In October 2009 the journal Science published a study investigating chronic fatigue syndrome (CFS) that identified an infectious retrovirus called xenotropic murine leukemia (XMRV) in a majority of the patients affected by CFS.

The study provided an explanation about a syndrome that is extremely difficult to diagnose - some even suspect CFS is the result of an underlying psychiatric problem and not a physical condition.

Now, patients and practitioners are back to square one. Last week Science issued a full retraction of the study, citing poor quality control in a number of specific experiments in the original report.

“Multiple laboratories, including those of the original authors, have failed to reliably detect XMRV or other murine leukemia viruses in CFS patients,” wrote Science Editor-in-Chief Bruce Alberts.

The study was the work of scientists from the Whittemore Peterson Institute, located at the University of Nevada, Reno, the National Cancer Institute, and the Cleveland Clinic.

Authors failed to indicate that CFS patient–derived peripheral blood mononuclear cells had been treated with azacytidine as well as phytohemagglutinin and interleukin-2 inconsistently across the patient sample, potentially skewing the results.

“Given all of these issues, Science has lost confidence in the report and the validity of its conclusions,” wrote Alberts. “We regret the time and resources that the scientific community has devoted to unsuccessful attempts to replicate these results.”

The US Centers for Disease Control and Prevention estimates 1 to 4 million Americans are affected by CFS. Symptoms include chronic fatigue that lasts for six months or more, sore throat, tender lymph nodes, pain in the muscles and joints, problems with memory and concentration, unusual headaches, poor or unrefreshing sleep, and feeling extremely tired after exertion.