[Therapy of inherited diseases of platelet function. Interdisciplinary S2K guideline of the Permanent Paediatric Committee of the Society of Thrombosis and Haemostasis Research (GTH e. V.)]. / Therapie hereditärer Thrombozytopathien. Interdisziplinäre S2K-Leitlinie der Ständigen Kommission Pädiatrie der Gesellschaft für Thrombose- und Hämostaseforschung e. V.

Inherited disorders of platelet function are a heterogeneous group. For optimal prevention and management of bleeding, classification and diagnosis of the underlying defect are highly recommended. An interdisciplinary guideline for a diagnostic approach has been published (AWMF # 086-003 S2K; Hämostaseologie 2014; 34: 201-212). Underlying platelet disorder, platelet count, age and clinical situation modify treatment. Exclusive transfusion of platelet concentrates may be inappropriate as potentially adverse effects can outweigh its benefit. A stepwise and individually adjusted approach for restitution and maintenance of haemostasis is recommended. Administration of antifibrinolytics is generally endorsed, but is of particular use in Quebec disease. Restricted to older children, desmopressin is favourable in storage pool disease and unclassified platelet disorders. Although licensed only for patients with Glanzmann thrombasthenia and alloantibodies, in clinical practice rFVIIa is widely used in inherited platelet disorders with severe bleeding tendency. This guideline aims at presenting the best available advice for the management of patients with inherited platelet function disorders.

Increased amounts of von Willebrand factor are bound to microparticles after infusion of desmopressin.

Effects of desmopressin (DDAVP) in platelet disorders and primary haemostasis cannot be attributed solely to the increase in FVIII/VWF (von Willebrand factor), as VWF/FVIII concentrates have no effect in these circumstances. Microparticles (MP) can support haemostasis by expression of phospholipids, tissue factor and VWF on their surface. We hypothesized that significant amounts of VWF are bound to MP after DDAVP administration and that consequently depletion of MP should influence VWF:Ag and VWF:RCo plasma levels. Platelet-poor plasma was either obtained well from healthy controls or before and after DDAVP administration from patients with von Willebrand's disease (type 1 or possible type 1) or patients with other bleeding disorders as controls. Concentrations of MP and VWF parameters were determined before and after MP depletion by different methods (magnetic bead selection, plasma microfiltration, ultracentrifugation). Platelet MP and VWF-bearing MP were significantly increased after DDAVP. MP depletion by magnetic bead selection led to a significant reduction in VWF:Ag (-18.0%) and VWF:RCo (-27.7%) plasma levels without changes in VWF multimer composition. As results were similar for DDAVP control subjects, the amount of VWF bound to circulating microparticles was significantly higher after DDAVP administration compared with healthy controls (reduction -11.7%). DDAVP leads to a release of microparticles and increases the amount of VWF bound to microparticles which might explain the clinical efficacy of DDAVP in platelet disorders.

Successful long-time treatment with mycophenolate-mofetil in a child with acquired factor VIII inhibitor.

UNLABELLED: Here, we report about a boy (age: 18 years) who developed an acquired factor VIII inhibitor at the age of 9 years. He presented with bleeding in his right ankle, multiple haematomas and a high-titer factor VIII type II inhibitor (400 BU). THERAPY: He received treatment with MMF (CellCept®), dexamethasone-immunoglobulin pulses, and rituximab together with high dose FVIII (Hannover protocol). His inhibitor titer decreased rapidly, and half-life and recovery normalized. Inhibitor titres increased after reduction of the factor VIII dose, and increased further after MMF was stopped. A second treatment course with MMF again resulted in reduction of the titre, improvement in half life and recovery, and no more bleedings. Inhibitor reappeared with MMF dose reduction, again accompanied by severe bleeding. Additional rituximab stopped the bleedings, and treatment with MMF has been continued since. CONCLUSION: Although the laboratory parameters showed no complete remission, severe bleedings and expensive factor replacement could be avoided by long-term treatment with MMF.

Prioritisation in haemophilia A: a qualitative study of stakeholder attitudes and preferences.

