experienced 10 or fewer bleeding episodes per year did not carry the factor V Leiden mutation, suggesting that the proportion of severe hemophiliacs whose mild clinical course can be attributed to the factor V Leiden mutation is small.

Recombinant factor VIIa is effective for bleeding and surgery in patients with Glanzmann thrombasthenia

Recombinant activated factor VII (rFVIIa) was found to be effective and safe in treating 24 bleeding episodes and to prevent bleeding during one bilateral herniorrhaphy in four children with Glanzmann thrombasthenia. One of the patients had alloantibodies to platelet membrane glycoprotein (GP) IIb/IIIa and was refractory to platelet transfusion. rFVIIa was administered at 89 to 116 microg/kg per injection every 2 hours, in association with antifibrinolytic drugs. Bleeding stopped in all cases, but platelet transfusion was required in one. Two bleeding episodes recurred 36 and 63 hours after discontinuation of rFVIIa, but were successfully treated with additional doses. No adverse effects of rFVIIa were observed. Although the number of patients is small, our study suggests that rFVIIa may be an alternative to platelet transfusions in patients with a severe congenital thrombocytopathy.

Allogeneic blood stem cell and bone marrow transplantation for acute myelogenous leukemia and myelodysplasia: influence of stem cell source on outcome

We have compared the outcomes of 87 patients with acute myelogenous leukemia (AML) and myelodysplasia (MDS) receiving matched sibling transplants with stem cells from peripheral blood (blood cell transplant, BCT) or bone marrow (BMT). In good risk patients (AML in CR1) granulocytes recovered to 0.5 x 10(9)/l a median of 14 days after BCT compared with 19 days after BMT (P < 0.0001). For patients with poor risk disease (AML beyond CR1 and MDS) corresponding figures were 16 vs 26 days (P < 0.0001). Platelet recovery to 20 x 10(9)/l was also faster after BCT (good risk 12 vs 20 days, P < 0.0001; poor risk 17 vs 22 days, P = 0.04). Red cell transfusions were unaffected by cell source, but BCT recipients required less platelet transfusions (good risk 1 vs 5, P = 0.002; poor risk 5 vs 11, P = 0.004). Blood cell transplants resulted in more chronic GVHD (86% vs 48%, P = 0.005) and a significantly higher proportion of recipients with KPS of 80% or less (48% vs 5%, P = 0.004). Disease-free survival at 4 years was 23% for both groups of poor risk patients but outcome in good risk patients was better after BCT (93% vs 62%, P = 0.047) related mainly to less relapse. While disease-free survival may be better after BCT than BMT for AML in CR1, quality of life may be relatively impaired.

Superior autologous blood stem cell mobilization from dose-intensive cyclophosphamide, etoposide, cisplatin plus G-CSF than from less intensive chemotherapy regimens

The study purpose was to determine if G-CSF plus dose-intensive cyclophosphamide 5.25 g/m2, etoposide 1.05 g/m2 and cisplatin 105 mg/m2 (DICEP) results in superior autologous blood stem cell mobilization (BSCM) than less intensive chemotherapy. From January 1993 until May 1997, 152 consecutive patients with non-Hodgkin's lymphoma (n = 55), breast cancer (n = 47), Hodgkin's disease (n = 14), multiple myeloma (n = 9), AML (n = 9), or other cancers (n = 18) initially underwent BSCM by one of three methods: Group 1: G-CSF alone x 4 days (n = 30). Group 2: disease-oriented chemotherapy, dosed to avoid blood transfusions, followed by G-CSF starting day 7 or 8, and apheresis day 13 or 14 (n = 82). Group 3: DICEP days 1-3, G-CSF starting day 14, and apheresis planned day 19, 20 or 21 (n = 40). A multivariate analysis was performed to determine which factors independently predicted BSCM. The median peripheral blood CD34+ (PB CD34+) cell count the morning of apheresis linearly correlated with the number of CD34+ cells removed per litre of apheresis that day. The median PB CD34+ cell count and median CD34+ cells x 10(6) removed per litre of apheresis were highest for Group 3, intermediate for Group 2, and lowest for Group 1. By multivariate analysis, mobilization group (3 > 2 > 1), disease other than AML, no prior melphalan or mitomycin-C, and less than two prior chemotherapy regimens predicted better BSCM. Out of 15 Group 3 patients who had infiltrated marrows, 11 had no detectable cancer in marrow and apheresis products after DICEP. These data suggest that DICEP results in superior BSCM than less intensive chemotherapy regimens.

