Can the genetic profile predict inhibitor development in hemophilia A?
Explore the source record for details and available documents.
Factor VIII↗
Biomedical subjects
E Santagostino
Publications and source records attributed to E Santagostino.
Total joint replacement in patients with inhibitors.
Today, total joint replacement is the treatment of choice for chronic haemophilic arthropathy of the knee and hip in developed and developing countries. After the last World Haemophilia Congress and Musculoskeletal Congress, we cannot say the same for haemophilic patients with inhibitors because elective surgery today is still limited to few centres and extremely few patients. This is because until the first half of the 1990s, performing surgery in haemophilic patients with inhibitors was associated with a high risk of bleeding. With the availability of activated recombinant factor VII, the first surgical procedures were performed, but they still remain limited because of the elevated costs of replacement therapy. Our goal for the future must be to ensure the same possibility of surgical intervention in haemophilic patients both with and without inhibitors. This will be possible, thanks to the experience of some centres with an increased number of patients, where today this kind of surgery is routinely performed.
Arthroplasty, Replacement↗
Inhibitor development, immune tolerance and prophylaxis in haemophilia A--the need for an evidence-based approach.
Explore the source record for details and available documents.
Blood Coagulation Factor Inhibitors↗
A prospective randomized trial of high and standard dosages of recombinant factor VIIa for treatment of hemarthroses in hemophiliacs with inhibitors.
AIM: A multicenter randomized open-label crossover prospective trial was designed to compare the efficacy, safety, and cost of standard and high dosages of recombinant factor VIIa (rFVIIa) for home treatment of hemarthroses in hemophiliacs with inhibitors. METHODS: Patients were instructed to treat, within 6 h from the onset of bleeding, four consecutive hemarthroses of ankles, knees, or elbows, either with the rFVIIa standard dose of 90 microg kg(-1) (repeated as necessary every 3 h) or with a single high dose of 270 microg kg(-1). Patients who did not achieve a clinical success within 9 h continued rFVIIa treatment with repeated standard doses. Response to treatment was assessed for up to 48 h by patients/caregivers, who reported on a Visual Analogue Scale (VAS) graded from 0 to 100 the improvement in symptoms and also rated the responses as effective, partially effective or ineffective. Success was defined a treatment course rated as effective and with a VAS score > or =70 and failure a treatment course rated as ineffective and VAS score < or =30, whereas treatment courses that did not fulfill these criteria were considered partial responses. RESULTS: Twenty hemophiliacs with inhibitors were originally enrolled (median age: 27 years), 18 of them treated 32 hemarthroses assigned to the standard-dosage and 36 to the high-dosage regimen, during the study period of 18 months. Forty-eight hemarthroses (71%) occurred in target joints. Success rates for standard- and high-dosage regimens were similar: 31% and 25% at 9 h, 53% and 50% at 24 h, 66% and 64% at 48 h, the end point for outcome assessment. The median number of rFVIIa infusions needed to achieve a successful course was significantly greater for the standard-dosage (n = 3) than for the high-dosage regimen (n = 1), and the median amount of rFVIIa ultimately used per successful course was identical (270 microg kg(-1)). CONCLUSION: Our results indicate that a high-dosage regimen with rFVIIa for home treatment of hemarthroses is effective, safe, does not imply an increased consumption of rFVIIa and requires the infusion of a smaller number of rFVIIa doses. Its convenience is particularly relevant in cases with difficult venous access and in hemorrhages into target joints.
Adolescent↗
Liver histology of an afibrinogenemic patient with the Bbeta-L353R mutation showing no evidence of hepatic endoplasmic reticulum storage disease (ERSD); comparative study in COS-1 cells of the intracellular processing of the Bbeta-L353R fibrinogen vs. the ERSD-associated gamma-G284R mutant.
