a follow-up on bleeding for the cause

By Alison Campbell 18/06/2010

A couple of days ago, on my post about World Blood Donor day, one of my commenters noted that the NZ Blood Service is apparently going to follow their Canadian & Australian counterparts in banning people from giving blood if they’ve ever had Chronic Fatigue Syndrome. (At the moment folks who’ve had CFS are OK to donate once they’re fully recovered.) The reason for doing so is a purported link between CFS & a particular retrovirus (XMRV, or xenotropic murine retrovirus). 

But the link between CFS & XMRV is not particularly clear-cut. A study in Nevada found that >60% of CFS sufferers (N=101) also had traces of XMRV in their blood, compared to <4% of healthy controls (N=218). (Sorry, the link is to Science & may not work for all.) This sounded like something that ERV would be interested in & I was fairly sure she’d written something on it earlier, so I checked. I was right: she’s got a very interesting commentary on the methods used by the Nevada researchers. But she’s aslo cautious about the overall conclusions: fairly obviously XMRV isn’t the sole agent involved in CFS (if it’ is an agent), given that 33% of CFS patients didn’t express it in their blood. It would also be important to know where the samples came from: if the individuals with CFS lived where XMRV infection is common, then this would skew the results & make any relationship appear stronger than it is. And It does look as if at least some other labs haven’t been able to replicate these findings.

I can understand the Blood Service wanting to err on the side of caution, given issues with contaminated blood in the past (the Hep C/haemophilia problem, for example). Consequently I have to disagree with Smut on this one – it probably is better to be safe than sorry. A ban can always be reversed if the apparent XMRV-CFS link turns out to be non-existent after all.

On the other hand, I find it concerning that various commenters, including the lead researcher in the Nevada study, have made statements explicityly linking CFS & XMRV – when a causal relationship has yet to be demonstrated. (It could equally well be an opportunistic infection.) A commercial test for XMRV is now available. While this is valuable as a research tool (in measuring the incidence of infection, for example), identifying a particular individual as +ve for the virus can’t at present assist in actually treating the patient. However, in at least some cases people with both CFS and an XMRV infection are taking powerful anti-retroviral drugs (commonly used against AIDS) that can themselves have significant side effects, in the hope that ridding themselves of the virus will also cure the CFS. This seems to be drawing a long bow indeed.

0 Responses to “a follow-up on bleeding for the cause”

  • Why don’t you want to be more accurate?
    Yes, the study that was published in “Sceince” found 67% of the ME/CFS patients tested by only PCR to be positive for XMRV. But the WPI told us afterwards, that they have some unpublished data: They checked the 33 patients that were negative for XMRV by PCR, with 3 other methods of testing (testing for viral protein expression, testing for infectious virus in the plasma and testing for antibodies). With these tests, 31 of the 33 tested positive for XMRV – and all together, 99 of the 101 patients were positive for XMRV – and that’s 98%. Pretty unlikely that if these numbers would be proven to be even close to accurate that XMRV is just an opportunistic infection, taklng into consideration that in the studies that found XMRV in healthy controls until today, the rate of infection there was just 1.7%-6%.
    And when everybody talks about antiretrovirals and how dangerous they are – They are saying that because they are not sick and they don’t have to suffer even one more minute before all the scientific work is done – not to mention months or years, which is the realistic time frame here. perhaps you should read Dr. Deckof-Jones’s, a ME/CFS patient and a medical doctor which she and her daughter started taking antiretrovirals, comment on that:
    “When I realized that the virus is sensitive in vitro to existing safe HIV drugs, I thought and still think that it is a miracle. In fact, I am stunned by the sudden overabundance of caution in the treating physicians

    It would seem that nobody wants to try it. Despite being given the key. Never mind that we are a patient population that has been experimented on for decades.

    HAART is a safe existing protocol for AIDS which includes three drugs which inhibit XMRV in vitro. We even know that the three possible combinations of those drugs are each synergistic in vitro.

    But, the sickest will die while the scientists try to figure it out, so it seems to me that it is up to the doctors to treat with the information available. As always.

    I believe that there is a rationale for treating the sickest patients now. Physicians are allowed to prescribe drugs off-label. I think they should be testing their patients, at VIP Dx, the only commercial lab right now that seems to be able to find XMRV in peripheral blood, using the methods validated in the Science paper.”

    And you know what? Perhaps you’d be surprised to hear that most of the anecdotal reports that I’ve heard from people with ME/CFS who started to take antiretrovirals are pretty positive – reporting significant improvements in their health.

    • But the problem is that these positive anecdotes are just that – anecdotes. Not data. The WPI’s ‘extra’ data remain unpublished so far. And drugs that appear to work in vitro don’t necessarily have the same effect in vivo, hence the caution of most scientists about this finding.