Antithrombin and ischemia/reperfusion

Acute inflammation, a localized response that occurs in various diseases, is characterized by neutrophil infiltration into tissues. This process requires neutrophils to initially tether and roll along the endothelium of postcapillary venules before undergoing firm adhesion and emigration out of the vasculature into the tissues. Recently, thrombin has been implicated at multiple sites in the inflammatory cascade, and may represent an important link between inflammation and thrombosis. Our recent studies demonstrate that thrombin is an important mediator of neutrophil-dependent injury in ischemia-reperfusion injury. Furthermore, antithrombin concentrate may be therapeutically efficacious in ischemia-reperfusion injury, as it is capable of attenuating the thrombin-mediated effects on neutrophil-endothelial interactions.

Single-agent high-dose melphalan salvage therapy for Hodgkin's disease: cost, safety, and long-term efficacy

BACKGROUND

Few data are available on the cost, safety, and long-term efficacy of single-agent high-dose melphalan (HDM) followed by autologous bone marrow (ABMT) or blood stem cell (ABSCT) transplantation in the salvage therapy of Hodgkin's disease (HD).

PATIENTS AND METHODS

From February 1981 to September 1996, 23 patients with relapsed (n = 15) or refractory (n = 8) HD received salvage therapy with HDM 140-200 mg/m2 followed by non-cryopreserved ABMT (n = 18) or cryopreserved ABSCT (n = 5). The cost of HDM/ABSCT in 1996, from initial consultation until transfer back to referring physician, was determined and compared to the estimate costs of two multi-agent regimens commonly used for HD.

RESULTS

HDM was well tolerated with no early transplant-related mortality. The five-year overall and progression-free survival rates were 52% and 50%, respectively. The average total cost in Canadian funds of HDM/ABSCT in 1996 was $34,400/patient. This cost was estimated to be $4,700-6,800 cheaper per patient than the multi-agent high-dose regimens.

CONCLUSION

These data suggest that HDM is safe, feasible, active, and reasonably inexpensive salvage therapy for patients with relapsed/refractory HD.

A hemi-nested, allele specific, whole blood PCR assay for the detection of the factor V Leiden mutation

We describe a novel hemi-nested, allele specific whole blood PCR assay for detection of the factor V Leiden mutation associated with the plasma defect, activated protein C resistance. This assay utilizes 5 microliters of whole blood without prior DNA extraction. The hemi-nested design, employing an outer primer pair in combination with nested, allele specific primers obviates the need for restriction enzyme digestion. PCR reactions are analysed directly on agarose or polyacrylamide minigels. The assay confirmed the genotypes of 50 individuals previously categorized by PCR and Mn11 digestion, and has been subsequently utilized in the genotyping of 445 individuals referred for thrombosis studies.

Partially mismatched blood cell transplants for high-risk hematologic malignancy

Eleven patients with high-risk hematologic malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from partially mismatched family members in whom progenitor cells had been mobilized by G-CSF. Donors were mismatched by up to one antigen in the GVH direction and up to three antigens in the rejection direction. Outcomes were compared with those of 22 patients receiving BCT from fully matched donors. Two mismatched patients died without engraftment on day 21 and 32. One had rejected bone marrow from the same donor, the other was mismatched by two antigens in the rejection direction and received the lowest dose of CD34+ cells. Median time to granulocyte engraftment was 21.5 (range 16-33) days for the mismatched group compared with 16 (11-28) days for the matched group (P = 0.01). No correlation was found between CD34+ cell dose and time to granulocyte or platelet recovery. In the mismatched and matched BCT groups respectively, the risk of grade II-IV acute graft-versus-host disease (GVHD) was 73% vs 28% (P = 0.001) and of chronic GVHD 100% vs 78% at 18 months (P = 0.01). The relationship of T cell dose to acute GVHD could only be evaluated in the matched group and no correlation was found. One of 11 mismatched patients and eight of 22 matched patients had relapse or persistent disease. Disease-free survival at 1 year was similar at 55% for mismatched and 50% for matched BCT. These results indicate that allogeneic BCT from partially mismatched family members is accompanied by a high incidence of GVHD but may result in comparable survival to BCT from fully matched donors.

