Well, I think it's obviously more likely that immunosuppressed people would have XMRV than people without suprression of the immune system - As it's probably more likely that immunosuppressed people would catch a lot of other bacteria's and viruses... But I don't think that it implies that XMRV is an opportunistic infection in ME/CFS... I mean, immunosupressed people that had the bacteria that causes tuberculosis i n their body before getting immunosupressors have higher chance of getting sick with tuberculosis... Does it say that the tuberculosis bacteria is an opportunistic infection in those who have tuberculosis? Well, it might be opportunistic, but it is the bacteria that causes their tuberculosis.
We might have caught XMRV for various of reasons (for exmple: Genetics or perhaps just bad luck). The immunosupressed people probably caught it more than those who are not on immunosupressors, since, well, their immune system is supressed and they might catch influenza more often too. But it doesn't say that our immune system was supressed before, and than we got XMRV, and that XMRV didn't cause our illnesses. And if the WPI's numbers of about 98% ME/CFS patients that has XMRV are even somewhat close to be correct, and the precentage of healthy people (3.7%) that have it is also somewhat close to be correct, I think it's very very unlikely that XMRV is just an opportunistic infection in people with ME/CFS - Because as you can see people with suppressed immune system get XMRV probably three times more than people with a normal immune system - but not 26.49 more times (which is the proportion between 98 and 3.7).
Am I wrong here people?