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What percentage of ME/CFS patients have XMRV??

Discussion in 'XMRV Research and Replication Studies' started by Tulip, May 3, 2011.

  1. Tulip

    Tulip Guest

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    I keep reading different amounts. I have read 67%, 87% and on the Dr Oz show about XMRV and CFS, he said 95% tested positive.

    So which is it?? :confused:

    Ta
     
  2. Jemal

    Jemal Senior Member

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    67% is the percentage of XMRV infected ME/CFS patients that the WPI found in the original study that was published in Science in 2009.
    However, the WPI later made announcements that they found XMRV like viruses in up to 95% of the ME/CFS patients that they tested. This data isn't published in a peer reviewed medium like Science, so it's not official yet (or at least: most scientists will disregard this data).

    In a separate study done by the FDA, NIH and Harvard in 2010, 87% of tested ME/CFS patients were found to be positive for XMRV like viruses.

    So that accounts for all the percentages :D

    These studies were not very large and testing procedures are not fully developed yet, so the "definitive" percentage could still drop or even rise. There could also be regional differences: XMRV might be more prominent in certain regions.
    Then there are also some scientists that believe XMRV is all contamination ;)
     
  3. Tulip

    Tulip Guest

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    Thanks :D

    So which one do we tell the public?? 95% as Dr Oz did??.
     
  4. Jemal

    Jemal Senior Member

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    :D
    Opinions differ. Some will only want to use percentages from validated research, others will say that we can't draw any conclusions yet, as not enough research has been done.

    What I do know: 95% will definitely make more of an impact than 67% when talking to people :D
    At the moment I have no reason to doubt the WPI, so personally I believe XMRV is found in almost 100% of ME/CFS patients. We'll see how it pans out...
     
  5. Dan_USAAZ

    Dan_USAAZ

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    My understanding is that the two percentages announced by the WPI represent two different testing techniques.

    The 67% published in the Science article was based on a PCR/culture test. I believe this test detects active virus circulating in the blood at that time.

    As testing techniques evolved, the serology test was developed. The serology test detects viral antibodies in the blood. The 95+% is based on serology testing.

    I believe getting a higher percent from serology is logical. An XMRV+ patient will not always have active, detectable virus circulating in their blood. The patient may test positive by culture this month, but negative by culture in 6 months from now. Conversely, once you have antibodies to the virus, I believe they will likely always be in the blood.

    It may be useful to communicate both percentages, if you believe the audience can understand the difference. Otherwise, I believe the serology (95%) result may be more representative of the actual association between XMRV and ME/CFS.

    Of course, what I site above is not fully (or even partially) accepted by the scientific/medical communities or governments at this time.
     
  6. Sushi

    Sushi Moderator and Senior Member Albuquerque

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    Hi Dan,

    I think the 95% represents to total percentage when adding together the positives by serology with the positives by PCR and culture. I don't think that the serology, by itself, has that high a percentage.

    I was found positive by culture and "none detected" by serology--which my doctor says is a common result for patients who have been very sick for a long time--as the virus attacks the B cells which make the anti-bodies.

    Sushi
     
  7. Dan_USAAZ

    Dan_USAAZ

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    Hi Sushi,
    Thanks for reading my post and questioning the statements. I do not have a scientific background and what I post is subject to my interpretation, which may be faulty. I appreciate all the help I can get. :D

    In this case, I found the information related to 95% testing positive for antibodies (serology) in a WPI press release. The following is an excerpt from the press release.

    Since the original Science paper was submitted, we have continued to refine our test for XMRV and have surprisingly found that 95 percent ME/CFS samples tested positive for XMRV antibodies in the plasma. This finding clearly points to the retrovirus as a significant contributing factor in this illness, said Judy Mikovits, Ph.D., director of research for WPI and leader of the team that discovered this association.

    It is my understanding that testing for antibodies is the serology test.

    Here is the link to the full WPI press release:

    http://www.wpinstitute.org/xmrv/docs/wpi_pressrel_100809.pdf

    My thought is that XMRV+ patients such as you, that test positive by culture and negative by serology, add to the 95% making the number closer to 100%.

    The primary point I hoped to make in my post is that there are valid scientific reasons for the differences in the percentages (67% & 95%) announced by the WPI. The results represent different/improved testing techniques.

    Please let me know if I have misinterpreted the information.
    Thanks,
    Dan
     
  8. Sushi

    Sushi Moderator and Senior Member Albuquerque

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    Hey Dan,

    Looks like you are right! I was calling on my faulty memory and didn't have that press release in front of me.

    I'd also guess that when they found XMRV in 95% of the patients' plasma, they were using a more refined test than the one used at VIP when we send our blood in for serology testing. Or maybe they tested patients many times in the WPI study.

    My serology test didn't say "negative," but rather "none detected," which may well mean that there are a small number of anti-bodies there but the test wasn't able to detect them. Not sure, but maybe VIP just tests a sample once for anti-bodies and could easily miss them if there are very few.

    Anyway, it is a good discussion!

    Thanks,
    Sushi
     
  9. Dan_USAAZ

    Dan_USAAZ

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    Sushi,
    Thats a great point of clarification. I used the word negative to describe a test result. Using that descriptor could be misinterpreted. As you point out, the VIPdx lab test results states None Detected and this does not mean that you are negative for what was tested.

    Thanks,
    Dan
     
  10. Hope123

    Hope123 Senior Member

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    When it comes to discrepant figures, I'd rather underplay than overplay the figure so you could use 'at least 67% of people with ME/CFS in some studies'. Or you could use a range '67%-95%.' Using the higher figure isn't as good because if it turns out to be wrong, you could have people doubting you more and we have enough doubt to contend with. "67%" is not a low percentage in and of itself.
     
  11. Forbin

    Forbin Forbin

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    Actually, this data was published in the Sep/Oct 2010 issue of Virulence, some three months after its initial submission to the peer-reviewed journal.

    http://www.landesbioscience.com/journals/40/article/12486/
     
  12. Snow Leopard

    Snow Leopard Senior Member

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    According to the polls on this site, around 46% were positive on the culture test and about 59% were positive on the serology test. Those that tested positive to both is likely <40%.
     
  13. Jemal

    Jemal Senior Member

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    Thanks! I didn't know it was published somewhere. It didn't seem to have much of an impact on the scientific community, unfortunately...
     

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