Haemophilia B: database of point mutations and short additions and deletions, 7th edition

The seventh edition of the haemophilia B database lists in easily accessible form all known factor IX mutations due to small changes (base substitutions and short additions and/or deletions of <30 bp) identified in haemophilia B patients. The 1535 patient entries are ordered by the nucleotide number of their mutation. Where known, details are given on: factor IX activity, factor IX antigen in circulation, presence of inhibitor and origin of mutation. References to published mutations are given and the laboratories generating the data are indicated.

Second allogeneic transplants for leukemia using blood instead of bone marrow as a source of hemopoietic cells

There is increasing interest in blood cell transplants (BCT) from normal donors as an alternative to BMT. Ten patients with relapsed or persistent leukemia after BMT received intensive cytotoxic conditioning followed by allogeneic BCT. Three BCT were from single-antigen mismatched donors; two of the corresponding recipients had rejected a BMT from the same donor. Two patients received BCT from a different donor (one matched, one single-antigen mismatched). The other six BCT were from the same, fully matched, bone marrow donors. Donors were given G-CSF to mobilize progenitor cells which were collected by a single 2-4 h leukapheresis. Methotrexate, CsA and folinic acid were used for GVHD prophylaxis for all transplants but CsA was discontinued sooner after BCT than after BMT. One patient died without engraftment having rejected a BMT from the same single-antigen mismatched donor 4 years previously. Nine patients had granulocyte recovery at a median of 14 days, up to 6 days faster than with their previous BMT. Platelet recovery was also 2-6 days faster than with BMT in four previously engrafting patients. Four patients died without platelet recovery after BCT within a year of BMT, three of treatment-related toxicity and one of relapse. Two patients developed grade II acute GVHD. Of six patients given BCT more than a year from BMT, four, all with acute leukemia, survive 7, 14, 29 and 29 months after BCT and one relapsed at 7 months. All four survivors developed chronic GVHD. These results indicate that BCT may be useful therapy for relapse occurring more than a year after BMT.

Characterization of an acquired IgG inhibitor of coagulation factor XIII in a patient with systemic lupus erythematosus

An acquired IgG inhibitor to factor XIII was identified in a 30-year-old Vietnamese woman with systemic lupus erythematosus. The IgG fraction was isolated from plasma by chromatography on an agarose gel column and by protein G adsorption. The anti-factor XIII activity, identified within the IgG fraction, inhibited factor XIII from both normal plasma (a2b2) and platelets (a2). A normal level of the b subunit was measured by immunoelectrophoresis of the patient's plasma, but the a subunit was not detected. These results suggested the presence of an IgG immunoglobulin which recognized the a subunit and interfered with its activity.

Allogeneic blood cell transplants for haematological malignancy: preliminary comparison of outcomes with bone marrow transplantation

Twenty-six patients with haematological malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from five- or six-antigen matched siblings in whom progenitor cells had been mobilized by G-CSF. Outcomes were compared with a historical control group of 26 BMT patients matched for age and disease status. Granulocyte counts recovered to 0.5 x 10(9)/l in a median of 16 days after BCT compared with 21.5 days after BMT (P = 0.0002). Platelet counts, unsupported for 3 days, reached 20 x 10(9)/l in a median of 14 days vs 20.5 days (P = 0.0003) after BCT compared with BMT in those patients who engrafted. In the BCT and BMT groups, respectively, the risk of grade II-IV acute GVHD was 37 vs 21% (P = 0.16) and of chronic GVHD at 1 year 53 vs 48% (P = 0.9). There was no significant difference in red cell transfusions but BCT patients required fewer platelet transfusions (median 3 vs 5, P = 0.015) and fewer days in hospital (20.5 vs 25, P = 0.02). These results indicate that allogeneic BCT from matched and partially mismatched family donors result in faster engraftment than BMT without a significant increase in GVHD. Allogeneic BCT may prove to be a more tolerable procedure than BMT for both donor and recipient and there are indications of improved cost-effectiveness.

