Hemophilia a and hemophilia B: different types of diseases?

Hemophilia A and B are traditionally considered clinically indistinguishable; however, differences in bleeding frequency, clinical scores, use of prophylaxis, and need for orthopedic surgery have been reported, suggesting that the bleeding tendency associated with factor IX deficiency may be less severe with consequent better outcomes in the long term.Hemophilia A and B show their own peculiar aspects, not only in terms of epidemiological and clinical features, including inhibitor incidence and associated symptoms, but also with respect to molecular defects. The type of factor VIII/IX mutation is a major determinant of the bleeding tendency as well as of the risk of inhibitor formation; thus, there is a biological plausibility behind the different clinical expression of these two forms of congenital hemophilia. The distinction of various bleeding phenotypes in hemophilia has considerable therapeutic implications; therefore, further research in this field is required to optimize treatment regimens.

[Haemophilia A and haemophilia B. Are there relevant clinical differences?]. / Hämophilie A und Hämophilie B. Gibt es relevante klinische Unterschiede?

UNLABELLED: Haemophilia B (HB) was described in 1952 as a single disease for the first time. In comparison to haemophilia A (HA) the bleeding tendency seemed to be less severe. The aim of this study was to investigate this hypothesis in all patients with HA and HB treated in the haemophilia care center of the Vivantes Klinikum. PATIENTS, METHODS: All patients with severe HA and HB treated at the haemophilia care center were included. We evaluated the regimen of replacement therapy and factor concentrate consumption within the last 5 years (1/2004 to 12/2008). Intracerebral bleeds were analysed over the whole life span of the included patients. RESULTS: 111/181 patients with HA had the severe form and 12/34 patients severe HB. 4/12 patients with severe HB had a history of intracerebral bleeding in comparison to 5/111 patients with severe HA. 2/8 adult patients with severe HB used a prophylactic treatment with factor concentrates (mean consumption 1289 IU factor IX/kg BW/year) in contrast to 60/95 adult patients with HA (mean consumption 2109 IU factor VIII /kg BW/year). CONCLUSION: The data suggest a milder bleeding type of patients with severe HB in comparison to patients with severe HA but may be patients with severe HB are at higher risk for intracerebral bleeds.

Influence of factor IX on overall plasma coagulability and fibrinolytic potential as measured by global assay: monitoring in haemophilia B.

We sought to determine the influence of factor IX (FIX) deficiency upon overall coagulative and fibrinolytic capacities in plasma using the clot formation and lysis (CloFAL) assay, and to investigate the role of this global assay as an adjunctive monitoring tool in haemophilia B. CloFAL assay parameters were measured in vitro in platelet-poor plasma in relation to FIX activity and antigen (FIX:Ag), and were determined ex vivo among FIX-deficient patients (n = 41) in comparison to healthy individuals (n = 48). Supplementation of FIX-deficient plasma with FIX in vitro demonstrated a non-linear concentration dependence of FIX upon overall plasma coagulability. Ex vivo, coagulability was significantly decreased in FIX-deficient vs. healthy subjects among adults [median coagulation index (CI): 4% vs. 104% respectively; P < 0.001] and children (median CI: 9% vs. 63%; P < 0.001). Fibrinolytic capacity was increased in adult FIX-deficient vs. healthy subjects (median fibrinolytic index: 216% vs. 125%, respectively, P < 0.001), and was supported by a trend in shortened euglobulin lysis time (ELT). Severe haemophilia B patients showed heterogeneity in aberrant CloFAL assay waveforms, influenced partly by FIX:Ag levels. Patients with relatively preserved FIX:Ag (i.e. dysfunctional FIX) exhibited a shorter time to maximal amplitude in clot formation than those with type I deficiency. During patient treatment monitoring, markedly hypocoagulable CloFAL assay waveforms normalized following 100% correction with infused FIX. The CloFAL global assay detects FIX deficiency, demonstrates differences in coagulability between dysfunctional FIX and type I deficiency, and appears useful as an adjunctive test to routine FIX measurement in monitoring haemophilia B treatment.

Diagnosis and treatment of congenital hemophilia with inhibitors a Latin American perspective.

The Committee of Latin America on the Therapeutics of Inhibitor Groups (CLOTTING) is composed of a number of hemophilia specialists from Latin America. The group aims to encourage the adoption of a good standard of care for Latin American patients with hemophilia. The occurrence of inhibitors in patients with hemophilia poses clinical challenges, and it is estimated that between 1000 and 3000 patients in Latin America are affected by hemophilia with inhibitors. There is an urgent need to establish a regional consensus and clinical guidelines for the diagnosis and treatment of these patients. We present an extensive review based on best current clinical practice and published literature, as seen from a Latin American perspective, taking into account the variable nature of hemophilia care available in the various countries in this Region.