To learn more about prioritisation in the health care system, we performed an exploratory qualitative study on haemophilia A. The aim was to generate haemophilia disease-specific criteria and to learn more about reasoning in the decision-making process. The 40 participants (patients, relatives, physicians, nurses) were asked in semi-structured interviews about their experiences regarding the German health care system in general and the management of haemophilia A. The 4 stakeholder groups agreed that treatment in haemophilia A was very good; there were complaints about increased bureaucracy. Arguments originated in personal past experiences (patients, relatives) and in the professional background (healthcare professionals). Decision-making criteria ranking high were the maintenance of mobility, social responsibility and the prospect of a long working life span. Criteria with lower ranking were a high social professional status and age. There was ambivalence as to whether savings in the healthcare system in general were necessary or inacceptable. Prophylactic factor administration was rejected when high-risk sports were practiced regularly. Decision-making among actual individuals was rejected as 'immoral'. Patient representatives should be included in the political decision-making process. In conclusion, solidarity in the German health insurance is a highly esteemed principle, but was not well comprehended. The findings demonstrate the variety of individual attitudes with strong context affinity to the disease and the background of the stakeholder groups. The challenge will be to find ways of prioritising in an accountable and transparent way to maintain an excellent health care service for the individual haemophilia patient while also serving the public good.

Inhibitor-immunology-study. Evaluation of inhibitor development in haemophilia B.

UNLABELLED: The development of inhibitors in haemophilia B is one of the most important complications of replacement therapy, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors, and to date, only little is known about its underlying mechanisms. Here, we present first results of the haemophilia B group of our Inhibitor-Immunology study. PATIENTS, METHODS: So far we have analysed 15 patients with haemophilia B. Four of them developed a high titre inhibitor; the remaining 11 had no inhibitor. We evaluated 9 SNPs in 8 genes (CD40, CTLA-4 , IL-1ß, IL-10, TLR2 , TLR4, TLR9, TNF-α). We compared the distribution of these alleles between inhibitor and non-inhibitor haemophilia B patients and between haemophilia B patients and a normal male control population. HLA typing was performed in all patients. Results, discussion: There appears to be a trend towards a skewed distribution of TLR 9, IL-10 and CTLA4 alleles in haemophilia B patients. Due to the limited number these differences are, however, not statistically significant. The t-test of all patients with inhibitor versus without inhibitor was significant for HLA-A*03 and DPB1*0401 and borderline for DRB1*0201.

Inhibitor-Immunology-Study. Different HLA-types seem to be involved in the inhibitor development in haemophilia A.

UNLABELLED: The development of inhibitors is one of the most important complications of replacement therapy in haemophilia, affecting mortality and morbidity. Inhibitor development is based on complex immunological factors. Cytokines and their receptors, T-cell receptors, and the Major Histocompatibility Complex may play important roles in the development of inhibitors. Earlier studies showed non significant associations between HLA class and inhibitor development. Later studies found an increased risk of inhibitor development if there was a combination between certain factor VIII mutations and HLA antigens. We performed HLA typing in 50 patients with haemophilia A in an effort to find associations with inhibitor development. RESULTS: 25 patients had developed an inhibitor (11 low titre, 14 high titre), and 25 never had. In logistic regression analysis, HLA-A 34, DRB1 0405, DRB1 1301 seemed to be involved in inhibitor development and HLA-A 30, B 13, B15, B 57, Cw 12, DQB1 0303, DPB1 0201 protection against inhibitor development. In our patients, the HLA-associations with inhibitor development were different from those in previous publications.

[Platelet retention test Homburg (RTH) and drug monitoring of platelet adhesive properties of von Willebrand factor]. / Plättchen-Retentionstest Homburg: Drugmonitoring der Plättchenadhäsivität des von-Willebrand-Faktors.

Platelet plug formation is initiated by the process of platelet adhesion, mainly mediated by the von Wille-brand factor (VWF). Therefore, apart from established criteria the platelet adhesion property is a further criterion to determine VWF e. g. in diagnosis and treatment of von Willebrand disease (VWD). The new platelet retention test Homburg (RTH) is designed to close this gap. It is characterized by its non-thrombogenic filter with interconnecting pores, which retains platelets from blood when pressed through this filter due to the resulting shear stress. The RTH, in particular, proved to be highly sensitive in detecting the platelet adhesive property of VWF after its release from endogenous storage sites by desmopressin or infusion in VWD patients or its supplementation in vitro.

