Between 2009 and 2012, the controversy over the retroviruses XMRV/XMLV and their role in ME/CFS involved a tumultuous roller-coaster ride for patients and scientists around the world. More than 50 scientific papers reported no association between the viruses and ME/CFS or other diseases – including one ME Research UK-funded study – and the final act in the drama came when Columbia University’s Prof. Ian Lipkin published the negative results of a definitive multicentre study in which none of the 293 patients or controls tested positive for the viruses using polymerase chain reaction (see our overview).
So what can we learn from this controversy? Well, a recent review article outlines the major take-home message for working scientists – the need for practical precautions in the laboratory. As it points out, the finding that XMRV was a “cell culture contaminant” as opposed to a clinically important pathogen highlighted an important fact: that murine endogenous gammaretroviruses were infecting commonly used laboratory human cell lines. In fact, since XMRV was discovered, many additional cell lines have been shown to harbour these gammaretroviruses, threatening not only the invalidation of experimental results but also the cross-contamination of uninfected cell lines grown in the same laboratory.
Today, all laboratories should be aware that additional precautions are needed, including routine testing for XMLVs in human cell lines developed by transplantation from one species to another, or any cell lines cultured in laboratories concurrently growing transplanted or known XMLV-infected cell lines.
Reference: Infection of Xenotransplanted Human Cell Lines by Murine Retroviruses: A Lesson Brought Back to Light by XMRV. Hempel HA et al. Front Oncol 2013 Jun 17; 3: 156