Prevalence and immunogenicity of HNA-3a and -3b antibodies and antigens

描述（由申请方提供）：输血相关急性肺损伤（TRALI）目前是输血相关死亡的主要原因，由向易感患者输注含有白细胞抗体和/或生物反应调节剂的血液制品引发。尽管许多不同的白细胞抗体已显示出诱导TRALI，但对白细胞抗原HNA-3a特异的那些抗体特别容易引起非常严重的，并且通常是致命的反应。不幸的是，不可能对献血者进行常规的抗HNA-3a筛查，因为其分子特性多年来一直困扰着研究人员，而且HNA-3a被认为是嗜中性粒细胞特异性的，一种难以用于血清学研究的细胞。因此，对献血者中抗HNA-3a的流行率知之甚少，并且对该抗原的免疫原性知之甚少。关于识别HNA-3b（HNA-3a的等位基因）的抗体的了解更少，尽管理论上它们应该和抗HNA-3a一样可能引起TRALI。我们最近发现，HNA-3a携带在胆碱转运蛋白样蛋白2（CTL 2）上，并且HNA-3a/B多态性几乎肯定是由10跨膜CTL 2蛋白的第一胞外环中的R>Q154（R=HNA-3a，Q = HNA-3 B）氨基酸取代决定的。这些发现提示了开发用于检测抗HNA-3a和抗3b的实用测定法的方法，其适用于常规供体筛选。在本申请中，我们提出了产生重组和合成的CTL 2和CTL 2片段含有R154和Q154，并表征其对一组HNA-3特异性抗体的反应。将大量生产被发现对于抗-CTL 2检测最敏感和特异的构建体，将其格式化为原型固相免疫测定，并用于筛选来自输血、非输血和经产男性和女性的7，000份血清样品，以确定这些人群中抗-HNA-3a的流行率。这些构建体的Q154版本应提供关于抗HNA-3b的可比信息。预计所取得的发现将1）首次确定献血者群体中抗HNA-3a和抗HNA-3b的流行率; 2）表征HNA-3和HNA-3b的免疫原性（通过输血或在怀孕期间暴露于抗原时诱导抗体的可能性）和3）建立确定是否对献血者进行抗HNA-3a和抗HNA-3a的常规筛查的基础。HNA-3B是必要的。 公共卫生相关性：输血相关急性肺损伤（TRALI）是输血的严重并发症，也是输血相关死亡的最常见原因。输注白色血细胞（白细胞）特异性抗体是TRALI的主要原因。针对HNA-3a白细胞抗原的抗体特别容易引起严重的、往往是致命的TRALI，但由于技术原因，还不可能对献血者进行检测。我们实验室最近的发现使得这一障碍有可能被克服，并且在本申请中描述了实现这一点的研究。）

DESCRIPTION (provided by applicant): Transfusion-associated acute lung injury (TRALI), currently the leading cause of transfusion- associated fatality, is triggered by transfusion of blood products containing leukocyte antibodies and/or biological response modifiers to susceptible patients. Although many different leukocyte antibodies have been shown to induce TRALI, those specific for the leukocyte antigen HNA-3a are especially prone to cause very severe, and often fatal reactions. Unfortunately, it has not been possible to screen blood donors routinely for anti-HNA-3a because its molecular properties have for many years eluded investigators and because HNA-3a was thought to be neutrophil-specific, a cell difficult to use in serologic studies. Thus, very little is known about the prevalence of anti-HNA-3a in blood donors and the immunogenicity of this antigen is poorly understood. Even less is known about antibodies that recognize HNA-3b, the allele of HNA-3a, although they should, in theory, be as likely to cause TRALI as anti-HNA-3a. We recently showed that HNA-3a is carried on choline transporter- like protein 2 (CTL2) and that the HNA-3a/b polymorphism is almost certainly determined by an R>Q154 (R=HNA-3a, Q = HNA-3b) amino acid substitution in the first extracellular loop of the 10- membrane-spanning CTL2 protein. These findings suggest ways to develop a practical assay for detection of anti-HNA-3a and anti-3b suitable for routine donor screening. In this application, we propose to generate recombinant and synthetic CTL2 and CTL2 fragments containing R154 and Q154 and characterize their reactions against a panel of HNA-3-specific antibodies. Constructs found to be most sensitive and specific for anti-CTL2 detection will be produced in quantity, formatted into a prototype solid phase immunoassay, and used to screen 7,000 serum samples from transfused, non-transfused and parous males and females to determine the prevalence of anti-HNA-3a in these populations. The Q154 version of these constructs should provide comparable information about anti-HNA-3b. Findings made are expected to 1) define, for the first time, the prevalence of anti-HNA-3a and anti- HNA-3b in blood donor populations; 2) characterize the immunogenicity of HNA-3 and HNA-3b (likelihood of an antibody being induced upon exposure to antigen through transfusion or during pregnancy) and 3) establish a basis for determining whether routine screening of blood donors for anti-HNA-3a and anti-HNA-3b is warranted. PUBLIC HEALTH RELEVANCE: Transfusion-associated acute lung injury (TRALI) is a serious complication of blood transfusion and the most common cause of transfusion-related mortality. Transfusion of antibodies specific for white blood cells (leukocytes) is a major cause of TRALI. Antibodies against a leukocyte antigen designated HNA-3a are especially prone to cause severe, often fatal TRALI but, for technical reasons, it has not been possible to test blood donors to detect them. Recent findings made in our laboratory make it likely that this obstacle can be overcome and studies to accomplish this are described in this application.))