Health status and health-related quality of life of children with haemophilia from six West European countries.

A multicentre, international, cross-sectional study was carried out in the frame of field testing of the first haemophilia-specific quality-of-life (QoL) questionnaire (Haemo-QoL). The aim of this paper is to describe health status and health care and their impact on QoL in haemophilic children in Western Europe. Children aged 4-16 years with severe haemophilia without inhibitors were enrolled by 20 centres in France, Germany, Italy, the Netherlands, Spain and the United Kingdom. Clinical information was collected by the physicians with a medical documentation form. Health-related QoL (HRQoL) of children was assessed with Haemo-QoL, available for three age groups. Clinical data were available in 318 patients, 85.5% with haemophilia A. The mean age at first bleeding was 11 months, at first joint bleed 25 months. Functional joint impairments were found in 11.3%. Prophylaxis treatment was given to 66.7% of children in whom breakthrough bleeds occurred 0.4 times a month compared to 1.1 bleeds in children receiving on-demand treatment. A significantly higher factor consumption was found only in the two younger age groups of prophylaxis patients compared to on-demand patients. HRQoL was satisfactory in this cohort: young children were impaired mainly in the dimension 'family' and 'treatment', whereas older children had higher impairments in the so-called 'social' dimensions, such as 'perceived support' and 'friends'. Health care of children in Western Europe is progressively improving with a large diffusion of home treatment and prophylaxis. This provides a high level of health status and HRQoL, being better in haemophilic adolescents on prophylaxis.

Symptomatic onset of severe hemophilia A in childhood is dependent on the presence of prothrombotic risk factors.

It has been recently suggested that the clinical phenotype of severe hemophilia A (HA) is influenced by co-inheritance with the factor V G1691A mutation. We therefore investigated 124 pediatric PUP patients with hemophilia (A: n = 111) consecutively admitted to German pediatric hemophilia treatment centers. In addition to factor VIII activity, the factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, antithrombin, protein C, protein S and antithrombin were investigated. 92 out of 111 HA patients (F VIII activity < 1%) were suffering from severe HA. The prevalence of prothrombotic risk factors in children with severe HA was no different from previously reported data: FV G1691A 6.5%, PT G20201A 3.2%, and protein C type I deficiency 1.1%. No deficiency states of antithrombin or protein S were found in this cohort of hemophilic patients. The first symptomatic bleeding leading to diagnosis of severe hemophilia (< 1%) occurred with a median (range) age of 1.6 years (0.5-7.1) in children carrying defects within the protein C pathway or the PT gene mutation compared with non-carriers of prothrombotic risk factors (0.9 years (0.1-4.0; p = 0.01). The cumulative event-free bleeding survival was significantly prolonged in children carrying additionally prothrombotic defects (log-rank/Mantel-Cox: p = 0.0098). In conclusion, data of this multicenter cohort study clearly demonstrate that the first symptomatic bleeding onset in children with severe HA carrying prothrombotic risk factors is significantly later in life than in non-carriers.

Prevalence of a 23bp insertion in exon 3 of the endothelial cell protein C receptor gene in venous thrombophilia.

BACKGROUND: The endothelial cell protein C receptor (EPCR) enhances protein C activation by the thrombin-thrombomodulin complex. As evidence is accumulating that EPCR is an important component of the protein C anticoagulant pathway, polymorphisms in the EPCR gene might be candidate risk factors predisposing to venous thromboembolism (VTE). Recently, a 23bp insertion in exon 3 of the EPCR gene has been identified, which duplicates the preceding 23 bases and results in a STOP codon downstream from the insertion point. However, the clinical significance of this mutation in VTE remains to be clarified. METHODS AND RESULTS: In this study we evaluated the EPCR 23bp insertion in 889 patients with documented VTE and in 500 healthy controls. The prevalence of the EPCR insertion among patients was 0.1%, which was not significantly different compared to controls (0.6%, p = 0.1). CONCLUSIONS: Our findings showed that the EPCR 23bp insertion is very rare in both patients with VTE and the general population and failed to support an association between the EPCR 23bp insertion and an increased risk of VTE.