BACKGROUND: Type I fibrinogen deficiencies (hypofibrinogenemia and afibrinogenemia) are rare congenital disorders characterized by low or unmeasurable plasma fibrinogen antigen levels. Their genetic bases are represented by mutations within the three fibrinogen genes. Among the 11 reported missense mutations, a few have been characterized by expression studies and found to have an impaired fibrinogen assembly and/or secretion. Histopathological analyses were previously reported in two hypofibrinogenemic cases with discernible hepatic disease, revealing that both underlying mutations (gamma-Gly284Arg and gamma-Arg375Trp) were associated with hepatic fibrinogen endoplasmic reticulum storage disease (ERSD). OBJECTIVE: The objective of this study was to investigate the liver histology in an afibrinogenemic patient, homozygous for the Bbeta-Leu353Arg mutation, and to study the intracellular processing of the mutant protein. PATIENTS AND METHODS: Liver histology was evaluated by light microscopy, electron microscopy and immunocytochemistry. Intracellular processing of mutant fibrinogen was analyzed by pulse-chase labeling and immunoprecipitation experiments. Messenger RNA levels were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The histopathological characterization of the liver showed no signs of fibrinogen accumulation, a difference from the previously reported findings in two hypofibrinogenemic kindreds with ERSD. To evaluate whether the Bbeta-Leu353Arg mutation and the ERSD-associated gamma-Gly284Arg mutation affected intracellular fibrinogen trafficking differently, both mutant proteins were expressed in COS-1 cells. Bbeta-Leu353Arg led to a more severe secretion defect, but no differences that could explain phenotype-genotype correlation were found in the intracellular processing. Endoglycosidase-H analysis demonstrated a secretion block before translocation to the Golgi medial stacks. Real-time RT-PCR studies showed normal levels of the Bbeta mRNA in the patient's liver. CONCLUSIONS: The results confirm that Bbeta-Leu353Arg is associated with impaired fibrinogen secretion, but not with hepatic ERSD.
Adolescent↗
Pharmacokinetics of activated recombinant coagulation factor VII (NovoSeven) in children vs. adults with haemophilia A.
To establish the pharmacokinetic profile of activated recombinant coagulation factor VII (rFVIIa; NovoSeven in children with haemophilia A, and to compare it with the pharmacokinetic profile in adults with haemophilia A. Twelve children (2-12 years) received one single dose of rFVIIa 90 and 180 micrograms kg(-1) in randomized order separated by a washout period of 48 h to 1 month. Six adults (18-55 years) received a single dose of rFVIIa 90 micrograms kg(-1). The pharmacokinetic analyses were based on a non-compartmental method. In children, the plasma level of FVII increased proportionally with the dose. The total body clearance normalized for body weight was significantly faster in children than in adults (FVII:C, 58 vs. 39 mL kg(-1) h(-1) and FVIIa, 78 vs. 53 mL kg(-1) h(-1), P < 0.05). A trend towards a larger volume of distribution at steady-state in children than in adults was observed (P > 0.05). Dose proportionality was established for plasma concentrations of FVII in children with haemophilia A at the dose levels investigated (90 and 180 micrograms kg(-1) rFVIIa). Following administration of rFVIIa 90 micrograms kg(-1), significantly faster clearance was observed in children compared with adults, suggesting that higher doses of rFVIIa may be needed to achieve the same plasma levels as in adults.
Child↗
Hepatitis C in haemophilia: lights and shadows.
Hepatitis C is a major cause of morbidity and mortality in haemophiliacs who received clotting factor concentrates before the availability of virus-inactivated factors in the mid-1980s. Early studies gave conflicting indications as to the severity of hepatitis C (originally termed non-A non-B hepatitis), as mild, slowly progressive hepatitis was documented in several infants and young adults with haemophilia who were examined with repeat liver biopsies, whereas more progressive hepatitis and cirrhosis was documented in others. One major point of dispute was whether these discrepancies could in part be accounted for by epidemiological differences among studies, as hepatitis C acquired early in life may initially run a benign course and later worsen owing to spontaneous recrudescence of hepatitis or interference with such comorbidity factors as alcohol abuse or infection with the human immunodeficiency virus (HIV). In the mid 1990s, the latter infection overshadowed hepatitis C as a cause of death in this patient population. Because hepatocellular carcinoma is emerging as an important complication in haemophiliacs with long-standing hepatitis C virus (HCV) infection who survived HIV infection, and because of recent advances in treating HIV, morbidity and mortality associated with chronic hepatitis C have regained emphasis amongst haemophiliacs. The development of newer interferon-based therapies provides an opportunity for modifying the natural history of HCV infection in a substantial number of haemophilic patients.
