车上充电好吗:关于慢性疲劳综合症和鼠源病毒的坏消息

关于慢性疲劳综合症和鼠源病毒的坏消息

A large, thorough hunt for a mouse retrovirus known as XMRV in people who have chronic fatigue syndrome (CFS)—including in patients who tested positive for the virus in other labs—has come up empty-handed, further deflating the hope that a cause for this baffling disease has been found. "I'd urge people to move on rather than to keep their hopes hanging on the link between XMRV and CFS," says Ila Singh, a virologist at the University of Utah in Salt Lake City who led the new study.

大鼠上的一种反转录病毒，侵染人体后可导致慢性疲劳综合症[CFS]，被称为XMRV[xenotropic murine leukemia virus-related virus异嗜性小鼠白血病相关病毒]。在对该病毒进行了详细彻底的研究，包括分析其他实验室该病毒检测结果呈阳性的患者血液样本之后，结果是一无所获，这使得人们渴望找到该疾病真正诱因的美好愿望更加遥不可及。盐湖城犹他大学的病毒学家Ila Singh说“我希望研究者们能向前看，而不要总寄希望于XMRV和CFS两者的关系上停滞不前。”

The link between XMRV, which stands for the cumbersomely named xenotropic murine leukemia virus-related virus, and CFS has sparked debate since it was first reported in a study published online 8 October 2009 issue of Science. Singh's study is the latest of several that have failed to find XMRV in CFS patients. It is also the first to analyze samples from patients who were part of the original study. As Singh and her colleagues report online in the 4 May Journal of Virology, they analyzed blood samples from 100 CFS patients—including 14 who tested positive in the Science report—and 200 healthy controls. The team looked for evidence of XMRV in several ways, including fishing for viral sequences with the ultrasensitive PCR assay, trying to grow infectious virus in cell cultures, and scouring the blood for antibodies to viral proteins. (XMRV earlier had been tied to prostate cancer; the current Singh study does not address that link.)

XMRV，就是异嗜性小鼠白血病相关病毒这样一个繁琐名字的简写。自从2009年10月8号在Science上发表了第一篇关于XMRV和CFS两者关系的研究报道之后，这一研究方面的争论就从未停止过。Singh的实验数据是迄今为止关于此方面最新的研究结果，同样，在CFS患者体内未发现XMRV。他们的实验首次重新检测了以往研究的患者样本。这如Singh和她的同事在5月4号发表在《病毒学杂志》的文章中所写的那样，他们分析了100位CFS患者的血液样本，其中14位在Science上曾报道XMRV检测结果为阳性。另外还有200位健康对照。该科研团队希望用不同方法找到XMRV存在的证据，包括用超敏感PCR反应钓病毒序列，尝试在细胞培养基上培养病毒，在血液样本中寻找病毒蛋白的抗体。（早期研究结果显示XMRV和前列腺癌相关，但Singh的该实验目的不在于此。）

"Singh bent over backward to try to use the same assays as published, allowing her to knock down what I consider to be a real straw man but that nonetheless was out there," says retrovirologist John Coffin of Tufts University in Medford, Massachusetts. Coffin initially supported theScience report but subsequently concluded, with many others, that XMRV is a contaminant. In a recent study he provided evidence that the virus accidentally originated during mouse lab experiments.

马萨诸塞，梅德福Tufts大学的反转录病毒学家John Coffin说“Singh尽量使用和发表文章中完全相同的方法进行检测分析，从而减少人为误差。我起初认为她重新检测完全是搞错对象，但后来结果却真的不同。”Coffin起初支持Science上的报道，即认为XMRV和CFS有一定关系，但后来随着研究发现，他和其他学者一同认为，XMRV是污染物。他提供的最新研究结果证实，在实验室的大鼠实验过程中也会偶然检测到XMRV病毒。

Singh says she and her co-workers also had problems with contamination. When they ran one PCR assay that had been used in the original Science report, they found 5% of both CFS and control samples tested positive for XMRV. "It was very confusing until we figured out it was contamination," says Singh. Specifically, they fingered a PCR reagent, the Taq polymerase enzyme, as the source of the mouse sequences they detected. They further found that one of the machines they used to test samples also had been contaminated with XMRV in studies they had done months before the current analysis. "Everyone who works with mice has mouse retrovirus contamination in their lab," says Coffin. "I probably have it in my home swimming pool."

Singh说，污染问题也同样困扰她和她的同事们。当他们用PCR方法检测分析原始Science报道上的样品时，发现CFS样品和对照组都有5%的XMRV检测阳性率。“这很令人困惑，直到我们发现是污染的问题。”Singh说，尤为特别的是，她指出PCR所用的一种试剂，即Taq酶，一种鼠源的生物试剂，而她们扩增的目的序列也是该鼠源的。她们还发现，一台用来检测样品的机器也在几个月之前的研究过程中被XMRV污染了。Coffin说，“每个实验室研究小鼠的科研人员都会受到鼠反转录病毒的污染。我们家的游泳池里可能也有该病毒。”

The lead author of the contested Science paper, retrovirologist Judy Mikovits of the Whittemore Peterson Institute for Neuro-Immune Disease in Reno, Nevada, isn't persuaded by the Singh group's inability to detect XMRV in anyone. "I was astounded when I leaned that Ila [Singh] didn't find it," says Mikovits. "These are good scientists."

