Steve A :
"There is no doubt whatsoever that Dr. Singh and colleagues are able to detect XMRV DNA in clinical specimens. "
This seems to be an unsubstantiated assertion. Where in the paper did they demonstrate the ability of their assays to detect XMRV in clinical samples? Perhaps their assays *should* detect it, but this was never demonstrated.
In fact, their inability to find XMRV in suspected positive clinical samples (WPI samples) can be interpreted two ways, as I stated in my previous post. Their efforts add nothing but confusion (or feigned certainty for those desperate for this to go away).
One minor point is that these WPI samples were freshly drawn. As we know from the macaque study, XMRV is found transiently in the blood, so the particular samples taken could have been transiently negative.
But the major point is this: the honest thing to do with these WPI samples after finding them negative with their novel assays would have been to work closely with the WPI to exactly duplicate the WPI's methodology. Once Singh et al can reproduce the findings of the WPI w.r.t. these samples, then they could systematically explore what causes the differing results between the novel assays in this paper and the methods of the WPI.
Instead, they skirted the issue and the world has learned nothing new except a very detailed assay that cannot find XMRV (be it truly there or not).