Circulating FVIII-specific IgG, IgA and IgM memory B cells from haemophilia A patients.

INTRODUCTION: Approximately, 25% of haemophilia A (HA) patients treated by factor VIII (FVIII), develop antibodies, known as inhibitors, neutralizing the activity of infused FVIII. This immune response involves B cells (BC), including FVIII-specific memory B cells (MBC). Production of anti-FVIII antibodies after stimulation of FVIII-specific MBC suggests a role of these cells in the immune response to FVIII. Animal models allowed the study of circulating FVIII-specific cells, however few data are available on HA patients. AIM AND METHODS: In the present study, we simultaneously detected, via ELISpot assay, different isotypes of MBC in the blood of HA patients, after polyclonal activation. Patients included: three with active inhibitors; three with a history of inhibitors; six without any past or active inhibitor. RESULTS: FVIII-specific MBC were detected in peripheral blood of HA patients: (i) patients with active inhibitors (IgG: 4-5.2/10(6) BC; IgA: 2.9-4/10(6) BC) (ii) patients with a past of inhibitors (no IgG BC; IgA: 5-7.5/10(6) BC) (iii) patients without inhibitors (no IgG BC or IgA BC except one patient had two FVIII-specific IgA BC/10(6) BC). CONCLUSION: FVIII-specific IgA MBC were detected in HA patients with past and current immune responses against FVIII and FVIII-specific IgG MBC were found only in those with positive inhibitors. This study shows the possibility to detect and characterize easily and simultaneously the MBC from patient blood and that MBC seem different according to anti-FVIII immune history. It could be a useful tool to study anti-FVIII response and Immune Tolerance Induction cellular mechanisms.

Women with congenital factor VII deficiency: clinical phenotype and treatment options from two international studies.

INTRODUCTION: A paucity of data exists on the incidence, diagnosis and treatment of bleeding in women with inherited factor VII (FVII) deficiency. AIM: Here we report results of a comprehensive analysis from two international registries of patients with inherited FVII deficiency, depicting the clinical picture of this disorder in women and describing any gender-related differences. METHODS: A comprehensive analysis of two fully compatible, international registries of patients with inherited FVII deficiency (International Registry of Factor VII deficiency, IRF7; Seven Treatment Evaluation Registry, STER) was performed. RESULTS: In our cohort (N = 449; 215 male, 234 female), the higher prevalence of mucocutaneous bleeds in females strongly predicted ensuing gynaecological bleeding (hazard ratio = 12.8, 95% CI 1.68-97.6, P = 0.014). Menorrhagia was the most prevalent type of bleeding (46.4% of patients), and was the presentation symptom in 12% of cases. Replacement therapies administered were also analysed. For surgical procedures (n = 50), a receiver operator characteristic analysis showed that the minimal first dose of rFVIIa to avoid postsurgical bleeding during the first 24 hours was 22 µg kg(-1) , and no less than two administrations. Prophylaxis was reported in 25 women with excellent or effective outcomes when performed with a total weekly rFVIIa dose of 90 µg kg(-1) (divided as three doses). CONCLUSION: Women with FVII deficiency have a bleeding disorder mainly characterized by mucocutaneous bleeds, which predicts an increased risk of ensuing gynaecological bleeding. Systematic replacement therapy or long-term prophylaxis with rFVIIa may reduce the impact of menorrhagia on the reproductive system, iron loss and may avoid unnecessary hysterectomies.

Genotype and phenotype relationships in 10 Pakistani unrelated patients with inherited factor VII deficiency.

Inherited factor VII (FVII) deficiency is one of the commonest rare bleeding disorders. It is characterized by a wide molecular and clinical heterogeneity and an autosomal recessive pattern of inheritance. Factor VII-deficient patients are still scarcely explored in Pakistan although rare bleeding disorders became quite common as a result of traditional consanguineous marriages. The aim of the study was to give a first insight of F7 gene mutations in Pakistani population. Ten unrelated FVII-deficient patients living in Pakistan were investigated (median FVII:C = 2%; range = 2-37%). A clinical questionnaire was filled out for each patient and direct sequencing was performed on the coding regions, intron/exon boundaries and 5' and 3' untranslated regions of the F7 gene. Nine different mutations (eight missense mutations and one located within the F7 promoter) were identified on the F7 gene. Five of them were novel (p.Cys82Tyr, p.Cys322Ser, p.Leu357Phe, p.Thr410Ala, c-57C>T, the last being predicted to alter the binding site of transcription factor HNF-4). Half of the patients had single mutations in Cys residues involved in disulfide bridges. The p.Cys82Arg mutation was the most frequent in our series. Six of seven patients with FVII:C levels below 10% were homozygous in connection with the high percentage of consanguinity in our series. In addition, we graded the 10 patients according to three previously published classifications for rare bleeding disorders. The use of the bleeding score proposed by Tosetto and co-workers in 2006 appears to well qualify the bleeding tendency in our series.

[Rare bleeding disorders and invasive procedures]. / Déficits rares de la coagulation et gestes invasifs.