Haemophilia B (sixth edition): a database of point mutations and short additions and deletions

The sixth edition of the haemophilia B database lists in easily accessible form all known factor IX mutations due to small changes (base substitutions and short additions and/or deletions of <30 bp) identified in haemophilia B patients. The 1380 patient entries are ordered by the nucleotide number of their mutation. Where known, details are given on factor IX activity, factor IX antigen in circulation and origin of mutation. References to published mutations are given and the laboratories generating the data are indicated.

Factor XIIIA Calgary: a candidate missense mutation (Leu667Pro) in the beta barrel 2 domain of the factor XIIIA subunit

Molecular analysis performed on a Canadian family with congenital factor XIII deficiency revealed a homozygous missense mutation (Leu667Pro) in exon 14 of the A subunit gene in three affected siblings. The mutation results from a T-to-C transition at nucleotide position 2087 and generates a new Msp1 restriction site. Digestion of an amplified fragment containing exon 14 with this restriction enzyme enabled the heterozygous allele to be identified in both parents (who were third cousins) and three other family members. SSCP analysis detected no additional mutations in the coding or consensus splice sequences of the A subunit gene. The mutant nucleotide substitution was absent in 60 normal alleles and 10 unrelated patients with XIIIA deficiency. Leu667 is located in the carboxyl terminal beta barrel 2 domain of the A subunit molecule. Computer modelling based on 3D crystallographic data predicts that the mutant protein has aberrant folding and is likely to be rapidly degraded following translation.

Desmopressin induces endothelial P-selectin expression and leukocyte rolling in postcapillary venules

Desmopressin, (DDAVP; 1-desamino-8-D-arginine vasopressin) increases the release and activity of von Willebrand factor (vWF); however, its effects on the other major constituent of endothelial Weibel-Palade bodies, P-selectin, has not been investigated. DDAVP-induced P-selectin expression may explain DDAVP's efficacy in bleeding disorders in which vWF levels are normal. Therefore, the objective of this study is to assess the effect of DDAVP on P-selectin expression on endothelial cells of postcapillary venules in vivo and on human umbilical vein endothelium in vitro, and to determine whether DDAVP has direct effects on leukocyte behavior in postcapillary venules. DDAVP (0.1 and 1.0 microgram/mL) induced a significant but transient increase in P-selectin expression on human umbilical vein endothelial cells as well as on rat and human platelets. Immunohistochemical analysis of rat postcapillary venules showed that in contrast to saline, DDAVP injection (1 microgram/kg, intravenous) induced significant endothelial P-selectin expression. DDAVP administration also induced a rapid and significant increase in leukocyte rolling in rat mesenteric venules in vivo. This response was entirely dependent on P-selectin, as an anti-P-selectin antibody rapidly reversed the DDAVP-induced increase in leukocyte rolling. DDAVP induced leukocyte rolling in medium (20 to 40 microns) and large (> 40 microns), but not small (< 20 microns), postcapillary venules. In animals that were treated with DDAVP, there was a steady and significant increase in leukocyte adhesion. This study shows that DDAVP can directly induce P-selectin expression on endothelium in vitro and in vivo and that the latter response is capable of supporting prolonged leukocyte rolling in rat postcapillary venules.

