Koppelman M H G M, Rood I G H, Fryer J F, Baylis S A, Cuypers H T M
Sanquin, Diagnostic Services Division, Amsterdam, The Netherlands.
Vox Sang. 2007 Oct;93(3):208-15. doi: 10.1111/j.1423-0410.2007.00957.x.
Parvovirus B19 (B19V) DNA screening has been introduced to comply with European regulations for certain plasma products. Current commercial and some in-house B19V DNA assays fail to detect or under-quantify the recently identified genotypes 2 and 3. In this report, we describe 2-year experience with B19V DNA screening using the commercial assay from Roche (detecting only genotype 1) combined with an in-house assay (detecting genotypes 1, 2 and 3). This dual testing approach enables the identification of molecular variants of B19V.
Between 2005 and 2007, approximately 2.6 million plasma donations were screened for B19V DNA loads exceeding 10(6) IU/ml using the Roche and the in-house real-time polymerase chain reaction assay.
A total of 232 plasma units were identified with B19V DNA loads above 10(6) IU/ml. Concordant results were observed for the majority of B19V positive samples; however, three of these showed discrepant results between the two assay systems. One was a B19V genotype 2 strain not detected by the Roche assay; another was a B19V genotype 1 strain with a mismatch in the 3'-end of the reverse primer and therefore under-quantified by the Roche assay; and the third one was also a B19V genotype 1 strain that gave an unusual amplification plot in the in-house assay due to a mismatch in the probe-binding site.
New, high viral load, B19V genotypes 2 and 3 infections are rare in blood donors tested by Sanquin. One case was found while testing 2.6 million donations. The prevalence of B19V genotype 1 variants not detected by commercial or in-house assays might be in the same range or even higher than the prevalence of B19V genotype 2 viruses, which remain undetected.
为符合欧洲对某些血浆制品的规定，已引入细小病毒B19（B19V）DNA筛查。目前的商业检测方法以及一些内部B19V DNA检测方法无法检测到或对最近鉴定出的2型和3型基因型进行定量不足。在本报告中，我们描述了使用罗氏公司的商业检测方法（仅检测1型基因型）与一种内部检测方法（检测1型、2型和3型基因型）进行B19V DNA筛查的两年经验。这种双重检测方法能够鉴定B19V的分子变体。
在2005年至2007年期间，使用罗氏公司和内部实时聚合酶链反应检测方法对约260万份血浆捐献进行了筛查，以检测B19V DNA载量是否超过10⁶IU/ml。
共鉴定出232个血浆单位的B19V DNA载量高于10⁶IU/ml。大多数B19V阳性样本的检测结果一致；然而，其中三个样本在两种检测系统之间显示出不一致的结果。一个是罗氏检测方法未检测到的B19V 2型毒株；另一个是B19V 1型毒株，其反向引物的3'端存在错配，因此罗氏检测方法对其定量不足；第三个也是B19V 1型毒株，由于探针结合位点存在错配，在内部检测方法中给出了异常的扩增图谱。
在Sanquin检测的献血者中，新的、高病毒载量的B19V 2型和3型基因型感染很少见。在检测260万份捐献时发现了1例。商业或内部检测方法未检测到的B19V 1型变体的流行率可能与未被检测到的B19V 2型病毒的流行率处于同一范围甚至更高。
