Xenotropic murine leukemia virus-related virus (XMRV) and polytropic murine leukemia virus (MLV)–related virus are recently described human gammaretroviruses that have been associated with prostate cancer and chronic fatigue syndrome. These studies have been controversial because a number of laboratories have been unable to find evidence of XMRV in similar groups of patients or controls. Because the existence of XMRV raises many questions, we decided to study its presence in a group of patients infected with HIV-1 with a high proportion of intravenous drug use and coinfection by hepatitis C virus.
Forty HIV-1–infected patients under follow-up in our institution were screened for XMRV/MLV by nested polymerase chain reaction using primers targeting the gag and env region. Specific primers for mouse mitochondrial DNA were used to rule out contamination.
No evidence of XMRV or polytropic MLV-related sequences was found in any sample from patients or controls. Four samples yielded polymerase chain reaction bands whose sequence corresponded to murine endogenous retroviral sequences, however, contamination with mouse cell DNA was subsequently confirmed.
XMRV/MLV viruses do not seem to be associated with HIV-1 infection or intravenous drug use. Contamination of samples or reagents by genomic murine DNA or XMRV vectors could account for the sporadic detection of positive samples for XMRV and related agents.
*Laboratory of Molecular Microbiology, Instituto de Investigación i+12, Hospital Universitario 12 de Octubre, Madrid, Spain
†HIV Unit, Instituto de Investigación i+12, Hospital Universitario 12 de Octubre, Madrid, Spain
Correspondence to: Rafael Delgado, MD, Laboratory of Molecular Microbiology, Hospital Universitario 12 de Octubre, Avda de Córdoba s/n, 28041 Madrid, Spain (e-mail: firstname.lastname@example.org).
Supported by funds from EU-FP7 (PITN-GA-2008-213592, CARMUSYS), ISCIII-FIS080806, and FIPSE-36749 to R.D.
Partially presented at 18th Conference on Retroviruses and Opportunistic Infections, February 27th to March 2, 2011, Boston, MA. Abstract #236.
The authors have no conflicts of interest to disclose.
Received July 29, 2011
Accepted September 20, 2011