Pulmonary edema during IL-2 therapy: combined effect of increased permeability and hydrostatic pressure

Systemic administration of recombinant interleukin-2 (rIL-2) has been shown to be promising against certain metastatic cancers. However, major side effects, such as pulmonary edema, have limited its widespread use. Although this pulmonary edema has been attributed to a vascular leak syndrome, this hypothesis has not been verified in humans. The purpose of our study was to determine both the severity and mechanism of pulmonary edema in seven patients treated with rIL-2. The severity of edema was assessed by daily evaluation of chest radiographs, using a semiquantitative scale, as well as by repeated measurements of the alveolar-to-arterial oxygen gradient (A-aDO2) in each patient. To determine the mechanism of pulmonary edema, we serially measured in each patient the lung clearance of technetium 99m-diethylenetriamine pentaacetic acid (DTPA) 99mTc-DTPA), the plasma levels of Von Willebrand factor antigen, and the pulmonary capillary wedge pressure (PCWP). Our results show that there was a gradual increase in the chest radiography edema score that was paralleled by a significant increase in A-aDO2 over its baseline value. During rIL-2 treatment, 99mTc-DTPA clearance was augmented, and the plasma concentration of Von Willebrand factor antigen was elevated. PCWP climbed from 7 to 14 mm Hg and serum total protein fell from 66.1 to 42.1 gm/L. The results obtained indicate that although pulmonary edema associated with rIL-2 treatment is partially dependent on increased permeability of the lung, changes in hydrostatic and oncotic forces may be the principal determinants of edema development.

The Canadian Hemophilia Registry as the basis for a national system for monitoring the use of factor concentrates

BACKGROUND

Canada's publicly funded blood system has recently introduced high-purity concentrates as the standard treatment for individuals with hemophilia. The added cost and the need to document patient outcomes have prompted the consideration of a national blood product monitoring system.

STUDY DESIGN AND METHODS

This study investigates the suitability of the Canadian Hemophilia Registry (CHR) as the basis of such a monitoring system by assessing the degree to which it represents users of factor concentrates.

RESULTS

Currently, there are 1978 individuals registered with the CHR, of whom 1594 (81%) have hemophilia A and 384 (19%) have hemophilia B. The total prevalence is 7.2 per 10(5) population, with the prevalence of severe cases being 2.3 per 10(5). This overall prevalence is similar to that seen in other countries with national registries. The CHR national prevalence also compares favorably with that in the province of Quebec, where registration of users of blood products is compulsory. The CHR figures indicate that the number of persons currently infected with human immunodeficiency virus, both alive and dead, is 652, which is similar to the number of applicants (658) to the federal government's assistance program. The registry is stable, and the number of persons with severe cases, other than young children, newly registered or lost to follow-up during the last 2 years is very small.

CONCLUSION

The CHR includes the vast majority of factor concentrate users and is therefore ideal as the basis for a national monitoring system.

Contractile actions of thrombin receptor-derived polypeptides in human umbilical and placental vasculature: evidence for distinct receptor systems

1. We studied the structure-activity profiles of four thrombin receptor-derived polypeptides (TRPs) (P5, SFLLR; P5-NH2, SFLLR-NH2; P7, SFLLRNP; P7-NH2, SFLLRN) in contractile human placental artery (PA), umbilical artery (UA) and umbilical vein (UV) preparations and in a human platelet aggregation assay. 2. The contractile actions of the TRPs in the two arterial preparations were endothelium-independent, whereas in the UV tissue a contractile response was observed only in an endothelium-denuded preparation; no endothelium-mediated relaxation responses were observed in any of the vascular preparations. 3. In the three vascular preparations, the contractile responses required extracellular calcium and were attenuated by the tyrosine kinase inhibitor, genistein. 4. The relative contractile orders of potencies of the TRPs in the three vascular preparations were distinct from each other (PA: P7-NH2 > P7 > P5-NH2 > P5; UA: P7-NH2 > or = P5-NH2 approximately = P7 > > P5; UV: P5-NH2 > > P7-NH2 = P7 > > P5) and these were in turn distinct from the potency order observed in the platelet aggregation assay (P5-NH2 > or = P7-NH2 > P7 > > P5). 5. Despite the markedly dissimilar TRP potency orders in the placental artery and umbilical vein preparations, the cDNA sequences for the thrombin receptor obtained by polymerase chain reaction cloning of cDNA from the two tissue sources were identical. 6. We conclude that the four tissues studied possess functionally distinct thrombin receptor systems that interact in a distinct way with agonist peptides. In view of the identity of the thrombin receptor cDNA in the two tissues displaying the most dissimilar structure-activity profiles, we suggest that in different tissues, differences in post-translational receptor processing or differences in receptor-effector coupling interactions may result in unique thrombin receptor systems that can display distinct structure-activity profiles.

