A game of Russian roulette with the human species.

PCR is an enzyme driven biochemical reaction.


The yield of this reaction is determined by the nature and concentration of template, primers oligonucleotides.  In addition the efficiency of the taq polymerase is highly influenced by the concentration of magnesium, the PH and the ionic content of the medium.  The reaction volume and nature of the reaction vessel can also be critical because of kinetic factors and temperature gradients.  Finally, the annealing temperatures and times have  critical role in specificity and tolerance of mismatches.

Perhaps the editors of Science could explain how they consider that changing all these key variables (as the 00 studies have done), can possibly produce the same outcome as the biochemical reaction devised by Lombardi et al.  How can they justify their view that a lack of product produced by the chemical reaction parameters used in the 00 studies means that the virus was not present?

Knox et al. used a PCR assay to retest the patients of Dan Peterson, which had not detected XMRV GAG sequences in non viremic patients in Lombardi et al. either.  They then compared their results with those obtained by using the PCR assay in Lombardi which did discover GAG sequences in 67% of patients tested.  Unsurprisingly Knox et al. failed to detect the virus with that assay, just as Lombardi et al. had failed with that assay.  The use of the successful assay in lombardi et al. once again found the patients to be positive.  Knox et al., lead by Levy, decided that the results indicated that the Lombardi results were false positives!!

This may be a more personal way of explaining things.

Imagine a loved one being tested positive for HIV, using a PCR which had demonstrated time and time again the capability to detect HIV if present and was fully licensed.   This means that the analytical sensitivity and the clinical sensitivity had been demonstrated beyond doubt.  Your Loved one is diagnosed early and put on HAART therapy.  Then your loved one is retested using a PCR assay which is very good at detecting HIV in a test tube, but has never detected HIV in the blood of an infected person.  This means that the analytical sensitivity has been established but not the clinical sensitivity.

Your loved one tests negative and is so relieved that they stop their HAART and die a horrible death.

How would you feel about the people who could not be bothered to determine the clinical sensitivity of their PCR assay?

None of the research groups which have failed to find any evidence of XMRV have determined the clinical sensitivity of their PCR assays, so their conclusions are just hypotheses, because they can't demonstrate that their assays would have detected XMRV if present.

There is a big difference between detecting a virus in a test tube and detecting it in a clinical sample.

Finally, there are a number of independent variables which determine the yield of a chemical reaction.  The people who can't detect XMRV are changing all the independent variables and expecting the dependent variable to remain unchanged!!

If you doubt any of my facts please consult any independent biochemist or chemist.  People who exclusivly work with HIV have relied on commercial PCR kits.  They are assuming that a PCR kits that have been optimised by comercial companies to detect HIV (a lentivirus) can detect XMRV (a gammaretrovirus) which only exists in the blood for a very brief time after infection, but replicates in the spleen, thymus, lung, intestines and bone marrow.

Now is your chance to prove that British scientific journalism is a cut above anywhere else and prove the medics wrong.

XMRV class viruses are better known as oncoretroviruses. I will leave the rest to your imagination.

Should unvalidated tests be allowed to suppress research into an area which is so important?