A comparison between MRI, sonography and Functional Independence Score in Haemophilia methods in diagnosis, evaluation and classification of arthropathy in severe haemophilia A and B.

Evaluation of joints in children with haemophilia is important in detecting abnormalities, staging their severity and following the effects of treatment. The aim of this study is to evaluate the correlation of FISH score (Functional Independence Score in Haemophilia) with the scores obtained by MRI and sonography for the diagnosis, evaluation and classification of arthropathy in severe haemophilia. In this cross-sectional study on 25 severe haemophilia patients, FISH, MRI and sonography procedures were performed in the elbow or knee joint. All patients' information, including age, type of haemophilia, affected joint, scores of MRI, sonography and FISH, dose of factor consumed, weight and prophylaxis protocol were collected and analysed. Among the 25 patients (age range of 11-70 years), 22 patients were haemophilia A and three patients were haemophilia B. Affected joints were right knee in 12 patients, left knee in nine and right elbow in four. There was only a statistically significant negative correlation between FISH and MRI Additive (A) scale (rs = -0.537, P = 0.006). Considering cartilage loss domain (related MRI A scale: 13-20), 20 patients (80%) were classified in this group with FISH scores ranged from 17 to 22. On the basis of our results, FISH scores in severe haemophilia patients were negatively correlated with MRI A scale. Also, it seems that a FISH score less than 22 could be considered as loss of cartilage; however, due to the small number of our patients, it needs further assessment in different populations.

Haemophilia B Leyden in Greece.

In this paper, a five generation Greek family is described with haemophilia B. The disease is characterized by a normal ox-brain prothrombin time, normal levels of the vitamin-K dependent clotting factors VII and X and a proportional reduction of factor IX activity and antigen levels all of which is consistent with the cross-reacting material negative form of haemophilia B. However, in this family the factor IX levels in the three patients of generation V are around 1 U/dl while the three older patients in generation III have factor IX levels ranging from 28 to 44 U/dl. In the oldest patient of generation V we observed a rise of the factor IX level from 1 U/dl up to the age of 13 to 10 U/dl at age 14. In addition, the older patients have very mild bleeding symptoms or none at all, while the young ones have occasional spontaneous haemorrhages in muscles and joints, compatible with severe or moderately severe haemophilia. The disease appears to be similar to haemophilia B Leyden which has been described in a Dutch family.

An investigation of three patients with Christmas disease due to an abnormal type of factor IX.

Three patients with Christmas disease whose plasma was shown to have a prolonged one-stage prothrombin time with ox brain thromboplastin have been investigated. These patients have an inhibitor for the reaction between factor X, factor VII, and ox brain extract. The abnormal constituent responsible for this inhibitor appears to be factor IX whuch is functionally inactive but antigenically indistinguishable from normal factor IX. It is proposed that patients might be classified into haemophilia B(+) for patients with this defect (Christmas disease(+)) and haemophilia B(-) (Christmas disease(-)) for patients who have classical Christmas disease.

Redefining disease? The nosologic implications of molecular genetic knowledge.

How will developments in genetic knowledge affect the classification of disease? Leaders in genetics have suggested that knowledge of the role of genes in disease can determine nosology. Diseases might be defined by genotype, thus avoiding the limitations of more empirical approaches to categorization. Other commentators caution against disease definitions that are detached from the look and feel of disease, and argue for an interplay between genotypic and phenotypic information. Still others attribute nosologic change to social processes. We draw on an analysis of the scientific literature, our conversations with genetics clinicians, and reviews of patient organization Web sites to offer a revised interpretation of the nosologic implications of molecular genetic knowledge. We review the recent histories of three diseases--hemophilia, Rett syndrome, and cystic fibrosis--to argue that nosologic change cannot be explained by either biologic theories of disease etiology or sociologic theories of social tendencies. Although new genetic information challenges disease classifications and is highly influential in their redesign, genetic information can be used in diverse ways to reconstruct disease categories and is not the only influence in these revisions. Ironically, genetic information is likely to play a central role in producing a new, but still empirical, classification scheme.

An immunological investigation of hemophilia B with a tentative classification of the disease into five variants.