Acquired platelet dysfunction with eosinophilia in white children

Acquired platelet dysfunction associated with eosinophilia has been described mainly in indigenous Southeast Asian and East Indian children. We describe two white boys in whom this disorder developed after they had lived in Malaysia for 12 to 18 months. Acquired platelet dysfunction associated with eosinophilia should therefore be considered in children who, after a visit to this region, have easy bruising and esoinophilia.

Comparison of the recovery and half-life of a high-purity factor IX concentrate with those of a factor IX complex concentrate. Factor IX Study Group

BACKGROUND

Recovery and half-life estimations were carried out to compare a high-purity factor IX concentrate with an established factor IX complex concentrate.

STUDY DESIGN AND METHODS

Two high-purity factor IX concentrates, which are identical except for the presence or absence of heparin (Immuninehep-plus and Immuninehep-minus), were evaluated in two independent crossover studies using an intermediate-purity factor IX complex concentrate (Bebulin) as reference drug.

RESULTS

In the Immuninehep-plus crossover study (n = 27), Immuninehep-plus and Bebulin had, respectively, a recovery of 0.90 +/- 0.26 and 0.84 +/- 0.23 IU per dL per IU per kg, a compartmental half-life of 17.11 +/- 6.18 and 15.94 +/- 4.69 hours, and an effective half-life of 16.51 +/- 3.48 and 16.48 +/- 4.26 hours. In the Immuninehep-minus crossover study (n = 26), Immuninehep-minus and Bebulin had, respectively, a recovery of 0.92 +/- 0.31 and 1.02 +/- 0.36 IU per dL per IU per kg, a compartmental half-life of 17.42 +/- 5.60 and 18.77 +/- 6.27 hours, and an effective half-life of 16.39 +/- 4.44 and 16.48 +/- 4.28 hours. Equivalence tests indicated that the recovery and half-life of Immunine, with or without heparin, are equivalent to those of Bebulin.

CONCLUSION

The equivalence in pharmacokinetics and bioavailability indicates that the dosage schedule for Immunine should be the same as or very similar to that of Bebulin. The high specific activity of the former, however, allows administration at lower volumes.

Factor VIII gene rearrangement analysis and carrier determination in hemophilia A

Factor VIII (FVIII) gene rearrangements between the intron 22 F8A sequence in the FVIII gene and either of the two homologous F8A sequences 500 kilobases telomeric to the FVIII gene have recently been found to be responsible for the severe hemophilia A phenotype. We studied 27 patients with severe hemophilia A and 19 with moderate and mild hemophilia, and found FVIII gene rearrangement in 12 patients with severe hemophilia A and none in the patients with moderate or mild disease. Nine of the rearrangements were with the distal telomeric F8A sequence, two were with the proximal sequence, and one had variant distal rearrangement with loss of the FVIII intron 22 F8A band. Two patients with FVIII gene rearrangement had high responding inhibitors, contrary to one previous study suggesting that the presence of a FVIII gene rearrangement is correlated with the absence of inhibitor development. Carrier detection was performed in 17 female relatives, at risk of being carriers, from eight kindreds; 13 were carriers, being heterozygous for the normal and rearranged alleles. The rearrangement assay is particularly useful for carrier determination in families with sporadic cases of hemophilia not helped by linkage analysis with restriction fragment-length polymorphism or intragenic dinucleotide repeat analysis. In all five families with rearrangements and sporadic hemophilia, the mothers of all index patients were found to be carriers.

