Dreier Jens, Vollmer Tanja, Hinse Dennis, Heuser Ernst Joachim, Pisani Giulio, Knabbe Cornelius
Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Bad Oeynhausen, Germany.
National Centre for Immunobiologicals Research and Evaluation, ISS, Rome, Italy.
Transfus Med Hemother. 2016 Jan;43(1):28-36. doi: 10.1159/000440833. Epub 2015 Sep 28.
West Nile virus (WNV) can be transmitted by transfusion through infected blood components. In Germany, a 28-day deferral for blood donors of therapeutic blood components who had spent at least 2 days in WNV-endemic areas from June 1 to November 30, 2014 was enforced. Otherwise, screening of blood donors for WNV RNA or the application of pathogen reduction techniques are appropriate alternatives.
In the present study, we evaluated NAT screening for the detection of WNV in blood components. A total of 58 minipools consisting of 357 individual blood donors were screened for the presence of WNV RNA employing an automated high-volume extraction method using the RealStar WNV RT-PCR Kit. Additionally, different WNV reference reagents were quantified to prove the status quo of standardization. Four different WNV real-time NAT kits were compared using samples of an external quality assessment panel.
The 95% lower detection limit of the WNV MP-NAT was determined to 30.2 copies/ml (95% CI 24.2-45.4 copies/ml). No WNV RNA-positive minipool was detected. Quantification of WNV reference reagents revealed shortcomings in standardization. Comparison of several WNV NAT assays showed considerable differences in assay sensitivities and particularly a missing detection of WNV lineage 2. Implementation of seasonal WNV MP-NAT screening was demonstrated.
Actually, WNV infections in Germany are rare events introduced by returning travelers, but surveillance of these emerging infections is important for safety in blood supply. The validation study pointed out the need for standardization of WNV NAT because of current lack of an international standard for WNV RNA.
西尼罗河病毒（WNV）可通过受感染的血液成分输血传播。在德国，2014年6月1日至11月30日期间在WNV流行地区停留至少2天的治疗性血液成分献血者需推迟28天献血。否则，对献血者进行WNV RNA筛查或应用病原体灭活技术是合适的替代方法。
在本研究中，我们评估了核酸扩增技术（NAT）筛查在检测血液成分中WNV方面的应用。使用RealStar WNV RT-PCR试剂盒，采用自动化大容量提取方法，对总共58个混合样本（由357名个体献血者组成）进行WNV RNA检测。此外，对不同的WNV参考试剂进行定量，以证明标准化的现状。使用外部质量评估小组的样本比较了四种不同的WNV实时NAT试剂盒。
WNV混合样本NAT的95%较低检测限确定为30.2拷贝/毫升（95%置信区间24.2 - 45.4拷贝/毫升）。未检测到WNV RNA阳性混合样本。WNV参考试剂的定量显示标准化存在缺陷。几种WNV NAT检测方法的比较表明，检测灵敏度存在显著差异，特别是对WNV 2型谱系的检测缺失。证明了实施季节性WNV混合样本NAT筛查的可行性。
实际上，德国的WNV感染是由回国旅行者引入的罕见事件，但对这些新出现感染的监测对于血液供应安全很重要。验证研究指出，由于目前缺乏WNV RNA的国际标准，WNV NAT标准化很有必要。
