Finds No XMRV-Chronic Fatigue Link
Analysis of blood samples from 300 people in Utah did
not show an association between chronic fatigue syndrome
and infection with XMRV retrovirus.
prior research has indicated that xenotropic murine leukemia
virus-related virus (XMRV) and other murine leukemia virus
(MLV) relatives are common in people with chronic fatigue
syndrome (CFS), prostate cancer, and other conditions. CFS
is characterized by overwhelming fatigue that does not improve
In particular, a
study by Judy Mikovits from the Whittemore Peterson Institute
and colleagues, published in the October 23, 2009, issue of
Science, found that 67% of CFS patients had detectable XMRV
in peripheral blood mononuclear cells, compared with just
4% of people without chronic fatigue.
These findings have led some CFS patients to use antiretroviral
drugs developed for HIV on an off-label basis, and advocates
have urged that clinical trials be started for this new patient
Study results have not been consistent, however, and other
research teams have found no association between CFS and XMRV
or related viruses.
an effort to resolve this conflict, Clifford Shin and Ila
Singh from the University of Utah and colleagues collected
and analyzed blood samples from 100 CFS patients and 200 healthy
volunteers from the Salt Lake City area, using molecular,
serological, and viral growth assays. A majority (70%) of
the CFS patients reported flu-like symptoms at the onset of
fatigue, suggestive of viral infection.
As reported in the May
4, 2011, advance online edition of the Journal of Virology,
the researchers did not detect XMRV or related MLVs, or antibodies
against these viruses, in any of their patient samples. Furthermore,
they also performed a blinded analysis of stored samples from
CFS patients in the Mikovits study, but again found no evidence
of XMRV infection.
"Our experience has taught us that the detection of XMRV
in blood is fraught with difficulties," the researcher
wrote, explaining that different laboratory techniques yielded
conflicting results and suggesting contamination may play
a role. Positive readings were initially obtained using a
"biorobot," but when this equipment was abandoned
XMRV was no longer detected.
the lack of evidence for XMRV or XMRV-like viruses in our
cohort of CFS patients, as well as the lack of these viruses
in a set of patients previously tested positive, we feel that
that XMRV is not associated with CFS," they continued.
"We are forced to conclude that prescribing antiretroviral
agents to CFS patients is insufficiently justified and potentially
they added, "It is also vital to state that there is
still a wealth of prior data to encourage further research
into the involvement of other infectious agents in CFS, and
these efforts must continue."
"Chronic fatigue syndrome is a devastating disease for
which a cure needs to be found," Singh said in a press
release issued by University of Utah Health Sciences.
Investigator affiliations: Department of Pathology, University
of Utah, Salt lake City, UT; Fatigue Consultation Clinic,
Salt Lake City, UT; ARUP Laboratories, Salt Lake City, UT;
Department of Anesthesiology, University of Utah, Salt Lake
CH Shin, L Bateman, R Schlaberg, et al. Absence of XMRV
and other MLV-related viruses in patients with Chronic Fatigue
Syndrome. Journal of Virology (abstract).
May 4, 2011 (Epub ahead of print).
of Utah Health Sciences. Comprehensive Study Finds No Link
Between XMRV Retrovirus and Chronic Fatigue Syndrome. Press
release. May 4, 2011.