Researchers who analyzed the spinal fluid of people with chronic fatigue syndrome and post-treatment Lyme disease were able to find proteins that were specific to each disorder — and different from proteins in the spinal fluid of healthy people.
The discovery, published today in the journal PLoS One, opens up the possibility of finding diagnostic tests for the puzzling and controversial conditions.
Scientists still do not know what causes CFS or post-treatment Lyme disease, a condition affecting people diagnosed with and treated for Lyme disease whose symptoms persist long after finishing antibiotic treatment. Doctors sometimes consider patients who don’t recover from Lyme disease despite treatment to have a form of chronic fatigue syndrome. Some key symptoms do overlap, such as severe fatigue and cognitive dysfunction, making it challenging to distinguish the groups.
The finding of disease-specific proteins “lets you separate one disease from another,” says Steven E. Schutzer of the University of Medicine and Dentistry of New Jersey-New Jersey Medical School. Schutzer and Richard D. Smith of Pacific Northwest National Laboratory led the team of researchers, who looked at patients meeting the CDC’s definition for Lyme disease — including having a positive antibody test for the bacteria transmitted by tick bites.
The study’s findings could eventually lead to diagnostic tests for the conditions, although much more work still needs to be done. Scientists still don’t know the cause of CFS or why an estimated 10 to15 percent of people diagnosed and treated for Lyme disease don’t get better.
If researchers are able to determine which proteins are responsible for specific symptoms of the disorders, new or more effective treatments could eventually be developed, says John Aucott of Johns Hopkins School of Medicine, who was not involved with this study. He is the principal investigator for a study that is enrolling 100 patients with Lyme disease and following them over a two-year period in an effort to identify differences in blood samples between people who recover after treatment and those who don’t.
In the new study, researchers looked at the spinal fluid of three groups of people: 43 CFS patients, 25 people treated for Lyme disease who did not fully recover and 11 healthy people. They underwent lumbar punctures as part of their medical evaluation and the banked samples were used in the study. The spinal fluid was then analyzed using advanced technologies including mass spectrometry.
The researchers identified 738 proteins found in the CFS patients, but not healthy people or the treated Lyme patients. And they identified 692 proteins in the treated Lyme patients that weren’t in either CFS patients or healthy controls.
While this shows that the two conditions are distinct, it is still a long list of proteins. Researchers now want to start “narrowing it down to find candidate biomarkers,” Schutzer tells the Health Blog.
Some of the proteins in the spinal fluid may ultimately be shown to fuel the conditions.
Schutzer is also involved in a separate study looking for microbes — including the virus XMRV — in the spinal fluid of the 43 CFS patients. An abstract published earlier this month in Annals of Neurology reported that the team was unable to find XMRV in the spinal fluid of the CFS patients. Schutzer says the study is still underway and that he can’t comment further because it hasn’t been published yet.
Ultimately, once the researchers narrow down the list of proteins, they will then look for the same proteins in patients’ blood, the next step towards a diagnostic test.
“It’s difficult to have a diagnostic test based on spinal fluid,” says Suzanne Vernon of the CFIDS Association of America, a CFS patient advocacy group, who was a consultant on the PLoS study. “You can’t just go poking everyone in the spine.”