Effective treatment of infantile choriocarcinoma in the liver with chemotherapy and surgical resection: a case report.

Infantile choriocarcinoma of the liver is an extremely rare entity, and outcome has been fatal in almost all published cases. To the authors' knowledge, this is the first report on successful treatment with preoperative chemotherapy. A 10-week-old girl presented with a large liver tumor, ovarian cysts, cardiac insufficiency, progressive hemolytic anemia, and thrombocytopenia. Ultrasound scan and magnetic resonance tomography (MRT) showed the typical pattern of infantile hemangioendothelioma. An emergency laparotomy was performed because of increasing cardiac insufficiency with ligation of the right hepatic artery, tumor biopsy, and subtotal resection of the ovarian cysts. Histology findings showed a choriocarcinoma of the liver and corpus luteum cysts of the ovaries. Serum beta-human chorionic gonadotropin (beta-HCG) was elevated to 1.600.00 U/L. Chemotherapy was initiated with etoposide and cisplatin. When x-ray examination showed development of lung metastases, chemotherapy was intensified with etoposide, cisplatin, and ifosfamid according to the German Study Group of Extracranial Nontesticular Malignant Germ Cell Tumors in Childhood and Adolescence (MAKEI-96). Serum beta-HCG levels decreased further, ultrasound examination showed significant tumor reduction, and pulmonal metastasis could no longer be found in chest x-rays. After the fourth course, a complete tumor resection was achieved by an extended right hemihepatectomy with adjuvant chemotherapy being administered after the operation. The child has been in complete remission for 22 months. The authors' experience shows that chemotherapy is effective for preoperative tumor reduction.

Cerebral venous sinus thrombosis in children with acute lymphoblastic leukemia carrying the MTHFR TT677 genotype and further prothrombotic risk factors.

BACKGROUND: The present study was designed to prospectively evaluate the role of prothrombotic risk factors in leukemic children treated according to the ALL-BFM 90/95 study protocols with respect to the onset of cerebral venous sinus thrombosis. PATIENTS: 317 consecutive leukemic children aged 6 months to 18 years were enrolled in this study. 288 of the 317 patients were available for thrombosis-free survival analysis. RESULTS: In 17 (5.9%) of these 288 patients cerebral venous sinus thrombosis occurred. The overall event-free survival of thrombosis in the central nervous system in patients with at least one prothrombotic defect (n = 12) was significantly reduced compared with patients without a prothrombotic defect (p < 0.0001). 15 patients showed acute clinical symptoms at onset of cerebral venous sinus thrombosis, two were asymptomatic. Three of the 17 patients affected (17.6%) died directly associated with the thrombotic event during induction therapy, the remaining 14 patients did not show prolonged clinical symptoms. CONCLUSIONS: Prothrombotic risk factors should be included in a screening program in ALL children treated according to the BFM study protocols. Further prospective studies are recommended to establish adequate prophylactic anticoagulant treatment during ALL (BFM) polychemotherapy.

Prospective evaluation of the thrombotic risk in children with acute lymphoblastic leukemia carrying the MTHFR TT 677 genotype, the prothrombin G20210A variant, and further prothrombotic risk factors.

