Summary. Recent reports have suggested that the incidence of inhibitors in haemophilia is the highest in those first exposed to factor VIII under 6 months of age. In this study, we investigated inhibitor development in children first exposed to FVIII as neonates and also examined the effect of other genetic and environmental variables. Three hundred and forty-eight children with severe haemophilia A were investigated. Inhibitors developed in 68 of 348 (20%), with 34 of 348 (10%) high titre inhibitors. The incidence in relation to initial FVIII exposure was: <1 month nine of 35 (26%), 1-6 months 13 of 51 (25%), 6-12 months 27 of 130 (21%), 12-18 months 13 of 66 (20%) and >18 months six of 66 (9%). While we observed a significant difference in inhibitor development and age at first exposure across all age groups (P ¼ 0.018), no significant difference was observed in children treated at different time points during the first year of life (P ¼ 0.44). Similar results were obtained for high titre inhibitors. There was also no difference in the incidence of inhibitors in relation to initial FVIII exposure in a subgroup of 144 children with the intron 22 mutation. Inhibitors developed more frequently in those initially treated with recombinant when compared with plasma-derived FVIII (P ¼ 0.006) and in those with a major molecular defect (P ¼ 0.009). In this study, exposure to FVIII during the neonatal period was not associated with a higher incidence of inhibitors than those treated later during the first year of life. Initial treatment with recombinant FVIII and the presence of a major molecular defect were the most important variables affecting inhibitor development.

Newcastle Hospitals NHS Trust, UK SummaryConsensus-based guidelines supported by the literature are presented on the role of prophylactic administration of factor VIII concentrate in children and adults with severe haemophilia A. The timing of initiation of prophylaxis, the choice of prophylactic regimen, monitoring, management of breakthrough bleeding and education of the patient and family are discussed.

Summary. Significant subclavian vein thromboses associated with indwelling fully implanted (port-a-cath) devices are described in two boys with severe haemophilia A and factor VIII inhibitors. Investigations were prompted by prominent chest wall veins in one case, whereas the thrombosis was a chance finding in the other case during investigation of mechanical dislocation of the catheter tubing. Extensive collateral venous circulations were demonstrated by venography in both instances indicating that the thrombus had been present for some time. Possible contributing factors to the thromboses included desensitization therapy (both patients), high-dose FEIBA (in one patient) and use of lower doses of heparin for line flush than that recommended by some authors. Neither patient had a familial or non-familial predisposition to thrombosis.

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Clinical research should form a core component of the role of haemophilia nurse specialists. The UK Haemophilia Nurses Association sought to determine the barriers that prevent nurse specialists from engaging in research and to seek ways to promote clinical research by haemophilia nurses in the UK. Web-based survey with subsequent workshop discussion was conducted. Responses were received from 32 nurses (a 50% response rate), all of whom agreed that haemophilia nurses should be actively involved in nursing research although only 21 had actually participated in research specifically related to haemophilia practice. Of these, most research had been related to educational programmes or (less commonly) was limited to data collection as part of multidisciplinary studies. Involvement in research rarely resulted in publication. Some barriers to involvement in nursing research and subsequent publication were suggested by survey respondents. They also identified key practice areas that warranted nurse-based research including carriership and antenatal decision-making, along with the role and impact on care of the specialist haemophilia nurse, education and empowerment. To overcome the barriers to engaging in research and publishing, nurses require dedicated research time, mentorship and collaboration with more experienced haemophilia nurse researchers.