Molenaar-de Backer M W A, Russcher A, Kroes A C M, Koppelman M H G M, Lanfermeijer M, Zaaijer H L
Sanquin Blood Supply Foundation, Department of Blood-borne Infections, Amsterdam, The Netherlands.
Leiden University Medical Center, Department of Medical Microbiology, Leiden, The Netherlands.
J Clin Virol. 2016 Nov;84:19-23. doi: 10.1016/j.jcv.2016.09.004. Epub 2016 Sep 13.
Parvovirus B19 (B19V) DNA can be detected in blood over a long period after acute infection. Several reports associate the presence of B19V DNA with disease, irrespective of timing of the initial B19V infection.
This study aims to analyze the properties of B19V DNA in blood, differentiating between bare, non-infectious strands of DNA and B19V DNA in viable virions.
Ten blood donors with asymptomatic acute B19V infection were followed and sampled up to 22 months after infection. The samples were treated with and without an endonuclease and tested for B19V DNA, to distinguish between DNA in virions and naked DNA.
In the acute phase of infection, high levels of B19V DNA were detected, concurrent with B19V IgM antibodies. B19V DNA apparently was encapsidated, as indicated by resistance to endonuclease degradation. Subsequently, B19V DNA remained detectable for more than one year in all donors at low levels (<10 IU/mL). Approximately 150days after infection B19V DNA became degradable by an endonuclease, indicating that this concerned naked DNA. In some donors a second endonuclease-resistant peak occurred.
Detection of B19V DNA in blood by PCR does not necessarily imply that B19V replication takes place and that infectious B19V virions are present. We propose that remnant B19V DNA strands can be released from tissues without active replication. This finding urges to reconsider an assumed role of B19V infection mainly based on B19V DNA detection in blood, a much debated subject in clinical syndromes such as myocarditis and arthritis.
细小病毒B19（B19V）DNA在急性感染后的很长一段时间内都能在血液中被检测到。几份报告将B19V DNA的存在与疾病联系起来，而不考虑最初B19V感染的时间。
本研究旨在分析血液中B19V DNA的特性，区分裸露的、无感染性的DNA链和活病毒颗粒中的B19V DNA。
对10名无症状急性B19V感染的献血者进行随访，并在感染后长达22个月进行采样。对样本进行有无核酸内切酶处理，并检测B19V DNA，以区分病毒颗粒中的DNA和裸露DNA。
在感染急性期，检测到高水平的B19V DNA，同时伴有B19V IgM抗体。B19V DNA显然被包裹起来，这表现为对核酸内切酶降解具有抗性。随后，所有献血者在一年多的时间里都能检测到低水平（<10 IU/mL）的B19V DNA。感染后约150天，B19V DNA变得可被核酸内切酶降解，表明这涉及裸露DNA。在一些献血者中出现了第二个核酸内切酶抗性峰。
通过PCR检测血液中的B19V DNA并不一定意味着发生了B19V复制且存在有感染性的B19V病毒颗粒。我们认为残余的B19V DNA链可以在没有活跃复制的情况下从组织中释放出来。这一发现促使人们重新考虑主要基于血液中B19V DNA检测而假定的B19V感染的作用，这在心肌炎和关节炎等临床综合征中是一个备受争议的话题。