The reported incidence of thromboembolism in children with acute lymphoblastic leukemia (ALL) treated with L-asparaginase, vincristine, and prednisone varies from 2.4% to 11.5%. The present study was designed to prospectively evaluate the role of the TT677 methylenetetrahydrofolate reductase (MTHFR) genotype, the prothrombin G20210A mutation, the factor V G1691A mutation, deficiencies of protein C, protein S, antithrombin, and increased lipoprotein (a) concentrations in leukemic children treated according to the ALL-Berlin-Frankfurt-Muenster (BFM) 90/95 study protocols with respect to the onset of vascular events. Three hundred and one consecutive leukemic children were enrolled in this study. Fifty-five of these 301 subjects investigated had one established single prothrombotic risk factor: 20 children showed the TT677 MTHFR genotype; 5 showed the heterozygous prothrombin G20210A variant; 11 were carriers of the factor V G1691A mutation (heterozygous, n = 10; homozygous, n = 1); 4 showed familial protein C, 4 protein S, and 2 antithrombin type I deficiency; 9 patients were suffering from familially increased lipoprotein (a) [Lp(a)] concentrations (>30 mg/dL). In addition, combined prothrombotic defects were found in a further 10 patients: the FV mutation was combined with the prothrombin G20210A variant (n = 1), increased Lp(a) (n = 3), protein C deficiency (n = 1), and homozygosity for the C677T MTHFR gene mutation (n = 1). Lp(a) was combined with protein C deficiency (n = 2) and the MTHFR TT 677 genotype (n = 2). Two hundred eighty-nine of the 301 patients were available for thrombosis-free survival analysis. In 32 (11%) of these 289 patients venous thromboembolism occurred. The overall thrombosis-free survival in patients with at least one prothrombotic defect was significantly reduced compared with patients without a prothrombotic defect within the hemostatic system (P <.0001). In addition, a clear-cut positive correlation (P <.0001) was found between thrombosis and the use of central lines. However, because the prothrombotic defects diagnosed in the total childhood population studied were all found within the prevalences reported for healthy Caucasian individuals, the interaction between prothrombotic risk factors, ALL treatment, and further environmental factors is likely to cause thrombotic manifestations.

Clinical relevance of genetic risk factors for thrombosis in paediatric oncology patients with central venous catheters.

UNLABELLED: We prospectively evaluated the clinical relevance of genetic risk factors of thrombosis in 137 paediatric patients with solid tumours or leukaemia/lymphoma. The factor V G1691A (FV-L), the prothrombin G20210A (FII-L) and the homozygous MTHFR variant were examined. In addition, protein C, protein S and antithrombin (AT) deficiency were evaluated in patients with ALL or thrombosis. The inter-group incidence of risk factors and thrombotic events was compared. 73 of the 137 patients had ALL and 64 another form of leukaemia, lymphoma or a solid tumour. They were treated according to the established paediatric tumour protocols ALL-BFM, NHL-BFM, COSS, CWS and others. All patients had central venous lines. No patient received heparin or any other anticoagulant. Endpoints of the study were thrombosis, regular completion of chemotherapy or death. Incidence of mutations in the whole group: FV-L (7.3% heterozygous, 0.7% homozygous); FII-L (2.9% heterozygous, no homozygotes); MTHFR (51.8% heterozygous, 10.9% homozygous). Ten patients (7.3%), 6 with ALL and 4 with solid tumours, developed thrombosis. 4 of the 6 patients with ALL and thrombosis (67%) but only 21% of ALL patients without thrombosis had a genetic risk factor (P < 0.013, chi2). No genetic defect was found in the 4 patients with other malignancies and thrombosis. However, besides a tumour, these patients had additional exogenous risk factors including diabetes insipidus and hemiparesis. CONCLUSION: Genetic mutations appear to be additional risk factors for the development of thrombosis in patients with ALL. In contrast, these mutations do not appear to be relevant risk factors for thrombosis in the small number of children with other malignant diseases reported here. This difference may be due to asparaginase and corticosteroids being used in ALL but not in solid tumour protocols.

Severe protein C deficiency and aseptic osteonecrosis of the hip joint: a case report.

UNLABELLED: Homozygous congenital protein C deficiency is accompanied by severe thrombophilia. Thrombotic events can be reduced in number and severity by lifelong oral anticoagulation therapy. A 4-year-old boy was first diagnosed as having severe congenital homozygous protein C deficiency during the neonatal period when purpura fulminans occurred as the first manifestation of thrombosis. From this time he had been treated with phenprocoumon (INR 3.5-4.5). During an infection of the upper respiratory tract he developed signs of a new episode of purpura fulminans (INR 2.6). Additional anticoagulation therapy with LMW heparin (Clexane) and protein C concentrate was given while the oral anticoagulation therapy was continued. On the third day of this episode the boy suffered from pain of unknown origin. MRI of the abdomen and of the pelvis revealed nontraumatic osteonecrosis of the hip joint. After a few weeks of immobilisation no special treatment was necessary. One year later he was able to walk with no problem. CONCLUSION: Aseptic osteonecrosis of the hip joint is associated with a variety of disorders including vascular thrombosis and haemorrhage. Especially young children and handicapped patients with thrombophilia and pain of unknown origin are suspected to have thrombosis in atypical regions.