内华达，里内，Whittemore Peterson神经免疫病研究中心的反转录病毒学家Judy Mikovits是那篇在Science上发表的有争议性的文章的作者。Singh的科研团队未能在任何样品中检测到XMRV的这一结果未能令她信服。Mikovits说，“当听说Singh没能检测到XMRV的时候我真的很惊讶。她们都是那么优秀的科学家啊。”

Mikovits says she remains confident that the 14 CFS patients she selected for Singh's group have XMRV in their bodies. "These people are infected," says Mikovits. "This study says nothing. We have complete confidence in every bit of the results in the Science paper. We don't think any of it is wrong. There is no evidence of contamination in our lab, and we have controlled for that all along."

Mikovits说她仍然相信那14位CFS患者体内是含有XMRV病毒的。Mikovits说，“他们确实被感染了。Singh的结果说明不了什么。我们完全相信那些发表在Science上的每一个结果。我们没有错。我们的实验室不存在污染，在整个实验过程中我们都控制的很好。”

Mikovits notes that Singh's group did not use the identical protocols for every analysis, and stresses that discrepancies between their labs may also reflect her own finding that XMRV levels vary in patients day to day. Singh counters that although some protocol differences exist, they worked closely with Mikovits' team to replicate the original work. Singh says the fact that they didn't find XMRV in any of these patients is significant. "She [Mikovits] pointed us toward patients that she had repeatedly tested positive," says Singh. "We should have found at least one that was positive. Not all of them would have gone negative on the day when a phlebotomist met with them."

Mikovits提到Singh的团队并不是在每一个分析环节都采取和她同样的实验操作步骤，并强调两个实验室得出的不同结果恰好反映了她文章中提到的观点，即CFS患者体内的XMRV病毒含量是随着天数而变化的。Singh反驳说，尽管存在一些操作步骤的不同，但她们几乎是完全相同的重复Mikovits的原始实验。Singh说，事实上她们在任何一个CFS患者体内都没有检测到明显含量的XMRV病毒。“我们至少应该能检测到一个阳性的吧，不可能医生给那些患者抽血的时候都刚好碰上他们体内XMRV呈阴性的一天吧。”

Mikovits cautions that her Science report did not assert that XMRV causes CFS but only claimed to have detected XMRV in CFS patients. But the large community of CFS patients, who often find themselves confronting a medical establishment that questions the very existence of their disease, pounced on this finding, and some even started taking antiretroviral medicine to treat their supposed XMRV infections.

Mikovits明确提到，她的研究报告上只是说在CFS患者体内检测到XMRV病毒的存在，并没有声称CFS是由XMRV引起的。但大批的CFS患者，那些常常被医疗机构质疑他们是否真正患有此病的人们，其中一些人已经开始服用抗反转录病毒的药物，以此来对抗体内假想的XMRV侵染。

Singh's lab earlier reported that antiretroviral drugs do work against XMRV in test tube studies. But she now cautions CFS patients that taking them is unwarranted and even dangerous.

Singh实验室早期报道声称，抗反转录病毒药物在试管实验中确实能对抗XMRV病毒。但现在她告诫那些CFS患者，擅自服用抗反转录病毒药物来治疗CFS的方法不可靠，甚至是危险的。

The XMRV saga is far from over. Unlike Coffin and many other skeptics, Singh contends that a virus similar to XMRV does infect humans, and her own work supports the prostate cancer connection. "There is still considerable data supporting the link to prostate cancer that cannot be easily explained by contamination," she says. "More work needs to be done before that question can be settled."

关于XMRV的故事还远远没有结束。和Coffin等许多怀疑者的观点不同，Singh坚信一种类似于XMRV的病毒确实侵染了人类。她目前的工作是期望找到前列腺癌和XMRV两者的关系。“目前一些数据的确证实了前列腺癌和XMRV间存在某种关联，这种关联无法用早期的污染问题而解释。”她说，“在真正找到问题答案之前还有许多工作要做。”

The debate about whether XMRV infects humans and is linked to disease promises to come to a head later this year, when two different studies sponsored by the U.S. National Institutes of Health are completed. The studies both involve Mikovits and several other independent labs testing the same samples. Mikovits says if all the samples in these studies test negative, including in her own lab, the day could come when she changes her mind. "But I don't expect to get to that day," she says.

关于XMRV是否侵染人类且是否真正导致了CFS疾病的争论将会在今年年底有个最终结果，因为年底的时候，由美国健康学会资助的两个不同方向的研究课题就会结题。这其中包括Mikovits实验室和其他一些同样检测了那些血液样本的独立实验室。Mikovits说，如果这些实验中所有的样品，包括她自己实验室的那些，检测结果真的全部为阴性的话，她将会改变自己的看法。但她也说，“我希望永远不要有那一天。”