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Help, still confused about the # of healthy positives, please explain

Discussion in 'XMRV Testing, Treatment and Transmission' started by leaves, Jan 28, 2010.

  1. leaves

    leaves Senior Member

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    Hi All,

    Sorry if this is all clear but I just dont get it.
    Mikovits finds that 3.7% tests positive for pcr. Does that mean that she DID NOT test the antibodies, viral culture etc of the healthy population, and that thus theoretically everybody can have xmrv?

    I hope someone can help me out. i am slowly but surely starting to accept that the cause for my illness is finely established, but I just cant handle another disappointment, so i first want to make sure that it is not the case that cfs people just have more xmrv then everybody else.

    Thanks for your help, and sorry for the stupid question
    :Sign Please:
  2. V99

    V99 *****

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    I assume they went and also tested the controls with the same methods. Does anyone know?
    It would still be the case, that with PCR, it was 3.7% controls, 68% CFS.
  3. Not a stupid question, leaves. I'd wondered about this myself.

    I'm pretty sure that they did all the range of tests on all the healthy control samples. Otherwise they wouldn't have been accepted into the Science paper, because you have to experiment on the controls in exactly the same way as you did with the main samples.

    As I understand it, Judy Mikovits explained in her lecture on the 22nd that you need to think about HIV and AIDS when you consider XMRV and M.E. or XAND as it will soon (hopefully) be known.

    HIV can be present in a completely healthy person. But then something happens to turn the virus on and they get AIDS.

    The same may (they think) be happening with XMRV. You can be a carrier and not know it. The virus might switch itself on inside you or it might not.

    -Rachel xx
  4. leaves

    leaves Senior Member

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  5. V99

    V99 *****

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    leaves.

    Judy will know.
  6. kurt

    kurt Senior Member

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    Not a stupid question at all. There was no mention of WPI testing controls in a large group, but they did mention somewhere that they ran a small control sample. However, there have been other studies, for prostate cancer, that establish some controls. In Japan one prostate study for XMRV found the virus in 1.7% of the Japanese population.

    Anyway, in my opinion this is one of the big omissions in the Science article, the lack of a large control group study for the antibody testing. There are other issues, for instance, the antibody used, MuLV, is not specific for XMRV. It is known to cross-react with HERVs, for example (endogenous retroviruses we ALL have already, in our DNA). If HERVs are not expressed/active, then no problem, but HERVs are known to be active in CFS, so that is a real confounding issue.

    Sorry if this is not making things more clear. With regard to XMRV I am in the category 'I want to believe'.... but have not yet seen convincing evidence. We need many more studies, and they are on the way. This could still go either way, even if XMRV is in fact validated and proven to be present in CFS, because we have not seen any causal model research yet. That would be a study to prove that XMRV is pathogenic, and not just a passenger. In other words, XMRV could be present BECAUSE our NK cells don't work right. So too early to call this game, waaaay to early.

    Here is what I think we CAN accept, based on the entire field of CFS research over the last two years. A type of critical mass is building up that will eventually lead to both political and scientific solutions for CFS. The CFS bus is finally out of the ditch and back on the road... It may turn out that treating the co-infections is the most important thing to do with or without proof of a retrovirus. That is something we already can tackle, the tests for CFS co-infections are available today, as are treatments. There IS hope.
  7. leaves

    leaves Senior Member

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    Hey Rachel,

    simultaneous post :)
    thanks for your explanation, are you really sure they did do the same tests? I thought that paper was only about establishing the infectiveness of the virus and NOT about the spread of latent virus. Since they only mentioned the PCR (at least that's what I understood) I thought they might not have done the other tests. But, I don't know, just worried of being dissapointed.
  8. leaves

    leaves Senior Member

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  9. Have you read the transcripts of Judy's lecture that everybody has been working on, leaves?
    Might help answer your questions...

    Rachel xx
  10. kurt

    kurt Senior Member

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  11. acer2000

    acer2000 Senior Member

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    This is exactly what it said in the paper:

    "Using the Whittemore Peterson Institute’s (WPI) national tissue repository, which contains samples from well-characterized cohorts of CFS, we isolated nucleic acids from PBMCs and assayed the samples for XMRV gag sequences by nested PCR (5, 6). Of the 101 CFS samples analyzed, 68 (67%) contained XMRV gag sequence. Detection of XMRV was confirmed in 7 of 11 WPI CFS samples at the Cleveland Clinic by PCR-amplifying and sequencing segments of XMRV env (352 nt) and gag (736 nt) in CFS PBMC DNA (Fig. 1A) (6). In contrast, XMRV gag sequences were detected in 8 of 218 (3.7%) PBMC DNA specimens from healthy individuals. Of the 11 healthy control DNA samples analyzed by PCR for both env and gag, only one sample was positive for gag and none for env (Fig. 1B)."

    I am not an expert in virology, but to me that means 68/101 patients tested were positive by PCR WPI ran the set. It appears they also sent 11 samples to the cleveland clinic who then detected 7/11 positives by PCR as well. There appear to have been 218 controls tested for the WPI batch, 8 of which were PCR positive. 1/11 were positive in the 11 samples the cleveland clinic tested.