Rare inherited bleeding disorders include fibrinogen disorders, and deficiencies of factors II (prothrombin), V, VII, X, XI, XIII, and combined V+VIII, and combined vitamin K-dependent factors, with general population prevalence rates between 1/500,000 and 1/2,000,000. These inherited disorders, transmitted as autosomal recessive traits, are characterized by a heterogeneous clinical presentation (asymptomatic, mild, moderate or severe bleeding tendency); this variability is more important for deficiencies with factor levels ranging from 5 to 50%. Individual bleeding risk assessment before an invasive procedure or during peri-partum period remains difficult, although an essential step to decide whether a substitution with clotting factor is necessary or not. Because there is a poor correlation between factor activity levels and the severity of bleeding symptoms, factor correction before an invasive procedure should not be based on factor level only, but physicians must also take into account the patient phenotype as well as the haemorrhagic risk of the procedure.

Coagulation factor activity and clinical bleeding severity in rare bleeding disorders: results from the European Network of Rare Bleeding Disorders.

BACKGROUND: The European Network of Rare Bleeding Disorders (EN-RBD) was established to bridge the gap between knowledge and practise in the care of patients with RBDs. OBJECTIVES: To explore the relationship between coagulation factor activity level and bleeding severity in patients with RBDs. PATIENTS/METHODS: Cross-sectional study using data from 489 patients registered in the EN-RBD. Coagulation factor activity levels were retrieved. Clinical bleeding episodes were classified into four categories according to severity. RESULTS: The mean age of patients at data collection was 31 years (range, 7 months to 95 years), with an equal sex distribution. On linear regression analysis, there was a strong association between coagulation factor activity level and clinical bleeding severity for fibrinogen, factor (F) X, FXIII, and combined FV and FVIII deficiencies. A weaker association was present for FV and FVII deficiencies. There was no association between coagulation factor activity level and clinical bleeding severity for FXI. The coagulation factor activity levels that were necessary for patients to remain asymptomatic were: fibrinogen, > 100 mg dL(-1); FV, 12 U dL(-1); combined FV + VIII, 43 U dL(-1); FVII, 25 U dL(-1); FX, 56 U dL(-1) ; FXI, 26 U dL(-1); FXIII, 31 U dL(-1). Moreover, coagulation factor activity levels that corresponded with Grade III bleeding were: undetectable levels for fibrinogen, FV and FXIII, < 15 U dL(-1) for combined FV + VIII; < 8 U dL(-1) for FVI; < 10 U dL(-1) for FX; and < 25 U dL(-1) for FXI. CONCLUSIONS: There is a heterogeneous association between coagulation factor activity level and clinical bleeding severity in different RBDs. A strong association is only observed in fibrinogen, FX and FXIII deficiencies.

A retrospective analysis of 157 surgical procedures performed without replacement therapy in 83 unrelated factor VII-deficient patients.

BACKGROUND: Inherited factor (F)VII deficiency is the commonest of the rare bleeding disorders, with a wide set of hemorrhagic features. Other than for the severe clinical forms (for which treatment guidelines are well defined), consistent recommendations regarding perioperative replacement management do not exist for mild and asymptomatic FVII-deficient patients. OBJECTIVES: The present study aimed to evaluate the influence of bleeding history, FVII procoagulant activity levels (FVII:C) and the type of surgical procedure on the management of inherited FVII-deficient patients before surgery. PATIENTS: One hundred and fifty-seven surgical procedures, performed without replacement therapy, in 83 unrelated FVII-deficient patients (median FVII:C=5%, range 0.6%-35%) were analyzed. RESULTS: The overall bleeding rate was 15.3%. We found a significant relationship between previous deep traumatic hematomas and bleeding at surgery, although relationships with previous common epistaxis, easy bruising and menorrhagia were not significant. The receiver-operating characteristic (ROC) curve analysis performed on the first 83 procedures allowed us to define a cut-off value of 7% with a sensitivity of 87% (negative predictive value: 94%). To enhance the sensitivity, and to take into account the potential variation resulting from non-standardized FVII:C measurements, we would suggest applying a threshold of 10%. CONCLUSION: We have proposed recommendations for the perioperative management of FVII-deficient patients based on FVII:C levels, a thorough bleeding history and the type of surgery involved. By applying these recommendations, minor procedures that risk only external or controlled hemorrhage can be performed in asymptomatic or mildly affected adults, even those with FVII:C levels below 10%.

Recombinant activated factor VII for a patient with factor VII deficiency undergoing urgent intracerebral haematoma evacuation with underlying cavernous angioma.

Inherited factor VII (FVII) deficiency is a rare autosomal-recessive bleeding disorder. There are no clear guidelines regarding therapy in such patients when intracerebral surgery is performed. We report the use of recombinant activated FVII (rFVIIa) for the prophylaxis of bleeding in a female with FVII deficiency (8% of activity) undergoing urgent removal of a right fronto-rolandic intracerebral haematoma secondary to a bleeding from a cavernous angioma. To assist haemostasis during and after surgery, rFVIIa boluses were administered during the procedure and continued every 12 h during 3 days after operation to maintain a prothrombin time <15 s. Using this approach, no abnormal bleeding or thromboembolic complications were observed and rFVIIa appeared safe in this context.