23 patients with hemophilia B have been investigated by means of several immunological methods. 16 patients (69.9%) had no detectable factor XI antigen. Five had a normal factor IX antigen and the electrophoretic mobility of this abnormal factor IX was similar to that of its normal counterpart. One of these five patients had hemophilia Bm, since ox brain thromboplastin clotting time was severely prolonged. The remaining two patients had reduced or decreased factor IX antigen. Several patients showed a slight protongation of ox brain thromboplastin time due to an associated slight factor VII deficiency. On the basis of these results, a tentative classification of hemophilia B into five variants is proposed, namely: hemctor IX antigen; hemophilia Bra, or with reduced factor IX antigen; hemophilia Bm, or with normal factor IX antigen and severely prolonged ox brain thromboplastin; hemophilia B patients is feasible only by means of a battery of tests, namely:factor IX activity assay, factor IX antigen determination, ox brain thromboplastin clotting time, factor VII activity assay.

Incidence, significance, and subtypes of hemophilia BM in a large population of hemophilia B patients.

Eleven patients with hemophilia BM were found out of a population of 66 patients with hemophilia B. Factor IX activity in the hemophilia BM varied between less than 1% and 1.6% of normal but factor IX antigen was normal or only slightly reduced in each instance. Thrombotest clotting time was variably prolonged and was not corrected by the addition of normal plasma. Thrombotest mixing experiments and dilution curve studies confirmed the presence of the inhibitor in every patient. There are at least two forms of hemophilia BM, a severe one and a mild one. In the first form, Thrombotest is severely prolonged (90-120 s). In the other, the prolongation is mild or moderate (60-80 s). A positive correlation exists between the antigen-activity difference (delta antigen-activity) and the prolongation of Thrombotest both in the propositi and in obligatory carriers. The criteria for the diagnosis of hemophilia BM are the following: prolonged PTT, prolonged Thrombotest, lack of correction of Thrombotest by the addition of normal plasma while PTT is fully corrected. The lack of correction of Thrombotest in the presence of a full correction of PTT, is the unique clotting feature.

Sensitive solid phase enzyme immunoassay for factor IX antigen and classification of hemophilia B.

A sensitive solid phase enzyme immunoassay (EIA) was developed for the measurement of factor IX antigen (IX:AG), using rabbit antihuman factor IX antiserum and beta-D-galactosidase, which enabled us to detect IX:AG as low as 10(-4)U/ml. 37 patients with severe hemophilia B have been investigated by EIA, inhibitor neutralization assay and bovine brain prothrombin time. They could be divided into four genetic variants. 25% had normal levels of IX:AG but decreased levels of factor IX clotting activity. On crossed immunoelectrophoresis of the hemophilia B+ and hemophilia BM, we could not find abnormalities in electrophoretic mobilities compared to normal subjects in the presence of 1 mM Ca++ lactate.

Problems involved in grading the severity of hemophilia by test results.

Some problems involved in grading the severity of hemophilia were discussed. No definite correlation existed between the clinical severity of hemophilia and the results of coagulation tests (activity of deficient factors, whole blood clotting time, thromboplastin screening test). There was also no correlation between the presence or absence of oral bleeding or hemarthrosis and the test results. It was concluded that the clinical severity of the disease can be graded more reasonably on the basis of clinical hemorrhagic symptoms than according to the activity of deficient factors.

Diagnosis and treatment of congenital hemophilia with inhibitors: A Latin American perspective / Diagnóstico y tratamiento de la hemofilia congénita con inhibidores: Una perspectiva latinomericana

The Committee of Latin America on the Therapeutics of Inhibitor Groups (CLOTTING) is composed of a number of hemophilia specialists from Latin America. The group aims to encourage the adoption of a good standard of care for Latin American patients with hemophilia. The occurrence of inhibitors in patients with hemophilia poses clinical challenges, and it is estimated that between 1000 and 3 000 patients in Latin America are affected by hemophilia with inhibitors. There is an urgent need to establish a regional consensus and clinical guidelines for the diagnosis and treatment of these patients. We present an extensive review based on best current clinical practice and published literature, as seen from a Latin American perspective, taking into account the variable nature of hemophilia care available in the various countries in this Region.

El Comité Latinoamericano sobre la Terapéutica de Personas con Inhibidores (CLOTTING) está compuesto por un grupo de especialistas en hemofilia de Latinoamérica. El objetivo del grupo es promover la adopción de un estándar de tratamiento óptimo para los pacientes con hemofilia en Latinoamérica. La prevalencia de inhibidores en pacientes con hemofilia en Latinoamérica determina desafíos clínicos y se estima que de 1000 a 3000 pacientes en esta región están afectados con hemofilia e inhibidores. Existe una necesidad urgente de establecer un consenso regional y guías clínicas para el diagnóstico y tratamiento de estos pacientes. Nosotros presentamos una revisión exhaustiva basada en las mejores prácticas clínicas vigentes y en los datos publicados en la literatura, con una perspectiva latinoamericana, tomando en cuenta la variabilidad existente de los tratamientos de la hemofilia disponibles en los diferentes países de esta Región.