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More questions over link between XMRV and chronic fatigue syndrome


A comprehensive study on the purported link between XMRV and chronic fatigue syndrome (CFS) has failed to find any trace of the virus. The study published yesterday in the Journal of Virology also hints that contamination of laboratory reagents with mouse DNA may explain some of the previous positive results.

In 2009, a team led by Judy Mikovits at the Whittemore Peterson Institute for Neuro-Immune Disease in Reno, Nevada reported in Science the discovery of the retrovirus in up to two-thirds of patients with CFS, which is also known as myalgic encephalomyelitis (ME). The discovery raised the hopes of patients with CFS/ME because it offered a clear explanation for the mysterious condition, as well as hope of a treatment.

Over the last two years, however, the link between XMRV and CFS/ME has clouded considerably, and no lab has been able to replicate Mikovits’ results. I covered this saga in a recent feature, “Fighting for A Cause”, which included the revelation that XMRV was created in a laboratory in the 1990s and therefore was extremely unlikely to underlie CFS/ME.

Mikovits’s primary response has been that the studies failing to find XMRV have not replicated her lab’s methods precisely, which involved detecting virus genetic material, patient immune responses, as well as the ability of the virus to divide in cell culture.

The new study, led by Ila Singh at the University of Utah in Salt Lake City, has now done all that and still come up with no sign of XMRV in 100 CFS/ME patients as well as 200 healthy people. What’s more, Singh’s team failed to find the virus in 14 patients who previously tested positive for the virus in Mikovits’ lab. They also find evidence that mouse DNA contaminates some of the reagents used to search for XMRV DNA, offering a possible explanation for some positive results.

For a technical, yet highly readable explanation of Singh’s study, check out Vincent Racaniello’s Virology Blog, which covered the new paper yesterday.

Also significant is the fact that Singh has previously found XMRV in tissue from prostate cancer patients and shown that the virus is sensitive to antiretroviral drugs.

In the new paper, her team writes:

Given the lack of evidence for XMRV or XMRV-like viruses in our cohort of CFS patients, as well as the lack of these viruses in a set of patients previously tested positive, we feel that that XMRV is not associated with CFS. We are forced to conclude that prescribing antiretroviral agents to CFS patients is insufficiently justified and potentially dangerous.

While it’s tempting to call this paper the “nail in the coffin” for XMRV, other similarly thorough replication studies are in the works. The largest of those is a $1.3 million effort funded by the US National Institute of Allergy and Infectious Disease and being led by microbial epidemiologist W. Ian Lipkin at Columbia University in New York. Results from that study are expected by the end of this year.

Image of XMRV particles courtesy Wikimedia Commons


  1. Report this comment

    Laurence Swift said:

    The article’s title is a misleading misnomer. It should really be called “Absence of the Ability of Our New Test Protocol to Detect XMRV Even In WPI’s Positive Samples”. That says it all.


I used to think that Ila Singh was “on our side”. Now she’s involved in poor testing techniques that can’t even find XMRV in WPI’s patients’ +ve samples. Use of wrong culture cells, refrozen samples, wrong PCR reagents, annealing temperatures – there’s so many places to go wrong. I’m sure Judy M will be easily able to shoot holes in this paper. Just WHY DON"T these people use exactly the same techniques etc as WPI?

    And as for "… encourage further research into the involvement of other infectious agents in CFS, and these efforts must continue”, this is evidence to say that this team has been nobbled by the Dark Forces, in that they are trying to divert attention away from XMRV and into various blind alleys.

    Perhaps a clinical trial of antiretrovirals is the best way to go from here. We have a number of anecdotes saying that patients have improved markedly after some months on ARV’s. How many anecdotes constitute scientific proof? 10? 100? We’ve known it’s a retrovirus for 25 years, so why not try ARV’s? They’re no worse than long-term antibiotics, and my son has been on a tetracycline for over a year – for acne.

    People trialling ARV’s at present are apparently having few or no troubles with them. Some of these (like Dr Jamie D-J of the WPI) are doctors themselves – the virus does not discriminate according to status or education. There is plenty of experience with these drugs in people with HIV/AIDS.

    If you were reduced to the level of a vegetable and found that there was a drug available that could make you once again at least half-functional, wouldn’t you want to try it?

    Ila Singh has found XMRV in previous studies. So why not now? – and why did she even bother to publish the paper? It doesn’t add anything to science, just another negative paper, to join all the others that refused to use the same techniques as the WPI. I suspect if they DID do a true replication study, they would find lots of XMRV.

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    Agustin Legido said:

    All medicine have any side effects so it is suggested that before buying prescription drugs – hydrocodone, vicodin or oxycodone – consult with your doctor or seek information online medicine.

    Agustin Legido


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    Justin Reilly said:

    Thanks for reporting on this very important topic (and not simply regurgitating the press release). I think you gave it good treatment (though I wouldn’t even be tempted to think this was a ‘nail in the coffin’ regardless of other upcoming studies).

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    Mike Stewart said:

    This issue has been clouded as acknowledged and most likely still is. Hopefully more will come to light to help CFS patients to have hope for at least some improvement and perhaps an eventual cure. Compassion for those affected and help of any kind can make their lives more bearable and maybe at times a little enjoyable, something most of us take for granted. I commend the research effort and the human effort of all involved.

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    G Lyon said:

    You mention that the Ian Lipkin study is expected by the end of this year. At last month’s NIH State of the Knowledge conference on ME/CFS, it sounded like we wouldn’t see the results of that study for at least a couple of years. I’m wondering what your source is, or what you’ve heard that we haven’t?

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    Matt said:

    Comprehensive in using novel assays that are unvalidated. Please read the details. Lombardi used Nested RT-PCR no Nested PCR. Singh did not use any of her previous methods.

    Lo et al validated Lombardi et al. XMRV is a poly and xeno hybrid.

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