Vaccinations are not associated with inhibitor development in boys with severe haemophilia A.

BACKGROUND: Inhibitor development in previously untreated patients (PUPs) with severe haemophilia A is a multifactorial event. It is unknown whether paediatric vaccinations given in close proximity to factor VIII (FVIII) are associated with inhibitor development. OBJECTIVE: To assess whether paediatric vaccinations in close proximity to FVIII within the first 75 exposure days (EDs) are associated with inhibitor development in PUPs with severe haemophilia A. METHODS: We included 375 PUPs with severe haemophilia A (<0.01 IU/mL) from the PedNet Registry who had received vaccinations between the first and 75th ED or inhibitor development. Inhibitor risk was compared between patients who did and who did not receive vaccinations within 24, 72 or 120 hours of FVIII infusion. Unadjusted and adjusted hazard ratios were calculated for any or repeated vaccinations in close proximity to FVIII, using Cox regression. RESULTS: Inhibitor development occurred in 77 of 375 patients (20.5%). Overall inhibitor development appeared similar or lower in patients receiving vaccinations in close proximity to FVIII as compared to patients receiving vaccinations without FVIII: for 24 hours, this was 19.2% and 21.4% (P = .186), for 72 hours, 16.4% and 27.3% (P = .023) and for 120 hours, 18.3% and 25.0% (P = .085), respectively. CONCLUSION: We found no association between vaccinations given in close proximity to FVIII exposure within the first 75 EDs and inhibitor development. Our data do not support avoiding administration of FVIII at time of routine vaccinations.

Imaging features of atypical bleeds in young patients with hemophilia.

Hemarthroses and muscle bleeds are well-known and well-documented complications in pediatric and young adult hemophilia patients. In contrast, deep bleeds in atypical locations can be a diagnostic challenge, since clinicians and radiologists are often unfamiliar with their clinical and radiological features. Some atypical bleeds, however, can be life-threatening or severely disabling, highlighting the need for prompt, accurate diagnosis. Rare bleeds include central nervous system bleeds (including intracranial and spinal hematomas), urogenital bleeds, intra-abdominal bleeds (mesenteric and gastrointestinal wall hematomas) and pseudo tumors in unusual locations like the sinonasal cavities. Because clinical assessment can be difficult, clinicians and radiologists should be aware of the possibility of these rare complications in their hemophilia patients, so that they can avoid unnecessary invasive diagnostic and surgical procedures and institute prompt, appropriate treatment. The purpose of this review is to illustrate the imaging features of bleeds that occur in rare locations in young (i.e., children and young adults) patients with hemophilia to make the reader more familiar with these conditions.

Evidence for persistent hepatitis C virus (HCV) infection in hemophiliacs.

Hepatitis C virus (HCV) is the major etiologic agent associated with non-A, non-B hepatitis. This study was designed to assess virologic and serologic markers in hemophiliacs exposed to non-heat-treated and/or virus-inactivated plasma derivatives. Serial bleeds from 48 hemophilic patients were analyzed for the presence of HCV viral RNA sequences as detected by polymerase chain reaction (PCR) and antibodies to structural (core) and nonstructural (C-100 and 33C) proteins by specific dot immunoblot assay. All patients exposed to non-heat-treated products, and four of six patients exposed only to virus inactivated products, had evidence of HCV infection. However, over the 5-yr study period, six exposed patients (13%) consistently lacked detectable anti-C-100 and seven (15%) lost this antibody. HCV viremia (PCR positive) was found in 91% of exposed patients, and was significantly more frequent in HIV seropositive hemophiliacs (P less than 0.05). Six patients had high antibody level to HCV and elevated ALT, but appeared to clear viremia. Four hemophiliacs were HCV seropositive but lacked detectable viremia. These data indicate that hemophiliacs remain persistently infected by HCV and that antibody to the core antigen of HCV is a reliable marker of this transfusion transmissible agent.

[Mild hemophilia A fortuitously discovered during Henoch-Schönlein purpura]. / Découverte fortuite d'une hémophilie A mineure à l'occasion d'un purpura rhumatoïde.

Henoch-Schönlein purpura is a common form of immunological vasculitis in children. Hemophilia A is a genetic disorder, inherited in a X-linked recessive pattern, and characterized by spontaneous hemorrhage or prolonged bleeding due to factor VIII deficiency. The clinical signs depend on the severity of factor VIII deficiency. We herein report the case of a 4-year-old boy admitted to the emergency room for typical rheumatoid purpura, associated with a lengthening of aPTT, whose exploration had uncovered mild hemophilia A. Laboratory assays should explore lengthening of aPTT: firstly the presence of lupus anticoagulant without bleeding risk, in an inflammatory context; secondly a deficiency of VWF and one of the factors involved in the extrinsic coagulation pathway associated with bleeding risk.

[French guidelines. Long-term prophylaxis for severe haemophilia A and B children to prevent haemophiliac arthropathy]. / Prophylaxie de longue durée chez les enfants hémophiles A et B sévères en pévention de l'arthropathie hémophilique.

During the last decades, long-term prophylaxis has become the gold standard for the treatment of children with severe haemophilia A or B. Prophylactic replacement regimens modify the natural history of the disease by aiming at the prevention of haemarthrosis, target joints and arthropathy. This treatment represents a constraint and an enhanced exposure to anti-haemophilic concentrates, which means potential increase of related risks and significant additional cost. The context of crisis of confidence due to the blood borne infections in the 1980s, may have delayed prophylaxis as an universal gold standard.In the early 2000s, the French group CoMETH proposed recommendations based on the review of the international experience. At first, specific guidelines of long-term prophylaxis were dedicated to children with severe haemophilia A or B, aged 3 years or less, with no history of target joint or arthropathy. The main concerns of this regimen consist in the early start and the escalating intensification of the treatment. In the French haemophilia care centres, the diffusion of these guidelines has apparently induced a significant turning point in therapeutic practices for haemophilia children. In 2006, more comprehensive recommendations were diffused to take into account all the children with severe haemophilia, whatever the bleeding history and joint status. The analysis of their impact, jointly with the National cohort "France Coag Network", will first assess the widespread implementation of the recommendations and the observance of the prophylactic regimen and identify factors associated to the compliance.