From Science magazine, Science Insider column, 21 June 2010.Blood banks should ask patients with chronic fatigue syndrome (CFS) not to donate blood or blood products because they may pass on a virus suspected of causing the elusive syndrome. That's the new advice coming from the AABB, an international association formerly known as the American Association of Blood Banks. The recommendation is based on a controversial paper published last year in Science that suggested that a human retrovirus may play a role in CFS.
Some scientists say the decision is premature, because the evidence for the link between xenotropic murine leukemia virus-related virus (XMRV) and CFS is tenuous, and three teams have failed to replicate the findings. “It's way too early for this. They're just spreading fear,” says Jos van der Meer, a CFS researcher at Radboud University Nijmegen Medical Centre in the Netherlands. “Let's do some more serious science first.”
But the CFIDS Association of America, a patient advocacy group, commends the panel for its recommendation in a statement. The group has advised patients against donating blood or organs for years. (CFIDS, or chronic fatigue and immune dysfunction syndrome, is another name for CFS, as is myalgic encephalomyelitis.)
The new recommendations were announced in a short statement posted on AABB's Web site on Friday; they came from a special XMRV taskforce, but were adopted by the AABB Board of Directors and published in an Association Bulletin sent to members.
Over the decades, a slew of viruses and bacteria have been proposed as the culprit in CFS—sometimes to much fanfare—but so far, each one of them has proven innocent upon closer examination. That's why many researchers were skeptical last year when a group of researchers reported to have found traces of the DNA of XMRV in the white blood cells of 67% of a group of 101 CFS patients, compared with only 3.7% among healthy controls. The researchers, led by Judy Mikovits of the Whittemore Peterson Institute in Reno, Nevada, also found that the virus could infect white blood cells, and concluded that it could play a role in CFS pathogenesis. XMRV had previously been linked to prostate cancer.
Since the Science paper appeared, three other teams—two from the United Kingdom and one from the Netherlands—have looked for XMRV in their own samples from a total of 388 CFS patients. As they reported in PloS One, Retrovirology, and the British Medical Journal (BMJ), they found it in none of the patients; the two studies that included healthy controls, failed to detect XMRV in them as well. Van der Meer, the first author on the BMJ paper, says he has heard of several other as-yet unpublished studies that failed to find a link.
CFS scientists also poked holes in Mikovits's paper's methodology in three Technical Comments published by Science last month, with one team calling the paper “potentially misleading.” Among other things, the critics said, the study failed to properly describe the patient population, and it seemed not to have considered the possibility that patients might be infected with XMRV as a result of having CFS, rather than the other way around. (A rebuttal by Mikovits and co-author Francis Ruscetti of the National Cancer Institute in Bethesda, Maryland is here.)
Canada, Australia, and New Zealand have already announced measures to avoid CFS patients from becoming donors. The ultimate responsibility for the blood supply in the United States lies with the Food and Drug Administration, which so far has not issued guidelines pertaining to XMRV. But based on the recommendations, individual blood banks should actively discourage CFS patients through information materials available at the site where they give blood, the AABB task force says. There is no approved blood test for XMRV.
Louis Katz, a member of the task force on XMRV, says the reasoning behind the recommendations is “pretty straightforward.” Although not all the answers are in about the agent's involvement in CFS, it's a “prudent approach” to have patients avoid blood donations, he says. “If [XMRV] turns out to be important, I don't want to be criticized later for doing nothing when I could have done something,” says Katz, who is medical director at the Mississippi Valley Regional Blood Center in Davenport, Iowa.
Besides, he says, the measure won't greatly affect the number of donors. Current CSF patients are unlikely to give blood anyway; the panel is primarily worried about those who decide to donate after recovering, says Katz. “I think the blood supply can tolerate it if they lay out while we sort this all out,” According to the CFIDS Association, a survey conducted by the group has shown that more than 6% of CFS patients has given blood at least one time following their diagnosis.
In an e-mail sent to ScienceInsider, Mikovits says she stands by her results and says that the recommendations are “absolutely not premature … no one who has a CFS diagnosis, and thus is possibly infected XMRV, should donate blood.”