Adult↗
Optimizing factor prophylaxis for the haemophilia population: where do we stand?
The hallmark of severe haemophilia, defined as a circulating level of factor (F) VIII (haemophilia A cases) or FIX (haemophilia B cases) of < 1%, is recurrent bleeding into muscles and joints (haemarthroses) from an early age of life. The inevitable result of such bleeding is progressive joint damage, leading to disabling arthritis that is typically evident within the first 2 decades of life in people with haemophilia who have limited or no access to regular factor replacement therapy, or those in whom factor replacement therapy is ineffective because of the presence of high-titre inhibitors. For children with severe haemophilia and no evidence of inhibitors, the unwanted musculoskeletal complications of severe haemophilia can be effectively prevented by the early initiation of a programme of long-term factor prophylaxis. In order to achieve the best outcome (a perfect musculoskeletal status for age) the programme of prophylaxis should be started before the onset of joint damage (primary prophylaxis). The gold standard primary prophylaxis regimen (the Malmo protocol) was pioneered and tested in Sweden and involves the infusion of 20-40 IU of FVIII per kg body weight on alternate days (minimum three times per week) for haemophilia A cases, and 20-40 IU kg(-1) of FIX twice weekly for haemophilia B cases. This protocol is, however, demanding on peripheral veins and very expensive. Modifications of the parent protocol such as starting primary prophylaxis with once-weekly infusions via peripheral veins with rapid escalation to full-dose prophylaxis or dose escalation based on frequency of bleeding are increasingly implemented in haemophilia treatment centres in countries that can afford the high cost of such programmes. These modified programmes can be achieved in the majority of young children with severe haemophilia without the need for central venous access devices (e.g. Port-a-Caths) and with avoidance of device-associated complications such as infection and thrombosis. In at least one centre, experience with arteriovenous fistulae as a strategy to ensure reliable venous access is being accumulated. The issues of compliance (adherence) to recommended prophylaxis protocols and when, if ever, to stop a programme of primary prophylaxis once started are real and require ongoing prospective studies. Such studies should incorporate outcome measures such as health-related quality-of-life and economic analyses.
Blood Coagulation Factors↗
Sustained suppression of hepatitis C virus by high doses of interferon and ribavirin in adult hemophilic patients.
BACKGROUND: In a recent randomized controlled study, only a minority (15%) of adult hemophiliacs with chronic HCV achieved a sustained virologic response to treatment with interferon (IFN) and ribavirin given at standard doses. STUDY DESIGN AND METHODS: Whether the therapeutic response might be improved in these patients by increasing the doses of IFN was evaluated. Thirty-four previously untreated, adult hemophiliacs with chronic HCV but negative for HIV were investigated. There were 33 men and 1 woman, aged 21 to 60 years (mean, 36). Twenty-three patients (68%) had genotype 1, and median serum HCV-RNA was 473 x 10(3) IU per L (range, 3.6-2145). Patients were treated with IFN at 5 million units (MU) thrice weekly for 6 months, followed by 3 mol/L for 6 additional months in combination with daily oral doses of 1 or 1.2 g of ribavirin. RESULTS: A total of 33 patients (97%) completed the study; one patient withdrew because of treatment-related symptoms. Treatment dosage had to be reduced in 20 patients (59%). By intention-to-treat analysis, 14 patients (41%) had a sustained virologic response, particularly those infected by HCV genotype 2 or 3 (70% vs. 29% with genotype 1 or 4, p < 0.05). Sustained response rates were similar in the 13 compliant patients and the 20 patients who had to reduce IFN and/or ribavirin doses (54% vs. 35%). CONCLUSIONS: High-dose IFN therapy plus ribavirin provided high rates of sustained virologic responses in adult hemophiliacs with chronic HCV, even if side-effects led to dose reduction in half of these patients.
