Chronic fatigue syndrome (CFS) is a multi-system disorder characterized by prolonged and severe fatigue that is not relieved by rest. Attempts to treat CFS have been largely ineffective primarily because the etiology of the disorder is unknown. Recently CFS has been associated with xenotropic murine leukemia virus-related virus (XMRV) as well as other murine leukemia virus (MLV)-related viruses, though not all studies have found these associations. We collected blood samples from 100 CFS patients and 200 self-reported healthy volunteers from the same geographical area. We analyzed these in a blinded manner using molecular, serological and viral replication assays. We also analyzed samples from patients in the original study that reported XMRV in CFS. We did not find XMRV or related MLVs, either as viral sequences or infectious virus, nor did we find antibodies to these viruses in any of the patient samples, including those from the original study. We show that at least some of the discrepancy with previous studies is due to the presence of trace amounts of mouse DNA in the Taq polymerase enzymes used in these previous studies. Our findings do not support an association between CFS and MLV-related viruses including XMRV and off-label use of antiretrovirals for the treatment of CFS does not seem justified at present.
This study was done by the university of Utah and has Ila Singh's name on it... which is rather worrisome (at least for people like me, who are strong XMRV believers). Is this the study from her we have been waiting for?
I hope the WPI will give a reaction to this.
Also see this article on the website of the University of Utah:
In her own study, Singh initially obtained false positives for XMRV in blood samples. But she determined those false readings were related to robotic equipment that previously had been used for extraction of DNA from XMRV-infected tissue culture cells. Several months later, this equipment led to new samples getting contaminated. When the robotic equipment was abandoned, no more false positives were detected in either CFS patients or healthy patients. Its easy to see how sample extraction and tissue culture processes might be vulnerable to contamination, Singh said.