Wednesday, September 22, 2010

The role of XMRV in Chronic Fatigue Syndrome remains unclear

A few weeks ago we posted about the confusion over research into Chronic Fatigue Syndrome (CFS), or myalgic encephalitis (ME), which is or isn't caused by the recently discovered virus, XMRV, which also does or does not cause a form of hereditary prostate cancer.

Science reports that a meeting of several hundred researchers took place two weeks ago to discuss the controversy surrounding the role of this virus in disease.  But, as one of the organizers of the workshop concluded, the field remains "a zone of chaos". The presence of XMRV has been confirmed in men with prostate cancer by some groups in the US, but not in Europe, and in some people with ME but not others -- by some labs.  Some labs have definitively documented contamination with XMRV, and thus can't confirm its role in disease, while others report finding it in most cases they've tested but few controls, suggesting it's real and not contaminant.  The ability of all labs that have reported results of tests for the virus, whether positive or negative, to detect the virus has been tested and all were able to, so it seems that the possibility that there's an easy answer to this, and the conflicting results are due to varying laboratory techniques is not to be.

The head of the National Institute of Allergy and Infectious Diseases, Anthrony Fauci, has asked an epidemiologist at Columbia to test blood samples from 100 CFS patients from four different areas of the US and 100 controls for the presence or absence of XMRV.  It's unlikely that throwing the results from yet another lab, whether positive or negative, into the mix will convince anyone on either side of this issue, however.  Meanwhile, we conclude this post as we did our previous post on the subject -- it's possible that the only way the controversy over whether XMRV causes disease will be sorted out is if CFS patients can be successfully treated with antiretroviral medications.

Precedent isn't very helpful.  Theories of disease come and go, and viral theories are no exception.  At one point that was cancer's general cause, but not cervical cancer which was due to promiscuity.  Ulcer was due to stress, not bacteria.  And so on.  It is not clear how we can know with confidence, but in some examples like these there is an answer, and a rather clear one.  In others, the theory simply fades away.  It will be very interesting to see how this one goes.

1 comment:

Anonymous said...

Meanwhile people with CFS in the U.S. can continue to give blood as they have not yet been banned from doing so. The U.S. has now fallen behind Canada, Australia, New Zealand, United Kingdom, and Malta in banning CFS patients from donating blood as a precaution.

The U.S. needs to ban CFS patients from donating blood NOW.