Adult↗
Continuous infusion of porcine factor VIII: stability, microbiological safety and clinical experience.
Porcine factor VIII (pFVIII) is an effective haemostatic treatment for bleeding in selected patients with FVIII inhibitors. Its use is sometimes associated with a transient fall in platelet count and transfusion reactions, the risk of which may be related to the rate of administration. Theoretical considerations suggest that the administration of pFVIII by continuous infusion should be effective, and could have pharmacokinetic advantages that lead to an improvement in the side-effect profile. The results of a retrospective survey of continuous infusion of pFVIII with respect to clinical safety and efficacy are reported. Porcine FVIII stability and microbiological studies are included. It is concluded that pFVIII given by continuous infusion is safe and effective. The risk of transfusion reactions and fall in platelet count appears to be reduced, compared with bolus administration. Stability studies showed that pFVIII activity declined at room temperature, most rapidly in the dilute solution (5-10 U mL(-1)). More concentrated mixtures showed acceptable stability for up to 24 h using a variety of infusion devices. Various concentrations of pFVIII did not support the growth of Escherichia coli or Staphylococcus aureus. These observations suggest that the porcine factor is suitable for continuous infusion (CI).
Adolescent↗
Congenital afibrinogenemia: mutations leading to premature termination codons in fibrinogen A alpha-chain gene are not associated with the decay of the mutant mRNAs.
Congenital afibrinogenemia is a rare coagulation disorder with autosomal recessive inheritance, characterized by the complete absence or extremely reduced levels of fibrinogen in patients' plasma and platelets. Eight afibrinogenemic probands, with very low plasma levels of immunoreactive fibrinogen were studied. Sequencing of the fibrinogen gene cluster of each proband disclosed 4 novel point mutations (1914C>G, 1193G>T, 1215delT, and 3075C>T) and 1 already reported (3192C>T). All mutations, localized within the first 4 exons of the A alpha-chain gene, were null mutations predicted to produce severely truncated A alpha-chains because of the presence of premature termination codons. Since premature termination codons are frequently known to affect the metabolism of the corresponding messenger RNAs (mRNAs), the degree of stability of each mutant mRNA was investigated. Cotransfection experiments with plasmids expressing the wild type and each of the mutant A alpha-chains, followed by RNA extraction and semiquantitative reverse-transcriptase-polymerase chain reaction analysis, demonstrated that all the identified null mutations escaped nonsense-mediated mRNA decay. Moreover, ex vivo analysis at the protein level demonstrated that the presence of each mutation was sufficient to abolish fibrinogen secretion.
Adult↗
TT virus contaminates first-generation recombinant factor VIII concentrates.
Recombinant factor VIII and factor IX concentrates, human-plasma-derived albumin, and samples from previously untreated patients with hemophilia were examined for the presence of TT virus (TTV) by using polymerase chain reaction testing. Blood samples from the patients were obtained prospectively before and every 3 to 6 months after therapy was begun. TTV was detected in 23.5% of the recombinant-product lots and 55.5% of the albumin lots tested. Only first-generation factor VIII recombinant concentrates stabilized with human albumin were positive for TTV, whereas all second-generation (human protein-free) concentrates were negative for the virus. In 59% of patients treated with either first- or second-generation recombinant factor concentrates, TTV infection developed at some point after the initial infusion. Infection with TTV in these patients before and after treatment did not appear to be clinically important. Thus, first-generation recombinant factor VIII concentrates may contain TTV and the source of the viral contamination may be human albumin.
Blood Transfusion↗
Relationship between factor VII activity and clinical efficacy of recombinant factor VIIa given by continuous infusion to patients with factor VIII inhibitors.
