170 more CFS samples from two different cohorts.395 more healthy controls.
No Simon Wesseley.
No XMRV by regular PCR, boosted PCR, or qRT-PCR on DNA or cDNA.
No meaningful anti-XMRV antibodies.
Still no XMRV in the Europe.
Longer “Absence of xenotropic murine leukaemia virus-related virus in UK patients with chronic fatigue syndrome“:
Basic PCR–
They extracted genomic DNA from white blood cells with a Qiagen kit. This is about stock-standard as it comes. They then used the exact primers the Reno group used to look for gag, env, and GAPDH. No amplified DNA from CFS patients or controls.
‘Boosted’ PCR–
Just in case they didnt have enough genomic DNA for some reason (I dunno why, they are just being super careful), they used another Qiagen kit to boost their overall signal. Just in case. Still no XMRV.
Quantitative Real-Time PCR–
THANK YOU. Finally. They looked for XMRV proviruses and XMRV RNA. Nothing. Very pretty standards were positive down to 16 copies– Viral plasmid diluted in healthy genomic DNA. Very pretty standards *nod*.
Neutralization assays–
Just because they cant find XMRV in anyone doesnt mean it was never there. People will have antibodies to XMRV if they were exposed– thats the whole point of vaccinations. So they looked for antibodies that could neutralize XMRV (mix patient antibodies with viruses, can the viruses still infect target cells? If not, youve got antibodies!).
They did find people with a neutralizing antibody response to XMRV.
In 25 healthy controls.
And one CFS patient.
*blink*
And the ‘reactive’ patient sera? It works on other viruses too. Its not XMRV specific (the patient sera neutralizes other viruses, even nonretroviruses like VSV), so there is no reason to believe they were created by an XMRV infection.
So, still no XMRV in Europe.
Thanks to Bora for the tip, and thanks to Virology Blog for finding this first!