Failure to detect Xenotropic murine leukaemia virus-related virus in Chinese patients with chronic fatigue syndrome

Graduate School, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
Virology Journal (Impact Factor: 2.18). 09/2010; 7(1):224. DOI: 10.1186/1743-422X-7-224
Source: PubMed


Recent controversy has surrounded the question of whether xenotropic murine leukaemia virus-related virus (XMRV) contributes to the pathogenesis of chronic fatigue syndrome (CFS). To investigate the question in a Chinese population, 65 CFS patients and 85 blood donor controls were enrolled and multiplex real-time PCR or reverse transcriptase PCR (RT-PCR) was developed to analyze the XMRV infection status of the study participants. The assay was standardized by constructing plasmid DNAs and armored RNAs as XMRV standards and competitive internal controls (CICs), respectively.
The sensitivities of the multiplex real-time PCR and RT-PCR assays were 20 copies/reaction and 10 IU/ml, respectively, with 100% specificity. The within-run precision coefficient of variation (CV) ranged from 1.76% to 2.80% and 1.70% to 2.59%, while the between-run CV ranged from 1.07% to 2.56% and 1.06% to 2.74%. XMRV was not detected in the 65 CFS patients and 65 normal individuals out of 85 controls.
This study failed to show XMRV in peripheral blood mononuclear cells (PBMCs) and plasma of Chinese patients with CFS. The absence of XMRV nucleic acids does not support an association between XMRV infection and the development of CFS in Chinese.

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    • "Despite these early reports and the excitement they generated in the CFS patient community, the association of XMRV with CFS has been disproven. Many studies have failed to detect XMRV in CFS cohorts around the globe.27,41,42,43,44,45,46,47,48,49,50,51,52 Surveys also have not identified XMRV infection in the general human population 53,54,55,56 or in humans at high risk for viral infections (e.g., HIV-1-infected individuals).57,58,59,60,61,62 "
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    ABSTRACT: Xenotropic murine leukemia virus-related virus (XMRV) was discovered in 2006 in a search for a viral etiology of human prostate cancer (PC). Substantial interest in XMRV as a potentially new pathogenic human retrovirus was driven by reports that XMRV could be detected in a significant percentage of PC samples, and also in tissues from patients with chronic fatigue syndrome (CFS). After considerable controversy, etiologic links between XMRV and these two diseases were disproven. XMRV was determined to have arisen during passage of a human PC tumor in immunocompromised nude mice, by activation and recombination between two endogenous murine leukemia viruses from cells of the mouse. The resulting XMRV had a xentropic host range, which allowed it replicate in the human tumor cells in the xenograft. This review describes the discovery of XMRV, and the molecular and virological events leading to its formation, XMRV infection in animal models and biological effects on infected cells. Lessons from XMRV for other searches of viral etiologies of cancer are discussed, as well as cautions for researchers working on human tumors or cell lines that have been passed through nude mice, includingpotential biohazards associated with XMRV or other similar xenotropic murine leukemia viruses (MLVs).
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    • "Currently, XMRV infection and replication is quantified by measuring proviral DNA numbers in infected cell cultures, or by determining virion associated genomic RNA copy numbers and reverse transcriptase activities in the supernatants of infected cells [24,25,36,37]. Alternatively, productive infection with release of infectious XMRV has also been analyzed by titrating progeny virus on reporter cell lines [26,38]. "
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    • "XMRV was also not or rarely detected in general populations worldwide. Only about 1% of control groups were found to be positive for XMRV in Germany [10], the U.K [12] and Japan [30], but no XMRV was detected in Chinese blood donors [31]. Negative results were reported for XMRV testing of blood donors or individuals infected HIV-1 in Africa [22]. "
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