I've been asked about Dr Blomberg's finding of 3/5 of Dr Mikovits samples as positive for XMRV, when all his own were found negative, and whether this could be explained by contamination of those samples. This prompted the following ramble/muse about these results, and about "contamination" in general, which I thought I might as well post here...
I suppose that, in short, all one can conclude is that Dr Mikovits' samples now contain what an independent researcher would assess as being XMRV, and that this independent researcher was NOT finding the positives using contaminated equipment. He, too, says he finds XMRV in those samples.
I would argue that there is really just the one simple question, which comes up in every context: whether the XMRV-like sequences that are being detected by a variety of researchers are ALL 'contamination', meaning that it comes not from the patient sample but from some other part of the apparatus, or whether it does indeed come from the patients' blood.
To put it another way, if one were saying these samples Dr Mikovits supplied were contaminated, then such contamination would very much imply that her lab is or may be contaminated, and in turn that her previous results were due to contamination. So: it amounts to the same original question about contamination, it doesn't change that...
I suspect that whether all the people who detected XMRV so far were using contaminated samples (using common contaminated ingredient(s), presumably) ultimately remains an open question until Dr Alter completes the 'extra gold standard' sequencing step, showing XMRV within an infected cell; they need to show it integrated into infected tissue (but I think you have to find out where the tissue reservoir is to have a decent chance of detecting this; it also would take about 6 months, but I believe/hope that job is under way). And note that when they do so, the scientific argument then swings to needing to demonstrate that it definitely isn't an ERV sequence, which has been done but again I imagine that will be scrutinised more deeply if cell DNA integration were shown.
Anyway I'm rambling because I'm not sure what the short answer is as to "what can we interpret from this?". Firstly one has to note: this came from Mindy Kitei; it would be interesting to see what she thought of the full context of discussion about these positives, because Dr Blomberg seems to be asserting that his XMRV test found XMRV in those samples. Even if it was contamination of the samples, it could not have been contamination of Blomberg's equipment...
...Yes I think that's basically what one can conclude logically, taking all these bits of information into account: noting that Blomberg is saying "yes I detect XMRV in these, but in nothing else", he is independently confirming Dr Mikovts' finding of XMRV in those 3 of her 5 samples, unlike any other samples he tested (using, one trusts, the same equipment...but the details will be important of course, as ever...). Conversely, if there is a contamination issue, then it is (at least now) present in the samples Dr Mikovits provided. One way or another, it all points to the sample collection and preparation...
I think this conclusion moves us to exactly where we are going anyway, or indeed where we already are, which is to say: is this difference in sample preparation and storage methodology that is required to detect XMRV caused by (for example) some property of XMRV that requires the sample to be handled in a certain way, or is that required methodological difference the result of contamination? In other words, where are the XMRV and the other sequences MLV-related sequences actually coming from?
I should add, though, that to me this is a purely academic argument, in view of the overwhelming evidence against contamination.
For me, one of the clinching factors is the consistency of the percentages (in PC controls as well as CFS controls) found by a variety of diverse and neutral groups.
The variability in rates is well within what one would expect, averaging to around 3-8%, and the positive studies in both PC and CFS are all close enough, with no real outliers (the Chinese study is the furthest out; evidence of a contaminated lab doesn't count) to be clearly clustering around something real, and most importantly (taking Dr Singh's association with the PC prognosis scale into account especially), these researchers who do find XMRV are consistently finding this "contamination" disproportionately in people with the worst PC and CFS as compared with controls.
This last point means that IMO we can now safely say that either:
(a) The XMRV detected is actually coming from something used by the +ve studies in their blood collection and storage process, AND therefore the blood of those PC + CFS patients is a specially suitable environment for contaminant XMRV retrovirus to thrive in, in vitro at least, AND therefore the PC and CFS patients are very probably disproportionately immune-suppressed,
...or...
(b) The XMRV detected is coming from the patients blood, AND it seems then likely that this is associated with immune-suppression, likely also to play a key causal role, but possibly purely a passenger.
So in this sense there isn't quite such a huge gulf between the two scenarios as may at first appear: in both cases one has strong evidence of a certain kind of retrovirus-related immune vulnerability to xmrv in geographically diverse groups of patients, and that immune vulnerability demands explanation. Even in case of contamination, the difference in results between PC/CFS and controls would still imply a very significant breakthrough in understanding ME, although the political impact would of course be greatly diminished.
Arguably the recent Scottish study makes up for much of the political capital that may be lost (insofar as the UK is significant): that study too establishes that there are virus(es) afoot, which should now at last be hunted.
But my view on XMRV/ME is that an incredibly solid level of scientific proof will be needed for full international acceptance and that may take some years to happen, even though on examination of the evidence in the round it is extremely likely to be true.
If we are not out-and-out conspiracy theorists, we now also have massively more confidence that the complexity of the issue and the political confusion won't, this time, prevent a proper scientific examination to explain the results. Collins and Lipkins' involvement is a massive boost in that respect.
In conclusion:
1. Contamination will be and always would have been an open scientific question until the 'gold standard' techniques of demonstrating viral integration were achieved,
2. The results in the round, however, continue to make it very unlikely IMO,
3. Blomberg's findings show that any contamination explaining the results would have to be present in the samples themselves, which she supplied to Blomberg, and is not in his equipment, at least,
4. Thus any contamination would have to be something that affects the blood sample collection and storage process, which is what is at issue anyway,
3. Even if contamination were the explanation, apparent immune suppression in these patients demands to be explained,
4. Even if contamination weren't the explanation, immune suppression would still be a theoretical possible explanation of the results until causality is proven,
5. If one is confident that contamination is not the explanation (and also if not), one can at least now be confident that the truth will be revealed within (estimated) a few months to a year from now - unless one doubts the impartiality of the team of Collins, Fauci and Lipkin (most importantly, Lpikin) and assumes them part of, or victims of, the conspiracy.
6. Meanwhile, details from the positive studies and further findings will continue to roll in...and the urine testing could potentially deliver lots of interesting data quite quickly - if such data showed significant and obvious patterns of association with various specific disease(s), all the other questions would become relatively moot points anyway...