The paradoxical association between inherited factor VII deficiency and venous thrombosis.

Inherited factor VII (FVII) deficiency is considered to be a haemorrhagic disease. Nonetheless, some patients paradoxically present with venous thrombosis. We assessed whether there was a link between phenotype and genotype in seven patients with inherited FVII deficiency and thrombosis (eleven venous thrombotic events). For each patient (FVII:C < 50%), clinical data were collected, aetiological assessment of risk factors for thrombosis was investigated, and direct sequencing of the nine exons and promoter of the FVII gene (F7) was performed. We present the second series ever published on FVII patients with thrombosis. In nine of the eleven thrombotic events, there was at least one classical triggering risk factor; clinical (n = 4), familial antecedent (n = 2), or biological, defined by phospholipid-binding antibodies or elevated FVIII:C levels (n = 7). In contrast to a previous series, only two events occurred after surgery, performed both with and without replacement therapy. The thrombotic event remained unexplained in one young patient, highlighting the lack of 'protection' against venous thrombosis by low FVII:C levels. Genetic mutations were found to be heterogeneous. Among the seven F7 sequence alterations identified in the present study, only two (p.Ala354Val and p.Arg364Gln) have previously been reported in FVII-deficient patients presenting with venous thrombosis. Our genetic analyses of the F7 mutations in these patients show the complexity of FVII deficiency associated with thrombosis. These data justify a holistic, clinical and biological approach for patients with these specific symptoms. This series also strongly suggest that mild FVII deficiency should not prevent physicians from using antithrombotic prophylaxis in FVII-deficient patients.

Transferrin receptor-2 gene and non-C282Y homozygous patients with hemochromatosis.

More than 80% of the patients affected by hereditary hemochromatosis, a common inherited iron disorder, are homozygotes for the 845G --> A (C282Y) mutation of the HFE gene. However, depending on the population, 10-20% of hereditary hemochromatosis can be linked either to other HFE genotypes, particularly the compound heterozygous state for C282Y and the 187 C --> G (H63D) mutation, or to mutations of new other genes. Recently, Camaschella et al. (Nat. Genet. 25, 14-15, 2000) identified a stop mutation (exon 6 nt 750 C --> T, Y250X) on the transferrin receptor-2 (TFR2) gene in two unrelated Sicilian families with hereditary hemochromatosis. The TFR2 gene is a transferrin receptor gene homologue that seems to be involved in iron metabolism. Moreover, one of the patients described by Camaschella et al. was a H63D homozygote. H63D homozygosity can be associated with various phenotypes from asymptomatic subjects to patients with a typical form of hereditary hemochromatosis. Thus, the Y250X mutation could be the molecular defect responsible for hereditary hemochromatosis in subjects with atypical HFE genotypes. We have searched for the Y250X mutation in 63 unrelated French subjects. Forty-three had a diagnosis of hereditary hemochromatosis based on classical criteria. This group included 12 H63D homozygotes, 3 C282Y heterozygotes, and 3 patients with none of the two most prevalent HFE mutants. These 18 patients had no other HFE sequence change and were subsequently subjected to DNA sequencing of the 15 last exons and flanking sequences of the TFR2 gene. The 25 remaining hereditary hemochromatosis patients who were tested for the Y250X mutant were compound heterozygotes for the C282Y and H63D mutations. Finally, we also tested for this TFR2 mutation 20 H63D homozygotes with milder manifestations of iron overload and no acquired cause of iron overload. None of the 63 tested subjects had the Y250X mutation. Concurrently, none of the 18 hereditary hemochromatosis patients who had their TFR2 gene sequenced had any deleterious mutation. Thus, TFR2 mutations are not responsible for hemochromatosis in non-C282Y homozygous patients of our area.

Analysis of the genotypes and phenotypes of 37 unrelated patients with inherited factor VII deficiency.

Severe inherited factor VII (FVII) deficiency is a rare autosomal recessive disorder with a poor relationship between FVII coagulant activity and bleeding tendency. Both clinical expression and mutational spectrum are highly variable. We have screened for mutations the FVII gene of 37 unrelated patients with a FVII coagulant activity less than 5% of normal pooled plasmas. The nine exons with boundaries and the 5' flanking region of the FVII gene were explored using a combination of denaturing gradient gel electrophoresis and direct DNA sequencing. This strategy allowed us to characterise 68 out of the 74 predicted FVII mutated alleles. They corresponded to a large panel of 40 different mutations. Among these, 18 were not already reported. Genotypes of the severely affected patients comprised, on both alleles, deleterious mutations which appeared to be related to a total absence of activated FVII. We suggest that this absence of functional FVII can explain the severe clinical expression. Whether a small release of FVII is sufficient to initiate the coagulation cascade and to prevent the expression of a severe phenotype, requires further investigations.