A multicenter prospective study of recombinant activated factor VII (rFVIIa) given by continuous infusion (CI) to treat severe hemorrhages and to handle surgical procedures was carried out. Relations between clinical efficacy, dosages used and levels of FVII coagulant activity (FVII:C) achieved in plasma were also evaluated. Case material included 25 patients with hemophilia (9 children and 16 adults) with high-responding inhibitors and 3 patients with acquired factor VIII inhibitors. Overall, 35 CI courses were given for 10 spontaneous bleeding episodes, 11 major surgical procedures and 14 minor surgical procedures. Bolus doses of 90 to 150 microg/kg (median: 100) were followed by CI given at median rates of 20 microg/kg/h for major surgery and of 17 and 16 microg/kg/h for minor surgery and spontaneous hemorrhages. Satisfactory hemostasis was obtained in 30 of 35 courses (88%). rFVIIa CI was ineffective in 2 hemophiliacs undergoing surgical operations and in another hemophiliac with hemoperitoneum who had to be switched to other treatments (high doses of porcine or human factor VIII concentrates). rFVIIa CI was partially effective in 2 hemophiliacs who had mild local bleeding after minor surgery. The CI rates and the corresponding FVII:C levels in plasma were similar in effective, partially effective and ineffective courses (median rate: 17, 20 and 20 microg/kg/h, respectively; median FVII:C:14, 18 and 18 IU/ml, respectively). A single adverse event was observed, superficial thrombophlebitis. This study confirms that rFVIIa given by CI is effective in a high proportion of patients with factor VIII inhibitors. It also demonstrates that FVII:C levels attained in plasma do not always predict efficacy because similarly high levels were attained during successful treatments and in those that failed.
Adult↗
Afibrinogenemia: first identification of a splicing mutation in the fibrinogen gamma chain gene leading to a major gamma chain truncation.
Congenital afibrinogenemia is a rare autosomal recessive disorder characterized by the complete absence of plasma fibrinogen and by a bleeding tendency ranging from mild to moderately severe. Beside a deletion of the almost entire Aalpha-chain gene, only 2 missense mutations in the C-terminal domain of the Bbeta-chain have been very recently described as being associated with afibrinogenemia. We studied a Pakistani patient with unmeasurable plasma levels of functional and immunoreactive fibrinogen. Sequencing of the fibrinogen genes revealed a homozygous G-->A transition at position +5 of intron 1 of the gamma-chain gene. The predicted mutant fibrinogen gamma-chain would contain the signal peptide, followed by a short stretch of aberrant amino acids, preceding a premature stop codon. To demonstrate the causal role of the identified mutation, we prepared expression vectors containing a region of the fibrinogen gamma-chain gene spanning from exon 1 to intron 4 and carrying either a G or an A at position +5 of intron 1. Transient transfection of the mutated plasmid in HeLa cells, followed by RNA extraction and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, allowed us to demonstrate the production of an erroneously spliced messenger RNA (mRNA), retaining intron 1, as shown by direct sequencing. A normal splicing occurred in HeLa cells transfected with the wild-type plasmid. This is the first report of a mutation in the fibrinogen gamma-chain gene causing afibrinogenemia and indicates that, in addition to the Aalpha and Bbeta-chain genes, the gamma-chain gene must also be considered in mutation screening for afibrinogenemia.
Afibrinogenemia↗
Shorter survival of SDF1-3'A/3'A homozygotes linked to CD4+ T cell decrease in advanced human immunodeficiency virus type 1 infection.
The SDF-1 3'A allelic polymorphism has been reported to influence either positively or negatively the progression of human immunodeficiency virus type 1 (HIV-1) disease. Therefore, the SDF-1 genotype of 729 HIV-1-infected individuals pooled from 3 distinct cohorts was determined. A statistically nonsignificant association between the SDF1-3'A/3'A genotype and accelerated disease progression was evident among seroconverters (n=319), but a striking correlation of decreased survival after either diagnosis of AIDS according to the 1993 definition or loss of CD4(+) T cell counts <200 was observed. The relative hazards for SDF1-3'A/3'A homozygotes, compared with heterozygotes and wild-type homozygotes were 2.16 (P=.0047), for time from diagnosis according to the 1993 Centers for Disease Control and Prevention AIDS case definition (AIDS-'93) to death, and 3.43 (P=.0001), for time from CD4(+) T cells <200 to death. Because no difference in survival was observed after diagnosis according to AIDS-'87, the association of the SDF1-3'A/3'A genotype with the accelerated progression of late-stage HIV-1 disease appears to be explained for the most part by the loss of CD4(+) T lymphocytes.
