Laboratory of Molecular Medicine and Neuroscience, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Building 10, Room 3B14, Bethesda, MD 20892, USA.
J Clin Virol. 2013 Jul;57(3):243-8. doi: 10.1016/j.jcv.2013.03.009. Epub 2013 Apr 23.
JC virus (JCV) is the etiologic agent for progressive multifocal leukoencephalopathy (PML), a demyelinating disease occurring in the brain of patients with underlying immune compromised states. All viable JCV genomes contain a conserved region in the T protein coding nucleotide sequence that when detected by PCR in CSF is a confirmatory diagnostic marker for PML along with clinical and neuroradiological evidence. The non-coding regulatory region (NCRR) is hypervariable, as evidenced by nucleotide sequence of the non-virulent variant, which is predominantly excreted in urine, versus that of virulent variants found in brain and CSF of PML patients. All variants can be found in blood.
A single assay that quantifies and identifies JCV DNA in clinical samples and discriminates between variants has significant value to physicians and patients at risk for PML.
Separate primer pairs were tested together to quantitatively detect conserved viral DNA nucleotide sequence in patient samples, while simultaneously detecting the NCRR specific for the non-virulent variant.
In testing using control plasmids and patients' CSF, blood, and urine, PML patients predictably demonstrated the non-virulent, archetype NCRR in urine, but virulent NCRR variants in CSF and blood.
The JCV qPCR multiplex assay targets two regions in JCV genomes to simultaneously identify and measure viral DNA, as well as distinguish between variants associated with PML and those that are not. The multiplex results could signal risk for PML if patients are viremic with JCV variants closely associated with PML pathogenesis.
JC 病毒（JCV）是进行性多灶性白质脑病（PML）的病原体，是一种发生在有潜在免疫缺陷状态的患者大脑中的脱髓鞘疾病。所有存活的 JCV 基因组都在 T 蛋白编码核苷酸序列中含有一个保守区域，当通过 PCR 在 CSF 中检测到时，这是 PML 的确认诊断标志物，同时还有临床和神经影像学证据。非编码调节区（NCRR）是高度可变的，这一点可以从非毒性变异体的核苷酸序列得到证明，该序列主要在尿液中排出，而在 PML 患者的大脑和 CSF 中发现的毒性变异体则不然。所有变体都可以在血液中找到。
一种能够定量检测和识别临床样本中 JCV DNA 并区分变体的单一检测方法，对有 PML 风险的医生和患者具有重要价值。
单独的引物对一起进行测试，以定量检测患者样本中的保守病毒 DNA 核苷酸序列，同时检测非毒性变体特有的 NCRR。
在使用对照质粒和患者的 CSF、血液和尿液进行测试时，PML 患者可预测地在尿液中表现出非毒性、原型 NCRR，但在 CSF 和血液中表现出毒性 NCRR 变体。
JCV qPCR 多重检测法针对 JCV 基因组中的两个区域，同时识别和测量病毒 DNA，并区分与 PML 相关的变体和不相关的变体。如果患者的 JCV 变体呈病毒血症，与 PML 发病机制密切相关，多重检测结果可能预示着 PML 的风险。
