实时荧光逆转录聚合酶链反应检测人类偏肺病毒方法的建立与应用

目的 建立一种快速、准确、特异的实时荧光逆转录聚合酶链反应方法(PCR),以检测人类偏肺病毒.方法 根据Hmpv-L基因序列设计引物和探针并对实时荧光PCR反应体系进行优化,提取总RNA,通过随机引物进行反转录反应;产生的cDNA通过实时荧光PCR进行鉴定.进一步评价实时荧光反转录PCR方法的特异性、灵敏度、重复性,对180例临床样本进行检测.结果 本实验所建立的实时荧光反转录PCR方法可准确、特异地检测人类偏肺病毒;该方法的灵敏度可达到1拷贝/μl;检测的批间和批内的变异系数均小于5%.180例肺炎和支气管炎患儿痰标本中共检测出28例人类偏肺病毒阳性,阳性率为15.56%(28/180);肺炎患儿检出率为15.60%(17/109);支气管炎患儿检出率为15.49%(11/71).男性患儿检出率18.56%(18/97),女性患儿检出率12.05%(10/83).患儿年龄小于2岁者检出率22.34%(21/94),2～5岁者检出率8.70%(6/69),大于5岁者检出率5.88%(1/17).结论 本研究建立的人类偏肺病毒实时荧光逆转录PCR方法快速、准确,结果可靠,实用性强;人类偏肺病毒已成为小儿呼吸道感染的重要病原体之一.     

Th1 and Th2 cytokine levels in nasopharyngeal aspirates from children with human bocavirus bronchiolitis.

BACKGROUND: Human bocavirus (hBoV) is regarded as one of the possible etiologic agents in lower respiratory tract infection and bronchial asthma exacerbation in children despite frequent co-detection with other respiratory viruses. The immunologic response in children with hBoV infection is still not clear. OBJECTIVES: To investigate the profiles of T helper-1 (Th1)/T helper-2 (Th2) cytokines in children with hBoV-associated bronchiolitis. STUDY DESIGN: This study utilized of 59 nasopharyngeal aspirates from 59 infants aged 24 months or younger, including 29 from children with hBoV-related bronchiolitis and 30 with respiratory syncytial virus (RSV)-related bronchiolitis. Eighteen infants hospitalized for elective surgeries were included as controls. Nasopharyngeal aspirates were tested simultaneously for cytokines interleukin (IL)-2, IL-4, IL-5, IL-10, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha using the Cytometric Bead Array. RESULTS: Significantly higher concentrations of IFN-gamma (p=0.0001), IL-2 (0.006), and IL-4 (p=0.0002) were observed in hBoV positive specimens than in controls. The concentration of IL-10 (p=0.04) and TNF-alpha (p=0.006) in the RSV-positive group was significantly higher than in the hBoV-positive group, while there was no difference in other cytokines concentration between the two groups. CONCLUSIONS: These results showed that both of Th1 and Th2 cytokines were increased in children with hBoV-related bronchiolitis compared to normal controls, but Th2-polarized responses were not observed.     

Evaluation of real-time reverse transcriptase PCR and real-time loop-mediated amplification assays for severe acute respiratory syndrome coronavirus detection

We compared the performance of a recently established real-time loop-mediated amplification (LAMP) assay with the one from a highly sensitive quantitative PCR assay. None of these assays produced false-positive results in this study. For samples isolated from patients within the first 3 days of disease onset, the detection rate of the quantitative PCR assay was higher (14 of 15 were positive) than the LAMP assay (9 of 15 were positive). By contrast, the detection rates of these assays toward specimens sampled from patients with more than 3 days of illness were similar (32 of 44 for PCR and 33 of 44 for LAMP were positive). The simpler operation of LAMP might be a possible solution for on-site diagnosis.     

Diagnosis of human metapneumovirus and rhinovirus in patients with respiratory tract infections by an internally controlled multiplex real-time RNA PCR.

BACKGROUND: Adequate laboratory diagnosis of human rhinoviruses (hRV) and human metapneumoviruses (h MPV) requires molecular methods as viral culture lacks sensitivity. However, setting up individual PCRs for all respiratory viruses is not practical so preferentially multiplex PCRs are used. OBJECTIVES: To develop for routine diagnosis a rapid real-time PCR assay for detection of hRV and h MPV including an internal control in a single tube multiplex reaction using probes carrying different fluorophores to discriminate targets. STUDY DESIGN: The multiplex real-time RNA PCR was optimized to include the internal control virus and a total of 358 respiratory samples from 239 patients taken over a one-year period were analyzed by the multiplex assay. RESULTS: The multiplex assay with co-amplification of the internal control was as sensitive and specific as the individual assays. Application of this assay on clinical samples from 239 patients in a one-year period resulted in an incidence of hRV and h MPV of 41/239 (17.1%) and 6/239 (2.5%), respectively. Inhibition, defined as poor internal control amplification, was detected in 8 (2.2%) samples. Culture was performed on these samples and only four hRV were detected. CONCLUSIONS: This real-time PCR method enables sensitive diagnosis of these two respiratory pathogens with the potential to expand the assay as part of a full molecular respiratory viral screen.     

Diagnosis and epidemiological studies of human metapneumovirus using real-time PCR.

BACKGROUND: Human metapneumovirus (hMPV) is prevalent in children, the elderly and immunocompromised individuals, but available epidemiological data is limited. OBJECTIVES: (1) To develop and validate a real-time PCR method for hMPV diagnosis. (2) To determine the percentage of hMPV in respiratory specimens from the community and its association with outbreaks in our geographic area. (3) To provide epidemiological data in terms of age distribution, seasonality and co-infections. STUDY DESIGN: A real-time PCR assay was designed for detection of hMPV lineages A and B. Prospective testing for hMPV over a 22-month period was then undertaken. RESULTS: The real-time PCR was sensitive and specific for detection of both lineages of hMPV. hMPV was detected in 9.5% (n=8239) of the specimens and 25% of the outbreaks (n=100) tested. The hMPV-positive patients ranged in age from 18 days to 99 years with a median age of 24 months. The number of positive samples peaked during the winter months of December, January and February. A high rate of co-infections was noted in the samples tested. CONCLUSIONS: hMPV is common in the community and is associated with outbreaks. Including hMPV in routine testing improves etiological diagnosis of acute respiratory infections.     

人端粒酶催化亚单位mRNA的实时荧光RT-PCR定量检测

目的 :建立可定量测定人端粒酶催化亚单位 (hTERT)mRNA的实时荧光反转录PCR方法。方法 :用Trizol 试剂从HepG2细胞中分离总RNA ,然后反转录为cDNA。利用一对基因特异引物和一条TaqManMGB探针 ,以实时荧光PCR定量hTERT的cDNA。同时定量测定人 β 肌动蛋白 (hBA)的mRNA作为内对照。用梯度稀释的克隆的人 β 肌动蛋白基因制作标准曲线。结果 :标准曲线的相关系数为 1.0 0。实时荧光反转录PCR方法的平均变异系数为 7.1%。HepG2细胞hTERTmRNA与hBAmRNA的比值为 (1.3± 0 .3)× 10 -4。结论 :建立了可定量测定人端粒酶催化亚单位 (hTERT)mRNA的实时荧光反转录PCR方法。本方法的建立将有助于研究端粒酶的生物功能