Acquired Immunodeficiency Syndrome↗
Missense mutations in the human beta fibrinogen gene cause congenital afibrinogenemia by impairing fibrinogen secretion.
Congenital afibrinogenemia is a rare autosomal recessive disorder characterized by bleeding that varies from mild to severe and by complete absence or extremely low levels of plasma and platelet fibrinogen. Although several mutations in the fibrinogen genes associated with dysfibrinogenemia and hypofibrinogenemia have been described, the genetic defects of congenital afibrinogenemia are largely unknown, except for a recently reported 11-kb deletion of the fibrinogen Aalpha-chain gene. Nevertheless, mutation mechanisms other than the deletion of a fibrinogen gene are likely to exist because patients with afibrinogenemia showing no gross alteration within the fibrinogen cluster have been reported. We tested this hypothesis by studying the affected members of two families, one Italian and one Iranian, who had no evidence of large deletions in the fibrinogen genes. Sequencing of the fibrinogen genes in the 2 probands detected 2 different homozygous missense mutations in exons 7 and 8 of the Bbeta-chain gene, leading to amino acid substitutions Leu353Arg and Gly400Asp, respectively. Transient transfection experiments with plasmids expressing wild-type and mutant fibrinogens demonstrated that the presence of either mutation was sufficient to abolish fibrinogen secretion. These findings demonstrated that missense mutations in the Bbeta fibrinogen gene could cause congenital afibrinogenemia by impairing fibrinogen secretion. (Blood. 2000;95:1336-1341)
Adolescent↗
A novel two base pair deletion in the factor V gene associated with severe factor V deficiency.
We studied a family in which the proband, a 13-year-old boy, had unmeasurable plasma levels of coagulation factor V antigen and activity. Clinical symptoms were severe, with several episodes of haemorrhages in the mucosal tracts (gastrointestinal, nose and urinary) and recurrent haemarthroses that caused permanent arthropathy. Sequence analysis of the factor V gene demonstrated the presence of a novel 2 base pair (bp) homozygous deletion in exon 13 at positions 2833-2834. This mutation, present in the heterozygous state in the asymptomatic mother and absent in the healthy brother, introduced a frameshift and a premature stop at codon 900. This would predict the synthesis of a truncated factor V molecule, lacking part of the B domain and the complete light chain. Because of the existence of a surveillance mechanism that selectively recognizes and degrades mRNA molecules carrying premature termination codons, we analysed the relative abundance of mutant vs. wild-type mRNA molecules in the platelets of the heterozygous proband's mother. The mutant mRNA was significantly reduced in amount (mutant/wild-type ratio 0.35). This is the first reported mutation in the factor V gene causing severe factor V deficiency, the effect of which was quantitatively analysed at mRNA level.
Adolescent↗
Guidelines on replacement therapy for haemophilia and inherited coagulation disorders in Italy.
In the last years, the availability in Italy of technologically advanced products for replacement therapy has produced significant changes in the management of haemophilia and of hereditary bleeding disorders in general. With the aim of a uniform approach to treatment, the Italian Association of Haemophilia Centres express in these guidelines a consensus on therapeutic strategies designed to ensure the highest degree of safety and efficacy for the treatment of inherited coagulopathies. The guidelines provide specific recommendations for the choice of the product according to updated scientific evidence, and advice on optimal dosages for the treatment of rare bleeding disorders. The system for haemophilia care and funding in Italy is briefly described.
Blood Coagulation Disorders↗