Background: Type 3 von Willebrand disease (VWD) is a severe bleeding disorder with a prevalence of 1:1 million live births. There are several von Willebrand factor (VWF) replacement products used in the treatment of acute bleeding episodes or as prophylaxis. Patients who receive multiple transfusions have an increased risk of developing antibodies against these products. These antibodies can lead to life-threatening anaphylactic reactions. Previous studies have identified immune complex formation and complement activation as the trigger for anaphylaxis, rather than IgE. IgE-mediated anaphylaxis against VWF concentrates has not yet been published. Case: A 4-year-old female patient with type 3 VWD was referred to our hospital because of an anaphylactic reaction during FVIII/VWF concentrate (Immunate®) infusion. She had previously received FVIII/VWF concentrate (Haemate P®) infusions 8 times without any complications. She did not have antibodies against VWF and FVIII, and serum IgA level was normal. Since she needed factor replacement therapy as a result of a growing hematoma on her scalp, we performed skin prick and intradermal tests 2 days after the reaction. The prick test, with FVIII/VWF (Immunate), was negative, but the intradermal test was positive. We administered a 12-step desensitization protocol with FVIII/VWF concentrate (Immunate) successfully without any reactions. Conclusion: Anaphylactic reaction to factor replacement products is a major problem for patients with VWD, especially type 3 VWD requiring multiple factor infusions. We achieved a successful desensitization with FVIII/VWF concentrate in a patient who had an anaphylactic reaction during the infusion of this product. Our patient is important since she represents the first case of IgE-mediated anaphylaxis against VWF concentrate reported in the literature.

中文翻译：

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对FVIII / VWF浓缩物可能由IgE介导的过敏反应的患者成功脱敏。

背景：3型血管性血友病（VWD）是一种严重的出血性疾病，患病率为1：100万活产。有几种von Willebrand因子（VWF）替代产品用于治疗急性出血发作或作为预防措施。接受多次输血的患者产生针对这些产品的抗体的风险增加。这些抗体可导致危及生命的过敏反应。先前的研究已经确定免疫复合物的形成和补体激活是引发过敏反应的触发因素，而不是IgE。IgE介导的针对VWF浓缩物的过敏反应尚未发表。病例：由于输注FVIII / VWF浓缩液（Immunate®）时出现过敏反应，将4岁3型VWD的女性患者转诊至我院。她以前曾接受过8次FVIII / VWF浓缩液（HaemateP®）输注，没有任何并发​​症。她没有针对VWF和FVIII的抗体，血清IgA水平正常。由于头皮上的血肿不断增长，她需要因子替代疗法，因此我们在反应后2天进行了皮肤点刺和皮内测试。FVIII / VWF（免疫）的点刺试验为阴性，而皮内试验为阳性。我们成功进行了FVIII / VWF浓缩液（免疫）的12步脱敏方案，没有任何反应。结论：因子替代产品的过敏反应是VWD患者的主要问题，尤其是需要多因子输注的3型VWD。对于在输注该产品期间出现过敏反应的患者，我们用FVIII / VWF浓缩液成功实现了脱敏。我们的患者很重要，因为她代表了文献报道的第一例IgE介导的针对VWF浓缩物的过敏反应。