The role of stage-specific oligonucleotide primers in providing effective laboratory support for the molecular diagnosis of reactivated Toxoplasma gondii encephalitis in patients with AIDS
The role of stage-specific oligonucleotide primers in providing effective laboratory support for the molecular diagnosis of reactivated Toxoplasma gondii encephalitis in patients with AIDS
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DOI：
10.1099/0022-1317-51-10-879
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发表时间：
2002-10-01
影响因子：
3
通讯作者：
Delia, S
中科院分区：
文献类型：
--
作者：
Contini, C;Cultrera, R;Delia, S
从缓殖子到速殖子的转变是导致艾滋病患者弓形虫脑炎（TE）的基本致病事件。这些阶段之间的区别是困难的，特别是当特定的治疗已经开始。一种新的方法，包括巢式PCR（n-PCR）检测进行抗寄生虫治疗前或后从艾滋病TE患者采集的脑脊液（CSF）标本，以评估引物集，扩增的目标序列上表达的缓殖子（SAG 4和MAG 1），速殖子（SAG 1）或两个阶段（B1）的弓形虫。从46名艾滋病患者中获得了CSF样本，其中27名患有TE（16名首次发病，11名复发），19名在没有TE的情况下患有其他艾滋病相关脑部病变（AIDS-OBL）。还检查了26例HIV阴性和免疫活性患者的CSF标本。用靶向B1、SAG-1、SAG-4和MAG-1基因的不同引物对测试所有样品。在B1中，75%的TE首次发作患者为阳性，而TE复发患者为36.3%，AIDS-OLB患者为5.2%。SAG 1基因在TE首次发作或TE复发的患者中分别为28.7%和45.4%，而在对照组中均为阴性。SAG 4和MAGI基因检测到TE复发患者的72.7%，而首次TE发作患者的25%和AIDS-OLB患者的5.2%。所有HIV阴性受试者均未显示阳性PCR反应。这些结果表明，基因SAG 4、MAGI和SAG 1的特异性引物可能对TE复发的AIDS患者有用，在这些患者中，使用靶向B1基因的PCR可能无法检测到DNA，特别是当已经开始预防或治疗时。
The switch from bradyzoites to tachyzoites is the fundamental pathogenic event that leads to Toxoplasma gondii encephalitis (TE) in patients with AIDS. Distinction between these stages is difficult, particularly when specific treatment has been started. A new approach consisting of a nested PCR (n-PCR) assay was performed on cerebrospinal fluid (CSF) specimens collected from AIDS patients with TE before or after antiparasitic therapy was initiated, to assess the efficacy of primer sets which amplify target sequences expressed on bradyzoites (SAG4 and MAG1), tachyzoites (SAG1) or both stages (B1) of T gondii. CSF specimens were obtained from 46 patients with AIDS, of whom 27 had TE (16 first episode, 11 relapse) and 19 had other AIDS-related brain lesions (AIDS-OBL) in the absence of TE. CSF specimens from 26 HIV-negative and immunocompetent patients were also checked. All samples were tested with different primer pairs targeting the B1, SAG-1, SAG-4 and MAG-1 genes. With B1, 75% of patients with first episodes of TE were positive, compared with 36.3% of those with relapse of TE and 5.2% of those with AIDS-OLB. The SAG1 gene yielded positive values in 28.7% and 45.4% of patients with first episodes of TE or relapse of TE, respectively, and in none of the controls. With the SAG4 and MAGI genes, 72.7% of patients with relapse of TE were detected, compared with 25% of patients with first episodes of TE and 5.2% with AIDS-OLB. None of the HIV-negative subjects showed positive PCR reactions. These results demonstrate that specific primers for the genes SAG4, MAGI and SAG1 may be useful in AIDS patients with relapse of TE, in whom the use of PCR targeting the B1 gene may fail to detect DNA, especially when prophylaxis or treatment has been started.