Sound the trumpets!  The long-awaited day is finally here – chronic fatigue syndrome is being taken seriously by the medical community!   

On Monday afternoon, August 23, 2010 in their early online edition, the Proceedings of the National Academy of Sciences (PNAS) published the much-anticipated research article "Detection of MLV-related virus gene sequences in blood of patients with Chronic Fatigue Syndrome and healthy controls" (in PDF format).

This study – a collaboration between the Food and Drug Administration (FDA), the National Institutes of Health (NIH) and Dr. Anthony Komaroff of Harvard Medical School – found murine leukemia virus (MLV)-related gene sequences in blood samples collected from patients diagnosed with chronic fatigue syndrome and a few healthy blood donors. 

The FDA/NIH study looked at blood samples from 37 CFS patients and 44 healthy controls.  The CFS samples used were preserved from another study done in the mid-1990s using clearly defined CFS patients.  The researchers found evidence of gene sequences for MLV-related virus in 32 of 37 CFS patients (86.5 percent) and three of 44 health controls (6.8 percent). 

Comparing FDA/NIH and WPI Studies

The Whittemore Peterson Institute (WPI) study, published October 23, 2009 in Science, found the  XMRV retrovirus in 67 percent of CFS patients and 3.7 percent of healthy controls.  (After further testing, the WPI reportedly found XMRV in 95% of their XMRV samples.)  XMRV stands for xenotropic murine leukemia virus-related virus.  The FDA/NIH study did not find XMRV in their samples, however, they did find MLVs that were closely related to polytropic murine leukemia viruses.  You're probably wondering what the difference is – I know I was. 

In yesterday's telebriefing for reporters, Dr. Harvey Alter from the NIH and Dr. Shyh-Ching Lo from the FDA explained that xenotropic and polytropic murine leukemia viruses were from the same family of viruses.  Murine means mouse and murine leukemia viruses are a group of viruses found in mice that can cause leukemia and other types of cancer in mice.  Polytropic viruses can infect both mouse and human cells, but when a virus becomes xenotropic, it can no longer infect mouse cells but only infects human cells.  So xenotropic and polytropic murine leukemia viruses are slightly different but very closely related.  Dr. Alter said he feels that murine leukemia virus-related virus is a better term to use because it encompasses XMRV as well as the other related viruses. 

The FDA/NIH study authors stated, "Although we find evidence of a broader group of MLV-related viruses, rather than just XMRV, in patients with CFS and healthy blood donors, our results clearly support the central argument by Lombardi et al. [the WPI study] that MLV-related viruses are associated with CFS and are present in some blood donors." (emphasis mine)  In fact, in the telebriefing, Dr. Alter revealed that the “WPI has found that their viruses were more diverse than originally published.”