Debyser Z, Van Wijngaerden E, Van Laethem K, Beuselinck K, Reynders M, De Clercq E, Desmyter J, Vandamme A M
Department of Microbiology and Immunology, Rega Institute and University Hospitals, Katholieke Universiteit Leuven, Belgium.
AIDS Res Hum Retroviruses. 1998 Mar 20;14(5):453-9. doi: 10.1089/aid.1998.14.453.
The level of HIV-1 RNA in plasma has become one of the most important markers in the follow-up of HIV-infected patients. Three techniques are commercially available: both the Amplicor HIV Monitor and the NASBA HIV-1 RNA QT are target amplification methods, whereas the Quantiplex HIV RNA assay is a branched DNA signal amplification technique. Detection in both target amplification techniques is based on a single primer pair and a single probe in the gag region, whereas multiple probes capture the pol region of the viral RNA in the branched DNA assay. We investigated the discrepant observation of an undetectable viral load in an immunodeficient pregnant HIV-1-infected patient of African origin with no prior antiretroviral treatment. Although clinical progression was present in this patient with tuberculosis and a low CD4 cell count, viral load determinations with both the Amplicor Monitor and NASBA assays revealed no detectable RNA levels. The presence of HIV-1 RNA in the plasma of the patient was demonstrated by an in-house RNA-PCR. Subsequent HIV-1 RNA quantification with the branched DNA method revealed a high viremia (460,000 copies/ml). DNA sequence analysis of the gag gene identified a subtype G HIV-1 strain (HIV-1BL). To our knowledge this is the first report of a patient harboring an HIV-1 genotype of the main group with a high viral load as quantified by the branched DNA assay, but undetectable with the two commercial HIV RNA amplification techniques because of genetic divergence. In the case of discrepant low viral loads determined by one amplification technique in patients with advanced clinical stage one should use an alternative quantification technique for confirmation.
血浆中HIV-1 RNA水平已成为HIV感染患者随访中最重要的标志物之一。有三种技术可供商业使用：Amplicor HIV监测法和NASBA HIV-1 RNA QT均为靶标扩增方法，而Quantiplex HIV RNA检测法是一种分支DNA信号扩增技术。两种靶标扩增技术的检测均基于gag区域中的一对引物和一个探针，而在分支DNA检测中，多个探针捕获病毒RNA的pol区域。我们调查了一名来自非洲的免疫缺陷HIV-1感染孕妇，该患者未接受过抗逆转录病毒治疗，病毒载量检测结果不一致的情况。尽管该患者患有结核病且CD4细胞计数较低，临床病情仍在进展，但使用Amplicor监测法和NASBA检测法进行的病毒载量测定均显示未检测到RNA水平。通过内部RNA-PCR证实了患者血浆中存在HIV-1 RNA。随后使用分支DNA方法进行的HIV-1 RNA定量显示病毒血症水平较高（460,000拷贝/ml）。gag基因的DNA序列分析鉴定出一种G亚型HIV-1毒株（HIV-1BL）。据我们所知，这是首例报告，该患者携带主要群体的HIV-1基因型，通过分支DNA检测法定量显示病毒载量较高，但由于基因差异，使用两种商业HIV RNA扩增技术均未检测到。对于临床晚期患者中由一种扩增技术测定的病毒载量较低且结果不一致的情况，应使用另一种定量技术进行确认。
