In light of conflicting data concerning XMRV, standardized diagnostic testing is important to identify patients in which XMRV is present and to determine whether it plays a role in the incidence of prostate cancer.
An article published in the April 2010 issue of Urology is a step in this direction as researchers from Emory University report the successful development of an experimental clinical test for XMRV.
“We cannot as a scientific community begin to answer the basic questions of XMRV transmission, frequency in the population, association with disease, etc. until we can effectively test for infection,” says principal investigator John A. Petros, MD, associate professor of urology, Emory School of Medicine and Veterans Administration Hospital.
Petros and co-investigators adapted technology developed in the HIV arena (neutralizing antibody assay) and have developed a serum test that can identify patients who have previously been infected with the virus. Two independent labs and independent technologies (PCR and FISH) confirmed the test.
The mode of transmission of the virus is unknown, notes Petros. No method is currently available to screen either blood or tissue donors for infection and no data are available regarding whether the virus can be transmitted by blood transfusion or tissue transplantation.
“The public deserves to know if the next blood transfusion or organ donation will give them XMRV retrovirus, an infection which lasts for life, and could possibly be related to prostate cancer,” says Petros. “The failure to develop accurate tests for this virus is a serious public health oversight.”
Although the test used in the present report involved the inhibition of infection of target cells by viral-like particles with the XMRV envelope protein expressed on their surface, results also suggest that more standard serologic tests for antibodies against specific viral antigens can be developed in the future.
“Our report adds to the growing body of evidence that XMRV is indeed a novel gamma-retrovirus capable of infecting humans and that at least some patients with prostate cancer have been infected with XMRV,” Petros and co-authors note.
“We have reported serologic evidence of infection and that the serology correlated with tissue-based assays,” say the authors. “The concordance of three independent methods of detecting infection added confidence to the assertion that this recently discovered virus is real and possibly related to human disease. Robust clinical assays are needed to detect XMRV infection, and much work remains to be done in determining whether XMRV is indeed an oncogenic virus or simply an associated epiphenomenon.”
The article, “XMRV Infection in Patients With Prostate Cancer: Novel Serologic Assay and Correlation With PCR and FISH,” was published in the April 2010 issue of the journal Urology.
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