Quantification of reverse transcriptase in ALS and elimination of a novel retroviral candidate
Quantification of reverse transcriptase in ALS and elimination of a novel retroviral candidate
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DOI：
10.1212/01.wnl.0000297552.13219.b4
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发表时间：
2008-01-22
期刊：
影响因子：
9.9
通讯作者：
Garson, J. A.
中科院分区：
文献类型：
--
作者：
McCormick, A. L.;Brown, R. H., Jr.;Garson, J. A.
背景：自从认识到小鼠和人类逆转录病毒均可引起 ALS 样综合征以来，多年来人们一直怀疑逆转录病毒参与肌萎缩侧索硬化症 (ALS)。非定量研究已证实 ALS 患者血清中存在逆转录病毒酶逆转录酶 (RT)，但 RT 活性的数量和来源尚不清楚。因此，我们开发了一种定量测定法来研究 ALS 中的 RT 水平，并检查了最近发现的人类伽马逆转录病毒 XMRV（异向性 MuLV 相关病毒）可能是 RT 活性来源的可能性。方法：使用定量产品增强 RT 测定法来测量血清和脑脊液中的 RT 活性水平。通过对从血液中提取的 DNA 和 RNA 进行 PCR 分析来寻找 XMRV 序列。结果：50% 的 ALS 患者血清含有 > 6 x 10(-8) RT 单位/mL，而对照血清中这一比例为 7% (p = 0.008)。 ALS 患者的 RT 活动水平与感染 HIV 的患者中观察到的水平相当。在测试的 25 个脑脊液样本中，仅 1 个检测到 RT 活性。从 ALS 患者血液中提取的 25 份核酸提取物中均未发现 XMRV 序列。 结论：这些发现进一步支持逆转录病毒参与肌萎缩侧索硬化症 (ALS) 的概念，并证明血清比脑脊液更适合检测该疾病的逆转录酶 (RT) 活性。检测到的血清 RT 活性水平与 HIV 感染中发现的水平相当。 ALS 患者的血液中无法检测到 XMRV，因此导致 ALS 相关 RT 活性的药物仍未确定。
Background: Retroviral involvement in amyotrophic lateral sclerosis (ALS) has been suspected for several years since the recognition that both murine and human retroviruses can cause ALS-like syndromes. Nonquantitative studies have demonstrated the retroviral enzyme reverse transcriptase (RT) in ALS patients' sera, but the amount and source of RT activity are unknown. We therefore developed a quantitative assay to study RT levels in ALS and examined the possibility that the recently discovered human gammaretrovirus XMRV (xenotropic MuLV - related virus) might be the source of the RT activity.Methods: A quantitative product-enhanced RT assay was used to measure RT activity levels in serum and CSF. XMRV sequences were sought by PCR analysis of DNA and RNA extracted from blood.Results: Fifty percent of ALS patients' sera contained > 6 x 10(-8) RT units/mL as opposed to 7% of control sera ( p = 0.008). The levels of RT activity in ALS patients were comparable to the levels observed in patients infected with HIV. RT activity was detected in only 1 of 25 CSF samples tested. XMRV sequences were not found in any of 25 nucleic acid extracts obtained from ALS patients' blood.Conclusions: These findings further support the concept of retroviral involvement in amyotrophic lateral sclerosis (ALS) and demonstrate that serum is more suitable than CSF for assay of reverse transcriptase (RT) activity in this disease. The levels of serum RT activity detected are comparable to those found in HIV infection. XMRV is not detectable in the blood of ALS patients, and the agent responsible for ALS-associated RT activity therefore remains unidentified.