Every now and again, I write about XMRV research as it pertains to ME/CFS (myalgic encephalomyelitis, aka "chronic fatigue syndrome"). Readers who are part of the ME community understand why it's important, but others may wonder why I keep writing about the medical thingy with the funny name. If you're one of those people, this little FAQ is for you.
What is XMRV?
A retrovirus, similar to HIV. Xenotropic murine leukemia virus-related virus was first discovered in 2006.
What's the connection to ME/CFS?
In October 2009, the Whittemore Peterson Institute for Neuro-Immune Disease and the Cleveland Clinic found that a significant majority of ME/CFS patients tested positive for XMRV, as compared to only 3.7 percent of healthy subjects. Another study by Alter and Lo found a link between this disease and MLVs—other retroviruses related to XMRV.
Does XMRV cause ME/CFS?
Unknown. It may be the cause, in the same way that HIV eventually leads to AIDS, or it may be one of many opportunistic infections that occur because ME/CFS patients' immune systems are already compromised. We'll need further research to tell cause from effect.
Why are you even writing about this? I read that recent studies showed there was no real link between XMRV and ME/CFS—that the positive results happened because of a lab contaminant.
Not exactly. Those four studies—by amazing coincidence all published on the same day—showed that it's possible to get false positives via contamination if you use a method of testing called PCR. They didn't disprove the studies that had previously been done.
OK, but don't the "contamination" studies at least cast doubt on the link between ME/CFS and XMRV?
Again, not exactly. The Whittemore Peterson Institute was keenly aware of the potential problems with PCR and used multiple methods to detect XMRV. Antibody testing, for instance, revealed that patients had antibody responses to XMRV. It isn't possible for a lab contaminant to cause antibody responses.
You can read a more in-depth explanation from a virologist here.
Has XMRV been linked to any other diseases, or just ME/CFS?
Some studies have found XMRV in patients with prostate cancer (where it was first discovered), chronic Lyme disease, and autism.
No offense, but I don't have any of those diseases. Why should I care?
Because it's infectious. There's a chance that you can contract XMRV the same ways you do HIV.
No problem. I always use condoms, and I don't shoot up with dirty needles.
That definitely helps! Unfortunately, there's a pretty good chance XMRV is also in the blood supply. Try not to need a transfusion.
If it's that big a problem, I'm sure there's already tons of grant money rolling in for XMRV research. We'll have treatments soon, right?
Remember how funding for AIDS didn't take off until it was a full-blown epidemic ...?
Yeah, but certainly we've learned from our mistakes.
It would appear not. As yet, the Whittemore Peterson Institute receives NO federal funding to study XMRV.
Gah! Do they take donations?
Thought you'd never ask!