Further doubt cast on virus link to chronic fatigue syndrome

Kate Bishop from the MRC National Institute for Medical Research worked with a team of researchers to test blood and serum samples from 170 CFS patients and 395 healthy controls, using quantitative PCR and a virus neutralization assay. She said, "No association between XMRV infection and CFS was observed in the samples tested, either by PCR or serological methodologies. Our findings therefore appear inconsistent with the previous report that isolated XMRV from the blood cells of CFS patients. We are confident that, although we were unable to replicate the detection, our PCR assay is more sensitive than the earlier method and possessed the necessary sensitivity to detect XMRV had it been present."

Bishop and her colleagues point out that CFS likely encompasses a range of diseases, and it is still possible that some of them might be associated with XMRV infection. They say, "There has been much discussion and controversy amongst CFS researchers and patients alike, which highlights the need for additional investigations in this area. Following our findings, it would seem a prudent next step for subsequent studies to compare samples and protocols between different laboratories around the world."

The findings of this Retrovirology study are supported by results from a recently published work from Imperial College London that also found no proof that XMRV infection is associated with CFS.