Although HIV-1 was amplified from 25% of the seminal plasma samples, no XMRV was detected, suggesting that either the prevalence of XMRV is very low in The Netherlands, or that XMRV is not naturally present in the seminal plasma.
I think that they missed out a possible reason for not detecting XMRV... That they were using an inadequate methodology.
I notice that they froze the plasma samples to store them which, as far as I remember, the WPI had to stop doing with their samples when looking for XMRV.
Also, as far as I understand, the only detection method employed was PCR, which as we know, is
not the most successful methodology for detecting XMRV.
I don't fully understand the WPI's methodology, but I would hazard a guess that this study doesn't come anywhere close to it.
Also, as thegodofpleasure mentioned in a previous post, the statistical likelihood of finding XMRV, in non-CFS patients, in such a small number of samples, where only 25% of samples (from HIV+ patients) tested HIV+, is almost zero.
A third alternative for the absence of XMRV in our samples could be that the XMRV found in other studies is an inadvertent laboratory contaminant, which has been reported before for other viruses, including another MuLV-related virus [25].
This demonstrates a lack of knowledge and understanding about the subject because, as we know, it is not possible for a person to have antibodies for a lab contaminant, and the genetic sequencing of XMRV shows that it is
not a mouse virus, and the virus has been observed infecting human cells, and the genetic sequences of XMRV have variability which doesn't happen in contaminants, etc. etc. etc.
As a positive PCR control, we used diluted total nucleic acid extracted from the prostate carcinoma cell line 22Rv1, containing approximately 10 copies of integrated XMRV DNA and producing viral RNA, in each PCR reaction series.
They were looking for the type of XMRV which is found in prostate cancer, and this might not be the most prevalent strain of XMRV.
Quote taken from the Conclusion:
Taken together our results suggest that either XMRV has a low prevalence in this mainly Dutch patient group, as it cannot be found in seminal plasma of 54 HIV-1 infected men, a group with an increased possibility of acquiring sexually transmitted pathogens, or that it is not naturally present in the seminal plasma.
In my opinion, this is a strange and slightly dangerous conclusion, considering the limitations of the study.
Taking everything into account, these authors do
not make any serious conclusions about XMRV at all, in my opinion...
This was just a small scale investigative research study, probably born out of curiosity, but not out of expertise in XMRV virology.