I think it is important to look at gay men and HIV positive people so this type of study is important. Maybe it's possible it's not in semen and that's why we havent heard about an epidemic of CFS in gay men? I understand some of the points people here have been making, but doesn't this address one of the biggest questions surrounding XMRV/CFS - if it is sexually transmissible via semen then why didn't CFS show up first or still mostly in gay male populations?
I do note from the methodology section of the paper it sounds like they did use the Lombardi test as they have referenced it and stated they used Lombardi primers (at least for the first part of the PCR). It sounds to me like it was a nested PCR on the GAG part of XMRV, though its not clear if the second round of the PCR was the same as what Lombardi used?
54 samples were tested, but none of these patients were diagnosed as having CFS. Therefore we'd expect about 4% of the samples to be XMRV positive (4% of 54 = 2.2). But they were not using the most sensitive tests in this study (I believe that testing for antibodies is the most sensitive test that the WPI use), so they might expect to find XMRV in 3% of the samples (3% of 54 = 1.6) (i.e. they would expect to find one positive sample). But the number of samples tested was so small that, statistically speaking, you might not expect to find any XMRV even if it was detectable at 1.6% in the wider HIV+ patient population. And if you add on top of that the fact that some of the patients in the study were taking anti-retrovirals, some of which have been shown to be active against XMRV, then you'd expect to find even fewer XMRV+ samples (i.e. fewer than 1.6 XMRV+ samples), just as the study only detected HIV in 5% of samples from the heterosexual HIV+ patients.
And XMRV might not be very prevalent in the HIV patient population because, as V99 said:
I wonder too if the WPI have looked at these groups or looked at semen. Hard to believe they haven't! Would be interesting to hear from them on this.