实时 PCR 检测流行前期和后期感染的班氏丝虫 HhaI 串联 DNA 重复序列：印度尼西亚移民中的一项研究。
Real-time PCR detection of the HhaI tandem DNA repeat in pre- and post-patent Brugia malayi Infections: a study in Indonesian transmigrants.
机构信息
Institute of Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Sigmund-Freud-Str, 25, D-53105 Bonn, Germany.
出版信息
Parasit Vectors. 2014 Mar 31;7:146. doi: 10.1186/1756-3305-7-146.
BACKGROUND
Lymphatic filariasis caused by Wuchereria bancrofti or Brugia spp. is a public health problem in developing countries. To monitor bancroftian filariasis infections, Circulating Filarial Antigen (CFA) test is commonly used, but for brugian infections only microfilariae (Mf) microscopy and indirect IgG4 antibody analyses are available. Improved diagnostics for detecting latent infections are required.
METHODS
An optimized real-time PCR targeting the brugian HhaI repeat was validated with plasma from microfilariae negative Mongolian gerbils (jirds) infected with B. malayi. Plasma samples from microfilaremic patients infected with B. malayi or W. bancrofti were used as positive and negative controls, respectively. PCR results of plasma samples from a transmigrant population in a B. malayi endemic area were compared to those of life-long residents in the same endemic area; and to IgG4 serology results from the same population. To discriminate between active infections and larval exposure a threshold was determined by correlation and Receiver-Operating Characteristics (ROC) curve analyses.
RESULTS
The PCR detected HhaI in pre-patent (56 dpi) B. malayi infected jirds and B. malayi Mf-positive patients from Central Sulawesi, Indonesia. HhaI was also detected in 9/9 elephantiasis patients. In South Sulawesi 87.4% of the transmigrants and life-long residents (94% Mf-negative) were HhaI PCR positive. Based on ROC-curve analysis a threshold for active infections was set to >53 HhaI copies/μl (AUC: 0.854).
CONCLUSIONS
The results demonstrate that the HhaI PCR detects brugian infections with greater sensitivity than the IgG4 test, most notably in Mf-negative patients (i.e. pre-patent or latent infections).
背景
由班氏丝虫或布鲁氏丝虫引起的淋巴丝虫病是发展中国家的一个公共卫生问题。为了监测班氏丝虫感染，通常使用循环丝虫抗原（CFA）检测，但对于布鲁氏丝虫感染，只有微丝蚴（Mf）显微镜检查和间接 IgG4 抗体分析可用。需要改进诊断方法来检测潜伏感染。
方法
针对布鲁氏 HhaI 重复序列的优化实时 PCR 已在感染马来布鲁氏丝虫的微丝蚴阴性蒙古沙鼠（沙鼠）血浆中得到验证。微丝蚴阳性患者的血浆样本分别作为阳性和阴性对照，来自布鲁氏丝虫流行地区的移民人群的 PCR 结果与同一流行地区的长期居民进行了比较；并与同一人群的 IgG4 血清学结果进行了比较。通过相关性和接收器操作特性（ROC）曲线分析确定了一个阈值，以区分活动性感染和幼虫暴露。
结果
PCR 检测到潜伏（56dpi）感染马来布鲁氏丝虫的沙鼠和印度尼西亚中苏拉威西的布鲁氏丝虫微丝蚴阳性患者的 HhaI。HhaI 也在 9/9 例象皮病患者中检测到。在南苏拉威西，87.4%的移民和长期居民（94%微丝蚴阴性）的 HhaI PCR 呈阳性。基于 ROC 曲线分析，将活动性感染的阈值设定为>53 HhaI 拷贝/μl（AUC：0.854）。
结论
结果表明，HhaI PCR 检测布鲁氏丝虫感染的敏感性高于 IgG4 检测，尤其是在微丝蚴阴性患者（即潜伏或潜伏感染）中。
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