Addition of low-dose folinic acid to a methotrexate/cyclosporin A regimen for prevention of acute graft-versus-host disease

A study was performed to determine whether the addition of folinic acid to a combination of methotrexate (MTX) and cyclosporin A (CsA) after allogeneic bone marrow transplantation (BMT) could improve tolerance to the regimen without inhibiting its ability to prevent graft-versus-host disease (GVHD). Sixty-nine adult BMT patients received CsA plus MTX 15 mg/m2 on day 1 and 10 mg/m2 on days +3, +6 and +11. Folinic acid 5 mg was started 24 h after each MTX dose and continued 6 hourly until 12 h before the next dose of MTX. The median age of the group was 37 years and 13 patients (19%) received bone marrow from mismatched and/or unrelated donors. No MTX doses were omitted or modified. Grade II-IV acute GVHD occurred in 18 patients (29%) and chronic GVHD in 35 of 56 (64%) patients at risk. There were no cases of grade > or = III stomatitis. Transplant-related mortality was 7% before 100 days and 20% overall (9% for low risk leukaemia) with a median follow-up of 41 months (range 24-88 months). This regimen of folinic acid rescue may contribute to a well tolerated GVHD prophylaxis protocol with reasonably low BMT-related mortality. Our results suggest that the ability of MTX to prevent acute GVHD is not abrogated by folinic acid given in this way.

Lymphocyte membrane modifications induced by HIV infection

Novel carbohydrate antigen expressions were observed on T lymphocytes from HIV infected patients using flowcytometric analysis with four mAbs; BM-1, ACFH-18, FH-2 and C-6. These carbohydrate antigens were also expressed on oncogenic transformed cells but were either not expressed or were weakly expressed in lymphocyte populations from healthy subjects. A dramatic change in glycosylation was induced on CD8+T cells from HIV infected patients. The glycosylation change correlated with the progression of the disease. The incidence of Ley antigen expression on CD8+T cells increased as the disease progressed with the ongoing impairment of immune function. The phenotype change that occurred with Ley antigen expression might reflect the abnormal activation of T lymphocytes of some specific, but unknown, population of CD8+T cells. Thus, carbohydrate changes on the cell surface may induce immunological abnormality and accelerate the damage within the CD4+T cell subset, resulting in an impairment of the antigen specific immune system.

Hemophilia B carrier determination based on family-specific mutation detection by DNA single-strand conformation analysis

Single-strand conformation (SSC) analysis can distinguish normal from variant DNA fragments containing single point mutations by conformation-induced electrophoretic mobility shifts in non-denaturing polyacrylamide gels. We studied 25 hemophilia B kindreds by using SSC analysis after polymerase chain reaction (PCR) amplification of the eight factor IX exons and their intron boundaries. Variant SSC fragments were unambiguously identified in 24 kindreds, and direct DNA sequencing of variant PCR fragments identified 20 different hemophilia B mutations. This technique was used for rapid and accurate carrier determination in female family members without the need for additional sequencing studies, because carriers have both normal and hemophilia family-specific SSC fragments. Of 25 obligate carriers from 15 kindreds, 24 were confirmed to carry variant fragments. The exception, a patient's daughter homozygous for the normal allele, was demonstrated by subsequent PCR genotyping to be the result of non-paternity. In the additional 32 at-risk females from 16 kindreds studied, 19 were identified as carriers and 13 as non-carriers. Eleven of the unique mutations affected restriction enzyme digestion sites, and carriers could then be identified by appropriate restriction enzyme digestion of amplified DNA. Our study, with hemophilia B as a model system, demonstrates the accuracy and efficiency of SSC analysis in screening and tracking unknown mutations in monogenic inherited disorders with known gene sequences.

Expression of embryonic zeta-globin and epsilon-globin chains in a 10-year-old girl with congenital anemia

A 10-year-old Danish girl with congenital anemia is described. At birth, she had severe anemia and erythroblastosis and was transfused a number of times during the first year. The need for transfusions has since declined steadily. Her reticulocyte counts varied between 2% and 15%, and her bone marrow aspirate showed some dyserythropoietic features. Her hemoglobin F level was consistently elevated, up to as much as 41%. Her erythrocytes had a normal level of I antigen but an undetectable level of i antigen. Moreover, embryonic zeta-globin and epsilon-globin chains were present in some of her circulating erythrocytes. These findings may represent the manifestations of a new variant of congenital anemia.