    We have all inferred from non published data that Dr. Mikovitz went back and tested the same samples using culture, antibody, and PCR. After this expanded set of testing 98 of the original 101 patients showing CFS symptoms tested positive *in one way or another* using those methods. In fact I think that in the slide deck that was used for the pro-health video, it shows the breakdown.

    I have not seen any data that says they went back and tested the controls using antibody or culture and if the number of positive controls increased or stayed the same. One could speculate that if the number of positives in the CFS symptom cohort went up when they used expanded testing, so would the number of positives in the control batch. But we don't know...

    But what if some of the aditional 31 patients that brought the "post paper" positive count to 98/101 were *only* antibody positive? This situation is conceivable if the person cleared the infection and developed immunity. And as mentioned above, since we don't know if they went back and tested controls with antibodies and culture, we don't know A) if there are more true positives that weren't picked up by PCR (culture positive) or B) that there weren't a significant amount of antibody carriers that presumably don't have the virus anymore but are immune.

    Also, its not clear to me what it would mean if you were culture positive and antibody positive, but not PCR positive. I guess I would presume that, at least at the time that sample was drawn, you had the virus but it was dormant and not replicating (at least not in the blood). Were people with that results sick? Or would the dormacy mean a remission?
  12. leaves

    leaves Senior Member

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    YES Asus389! that is what I want to know; if they did the same for the healthy population. That it the only way to establish that not everybody has the virus, right?

    I guess I have to do more studying, and keeping my fingers crossed, but for today Ill go back to bed. Thank you for all your help.
  13. Robin

    Robin Guest

    You're right about the antibody test needing to be run in healthy controls. And, no, to my knowledge this has not been spoken about officially or published, and I'm not even sure if it's been done.

    Right now testing for XMRV is difficult, and as we learned from the IC study, varied. There is no "best test". Remember that the CDC has a working group developing a standard test for XMRV. Part of their mission is to establish the prevalence of XMRV in the general population. Like you pointed out: if it is prevalent like EBV or CMV, its relationship to CFS would be coinfection status. I think this is information that we're going to learn in the next year. We all have to just hang in there and wait.
  14. acer2000

    acer2000 Senior Member

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    Yeah, well the implications of the virus in the control population would be very different if after further testing 8 of 218 are PCR positive, but 160 of the 218 are antibody positive but PCR and culture negative (hypothetically). That would imply exposure to the virus is very widespread in the general population but most people fight it off completely. Did I mention I really want to see this data about the controls? :)
  15. julius

    julius Watchoo lookin' at?

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    Whenever the post study tests are mentioned, they only talk about the 33 negatives from the CFS cohort. No one has ever even mentioned retesting the controls. I am certain that if they retested the controls they would mention it. At least once, Judy or Annette or someone would have at least mentioned retesting them.

    Because of that I really don't think they did it. I think they only retested the 33 neg by pcr pwc's.

    And that's a big oversight. asus389 is totally right. Much higher numbers in the controls would paint a completely different picture.
  16. busybee

    busybee Senior Member

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    George wrote this in November. Is it relevant to this discussion?

    After the testing was refined and made more sensitive, the incidence in CFS patients went up to 95%....what did the control go to? Did the control figure stay at 4% even with the more sensitive testing?

    We next investigated whether XMRV stimulates an immune response in CFS patients. For this purpose, we developed a flow cytometry assay
    that allowed us to detect Abs=antibody to XMRV Env by exploiting its close homology to SFFV Env (16). Plasma from 9 out of 18 CFS patients infected with XMRV reacted with a mouse B cell line expressing recombinant SFFV Env (BaF3ER-SFFV-Env) but not to SFFV Env negative control cells (BaF3ER), analogous to the binding of the SFFV Env mAb to these cells (Fig. 4D and S6A). In contrast, plasma from seven healthy donors did not react (Fig. 4D and fig. S6A). Furthermore, all nine positive plasma samples from CFS patients but none of the plasma samples from healthy donors blocked the binding of the SFFV Env mAb to SFFV Env on the cell surface (fig. S6B). These results are consistent with the hypothesis that CFS patients mount a specific immune response to XMRV.


    I would like to point out that in the supplement they state that they used healthy controls who did not test positive for XMRV in the original 67 %

    Original Post from this thread

    Bx
  17. garcia

    garcia Aristocrat Extraordinaire

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    In the recent Prohealth speech Judy Mikovits mentioned that they did test the healthy controls for antibodies.

    I'm too busy to look it up right now. Maybe someone can search the transcript?
  18. garcia

    garcia Aristocrat Extraordinaire

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    I'm the opposite. I don't want to believe that ME/CFS is caused by a retrovirus. Unfortunately up till now I haven't seen any convincing evidence to the contrary.
  19. leaves

    leaves Senior Member

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    Thanks for digging this up Busybee!!
    So if i understand correctly this tells us that only the cfs patients that tested positive e
    by pcr had an immune response. As we know that the other patients tested positive later with more advanced methods this implies that you can have the virus without having an immune response as measured by the test above. Theoretically therefore the healthy controls could still have xmrv somewhere in their system.
    Is that correct or am I missing something?
  20. garcia

    garcia Aristocrat Extraordinaire

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    The healthy controls were tested for antibody and came up negative.

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