A serious hat tip here to Danny Ze-Dog, whose scientific savvy was enormously helpful in putting this entry together.
So since the triumph that was the October 2009 announcement of Lombardi, et al., which found XMRV in people with ME/CFS, human gammaretroviruses have seemed to become increasingly controversial. Since the original study, performed with the cooperation of the Whittemore Peterson Institute, the Cleveland Clinic, and the National Cancer Institute, and published in the journal Science, there have been a number of negative studies that did not find XMRV. Many of them are what are termed 0/0 studies – they found no XMRV in ME/CFS patients or in healthy controls.
Recently, Science published another 0/0 paper, Knox et al. and along with that, they issued an editorial expression of concern. The Whittemore Peterson Institute responded with a press release and a letter from Judy Mikovits delineating why they believe the expression of concern is premature. I’d strongly suggest you read Dr. Mikovits’s letter, and do so slowly and carefully. I know it’s tough going in spots, but even if you’re not scientifically inclined, you’ll pick up enough of her points that you’ll see where she’s heading, and my attempts to summarize her words would not be as effective as her words themselves are.
One important part of Dr. Mikovits’s points that I will repeat here is that Papotka et al. claim in their study – the one published in the most recent issue of Science - that the contamination that seemed like XMRV was from the 22Rv1 cell line. This cell line has never been present in the WPI lab, nor have any of the other cell lines said to be contaminated with XMRV.
Anyway, that said, I acknowledge that it looks bad to have so many negative studies pile up. But unfortunately, they all have the same problem – they are not true replication studies. This is what the scientific process demands – replicating the conditions of the experiment exactly in order to judge whether the conclusions are accurate. A rough approximation is not good enough, especially in a difficult new line of research like the one the original study represents. The study that came closest to replication – Lo, Alter et al. – did not find XMRV, but did find another human gammaretrovirus in the same family, which they termed the P variant (XMRV being the X variant).
So what are the differences in the studies that have been done following on Lombardi, et al.? Here’s a set of tables (PDF download), again authored by Judy Mikovits, noting only some the differences in some of the studies conducted thus far. This is another thing to read slowly and carefully. Remember that the original paper Judy Mikovits is among the authors for is Lombardi et al. (the first study listed in a column), and the most recent paper published by Science is Knox, Levy et al. (the study in the rightmost column).
One of the problems with Knox, Levy et al., the 0/0 study in the rightmost column that also appears in the current issue of Science is this: In their serology testing, they used two testing methods on one patient. Those two methods were ELISA and Western Blot. This patient was positive by Western Blot, showing antibody reactivity to two viral proteins, and negative with ELISA…then all additional patients were tested only with ELISA, not Western Blot. Why?
Returning to the larger problem: There are a couple overarching questions that the critics of Lombardi, et al. have not been able to answer, to my knowledge, that I think are the most important. If XMRV is only a lab contaminant, why do patients have detectable antibodies to it? They would not produce antibodies to a lab contaminant. And why, given identical handling for the blood samples, is there such a difference in the percentage of ME/CFS patients and controls found to have XMRV? Lombardi, et al. found 3.7% of controls with XMRV and initially 67% of ME/CFS patients. Lo, Alter et al. also found a far lower percentage of controls carrying the P variant (6.8%) than they did the ME/CFS patients (86.5%).
It’s not all 0/0 papers – there are other studies that have found XMRV as well. Ila Singh found it in 4% of the prostate cancers she tested, but when she did her most recent study, she switched to a new assay, tested blood, and came up with a 0/0 study (which is also listed in that set of tables from the WPI). Fischer et al. found it in respiratory secretions – in 2.3% of healthy people and 9.9% of the immunocompromised.
All that said, XMRV is, admittedly, extraordinarily difficult to detect. Part of the difficulty of detecting it is that it has very low copy numbers in peripheral blood, unlike HIV, which basically teems there. Instead, XMRV is hanging out in reservoirs, like macrophages, or the prostate. There was a study last year in which they infected macaques with XMRV and subsequently detected only transient viremia in two out of three animals (that means they could only find the virus they knew was there some of the time in some of the animals). This thing is a sneaky bugger.
So what do I think should happen? I disagree with the decision to issue an editorial expression of concern. I believe the scientific process should be allowed to run its course. If true replication studies show no evidence of XMRV, well, we have to consider a new direction. But we’re not there yet, and there was no need for Science to attempt to steer things that way with strong-arm tactics.
Why are we not there yet? Because of the lack of replication, at this point, most patients are awaiting the results of further research. There is more to come from the WPI later this year. There is rumored to be additional positive work from others in the pipeline that has not made it to publication yet because of being stymied by the number of negative studies released.
Additionally, there’s the Lipkin study, which is supposed to wrap up by the end of the year. This study will use a new round of blood draws from doctors specializing in ME/CFS from several different cities, and have the analysis done at three different labs: the WPI, FDA/National Institutes of Health, and the Centers for Disease Control. It’s certainly not expected to be a perfect study, but testing the same samples at separate labs should help advance things some.
But what we need is true replication, and then, if that indicates that MLV-related viruses, the family that XMRV belongs to, are present, varying the experiments one element at a time. That’s the only way to truly move forward.
I mean, hell, even I did an XMRV study. I used baking soda and vinegar to make a volcano, and I didn’t find any evidence of XMRV. So it must be laboratory contamination.